THE 8UBCLA VIAN ARTER Y 631 



the sympathetic cord, the middle cervical ganglion resting upon the vessel, and, 

 reaching the lower border of the lateral lobe of the thyroid gland, it divides into 

 two branches, which supply the postero-inferior parts of the gland, and anasto- 

 mose with the superior thyroid and with the corresponding artery of the opposite 

 side. The recurrent laryngeal nerve passes upward, generally behind, but occa- 

 sionally in front of, the artery. Its branches are : 



Inferior laryngeal. (Esophageal. 



Tracheal. Ascending cervical. 



Muscular. 



The inferior laryngeal branch (a. laryngea inferior") ascends upon the trachea 

 to the back part of the larynx, in company with the recurrent laryngeal nerve, 

 and supplies the muscles and mucous membrane of this part, anastomosing with 

 the inferior laryngeal branch from the opposite side and with the laryngeal branch 

 from the superior thyroid artery. 



The tracheal branches (rami tracheales) are distributed upon the trachea, anasto- 

 mosing below with the bronchial arteries. 



The cesophageal branches (rami oesophagety are distributed to the oesophagus, 

 and anastomose with the oesophageal branches of the aorta. 



The ascending cervical (a. cervicalis ascendens) is a small branch which arises 

 from the inferior thyroid just where that vessel is passing behind the common 

 carotid artery, and runs up on the anterior tubercles of the transverse processes 

 of the cervical vertebrae in the interval between the Scalenus anticus and Rectus 

 capitis anticus major muscles. It gives branches to the muscles of the neck, 

 which anastomose with branches of the vertebral, and sends one or two branches 

 into the vertebral canal through the intervertebral foramina to be distributed to 

 the spinal cord and its membranes, and to the bodies of the vertebrae in the same 

 manner as the lateral spinal branches from the vertebral. It anastomoses with 

 the ascending pharyngeal and occipital arteries. 



The muscular branches supply the Depressors of the hyoid bone, the Longus 

 colli, the Scalenus anticus, and the Inferior constrictor of the pharynx. One 

 of the muscular branches passes between the transverse processes of the fourth 

 and fifth cervical vertebrae and reaches the deep muscles of the neck. It is called 

 the ramus profundus. 



Applied Anatomy. Before extirpating a goitrous lobe of the thyroid the superior and 

 inferior thyroid arteries of the diseased side are to be ligated. An incision is made along the 

 anterior border of the Sternomastoid down to the clavicle. After the deep fascia has been 

 divided, the Sternomastoid and carotid vessels are drawn outward and the carotid tubercle (Cka-s- 

 saignac's tubercle) sought for. The vessel will be found just below this tubercle, between the 

 carofid sheath on the outer side of the trachea and oesophagus on the inner side. In passing 

 the ligature great care must be exercised to avoid including the recurrent laryngeal nerve, which 

 is occasionally found crossing in front of the vessel. 



The suprascapular artery (a. transversa scapulae) (Figs. 438 and 458) passes 

 at first downward and outward across the Scalenus anticus and phrenic nerve, 

 being covered by the Sternomastoid ; it then crosses the subclavian artery and the 

 cords of the brachial plexus, and runs outward, behind and parallel with the 

 clavicle and Subclavius muscle, and beneath the posterior belly of the Omohyoid, 

 to the superior border of the scapula, where it passes over the transverse ligament 

 of the scapula, which separates it from the suprascapular nerve, and reaches the 

 supraspinous fossa. In this situation it lies close to the bone, and ramifies be- 

 tween it and the Supraspinatus muscle, to which it supplies branches. It then 

 passes downward behind the neck of the scapula, to reach the infraspinous fossa, 

 where it anastomoses with the dorsalis scapulae branch of the subscapular artery 



