288 ANATOMY IN A NUTSHELL 



LESSON LXXXI 



The Relations of the Right Common Carotid and the Left Common Carotid 

 arteries tin the neck). 



I\ Front. — (1) Integument, (2) Superficial fascia, (3) Deep cervical 

 fascia, (4) Platysma myoides, (5) Sterno-mastoid, (6) Sternohyoid. (7) Sterno- 

 thyroid. (8) Omo -hyoid, (9) Descendens and Communicans nerves. (10 

 Sterno-mastoid artery. (11) Superior thyroid vein, (12) Middle thyroid vein.. 

 13) Anterior jugular vein. 



Behind. — (1) Longus colli, (2) Rectus capitis amicus major, (3) Sym- 

 pathetic nerve, (4) Inferior thyroid artery. (.">) Recurrent laryngeal nerve. 



Externally.— (1) Internal jugular vein. (2) Pneumogastric nerve. 



Internally. — (1) Trachea, (2) Thyroid gland, (3) Recurrent laryngeal 

 nerve. (4) Inferior thyroid artery. (5) Larynx. (6) Pharynx. 



The common carotid arteries at the root of the neck are close together and 

 ■ iii ply situated, but higher in the neck they become separated and are more 

 superficial. The common carotid artery, internal jugular vein and the pneu- 

 mogastric nerve all lie in a common sheath. 



The external carotid artery is a branch from the common carotid artery at 

 the upper border of the thyroid cartilage, from which place it runs upward 

 and forward, then backward between the external auditory meatus and the 

 neck of the c< ndyle of the mandible (lower jaw). It now divides into a super- 

 ficial temporal and internal maxillary arteries. It lies in the superior caroitd 

 triangle (triangle of (lection) and passes through the substance of the parotid 

 gland. It is superficial to and nearer to the median line of the neck than the 

 internal carotid artery at its beginning. The branches < f the external carotid 

 artey are, (1) superior thyroid. (2) lingual. (3) facial, which are anterior 

 branches; (4) occipital ,(5) posterior auricular, which are posterior branches; 

 -rending pharyngeal, which is an ascending branch; (7) superficial tem- 

 poral, (8) interna] maxillary, which are' terminal branches. 



LESSON LXXXI I. 



The superior thyroid branch (Plate CXVI.) arises just below the great 

 cornu of the hyoid bone, and passes inward and upward across the superior 

 carotid triangle from which place it passes downward and forward to the upper 

 part of the thyroid gland, after passing under the Sterno-hyoid, Sterno-thyroid 

 and Omo-hyoid muscles. Besides giving branches to these muscle's and the 

 thyroid gland, it gives off (1) a hyoid branch which passes along the' lower 

 border of the' hyoid bone'. (2) Sterno-mastoid branch, also called super- 

 ficial des< ending, which passes to the Sterno-mastoid muscle after running 

 downward and outward across the sheath of the' common carotid artery. (3) 

 Superior laryngeal, which passes with the superior laryngeal nerve to the 



