• Area of the skin that is supplied by a single nerve root
Sensory examinaAon • NoAce how the dermatomes correlate with the peripheral nerves. • PropriocepAon and vibraAon: – large myelinated fiber and – dorsal column medial
• Light touch and temperature • small unmyelinated nerve fibers • Anterior lateral tract (spinothalamic)
L1
L1
L2
L2
L-‐3
L-‐3
L-‐4
L-‐4
L-‐5
L-‐5
S-‐1
S-‐1
S-‐2
S-‐2
S-‐3
S-‐4
Cutaneous nerves of lower extremity
• Cutaneous nerves are the sensory porAon of the peripheral nerves. They also provide motor funcAon to the sweat glands.
Ilioinguinal nerve (L1)
Ilioinguinal nerve (L1)
Genitofemoral nerve (L1-‐2)
Genitofemoral nerve (L1-‐2)
Lateral femoral cutaneous nerve L2-‐3
Lateral femoral cutaneous nerve L2-‐3
Cutaneous branch of Femoral nerve(L2-‐3)
Cutaneous branch of Femoral nerve(L2-‐3)
Saphenous nerve (L3-‐4)
Saphenous nerve (L3-‐4)
Posterior Femoral Cutaneous Nerve (S1-‐3)
Obturator Nerve (L2)
Obturator Nerve (L2)
Posterior Femoral cutaneous nerve (S1-‐3)
Lateral Sural Nerve (L4-‐S2)
Lateral Sural Nerve (L4-‐S2)
Superficial Peroneal Nerve(L4-‐5,S1)
Superficial Peroneal Nerve(L4-‐5,S1)
Sural nerve (S1-‐2)
Sural nerve (S1-‐2)
Deep Peroneal Nerve (L4-‐5)
Deep Peroneal Nerve (L4-‐5)
Tibial Nerve (S1-‐2)
Tibial Nerve (S1-‐2)
Medial Plantar Nerve(L4-‐5)
Medial Plantar Nerve(L4-‐5)
Lateral Plantar Nerve(S1-‐2)
Lateral Plantar Nerve(S1-‐2)
Muscle tesAng • Myotome: tesAng muscles that are innervated by a specific nerve root. – Key muscles faAgue with sustained resistance. – Indicate pressure on the ventral nerve root
• Reflex test: test the monosynapAc reflex of a specific nerve root level. – Exaggerated reflex may suggest upper motor neuron lesion. – Diminished reflexes is suggesAve of nerve root or peripheral nerve lesion
Myotomes/ Reflexes Lower Extremity x x
x x
x
Myotomes/ Reflexes Lower Extremity L1-‐2 hip flexion Hip extension L5, S1
