

THE SUBCLAVIAN ARTERY 581 



Ganglionic. The postero-medial ganglionic branches (Fig. 519) are a group of 

 smaH arteries which arise at the commencement of the posterior cerebral artery; 

 these, with similar branches from the posterior communicating, pierce the pos- 

 terior perforated substance, and supply the medial surfaces of the thalami and the 

 walls of the third ventricle. The posterior choroidal branches run forward beneath 

 the splenium of the corpus callosum, and supply the tela chorioidea of the third 

 ventricle and the choroid plexus. The postero-lateral ganglionic branches are small 

 arteries which arise from the posterior cerebral artery after it has turned around the 

 cerebral peduncle; they supply a considerable portion of the thalamus. 



Cortical. The cortical branches are: the anterior temporal, distributed to the 

 uncus and the anterior part of the fusiform gyms; the posterior temporal, to the 

 fusiform and the inferior temporal gyri; the calcarine, to the cuneus and gyrus 

 lingualis and the back part of the convex surface of the occipital lobe; and the 

 parietobccipital, to the cuneus and the precuneus. 



2. The thyrocervical trunk (truncus thyreocermcalis ; thyroid axis} (Fig. 520) is 

 a short thick trunk, which arises from the front of the first portion of the subclavian 

 artery, close to the medial border of the Scalenus anterior, and divides almost 

 immediately into three branches, the inferior thyroid, transverse scapular, and trans- 

 verse cervical. 



The Inferior Thyroid Artery (a. thyreoidea inferior} passes upward, in front of the 

 vertebral artery and Longus colli; then turns medialward behind the carotid sheath 

 and its contents, and also behind the sympathetic trunk, the middle cervical 

 ganglion resting upon the vessel. Reaching the lower border of the thyroid gland 

 it divides into two branches, which supply the postero-inferior parts of the gland, 

 and anastomose with the superior thyroid, and with the corresponding artery of 

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

 sionally in front, of the artery. 



The branches of the inferior thyroid are : 



Inferior Laryngeal.. Esophageal. 



Tracheal. Ascending Cervical. 



Muscular. 



The inferior laryngeal artery (a. laryngea inferior} ascends upon the trachea to 

 the back part of the larynx under cover of the Constrictor pharyngis inferior, in 

 company with the recurrent nerve, and supplies the muscles and mucous mem- 

 brane of this part, anastomosing with the branch from the opposite side, and with 

 the superior laryngeal branch of the superior thyroid artery. 



The tracheal branches (rami tracheales} are distributed upon the trachea, and 

 anastomose belo\v with the bronchial arteries. 



The esophageal branches (rami cesophagei] supply the esophagus, and anasto- 

 mose with the esophageal branches of the aorta. 



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

 arises from the inferior thyroid as that vessel is passing behind the carotid sheath; 

 it runs up on the anterior tubercles of the transverse processes of the cervical 

 vertebrae in the interval between the Scalenus anterior and Longus capitis. To 

 the muscles of the neck it gives twigs which anastomose with branches of the ver- 

 tebral, and it sends one or two spinal branches into the vertebral canal through 

 the intervertebral foramina to be distributed to the medulla spinalis and its mem- 

 branes, and to the bodies of the vertebrae, in the same manner as the spinal branches 

 from the vertebral. It anastomoses with the ascending pharyngeal and occipital 

 arteries. 



The muscular branches supply the depressors of the hyoid bone, and the Longus 

 colli, Scalenus anterior, and Constrictor pharyngis inferior. 





