Arteria subclavia. 



203 



547. The Basilary Artery and its Branches at the 

 Base of the Brain. 



3. The thyroid axis, Truncus thyreo-cervicalis ; this trunk soon divides 

 into three branches: a) the inferior thyroid, which passes upwards, and after 

 a short course bends inwards and downwards, and is distributed to the under 

 surface of the thyroid gland; its branches are the inferior laryngeal to the 

 larynx, t r a c h e a 1 to the trachea, oesophageal to the oesophagus and ascen- 

 ding cervical; b) the superficial cervical, which, in the supraclavicular 

 fossa passes to the M. trapezius, MM. spleniis and rliomboideis ; c) the trans- 

 verse scapular, or supras capular, which passes behind the clavicle 

 through the scapular notch to the supra- and iufraspinous fossae, and supplies 

 the muscles in those regions (see Fig. 550). 



4. The superior intercostal, Art. inter co stalls suprema, for the first 

 and second intercostal space, which, with the deep cervical for the deep 

 cervical muscles, forms the Truncus costo-cervicalis. 



5. The transversalis colli artery, arises between or beyond the 

 scaleni. It pierces the brachial plexus, passes to the upper border of the scapula, 

 Avhere it gives off the Ramus -supraspinatus for the MM. trapezius, deltoides, 

 levator scapulae and to the acromion, and then courses along the inner border 

 of the scapula as Art. dor sails scapulae (see Fig. 550). 



Heitzmann, Atlas. II. 27 



