Okajimas Folia Anat. Jpn 63(1): 37-44,

May 1986

Case Report

An Anomalous Case of the Common Carotid Artery Giving Off Several Branches and High Division of the Internal Carotid Artery by Masaki MATSUMOTO, Hitoshi OKUDA, Etsuo ISHIDOH and Hiroaki MITSUI Department of Anatomy, Osaka Dental University 1-47 Kyobashi, Higashi-ku, Osaka 540, Japan

(Director: Prof. Y. Ohta) -Received for Publication, November 24,1985-

Key Words: Abnormalities, Common carotid artery, External carotid artery, Internal carotid artery.

Summary: A rare anomaly, in which the left common carotid directly gave rise to the superior thyroid, the lingual, the facial and the ascending pharyngeal arteries and divided into the external and internal carotid arteries at a high level, was found in a 52-year-old Japanese male among cadavers for student dissection. The occipital artery in this case arose from the internal carotid.

A similar case has been reported previously by Kubota (1950).

cervicalvertebra.

Cadaver:Japanese, 52-year-oldmale, subject for student dissection in 1984. The cause of death was cardiacinsufficiency. The branching type of the aortic arch in this case belonged to type A of Adachi's classification(1928) without variations.No variation was observedin the right common carotid artery.

2. Lingualartery This artery (1.8 mm in width) left the anteromedial wall of the left common carotid, about 21 mm distal to the origin of the superior thyroid anteriorly at the level of the inferior margin of the third vertebra. 3. Facialartery This artery (1.9 mm in width) left the anterior wall of the left common carotid anterosuperiorly about 3 mm distal to the origin of the lingual artery.

A. Left common carotid artery This artery (7.3 mm in width at the level of C4) divided into the external and internal carotid arteries at the level of the second cervical vertebra. This position was remarkablyhigherthaninusualcases. Furthermore, the left common carotid gave rise to the followingarteries in order.

4. Ascendingpharyngealartery This artery (1.1 mm in width) left the anteromedial wall of the left common carotid anterosuperomedially, immediately distal to the origin of the facial. The ascending palatineartery alsoarose from this artery.

1. Superiorthyroid artery This artery (1.7 mm in width) left the anterior wall of the left common carotid anteroinferiorly at the level of the fourth 37

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B. Left external carotid artery The left common carotid artery divided into the external and internal carotid arteries, immediatelydistal to the origin of the ascending pharyngeal at the level of the middle of the second cervicalvertebra. The external carotid (2.4 mm in width) in this case left the anterior wall of the common carotid with a swelling (3.8 mm in width) at its origin, and ran anterosuperiorly between the stylohyoideus and styloglossus muscles up to a position lateral to the tip of the styloid process. This artery gave off the posterior auricular artery (1.1 mm in width) from its posterior wall posterosuperiorly at the level of the middle of the first cervical vertebra. It terminated in the maxillary (3.4 mm in width) and the superficial temporal arteries (2.6 mm in width). C. Left internal carotid artery. This artery (6.8 mm in width) ascended medial to the origins of the styloglossusand stylohyoideus muscles with the hypoglossal

Fig. 1.

nerve. It gave off the occipital artery (1.4 mm in width) posterosuperiorly from its posterior wall about 10 mm distal to the division between the external and internal carotid. D. Carotid glomus The right glomus was found just at the division of the right internal and external carotids. The left one, however, was not found owing to full completion of the dissection.

Discussion A case similar to the present example was not describedevenin the many examples observed by Adachi (1928). However, he reported the superior thyroid and the lingual arteries arising from the common carotid in a case in which a vascular island was formed between the common and internal carotids. Rauber-Kopsch (1919) and Gray

Schematic drawing illustrating the embryological processes in the present case (revised from Patten, 1968). Left, the normal pattern in which the internal carotid artery develops from the 3rd aortic arch. Right, the present case in which a section supposed to develop into the external carotid artery might be incorporated into the common carotid since the hyoid artery derived from the 2nd aortic arch remained and the 3rd aortic arch disappeared abnormally. Such processes might load to high-leveled division of the internal carotid artery.

An Anomalous

(1973) in their textbooks of anatomy stated that very rarely the common carotid. artery ascended in the neck without undergoing division, with either the external or the internal carotid being absent. They, however, did not givesuch an example. Kubota (1950) reported a case similar to the present anomaly. He stated that the external carotid artery was defective and the common carotid gaverise to the superior thyroid, the lingual,the sternocleidomastoid, the facial arteries and a common trunk between the posterior auricular, the superficial temporal and the maxillary arteries in that order. He describedthe external carotid of the present report as a common trunk between the above three vessels, and this trunk arose from the common carotid. The remaining section after the division of the internal carotid is termed the "external carotid" in the present report, although Kubota called it the common trunk as mentioned. The reason why the present authors indicate it as the external carotid is as follows. Firstly, this section follows just the same course as the external carotid in normal cases. Secondly, it might not develop from the 3rd aortic arch in the embryo, but probably from the 2nd aortic arch which is supposed to disappearnormally. Such a procedure might lead to highleveled division of the internal carotid. This interpretation follows from the angiogenesis of the head described by Padget (1948) and the embryological descriptions of Starck (1955). The three vessels arising from the

Case

of the Common

Carotid

ascending pharyngeal artery common carotid artery external carotid artery facial nerve facial artery hyoid bone hypoglossal nerve internal carotid artery lingual artery

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left common carotid in the present case might be distributed to derivatives of the 2nd and 3rd aortic arches since the internal carotid hypothetically might have developed from the 2nd aortic arch. The occipital artery arisingfrom the internal carotid could be interpreted as follows. Recently, various features of the cerebral vessels have been reported in the clinic field by means of angiography.Suzuki (1980) suggested that the origin of the occipital artery would be located on the internal carotid when the proatlantal intersegmental artery in the embryologicalperiod remained. References 1) Adachi,B.: DasArteriensystem der Japaner. Bd.1, Maruzen,Kyoto,43-96,1928. 2) Kopsch,F.: Rauber'sLehrbuchder Anatomie desMenchen. III,278-281,Leipzig,1919. 3) Kubota,K.: EineselteneAnomalievon Verzweigungender A. carotiscommunis.Acta Anat.Nippon.,25: 22-24,1950(In Japanese). 4) Padget,D.H.:The development of the cranial arteries in the human embryo. Contrib. Embryo!., XXXII:205-261,1948. 5) Patten, B.M.:Humanembryology.3rd ed., McGraw-Hill, NewYork,1968. 6) Starck,D.: Embryologic. 2. Aufl., Thieme, Stuttgart,1955. 7) Suzuki,M. & Y. Kuwabara:Relationsbetween the proatlantalintersegmental artery and the occipitalartery arisingfrom the internalcarotidartery.Jpn. J. Clin.Radio!., 25: 178-179, Kanehara,Tokyo, 1980 (In Japanese). 8) Warwick,R. & P. Williams: Gray'sanatomy. 35th ed.,622-631,Longman,London,1973.

Abbreviations ap : cc : ec : F : fa : H : HN: ic : la :

Artery

M : ma : oa : pa : SG : SM : sf : st :

mandible maxillary artery occipital artery posterior auricular artery submandibular gland stylohyoideus muscle superficial temporal artery superior thyroid artery

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et a/.

Explanation Plate Fig. 2.

of Figures I

Lateral view of the present case, showing the principal branches arising from the common , external and internal carotid arteries.

An Anomalous

Case

of the Common

Carotid

Artery

41 Plate I

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Plate Fig. 3.

II

Radiograph of the present case. The relations between the principal branches of the carotid arteries and cervical vertebrae are indicated by the numbering on their origins, as follows: 1, superior thyroid; 2, lingual; 3, facial; 4, ascending pharyngeal; 5, division between the external and internalcarotid at the level ofthe middle of the 2nd cervicalvertebra; 6, occipital artery from the internal carotid; 7, posterior auricular artery from the external carotid; 8, division between the maxillary and the superficial temporal from the external carotid; H, hyoid bone.

An Anomalous

Case

of the Common

Carotid

Artery

43 Plate II