POSTERIOR SCAPULAR ARTERY. 319 



ately after its origin into four branches, some of which are occasionally 

 branches of the subclavian artery itself. 



The INFERIOR THYROID ARTERY ascends obliquely in a serpentine 

 course behind the sheath of the carotid vessels, to the inferior part of 

 thyroid gland, to which it is distributed ; it sends branches also to the 

 trachea, lower part of the larynx, and oesophagus. It is in relation 

 with the middle cervical ganglion of the sympathetic, which lies 

 in front of it. 



The SUPRA-SCAPULAR ARTERY (transversalis humeri) passes ob- 

 liquely outwards behind the clavicle, and over the ligament of the 

 supra- scapular notch, to the supra-spinatus fossa. It crosses in its 

 course the scalenus anticus muscle, phrenic nerve, and subclavian 

 artery, is distributed to the muscles on the dorsum of the scapula, and 

 inosculates with the posterior scapular, and beneath the acromion pro- 

 cess with the dorsal branch of the subscapular artery. At the supra- 

 scapular notch it sends a large branch to the trapezius muscle. The 

 supra-scapular artery is not unfrequently a branch of the subclavian. 



The POSTERIOR SCAPULAR ARTERY (transversalis colli) passes 

 transversely across the subclavian triangle at the root of the neck, to 

 the superior angle of the scapula. It then descends along the posterior 

 border of that bone to its inferior angle, where it inosculates with the 

 subscapular artery, a branch of the axillary. In its course across the 

 neck it passes in front of the scalenus anticus, and across the brachial 

 plexus ; in the rest of its course it is covered in by the trapezius, levator 

 anguli scapulae, rhomboidous minor, and rhomboideus major muscles. 

 Sometimes it passes behind the scalenus anticus, and between the 

 nerves, which constitute the brachial plexus. This artery, which is 

 very irregular in its origin, proceeds more frequently from the third 

 portion of the subclavian artery than from the first. 



The posterior scapular gives branches to the neck, and opposite the 

 angle of the scapula inosculates with the profunda cervicis. It sup- 



Elies the muscles along the posterior border of the scapula, and estab- 

 shes an important anastomotic communication between the branches 

 of the external carotid, subclavian, and axillary arteries. 



The SUPERFICIALIS CERVICIS ARTERY (cervicalis anterior) is a 

 small vessel, which ascends upon the anterior tubercles of the trans- 

 verse processes of the cervical vertebrae, lying in the groove between 

 the scalenus anticus and rectus anticus major. It is distributed to the 

 deep muscles and glands of the neck, and sends branches through the 

 intervertebral foramina to supply the spinal cord and its membranes. 



The PROFUNDA CERVICIS (cervicalis posterior) passes backwards 

 between the transverse processes of the seventh cervical and first dor- 

 sal vertebra, and then ascends the back part of the neck, between the 



