ARTERIES 61 



RELATIONS OF 3RD PART OF SUBCLAVIAN. 



Contained in subclavian triangle, and enclosed in tube 01 

 deep cervical fascia. 



lit Front. Below. 



Skin. Supra-scapular artery. ist rib. 



Superficial fascia. Clavicle. 



Descending cutaneous Subclavius. tientnd. 



branches of cervical Nerve to subclavius. Scalenus medius. 



plexus. Lowest bracliial 



Platysma. Above. aerve trunk. 



Deep fascia. Brachial plexus. 



External jugular - 

 Subclavian 

 Branch from cephalic 



to external jugular 

 Supra-scapular 

 Transverse cervical 

 Anterior jugular 



BRANCHES FROM THE IST PART. 



VERTEBRAL : from upper and back part. Passes upwards 

 and backwards, behind inferior thyroid artery and internal 

 jugular and vertebral veins, then between scalenus anticus 

 and longus colli, to enter foramen in transverse process of 6th 

 cervical vertebra. Ascends in corresponding foramina as far 

 as axis, having vertebral vein in front, and cervical nerves 

 behind. It then passes outwards and upwards, through 

 foramen in atlas, and winds backwards and inwards in verte- 

 bral groove of atlas, lying on the floor of the suboccipital 

 triangle, having the trunk of the ist cervical nerve beneath it, 

 and the posterior branch of same nerve crossing it behind. 

 It pierces posterior occipito-atloid ligament and dura mater, 

 and enters skull through foramen magnum. It then winds 

 round bulb, passing between hypoglossal and anterior root 

 of ist cervical nerve to front of medulla, uniting with fellow, 

 to form the basilar artery (p. 73), at the lower border of the 

 pons. 



Cervical Branches : 



Lateral spinal : each enters spinal canal through an inter- 

 vertebral foramen, dividing into posterior to supply cord and 

 membranes, and anterior to supply bodies of vertebrae. 



Muscular : to deep cervical muscles. 



Cranial Branches : 



Posterior meningeal : arises before vertebral pierces dura 

 mater opposite foramen magnum, to falx cerebelli. and dura 

 in posterior fossa 



