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LECTURE 1 - INTRODUCTION AND SPINE INTRODUCTION: In this course we take a regional anatomy approach to studying the human body. What this means is that we study the anatomy of the human body in major parts or segments: 1. A main body consisting of the head, neck and trunk (subdivided into head, thorax, abdomen, back and pelvis and perineum) 2. Upper extremity 3. Lower extremity Anatomical positions: • Upright – all joints in 0 degrees (except forearm) Body planes: 1. Median plane (midsagital plane) – vertical plane passing longitudinally through the body, divides the body into equal left and right halves. Defines midline of head, neck and trunk. 2. Sagittal planes – vertical planes passing through the body parallel to the median plane. 3. Frontal planes – vertical planes passing through the body dividing into anterior and posterior parts. 4. Transverse planes – horizontal planes passing through the body dividing the body into superior and inferior parts. Sections of body: 1. appendicular skeleton: ! upper limb - arm vs. forearm ! lower limb - thigh vs. leg 2. axial skeleton: ! skull ! thoracic cage ! vertebral column Terms of relationship and comparison: • superior vs. inferior; cranial vs. caudal • posterior vs. anterior • medial vs. lateral • dorsal vs. ventral; dorsal vs. palmer; dorsal vs. plantar • superficial vs. intermediate vs. deep • proximal vs. distal
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Terms of movement: flexion vs. extension supination vs. pronation abduction vs adduction lateral rotation vs. medial rotation retraction vs. protraction These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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dorsiflexion vs. plantar flexion inversion vs. eversion elevation vs depression opposition vs reposition retraction vs. protraction Types of joints: Plane- permit gliding or sliding movements ! eg: acromioclavicular joint Hinge- permits flexion and extension only ! eg: elbow joint Saddle- permits movement in two different planes ! eg: carpometacarpal joint (between trapezium and metacarpal I) Condyloid- permits flex/extend, abduct/adduct, and circumduction. ! eg: metacarpophalangeal joint Ball-and-Socket-permits multiaxial movement; flex/extend, abduct/adduct, medial/lateral rotation, and circumduction ! eg: hip joint Pivot- permits rotation around a central axis. ! eg: atlanto-axial joint
Common and acceptable abbreviations: muscle = m. muscles = mm. nerve = n. nerves = nn. artery = a. arteries = aa. vein = v. veins = v. THE BACK: VERTEBRAL COLUMN SURFACE ANATOMY: 1. 2. 3. 4. 5.
posterior median furrow: when the back is not being flexed or the scapulae are not retracted the tips of the spinous processes lie deep to it. It ends as flattened triangle over the sacrum. intergluteal cleft: inferior continuation of posterior median furrow; created by left and right gluteal muscles and fat. nuchal groove: superior continuation of median furrow in the neck, overlies nuchal ligament (nuchal ligament). vertebral prominens: visible at the base of the neck, inferior to nuchal groove. It is the spinous process of the C7 vertebra. erector spinae: prominent vertical bulges, help to form borders of posterior median furrow caudally, laterally end at angles of ribs in thoracic region. These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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trapezius, latissimus dorsi, teres major: superficial muscles of the back and scapula-deltoid region that can be seen especially in muscular individuals 7. vertebral border, inferior angle and spine of scapula: features of the scapula that can be seen especially in lean individuals. 8. supraspinous ligament: ligament that overlies spinous processes of vertebrae. Can be palpated in median longitudinal furrow. 9. spinous processes of lumbar vertebrae: palpated in posterior median furrow 10. posterior superior iliac spines: create dimples (in some individuals) superior and lateral to gluteal cleft. A line connecting them overlies S2 vertebra. BONY FEATURES: Vertebral Column: • 24 individual vertebrae: 7 cervical, 12 thoracic, 5 lumbar • segmentation: 33 vertebrae of early development reduce to 26 bones • 5 sacral vertebrae fuse producing the sacrum • 4 coccygeal vertebrae fuse producing the coccyx 1. Curvatures: • Primary: Develop during the fetal period and are concaved anteriorly (flexed). Persists in the thoracic and sacral regions of the spine in the adult, known as kyphotic curvature • Secondary: There are two, which develop as an individual learns to hold head erect (cervical curvature) and assumes erect posture (lumbar curvature), known as lordosis. Concaved posteriorly (extension). Persists in the cervical and lumbar regions of the spine. • Abnormal curvatures: ! hyperkyphosis: exaggerated primary curvature; example "dowager's hunch", exaggerated thoracic curvature ! hyperlordosis: exaggerated secondary curvature; example "swayback", exaggerated lumbar curvature ! scoliosis: lateral distortion - rib/vertebrae angle > 30, then brace 2. Features of Typical Vertebrae: • body: chunky anterior portion (support) - compact bone surrounding spongy bone; gives strength to the vertebral column and supports body weight. • vertebral pedicles: rounded bars forming anterior sides of vertebral arch (protection), have notches that join to form the intervertebral foramen through which the spinal nerves exit the vertebral canal. • laminas: flat, thin plates forming posterior portion of vertebral arch (protection) • vertebral arch: formed by the right and left pedicles and laminae • vertebral foramen: space for spinal cord; collective foramen form vertebral canal • spinous process: projects posteriorly from vertebral arch at the junction of the laminae. ! provides attachment for various mm. (movement) • transverse process: laterally directed at junction of lamina and pedicle ! provide attachment for various mm. • articular processes: 2 superior and 2 inferior, also arise from junction of lamina and pedicle. Superior of one vertebra articulate with inferior of next highest vertebra forming zygapophysial (facet) joint, a plane type joint (limited movement). These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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! orientations of facet joints vary depending on region of spinal column ! cervical - transverse plane ! thoracic - coronal plane ! lumbar - saggital plane vertebral notches: superior of one vertebra joins inferior of next highest vertebra to form intervertebral foramen thru which exit the spinal nerves
3. Features of Regional and Individual Vertebrae: •
Cervical Vertebrae: 7 total ! transverse foramen (foramina transversaria): foramen within the transverse process that allow for passage of the vertebral artery and vein with the exception of C7 thru which only the vertebral vein passes. ! bifid spinous process: found in C3 through C6 ! anterior and posterior tubercles - located on transverse processes; anterior tubercle of C6 is called the carotid tubercle because the common carotid arteries may be compressed against them to control bleeding from the vessel. ! uncinate processes- superior, lateral elevated margins of the bodies; prevents posterior linear translocation of vertebral bodies and limits lateral flexion. ! C1, C2 and C7 are atypical: " Atlas (C1) - ring shaped bone, does not have a body or spinous process. They are replaced by anterior and posterior tubercles, respectively. - kidney shaped concaved superior articular surfaces for articulation with occipital condyles. - enlarged vertebral foramen to accommodate dens and brainstem - large superior and inferior articular processes for atlanto-occipital and atlantoaxial joints " Axis (C2) - dens/odontoid process, the pivot around which C1 rotates. " Vertebra prominens (C7) - larger spinous process is first easily palpated of vertebrae, reduced foramina transversaria carry only vertebral vein.
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Thoracic Vertebrae: 12 total ! costal facets for articulation with ribs # articulating facets on body and transverse processes for head and tubercle of ribs, respectively. ! heart shaped vertebral body (when viewed from above). ! inferiorly directed spinous process overlaps arch of next lowest ! vertebral foramen is circular and smaller than those of cervical and lumbar vertebrae ! vertebra (less pronounced in lower thoracic region)
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Lumbar Vertebrae: 5 total ! heavy chunky bodies for support and kidney bean shaped (when viewed from above). ! Due to orientation of the facets rotation movements are greatly reduces ! spinous processes are nearly rectangular ! posterior surface of base of transverse process has accessory process for attachment of intertransversarii muscles These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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posterior surface of superior articular process has mammillary process for attachment of multifidis and intertransversarii muscles L5/S1 facet is in coronal plane L5 is significantly taller anteriorly and is largely responsible for lumbosacral angle.
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Sacrum: 5 fused vertebrae ! sturdy triangular bone wedges between pelvic bones to transmit weight from vertebral column to lower limb. ! forms roof and posterosuperior wall of posterior half of pelvic cavity. ! anterior edge of the body is the sacral promontory ! lateral surface is auricular surface, for synovial sacroiliac joint ! auricular surfaces form slightly movable joint with iliac of pelvis ! fusion has resulted in: 1. spinous processes # median sacral crest 2. articular processes # intermediate sacral crests 3. transverse processes # two lateral sacral crests 4. intervertebral foramina # 4 pair of sacral foramina i. pelvic (for ventral primary rami) ii. dorsal (for dorsal primary rami) 5. vertebral foramina # sacral canal with cauda equina 6. incomplete fusion of lowest laminas # sacral hiatus
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Coccyx: 4 fused rudimentary coccygeal vertebrae (number can vary)
JOINTS OF VERTEBRAL COLUMN: 1. Intervertebral joints: symphysis type between vertebral bodies designed for weightbearing and strength. ! articulating surface of adjacent vertebral bodies are connected by fibrocartilaginous disc (IV discs) and ligaments. Provide strong attachments between the vertebral bodies. Each disc consists of: " anulus fibrosis – form circumference of IV discs, fibers run obliquely from disc to articular surface of vertebral body. " nucleus pulposus – core of IV discs. Are responsible for much of the flexibility and resilience of the IV discs and vertebral column. Serve as a shock absorber. This is the portion of the IV disc which protrudes into the vertebral canal when there is a herniation. ! intervertebral joints, collectively, are stabilized by: " anterior longitudinal ligament – connects anterior side of bodies from the pelvic surface of the sacrum to the occipital bone. It is the only ligament that prevents hyperextension " posterior longitudinal ligament – located on the floor of vertebral canal. Narrow band attached primarily to the IV discs. Superiorly becomes the tectorial membrane, attaching to occipital bone 2. Zygapophysial Joints: Synovial, plane gliding joints (also referred to as facet joints).
These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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Between superior and inferior articular processes of adjacent vertebrae. Permit gliding between the vertebrae. Enclosed in capsular ligaments. Accessory ligaments unite the laminae, transverse processes, and spinous processes and help to stabilize the joints these include: " supraspinous ligaments – connects the apices of the spinous process form C7 to sacrum. Merges superiorly with nuchal ligament. " interspinous ligaments – connect adjoining spinous processes, attaching rom the root to the apex of each process. " ligamenta flava – yellow ligaments, extend vertically connecting lamina. Form part of posterior wall of the vertebral canal. " nuchal ligament – Also referred to as nuchal ligament (nuchae means nape of neck). A broad, strong median ligament of the posterior neck. Extends from external occipital protuberance and posterior border of foramen magnum to spinous processes of cervical vertebrae. Provides site of attachment for some muscles (eg. trapezius)
3. Craniovertebral Joints: Synovial joints with no IV discs. Give a wider range of movement " atlanto-occipital joint : synovial condyloid joint between occipital condyles and superior articular processes of atlas, stabilized by three ligaments: 1. anterior atlanto-occipital membrane - continuation of anterior longitudinal ligament 2. posterior atlanto-occipital membrane - from arch of atlas to posterior margin of foramen magnum 3. tectorial membrane or membrana tectoria - continuation of posterior longitudinal ligament into internal periosteum of occipital bone "
atlantoaxial joint : 3 articulations; synovial pivoting joint between dens of axis and interior anterior surface of atlas, stabilized by: 1. cruciform ligament - consisting of transverse, superior and inferior fibrous bands. Attaches axis to foramen magnum, provides "socket" for dens 2. apical ligament – extends from the tip of the dens to the anterior margin of foramen magnum 3. alar ligaments – extends from the sides of the dens to the lateral margins of the foramen magnum. Prevents excessive rotation. provide attachment from dens to foramen magnum and secure dens within its "socket"
CLINICAL TERMS: 1. spondylolysis: degenerative condition in which there is defect in the vertebral arch resulting in a fracture usually between superior and inferior articular processes (pars inarticularis) that separates the vertebral arch from the body. 2. spondylolisthesis: can result from spondylolysis, when the fracture results in anterior displacement of the body of the vertebrae. 3. spondylosis: bony arthritic growth of vertebral bodies referred to as osteophytes
These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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LECTURE 2 - ANATOMY OF THE BACK BONY FEATURES: 1. Axial skeleton: skull, vertebral column and thoracic cage (ribs and sternum) ! vertebra: spinous and transverse processes ! skull " occipital bone: superior nuchal line, inferior nuchal line and external occipital protuberance (inion) " temporal bone: mastoid process 2. Appendicular skeleton: limbs and attachment girdles ! pectoral girdle# includes scapulas and clavicles " Scapula: spine, acromion and vertebral border " Clavicle: acromial end, clavicular end ! pelvic girdle# includes 2 pelvic bones " Os coxa: crest of ilium # attachment for latissimus dorsi m. and some deep back mm. ! Humerus: intertubercular sulcus # attachment for latissimus dorsi m. MUSCLES: A. Extrinsic Back Muscles: muscles associated with upper limb or ribs. During development they migrated to the back, so are supplied by anterior primary rami, with the exception of trapezius which is supplied by CNXI. Not considered true back muscles. Superficial group, superficial layer: 1. Trapezius: diamond-shaped (trapezoid) • attachments: from superior nuchal line, external occipital protuberance, nuchal ligament, spinous processes of C7 through T12 to lateral third of clavicle, acromion and spine of scapula. • innervation: cranial nerve XI (spinal accessory) and anterior primary rami of C3 and C4 (proprioception) • actions: extension of head; elevates, rotates and retracts scapula; descending fibers elevate, middle fibers retract and ascending fibers depress scapula; ascending and descending fibers act together in rotates glenoid cavity superiorly. 2. Latissimus dorsi: fan-shaped, covers lower back, widest (= latissimus) muscle of back • attachments: from spinous processes of T7-12 and thoracolumbar fascia, crest of ilium, and lower ribs to floor of intertubercular sulcus of humerus • innervation: thoracodorsal n. (C6 - C8) from posterior cord of brachial plexus • actions: medial rotation, extension and adduction of humerus Superficial group, deep layer: (all supplied by dorsal scapular nerve C4-5) 3. Rhomboid minor: rhombus-shaped
These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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attachments: nuchal ligament and spinous processes of C7 and T1 to vertebral border of scapula (at the root of scapular spine) • innervation: dorsal scapular n.(C4 - C5) upper root Brachial Plexus • actions: retraction and downward rotation of scapula; secure scapula to thoracic wall (with serratus anterior) Rhomboid major: rhombus-shaped • attachments: spinous processes of T2 – T5 to vertebral border of scapula from just below rhomboid minor to inferior angle • innervation: dorsal scapular n.(C4 - C5) upper root Brachial Plexus • actions: retraction and downward rotation of scapula; secure scapula to thoracic wall (with serratus anterior) Levator scapulae: • attachments: from post. tubercles of transverse processes of upper 4 cervical vertebrae to vertebral border of scapula from superior angle to root of spine • innervation: dorsal scapular n. (C4-5) from upper root of brachial plexus • actions: assist rhomboids and elevation of scapula •
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Intermediate group: 6. Serratus posterior mm.: very thin and supplied by intercostal n.,a.,v.’s 7. Serratus posterior superior: lies deep to rhomboids, fiber orientation parallel to rhomboids • attachments: spinous processes of upper thoracic vertebrae to superior ribs; • innervation: intercostal nerves • actions: assists inspiration 8. Serratus posterior inferior: lies deep to rhomboids, fiber orientation parallel to rhomboids • attachments: spinous processes of lower thoracic vertebrae to inferior ribs; • innervation: intercostal nerves • actions: assists expiration B.
Intrinsic back muscles: “true” back muscles, three deep layers ! fill in hollow between vertebral spinous processes and angles of ribs ! move the vertebral column and attach to vertebrae, ribs, pelvis and skull ! contained in a tube of deep fascia that attaches medially to the nuchal ligament, tips of the spinous processes, supraspinous ligament and the medial sacral crest and attaches laterally to the transverse process of cervical and lumbar fascia and angles of the ribs. ! in the thorax and lumbar region it is called the thoracolumbar fascia of which the lumbar aponeurosis is the thickened inferior portion with anterior and posterior layers to enclose the muscles ! only muscles of the body innervated by posterior primary rami of spinal n.
deep 1: splenius capitis and cervicis (superolateral fiber orientation) deep 2: erector spinae mm. (vertical-superolateral fiber orientation) deep 3: transversospinalis mm. (superomedial fiber orientation) DEEP 1: Splenius muscles arise from the midline and extend superiolaterally, covering the deep muscles like a bandage # splenion = bandage 9. splenius capitis: caput = head These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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attachments: nuchal ligament and spinous processes of C7 -T6 to superior nuchal line and mastoid process innervation: posterior primary rami of middle and lower cervical nn. actions: extension of head (both sides); ipsilateral rotation of head and neck
10. splenius cervicis: cervix = neck • attachments: nuchal ligament and spinous processes of C7 -T6 to post. tubercles of transverse process of C1-C3(C4). • innervation: posterior primary rami of middle and lower cervical nn. • actions: extension of head (bilateral); ipsilateral rotation of head and neck (unilateral) DEEP 2: Erector spinae mm. (aka "sacrospinalis"): ! Three columns of massive muscle extending from sacrum to skull. ! They lie in a groove between the spinous process and the angle of the ribs laterally. ! Encased in thoracolumbar fascia. ! Arise from a common inferior tendon that extends from the iliac crest to median sacral crest. ! Each column is divided into 3 parts based on their superior attachment # capitis, cervicis, thoracis or lumborum 11. iliocostalis: angles of lower ribs and transverse processes of cervical vertebrae 12. longissimus: longest, from sacrum to skull, attaches to ribs between tubercle and angle, transverse processes and eventually mastoid process 13. spinalis: spanning spinous processes of vertebrae on each side • innervation: posterior primary rami of spinal nerves. • actions: extension of vertebral column (both sides), ipsilateral rotation (single side) DEEP 3: Transversospinalis: ! From lower transverse processes to higher spinous processes ! Occupy space between transverse process and spinous process ! Extension and contralateral rotation of vertebral column, head and neck ! Innervated by posterior primary rami of spinal nerves ! 3 layers: 14. Semispinalis: • divided into 3 parts based on superior attachment (captitis, cervicis, and thoracic) • arise from transverse processes of T12 and superior • span 4-6 segments • important in holding up head 15. Multifidus (= many cleavages) • arise from posterior sacrum, posterior superior iliac spine, aponeurois of erector spinae, sacro-iliac ligaments, mammillary process of lumbar vertebrae and transverse processes. Most superior attachment is C2. • spans 2-4 segments • more prominent on lower spine 16. Rotatores These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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span 1 (brevis) to 2 (longus) vertebrae; arise from transverse processes of vertebrae best developed in thoracic region mainly stabilize spine
Minor deep layer: 17. interspinales: run between spinous processes 18. intertransversarii: run between transverse processes 19. levatores costarum: transverse processes to ribs between tubercle and angle VESSESLS: 1. transverse cervical artery: from thyrocervical trunk of the subclavian, supplies trapezius; typically the dorsal scapular a. is a branch of it 2. thoracodorsal a.: a branch of the subscapular a. that is from the axillary a. NERVES: 1. spinal accessory nerve: cranial nerve XI (CNXI); exits through the jugular foramen and supplied both trapezius and sternocleidomastoid muscles 2. dorsal scapular nerve: C4,5; supplies rhomboids and levator scapulae 3. thoracodorsal nerve: C6-8; supplies latissimus dorsi CLINICAL APPLICATION: 1. Triangle of auscultation: small triangular gap in the musculature allowing for good examination of posterior segments of the lungs by stethoscope. The border of the triangle are • superior horizontal border of latissimus • medial border of the scapula • inferior lateral border of trapezius 2. Whiplash: severe hyperextension of the neck during head butting in football or rear-end collision causes severe stretching and sometimes tearing of the anterior longitudinal ligament/ and or crushing or fracturing of posterior vertebral arch. Severe hyperflexion can occur with rebound, head-on collision or head blocking in football, can result in rupture of the IV disc (most common between C5/C6 and C6/C7). LECTURE 3: CONTENTS OF VERTEBRAL COLUMN SPINAL CORD AND MENINGES AND SUBOCCIPITAL REGION SPINAL CORD: • • • • •
Cylindrical structure slightly flattened anteriorly and posteriorly. Contains bundles of nerve tracts and central gray matter Begins as a continuation of the medulla oblongata and extends from foramen magnum to between L1 and L2 vertebrae (can range from T12 to L3) Conus medullaris: tapered inferior end of cord. Enlargments corresponding to innervations of limbs: These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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! cervical # C4-T1 ! lumbar # T11-S1 Dorsal and ventral medial sulci: run longitudinally Due to differential growth of cord and vertebral column in utero, cord segments are higher than corresponding bony segments caudally, resulting in the cord occupying approximately 2/3 length of vertebral canal. Spinal roots become progressively oblique inferiorly to reach appropriate exit point. Forming cauda equine (horse’s tail) inferior to conus medularis.
SPINAL NERVES: 31 pairs, mostly arising segmentally: • • • • •
cervical (8): C1-C8; exit vertebral column via intervertebral foramina ABOVE corresponding bony segment, except C8 exits below bony C7 thoracic (12): T1-T12; exit BELOW corresponding bony level lumbar (5): L1-L5; exit BELOW corresponding bony level sacral (5): S1-S5; branch into anterior and posterior rami within sacrum, respective rami pass through dorsal (posterior) and pelvic (anterior) sacral foramina. coccygeal (1): Co1; exits sacral hiatus with S5 ! Nerves arise from cord as anterior or ventral (motor) and posterior or dorsal (sensory) rootlets. " dorsal rootlet is associated with dorsal root ganglion ! Rootlets join together to form a spinal nerves which exit spinal canal via intervertebral foramen ! The spinal nerve then splits into: " a small posterior or dorsal primary ramus to supply the intrinsic back muscles and skin of the back " and a much larger anterior or ventral primary ramus that supplies the rest of the body. ! spinal nerves supply limbs via nerve plexuses: " brachial plexus - upper extremity; " lumbar and lumbosacral plexuses - lower extremity
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dura mater "tough mother": dense fibrous, outer membrane of the spinal cord. Forms the dural root sheaths continuous with epineurium. spinal dural sac: A tubular sheath within the vertebral canal. Attaches to the margin of the foramen magnum where it is continuous with the cranial dura mater. Terminates at the level of S2 vertebrae. epidural space: separates dura mater from vertebrae, contains fat and venous plexus arachnoid mater ("spidery mother"): delicate web-like membrane enclosing subarachnoid space containing spinal cord and filled with cerebrospinal fluid (CSF). It is not attached to dura mater but held against it by pressure of CSF. filum terminale: anchors dural sac to coccyx. Has an internal part, which is a fibrous strand covered by pia mate. It pierces the dural sac continuing through the sacral hiatus to attach to dorsum of coccyx. These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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lumbar cistern: An enlargement of the subarachnoid space in the dural sac, caudal to the conus medullaris and containing the cauda equina. ! this is the site of spinal taps between L3 and L4 vertebrae. pia mater ("delicate mother"): thin membrane intimately associated with spinal cord directly covers the roots of spinal nerves and spinal blood vessels. ! inferior to conus medularis continues as filum terminale. ! lateral extensions denticulate ligaments attach cord to dural sac suspending it in cerebrospinal fluid.
INTERNAL ANATOMY OF SPINAL CORD: The cord is made up of gray matter and white matter- in the gray matter are cell bodies and synapses and in the white matter are ascending and descending neural pathways. BLOOD SUPPLY: • The arteries supplying the spinal cord are branches of the: ! vertebral ! ascending and deep cervical ! intercostal ! lumbar ! sacral arteries. • 3 longitudinal arteries: 1. Anterior spinal artery (1): formed by the union of branches of the vertebral arteries. Runs inferiorly in the anterior median fissure. 2. Posterior spinal arteries (2): is a branch of vertebral arteries or posteroinferior cerebellar artery. Dermatome: the region of skin associated with a specific nerve (sensory). Based on what we just learned does C1 have a dermatome? SUBOCCIPITAL REGION SURFACE ANATOMY: 1. spinous process of C2: palpated inferior to external occipital protuberance 2. transverse processes of CI: palpated deeply behind mastoid processes 3. Borders: ! from inferior nuchal line of occipital bone to spinous process of axis to transverse process of atlas ! roof is the deep surface of semispinalis capitis m. ! floor is the posterior atlanto-occipital membrane ! Bounded by rectus capitis posterior major, superior and inferior oblique muscles BONY FEATURES: ! atlas: posterior tubercle, transverse process, posterior arch ! axis: spinous process of C2 ! occipital bone These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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MUSCLES: ! Muscles superficial to this region are trapezius, levator scapulae, splenius and semispinalis capitis (from superficial to deep) ! All of the muscles of the suboccipital region are innervated by the posterior primary rami of C1 (aka suboccipital nerve). * indicates muscles which make up the boundaries of the triangle 1. rectus capitis posterior minor: • attachments: below medial end of inferior nuchal line to posterior tubercle of atlas deep to rectus capitis posterior major and outside of triangle • innervation: suboccipital (C1) • actions: stabilizes atlanto-occipital joint 2. rectus capitis posterior major*: • attachments: below inferior nuchal line, lateral to rectus capitis posterior minor to spine of axis • innervation: suboccipital (C1) • actions: extends head, rotates atlas and head to same side 3. obliquus capitis superior*: • attachments: transverse process of atlas to inferior nuchal line, lateral to rectus capitis posterior major • innervation: suboccipital (C1) • actions: extends head 4. obliquus capitis inferior*: • attachments: spinous process of axis to transverse process of atlas, • innervation: suboccipital (C1) • actions: rotates atlas and head to same side NERVES: 1. Suboccipital nerve: posterior primary rami of C1. ! This nerve is motor only and usually has no sensory roots, sensory to this region is supplied by posterior primary rami of C2 (aka greater occipital nerve). ! Passes superior to the posterior arch of C1 and inferior to the vertebral artery to emerge from center of suboccipital triangle. 2. Greater occipital nerve: post. primary ramus C2. ! Emerges inferior to oliquus capitis inferior muscles, passes medially to pierce semispinalis capitis muscles; it then passes superolaterally to posterior scalp. ! Provides sensory to posterior neck and scalp. VESSELS: 1. Occipital artery: branch of external carotid artery. ! Enters region laterally from beneath the mastoid process, passes across superolateral margin en route to posterior scalp. 2. Vertebral artery: branch of subclavian a. ! Ascends in the neck via transverse foramina of cervical vertebrae 1 – 6 and passes over posterior arch of atlas to enter foramen magnum of skull ! lies deep to suboccipital muscles These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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! after entering foramen magnum, each vertebral a. joins the other to form the basilar artery. 3. Basilar artery: forms the vertebrobasilar system, an important circulatory supplier of the cerebrum ! obstruction can cause dizziness CLINICAL TERMS: 1. fracture of the dens: at the junction with the body of C2, account for 40% of fractures of the axis. 2. Burst (Jefferson) fracture: fracture of anterior or posterior arches of C1 3. Hangman's fracture: with hyperextension injury, fracture of the arch of C2 between superior and inferior articular processes (pars interarticularis) EMBRYOLOGY: Approximately 15 days after the beginning of menstruation ovulation occurs If the egg is fertilized within 24 hours in the oviduct then cellular divisions known as cleavages begins in which cell number increase without an increase in overall size of the embryo. DAY 3 4
EVENT morula formed, a solid ball of 32 cells enters the uterus. blastocyst formed, a hollow ball of cells forms which contains an inner cell mass and blastocytic cavity surrounded by trophoblast. ! inner cell mass gives rise to the embryo, amniotic sac and yolk sac ! trophobast gives rise to other extraembryonic structures 6 trophoblast layer begins implanting into the endometrium 7 inner cell mass organizes into epiblast (ectoderm) and hypoblast 8 amnion sac and yolk sac appear 9 extraembryonic mesoderm is present and the embryo becomes fully implanted into the endometrium 15 mesoderm, primitive streak, notochord form from ectoderm: 17 neural plate appears 27 neural tube closes Day refers to the number of day’s poster fertilization.
CLINICAL APPLICATION: Spina bifida: incomplete closure of the neural tube. There are three types: 1. occulta – Mildest form; the outer part of some of the vertebrae do not close. The split is so small that the spinal cord does not protrude. 2. meningocele – Rarest form; vertebrae develop normally but the meninges are forced out between the vertebrae and fill with fluid creating a cyst on the back. These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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3. myelomeningocele – Most severe; the unfused portion of the spinal column allow the meninges and part of the spinal cord exit through the gap. LECTURE 4 - SCAPULAR AND DELTOID REGION SURFACE ANATOMY: 1. 2. 3. 2.
posterior axillary fold: consists of skin, latissimus dorsi and teres major spine of scapula: root is located medially opposite tip of T3 spinous process inferior angle of scapula: opposite tip of T7 spinous process, over rib 7 triangle of auscultation: a relative thinning of the musculature of the back which allows respiratory sounds to be heard more clearly. It is located medially to the inferior angle of scapula. Created by gap between latissimus dorsi, rhomboid major, lateral border of trapezius.
IMPORTANT MUSCULAR ATTACHMENTS: • •
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pectoral girdle to axial skeleton: levator scapulae, rhomboids, trapezius, (serratus anterior, pectoralis minor, subclavius covered with upper extremity) humerus to pectoral girdle: deltoid, supraspinatus, infraspinatus, teres major and minor, subscapularis, (triceps and biceps, coracobrachialis covered with upper extremity) humerus to axial skeleton: latissimus dorsi, (pectoralis major covered with upper extremity) 1. Humerus: • head: articulates with the shallow glenoid fossa of scapula in the ball-and-socket glenohumeral joint • anatomical neck: ligamentous attachment of shoulder joint, site of the epiphyseal plate • surgical neck: site of fractures which may involve the axillary n. and post. humeral circumflex a. in quadrangular space • greater and lesser tubercles: next to anatomical neck; attachment site for rotator cuff mm.(SIT and SS) • greater creates the round countour of the shoulder; Loss of the contour is sign of dislocated shoulder joint. • intertubercular sulcus (bicipital groove for tendon of long head of biceps) • pectoralis major attaches to lateral edge • latissimus dorsi attaches to floor • teres major attaches to medial edge • deltoid tuberosity: insertion for deltoid m. • spiral groove: sulcus for radial n. and profunda brachii a.; between lateral and medial heads of triceps on back of humerus 2. Scapula: mobile bone encased in muscle These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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• • • • • •
•
• • • • •
vertebral (medial) border: attachment for rhomboids, levator scapulae, serratus anterior; runs from rib 2-7, used as imaging landmark inferior angle: teres major attachment; at the level of T7 axillary (lateral) border: attachment for teres major, teres minor and long head of triceps (infraglenoid tubercle) spine: deltoid and trapezius attach; bends laterally to form acromion acromion: deltoid and trapezius attach; acromioclavicular joint coracoid process: (corax = crow); palpable 1" below clavicle; pectoralis minor, coracobrachialis, short head of biceps brachii attach; coracoacromial and coracoclavicular ligaments stabilize acromioclavicular joint glenoid fossa: forms ball-and-socket joint with head of humerus; features supraglenoid and infraglenoid tubercles (for attachment of long heads of biceps and triceps, respectively); faces ant. and lat. so that humerus looks like it is in medial rotation supraspinous fossa: supraspinatus attaches Infraspinous fossa: infraspinatus and teres minor attach subscapular fossa: subscapularis attaches greater scapular notch (spinoglenoid notch): deep to acromion; provides passage for suprascapular n. and a. to infraspinous fossa suprascapular notch: scapular ligament closes superior border; suprascapular n. (under) and suprascapular a. (above) ligament
3. Clavicle: acromial extremity: attaches deltoid, trapezius, pectoralis major, subclavius, and sternocleidomastoid; acromioclavicular joint; first bone of body to ossify; most frequently fractured bone in body. • conoid tubercle • deltoid tubercle MUSCLES: Review trapezius (spinal accessory n.), rhomboids and levator scapulae (dorsal scapular n. C 4-5), latissimus dorsi (thoracodorsal n. C 6 - 8) 1. Deltoid (delta = triangle): • attachments: clavicle, scapular spine and acromion to deltoid tuberosity innervation: axillary n. (C5-6) from post. cord of BP • actions: most important function: abduction of arm w/supraspinatus; ! anterior part# flexion and medial rotation of humerus; ! middle part#major abductor of humerus; ! posterior part#extension and lateral rotation of humerus • innervation: axillary n. (C5-6) from post. cord of BP ROTATOR CUFF MUSCLES: supraspinatus, infraspinatus, teres minor, subscapularis (SITSS). Dynamic muscle, which means not only do they move the humerus but they stabilize the glenohumeral joint. ! secure humerus at shoulder These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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! responsible for the strength and stability of the glenohumeral joint ! tendons form rotator cuff 2. Supraspinatus: • attachments: supraspinous fossa to greater tubercle of humerus • actions: abducts humerus • innervation): suprascapular n. (C4-6) from upper trunk of BP 3. Infraspinatus: " attachments: from infraspinous fossa to greater tubercle of humerus " actions: laterally rotates humerus " innervation: suprascapular n. (C4-6) from upper trunk of BP 4. Teres Minor: • attachments: axillary border of scapula to greater tubercle • innervation: axillary n. (C5-6) from post. cord of BP • actions: laterally rotates humerus 5. Subscapularis: • attachments: subscapular fossa to lesser tubercle of humerus • innervation: upper and lower subscapular nn. (C5-7) post. cord BP • actions: adducts and medially rotates humerus Other muscle: 6. Teres Major: • attachments: axillary border of scapula to medial edge of intertubercular sulcus • innervation: lower subscapular n. (C5 - 7) from posterior cord BP • actions: secures humerus at shoulder; adducts and medially rotates humerus ARTERIES: • Arteries of scapular and deltoid region contribute to arterial anastomosis of posterior shoulder: 1. Transverse cervical artery: branch of thyrocervical trunk of subclavian a. 2. Suprascapular artery: branch of thyrocervical trunk crosses over suprascapular ligament and accompanies suprascapular n. through spinoglenoid notch; supplies posterior mm. of rotator cuff 3. Dorsal scapular artery: frequently a deep branch of transverse cervical a.; supplies mm. of medial border of scapula 4. Circumflex scapular artery: branch of subscapular a. (from axillary a.); passes around axillary border to supply teres major and minor mm. • Other arteries: 5. Posterior circumflex humeral artery: branch of axillary a., passes behind surgical neck of humerus, (quadrangular space) to supply deltoid and teres major mm. 6. Profunda Brachii artery (deep brachial a.): branch of brachial a.; passes deeply within triangular interval, accompanied by radial n., following spiral groove on back of humerus These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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NERVES: 1. Spinal accessory nerve (CN XI)- trapezius) 2. Dorsal scapular nerve C4-5 - rhomboids) 3. Suprascapular nerve: C4-6; from upper trunk of BP; passes posteriorly through suprascapular and spinoglenoid notches; supplies supraspinatus and infraspinatus 4. Axillary nerve: C5-6; terminal branch of posterior cord BP, passes posteriorly (quadrangular space) to supply deltoid and teres minor mm. 5. Radial nerve: C5 - T1; terminal branch of posterior cord BP, passes along back of humerus, (triangular interval) along radial groove; nerve supply to posterior compartments of upper limb ANATOMICAL SPACES: •
Triangular space: bounded by teres minor (medially), teres major (inferiorly) and long head of triceps brachii (laterally); contains circumflex scapular a.
•
Quadrangular (quadrilateral) space: bounded by teres major (inferiorly), teres minor (superiorly), long head of triceps brachii (medially) and medial aspect of surgical neck of humerus (lateral); transmits posterior circumflex humeral a. and axillary n. to posterior shoulder region
•
Triangular interval: bounded by lateral and long heads of triceps brachii (laterally and medially, respectively) and teres major (superiorly); contains profunda brachii a. and radial n.
JOINTS: 1. Glenohumeral: ball-and-socket joint between head of humerus and glenoid fossa of scapula; more freely mobile than hip, but less stable (easily dislocated) • glenoid labrum: ring of cartilage which deepens fossa, blends with tendon of long head of biceps superiorly • supra- and infraglenoid tubercles: attachments for long heads of biceps and triceps, respectively; tendon for long head of biceps passes thru the joint outside of the synovial membrane • capsule is open for entrance of tendon of long head of biceps and under coracoid process • subscapular bursa - between subscapularis tendon and neck of scapula communicates with the shoulder joint; weakest inferiorly • subacromial/subdeltoid bursa between deltoid and supraspinatus tendon no communication with shoulder joint • glenohumeral ligaments: anterior reinforcement of joint capsule • transverse humeral ligament - between tubercles, straps tendon • rotator cuff: SIT SS mm. ("dynamic ligaments")
These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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coracoacromial arch: acromion, coracoid process and coracoacromial lig., opposes upward displacement of humeral head, supraspinatus passes under it, with overlying subacromial/deltoid bursa ! anterior displacement (dislocation) – if arm is extended and laterally rotated and a posterior force is applied head of humerus will translocate anteriorly ! inferior displacement (dislocation) – if arm is abducted and a superior force is applied head of humerus will translocate inferiorly. •
2. Acromioclavicular Joint: weak plane or gliding joint between acromion of scapula and lateral extremity of clavicle; dislocates frequently • coracoclavicular ligament (strongest - trapezoid lateral, conoid medial) • acromioclavicular ligaments • articular cartilage intrudes from above into joint cavity ! lateral sliding of clavicle over acromion = "shoulder separation", ! shoulder falls away from the clavicle 3. Sternoclavicular Joint: saddle-type joint between medial extremity of clavicle and manubrium of sternum - manubrium side is like a socket; only bony connection of pectoral girdle with axial skeleton • fibrocartilagenous disk inside joint attaching to sternoclavicular lig., prevents medial displacement of clavicle • stabilized by sternoclavicular, interclavicular and costoclavicular ligaments • supported by subclavius muscle; rarely dislocates CLINICAL TERMS: Shoulder impingement: pressure on rotator cuff tendons passing under the acromion and coracoacromial arch. LECTURE 5 – POSTERIOR CERVICAL TRIANGLE SURFACE ANATOMY: • •
• • •
Subcutanteous platysma muscle Sternocleidomastoid as it goes from the mastoid process to the sternum and clavicle (2 heads). ! key muscular landmark in the neck, visibly divides each side of the neck into the anterior and posterior cervical triangles. ! lies between external and internal jugular vein. ! protects carotid sheath Jugular notch of the manubrium between sternal heads of sternocleidomastoid muscle (SCM) Suprasternal space with access to inferior end of the inferior jugular vein between the sternal and clavicular heads of SCM Subclavian triangle between the trapezius & SCM over the clavicle allows pulse palaption of the subclavian artery These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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Palpable Features: • • • • • •
hyoid bone transverse processes of the atlas inferior border of the mandible vertebra prominens # spinous process of C7 laryngeal prominence at level of C4 cricoid cartilage at level of C6
GENERAL ORGANIZATION: The neck is organized as tubes within a tube: • superficial fascia: contains platysma muscle (supplied by facial nerve) • deep fascia: ! investing layer: trapezius and SCM ! prevertebral fascia: cervical vertebral column including spinal cord, and true back muscles ! pretracheal fascia: infrahyoid muscles and cervical visera including: " digestive (esophagus) " respiratory (larynx, trachea) " endocrine (thyroid gland) ! carotid sheath: arteries and veins serving the head " common cartotid a. " internal jugular v. " vagus n. BOUNDARIES: • • •
anterior boundary # SCM posterior boundary # trapezius inferior boundary # clavicle ! Subdivisions: " “Carefree” and “careful” zones defined by spinal accessory nerve. " carefree zone is superior to spinal accessory. “three go up” these are lesser occipital n., great auricular n., and transverse cervical n. " careful zone is inferior to spinal accessory. “three go down” these are the supraclavicular nerves: medial, intermediate, lateral nn. This is referred to as the careful zone because deep within this zone is the brachial plexus and subclavian artery and vein. " subclavian triangle (omoclavicular) created within posterior cervical triangle by inferior belly of omohyoid.
BONY FEATURES: • • •
Temporal bone: mastoid process (SCM attachment) Sternum: anterior surface of manubrium (SCM attachment) Clavicle: medial third of clavicle (SCM attachment) These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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• •
Rib 1: scalene tubercle (anterior scalene attachment) and superior surface (middle scalene attachment) Cervical vertebrae: anterior and posterior tubercle of transverse processes (anterior and middle scalenes attachments, respectively).
MUSCLES: 1.
Platysma: • attachments: inferior border of mandible skin and subcutaneous tissue of lower face to fascia covering superior parts of pec major and deltoids • innervation: cervical branch of facial n. (CNV) • actions: draws cornes of mouth inferiorly and widens it as in expressions of sadness and fright; Draws skin of neck superiorly when teeth are clenched.
2.
Omohyoid: • attachments: from scapular ligament and superior border of scapula to hyoid (two bellies joined by intertendon passing through a sling from the medial extremity of the clavicle) • innervation: ansa cervicalis (C1-C3) • actions: depresses hyoid bone.
3.
Sternocleidomastoid: • attachments: lateral surface of mastoid process to anterior surface of manubrium (sternal head) and superior surface of medial third of clavicle (clavicular head) • innervation: cranial nerve XI (spinal accessory) and anterior primary rami of C2 and C3 (proprioception) • actions: ipsilateral flexion contralateral rotation, bilateral contraction causes: 1) extends neck at atlanto-occipital joints; 2) flexes cervical vertebrae; 3) thrusts chin out. Assist in respiration. " congenital fibrosus of SCM on one side causes a condition called torticollis AKA wryneck
4.
Anterior scalene: (scalenus anterior) • attachments: anterior tubercles of transverse process of C3-C6 to scalene tubercle of rib1. • innervation: anterior primary rami of cervical nn. • actions: flex head Middle scalene: (scalenus medius) • attachments: posterior tubercles of transverse process of C3-C7 to superior surface of rib1 (posterior to groove for subclavian a.) • innervation: anterior primary rami of cervical nn. • actions: flexes neck laterally, assist in respiration by elevating rib 1 during forced inspiration. Posterior scalene: (scalenus posterior) • attachments: posterior tubercles of transverse process of C3-C7 external surface of rib 2.
5.
6.
These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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innervation: anterior primary rami of cervical nn. actions: flexes neck laterally, assist in respiration by elevating rib 2 during forced inspiration. Subclavius: described with pectoral region Splenius capitis and levator scapulae: are located superior and posterior to the posterior scalene. • •
7. 8.
NERVES: Superficial: 1. Lesser occipital n.: C2; follows posterior border of sternocleidomastoid m. to supply sensory to skin posterior to ear. 2. Great auricular n.: C2 and C3; travels vertically on surface of SCM to supply sensory to skin around external ear. 3. Transverse cervical n.: C2 and C3; travels horizontally on surface of SCM to supply sensory to skin covering anterior cervical triangle. 4. Supraclavicular n.: C3 and C4, sensory to skin overlying neck clavicle and shoulder Deep: 5. Spinal accessory n.: supplies trapezius and SCM, has spinal roots from C1-C5, cranial roots supply larynx and pharynx (along with vagus). 6. Phrenic n.: C3-C5; crosses anterior scalene, provides motor to diaphragm ! accessory to phrenic n.: C5; may lie lateral to phrenic, not always present. 7. Brachial plexus: C5-T1; roots and trunks emerge between anterior and middle scalene. Superior, middle and inferior trunks located superior to the clavicle. 8. Suprascapular n.: C4-C6; from upper trunk of brachial plexus, innervates supraspinatus and infraspinatus. 9. Dorsal scapular n.: C4-C5; from C5 root receives contribution from C4, innervates rhomboids and levator scapulae. VESSELS: 1. subclavian a.: passes posterior to scalenus anterior m. to lateral border of rib 1 at which point it becomes the axillary a. Is found deep to the clavicle in the subclavian triangle. Important branches vertebral a., thyrocervical trunk, dorsal scapular a.*, * the dorsal scapular a. is sometimes a branch of the subclavian a. 2. thyrocervical trunk: 3 branches: suprascapular a., transverse cervical a. and inferior thyroid a. 3. suprascapular a.: travels posteriorly passing deep to the clavicle from thyrocervical trunk to supply dorsal scapular mm. 4. transverse cervical a: travels posteriorly across anterior scalene superior to the clavicle and deep to omohyoid; supplies trapezius. 5. dorsal scapular a.: branches from thyrocervical trunk (*sometimes subclavian a.); supplies rhomboids and levator scapulae mm. 6. subclavian v.: passes superficial to scalenus anterior m. CLINICAL TERMS: These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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•
Thoracic outlet syndrome - subclavian artery and vein, and T1 spinal nerve pass out of the thorax to enter the posterior cervical triangle, any pathology (tumor) or anomaly (cervical rib) can cause pressure and resulting symptoms on the artery, vein, and/or nerve distribution in the upper extremity. Symptoms are pain, decoloration of the hands, one hand colder than the other hand, weakness of the hand and arm muscles, and tingling are commonly present. EMBRYOLOGY OF THE LIMB 1. migration of epiblast cells forms a midline notochord and lateral paraxial, intermediate, and lateral plate mesoderm 2. as neural tube forms, embryo folds ventrally to form the gut tube 3. paraxial mesoderm organizes into segmental blocks of cells called somites, somitomeres in the head region, that differentiate into skull, vertebrae, muscles, dermis 4. intermediate mesoderm contributes to the urogenital system 5. lateral plate mesoderm splits into peripheral somatic (parietal) layer that lines the ectoderm and deeper splanchnic (visceral layer) that overlies gut tube 6. somites have ventromedial sclerotome (forming bone), dorsolateral and dorsomedial myotome forming hypomeric and epimeric (paraspinal) muscles, separated by dermatome that differentiates into dermis 7. limb development begins at 4th week 8. limb buds are outgrowths with a core of mesoderm from somatic layer of lateral plate mesoderm, covered by ectoderm 9. ectoderm at the tip thickens to form apical ectodermal ridge, inducing mesenchyme to condense as a progress zone to elongate it 10. girdles develop first, phalanges last 11. bones form from lateral plate mesoderm, muscles from migration of myotome of somites 12. as limbs elongate they rotate - upper 90 degrees laterally, lower 90 degrees medially 13. as the somite differentiates, derivatives are supplied by the nerve that serves that somite. 14. spinal nerves divide into dorsal primary ramus for epimere musculature, of that segment, ventral primary ramus for hypomere muscles from that segment, the dermatome is also supplied by the spinal nerve of that somite
These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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Zygote'
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3d' Morula' 4d' Blastocyst' 6d'implanta7on' Inner' cell'mass'
Trophoblast' 7d' Hypoblast' 8d' Yolk'sac'
8d'
15d' Endoderm'
7d' Epiblast'
15d' Ectoderm'
17d' Neural'Plate'
27d' Neural'Tube'
Central' Nervous' system'
15d' Mesoderm'
Amnio7c' sac'
Notochord' 15d' Lateral'plate' mesoderm'
Visceral' (splanchnic)' mesoderm'
Soma7c' (parietal)' mesoderm'
Intermediate' mesoderm'
mesonepheric' system'
metanepheric' system'
Paraxial' mesoderm'
Somite'
Sclerotome' Organs,' cardiovascular' system,'diges7ve' system'
4wk' Limb'bud'
Gonads'
bones'of' appendicular' skeleton'
Myotome'
Dermatome'
Kidney' bones'of'axial' skin'covering' Epimere' Hypomere' skeleton' back' Intrinsic'back' muscles'
Extrinsic'muscles,' abdominal' muscles,' appendicular' muscles'
LECTURE 6 - ANTERIOR CERVICAL TRIANGLE GENERAL ORGANIZATION: (review from anterior cervical triangle lecture) The neck is organized as tubes within a tube: • superficial fascia: contains platysma muscle (supplied by facial nerve) • deep fascia: ! investing layer: trapezius and SCM ! prevertebral fascia: cervical vertebral column including spinal cord, and true back muscles ! pretracheal fascia: infrahyoid muscles and cervical visera ! carotid sheath: arteries and veins serving the head: " common cartotid a. " internal jugular v. " vagus n. BOUNDARIES: • • • • •
lateral boundary # sternocleidomastoid medial boundary # midline of body superior # inferior border of mandible roof# investing fascia (deep to platysma) floor# pretracheal fascia
These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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! Subdivisions: (four constituent triangles) 1. submental: bounded by anterior bellies of digastric mm. and hyoid bone; mylohyoid m. forms the floor. 2. submandibular: bounded by anterior and posterior bellies of digastric m. and inferior border of mandible → location of submandibular salivary gland 3. muscular: bounded by sternocleidomastoid m., superior belly of omohyoid m.and midline; → contains infrahyoid strap mm. → thyroid gland is located deep to mm. 4. carotid: bounded by sternocleidomastoid m., superior border of omohyoid m. and posterior belly of digastric m. → contains carotid aa., vagus n. and internal jugular v. (within carotid sheath) BONY FEATURES: mandible: ! mylohyoid line (attachment for mylohyoid m.) ! digastric fossa (attachment for anterior belly of digastric m.) • hyoid: ! body (attachment for infrahyoid and mylohyoid mm.) ! greater and lesser cornua (attachment for suprahyoid mm.) • thyroid cartilage (of larynx): features laryngeal prominence ("Adam's apple") • cricoid cartilage(of larynx): at level of C6 vertebra •
MUSCLES: A.
INFRAHYOID MUSCLES: strap muscles; inferior to the hyoid bone • innervation: ansa cervicalis, a loop created by the fibers from C1 - C3 (*exception: n. to thyrohyoid (C1). • action: depress hyoid following swallowing; stabilize hyoid bone: 1. sternohyoid: from sternum to hyoid 2. omohyoid: from scapular ligament and superior border of scapula to hyoid (two bellies joined by intertendon passing through a sling from the medial extremity of the clavicle) 3. sternothyroid: from sternum to thyroid cartilage of larynx 4. thyrohyoid*: from thyroid cartilage of larynx to hyoid bone
B.
SUPRAHYOID MUSCLES: muscles superior to the hyoid bone, connecting to skull 1.
Digastric • attachments: mastoid process of temporal bone (posterior belly) to digastric fossa of mandible (anterior belly); the 2 bellies are joined by intertendon passing through a sling from lesser cornu of hyoid • innervation: These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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•
anterior belly: mylohyoid n. of mandibular division of trigeminal n. (CN V). posterior belly: branch of the facial n. (CN VII) actions: depression (extension) and retraction of mandible for chewing; elevation of hyoid for swallowing
2.
Mylohyoid m.: • attachments: from mylohyoid line of mandible to hyoid bone and median raphe; forms part of floor of oral cavity • innervation: mylohyoid n. (from mandibular division of trigeminal - V3) • actions: elevation of hyoid, floor of oral cavity and tongue for swallowing, speech 3. Stylohyoid m.: • attachments: from styloid process of temporal bone to hyoid bone (straddling intertendon of digastric) • innervation: branch of the facial n. (CN VII) • actions: elevation and retraction of hyoid 4. Geniohyoid: • attachments: mandible to body of hyoid • innervation: C1 (attached to CNXII) • action: pulls hyoid bone anteriorly and shorten floor of mouth VISCERA: • Thyroid gland - right and left lobes united by the isthmus anterior to 2-3rd tracheal cartilage. ! deep to sternothyroid and sternohyoid muscles ! extends to the 6th tracheal cartilage and sides of esophagus ! surrounded by thyroid capusle and pretracheal fascia ! attached to cricoid and thyroid cartilages ! supplied by sup. and inf. thyroid arteries, sympathetic nerves NERVES: 1. ansa cervicalis n.: supplies sternohyoid, sternothryoid, omohyoid; fibers of anterior primary rami of C1 - C3 form a loop (ansa = loop or handle; cervix = neck) via union of: ! descendens hypoglossi (C1 and 2) (superior root) ! descendens cervicalis (C2 and3) (inferior root) 2. hypoglossal n.: cranial n. XII, motor nerve to mm. of tongue, exiting skull by way of hypoglossal canal; descendens hypoglossi and n. to thyrohyoid attach to it before decending to innervate their target muscles. 3. spinal accessory n.: cranial n. XI, to trapezius and sternocleidomastoid, exiting skull by way of jugular foramen. 4. vagus n.: cranial X, major parasympathetic trunk carried in carotid sheath; supplies larynx (superior and recurrent laryngeal nn.), exiting skull by way of jugular foramen. 5. superior laryngeal n.:branch of vagus n. divides into: i. internal laryngeal - sensory to vocal folds and inferior pharynx; pierces thyrohyoid membrane of larynx. ii. external laryngeal - motor to cricothyroid and inferior constrictor of larynx These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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VESSELS: 1. internal jugular vein: drainage from cranial cavity (dural sinuses); descends in carotid sheath; joins subclavian to form brachiocephalic vein 2. common carotid artery: major supply to head from arch of aorta (left) or brachiocephalic trunk (right); ascends in carotid sheath, branching at level of hyoid bone (internal and external carotid aa.) ! carotid sinus (swelling at terminal branching): contains sensory organs for monitoring blood pressure 3. internal carotid a.: supplies cranial cavity (circle of Willis) 4. external carotid a.: supplies superficial structures of neck and head via several branches: i. superior thyroid a.: travels with external laryngeal n. to larynx and thyroid gland, branch is superior laryngeal a. that travels with internal laryngeal n. ii. lingual a.: to tongue iii. facial a.: through submandibular gland and over body of mandible to supply face iv. ascending pharyngeal a.: relatively minor branch v. occipital a.: passes posteriorly to supply posterior scalp (recall it in apex of posterior cervical triangle at superolateral edge of suboccipital region) vi. posterior auricular a.: smaller branch to skin behind the ear LECTURE 7 - PECTORAL REGION, AXILLA, BRACHIAL PLEXUS SPECIAL FEATURES: • The thoracic wall is made up of (from superficial to deep): epidermis, dermis, superficial fascia, deep fascia, muscle and bone, parietal pleura • breast - a modified sweat gland lying in the superficial fascia and overlying pectoralis major, separated from pectoralis by deep fascia • well developed in women • amount of fat surrounding the glandular tissue determines the size • extends to the axilla with axillary tails • lobules are drained by lactiferous ducts that open at the nipple • attached to the skin by Cooper’s ligaments (suspensory ligaments) • receives blood supply from internal thoracic, lateral thoracic, thoracoacromial and intercostal arteries • lymphatic drainage to axillary, parasternal, abdominal, and opposite breast-associated lymph nodes BONY LANDMARKS: 1. pectoral girdle (scapula and clavicle): attachment for the upper limb; attachment to axial skeleton at the sternoclavicular joint 2. scapula: acromion, coracoid process, vertebral border 3. clavicle: acromial extremity, sternal extremity, origins for pectoralis major, deltoid, and subclavius 4. humerus: head, greater and lesser tubercles, intertubercular sulcus (bicipital groove), anatomical neck, surgical neck and deltoid tuberosity These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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5. sternum: anterior attachment for the ribs (costal cartilages) at sternocostal joints - 3 parts: • manubrium (= handle): " jugular (suprasternal) notch " clavicular notch " sternoclavicular joint which articulates also with rib 1 at synchondrosis type joint " sternal angle (angle of Louis): junction of manubrium and body, rib 2 also articulates here. • body or gladiolus (= sword): articulates with manubrium (manubriosternal joint), xiphoid process (xiphisternal joint, symphysis type joint) and ribs 3 – 6. • xiphoid process (= dagger-like): danger of liver laceration articulates with body. Also articulates with rib 7. 6. Ribs: 12 pairs and costal cartilages: • 7 pairs vertebrosternal • 3 pairs vertebrochondral • 2 pairs vertebral • features of a typical rib (3 - 10): ! head articulates with vertebral bodies (costovertebral joints) ! tubercle with transverse process (costotransverse joint) ! shaft features angle (point of greatest curvature) and costal groove • atypical ribs: ! rib 1 (shortest) grooves for subclavian artery and vein and scalene tubercle ! rib 2 has tuberosity for serratus anterior ! ribs 11 and 12 no tubercle, reduced costal cartilage, single facet on head MUSCLES: Intrinsic muscles of the thoracic cage: considered to be true muscles of the thoracic wall. These muscles alter the position of the ribs and sternum affecting the a change in thoracic volume. These include the following muscles: " levatores costarum " serratus posterior superior accessory respiration " serratus posterior inferior " external intercostal - continuous with external oblique, fibers oriented medially from superior to inferior, replaced anteriorly by parasternal membrane " internal intercostal - continuous with internal oblique, fibers oriented laterally from superior to inferior; replaced posteriorly by paravertebral membrane " innermost intercostal - actually inner part of internal intercostal, VAN pass between " transversus thoracic – attach to posterior aspect of sternum BLOOD VESSELS: • intercostal arteries- branches of internal thoracic (mammary) from subclavian, and aorta These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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• Intercostal veins- drain to internal thoracic veins or azygos vein NERVES: • anterior primary rami of thoracic spinal nerves (T12 = subcostal) that also communicate with the sympathetic ganglia by way of white and gray rami • dermatomes T4- nipple, T10- umbilicus Extrinsic muscles of the thoracic cage: muscles attached to and/or covering the thoracic cage; are primarily involved in serving other regions. 1. Deltoid - innervated by axillary nerve, C5-6 (see lecture 4) 2. Pectoralis Major: • attachments: clavicle (clavicular head), sternum and sixth costal cartilage (sternocostal head) to lateral edge of intertubercular sulcus of humerus • innervation: lateral pectoral nerve (C5-7) innervates both heads; medial pectoral nerve (C8-T1) innervates only the sternocostal head. These nerves branch from the lateral and medial cords of brachial plexus respectively. • actions: adduction and medial rotation of humerus 3. Pectoralis minor: landmark for parts of the axillary artery. • attachments: ribs 3, 4 and 5 to coracoid process of scapula • innervation: medial pectoral nerve C8-T1 from medial cord of brachial plexus (also carries fibers of lateral pectoral n.) • actions: depression of scapula 4. Subclavius: • attachments: from first rib and manubrium of sternum to clavicle • innervation: nerve to subclavius C5-6 • actions: stabilization of clavicle and sternoclavicular joint; protection for subclavian vessels and brachial plexus in event of fractured clavicle 5. Serratus anterior: • attachments: first 8 or 9 ribs to anterior side of medial border of scapula • innervation: long thoracic nerve C5-7 (roots of brachial plexus) • actions: protraction of scapula, secures scapula to thoracic cage; (inability to contract produces "scapular winging") VESSELS: 1. Subclavian Artery: from brachiocephalic a. (right) or arch of aorta (left); passes laterally, deep to scalenus anterior m., continues as axillary a. at lateral border of rib 1; major branches: • thyrocervical trunk: branches#inferior thyroid a., transverse cervical a., suprascapular a. • vertebral a. # ascends cervical spine via transverse foramina to form vertebrobasilar system within cranium • internal thoracic a.# on either side of sternum to become musculophrenic and superior epigastric • costocervical trunk: to upper intercostal spaces and deep posterior neck These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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2. Axillary Artery: three parts: • Part 1: lateral border of rib 1 to medial border of pectoralis minor: one branch# superior (supreme) thoracic a. • Part 2: deep to pectoralis minor: two major branches#1) thoracoacromial trunk (medially) 2) lateral thoracic a. (laterally, larger in female, with mammary branches) • Part 3: from lateral border of pectoralis minor to inferior border of teres major: three major branches# 1) subscapular a. - splits into circumflex scapular and thoracodorsal aa. ; 2) anterior circumflex humeral aa.; 3) posterior circumflex humeral aa. 3. Brachial Artery: continuation of axillary a. into upper limb, beginning at inferior border of teres major 4. Cephalic Vein: lateral superficial vein of upper limb; traverses deltopectoral triangle and passes deep to enter axillary v. 6. Axillary and Subclavian Veins: parallel the corresponding aa. NERVES: 1. 2. 3. 4. 5.
Axillary Nerve: C5,C6; supplies deltoid; from posterior cord of brachial plexus Lateral Nerve: C5-7; supplies both heads of pectoralis major; from lateral cord of brachial plexus. Medial Pectoral Nerve: C8-T1; supplies pectoralis minor and sternocostal head of pectoralis major; from medial cords of brachial plexus; *sometimes they are joined in a bridge over the axillary artery. Long Thoracic Nerve: C5-7; supplies serratus anterior; from roots of brachial plexus. Nerve to Subclavius: C5,C6; supplies subclavius; from superior trunk of brachial plexus
AXILLA: Surface anatomy: • acromial end of clavicle rises higher than the acromion • infraclavicular fossa overlies deltopectoral triangle with access to the cephalic vein • sternocostal head of pectoralis major and serratus anterior in lean individuals • posterior axillary fold consisting of latissimus dorsi • anterior axillary fold consisting of pectoralis major Borders: • apex: bounded anteriorly by clavicle, posteriorly by superior border of scapula, medially by rib 1 • floor: (armpit) axillary fascia and skin • anterior wall: (anterior axillary fold) pectoralis major and minor m. • posterior wall: (posterior axillary fold) latissimus dorsi, teres major and subscapularis mm. • medial wall: serratus anterior m. and ribs • lateral wall: meeting point of anterior and posterior folds at intertubercular sulcus of humerus These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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Contents: fat, axillary a. and v., lymph nodes, cords of brachial plexus, long and short heads of biceps brachii, and coracobrachialis mm. BRACHIAL PLEXUS: pattern is a palindrome (5,3,6,3,5) • Roots (5): anterior primary rami of C5 - T1; ! branches: " dorsal scapular n. mainly from C4-5 (to rhomboids) " long thoracic n. from C5-7 (to serratus anterior) • Trunks (3): upper (C5 and C6); middle(C7); lower(C8 and T1); ! branches: " suprascapular n.C4-6 from upper trunk (supra and infraspinatus m.) " nerve to subclavius C5-6 (from upper) • Divisions (6): each trunk splits into an anterior and posterior division • Cords (3): named according to relationship to axillary a.: ! lateral: from anterior divisions of upper and middle trunks, source of: " lateral pectoral n. C 5-7 (to pectoralis major) ! medial: from anterior division of lower trunk, source of: " medial pectoral n. C8-T1 (to pectoralis major and minor) " medial brachial and antebrachial cutaneous nn. C8-T1 ! posterior: from posterior divisions of all trunks, source of: " upper subscapular nn. (to subscapularis) C5-7 " lower subscapular nn. (to subscapularis and teres major) C5-7 " thoracodorsal n. C6-8 (middle subscapular) to latissimus dorsi) • Terminal Branches (5): ! musculocutaneous n.: C5-7 ends lateral cord, supplies anterior compartment of arm, sensory to lateral forearm ! median n.: C5-T1 receives a contribution from lateral and medial cords; main n. supply to anterior forearm mm.; motor and sensory to hand ! ulnar n.: C8-T1 ends medial cord, motor to anterior forearm and hand, sensory to hand ! axillary n.: C5-6 from posterior cord to deltoid and teres minor mm. ! radial n.: C5-T1 from posterior cord, to posterior compartments of upper limb, sensory to wrist and hand
These notes have been adapted from the notes of Dr. Ted Hart and Dr. Mary Hurley
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