246 



HEAD AND NECK 



border of the clavicle ; the omo-hyoid, the sterno-hyoid, and 

 the sterno - thyreoid muscles. Deep to the muscles, the 

 branches of the ansa hypoglossi descend in front of its 

 sheath ; and the middle thyreoid vein crosses it to join the 

 internal jugular vein. 



Posterior to it lie the transverse processes of the cervical 

 vertebrae and the origins of the longus colli, longus capitis 

 (O.T. rectus capitis anticus major), and the scalenus anterior. 

 The inferior thyreoid artery crosses posterior to it at the level 

 of the cricoid cartilage ; and the vertebral artery lies between 

 it and the transverse process of the seventh cervical vertebra. 

 On the right side, the recurrent branch of the vagus crosses 



Thyreo-hyoid membrane 



Plica vocalis 

 Processus vocalis 

 Arytaenoid carti 

 Platysma 

 Posterior w 

 of phary 

 Retropharyn- 

 geal space 



Carotid sheath 



Sterno-hyoid 



Thyreo-hyoid 



Thyreoid cartilage 

 Omo-hyoid 



" ecessus piriformis 

 Superior thyreoid 

 Descendens 

 hypoglossi 

 Common carotid 

 Internal jugular 



i Vagus 



Scalenus anterior ' Sympathetic trunk 



Longus colli Vertebral artery 



FIG. 100. Transverse section through the Neck at the level of upper 

 part of Thyreoid Cartilage. 



posterior to it, immediately above its origin ; and on the left 

 side the thoracic duct turns laterally behind it, between it 

 and the vertebral artery. 



To its medial side, below, lie the trachea and oesophagus, 

 with the recurrent nerve in the angle between their adjacent 

 borders ; and to the medial side of its upper part are the 

 larynx and pharynx. The lateral lobe of the thyreoid gland 

 lies either medial to the artery, separating it from the 

 cesophagus, pharynx, trachea, and larynx, or it forms a direct 

 anterior relation (Figs. 97, 101). Between its upper extremity 

 and the inferior constrictor muscle of the pharynx lies the 

 carotid body. As a rule, the terminal divisions are the only 

 branches of the common carotid, but occasionally the 

 superior thyreoid or the ascending pharyngeal artery arises 



