72 



DISSECTION OF THE NECK. 



tached to the mastoid process one sterno-mastoideus will incline the head 

 towards the shoulder of the same side. 



VIEW OF THE ANTERIOR TRIANGULAR SPACE OF THE NECK (Quain's "Arteries"). 



1. Sterno-mastoideus. 7 Internal jugular vein. 



2. Sterno-hyoideus. 8. External jugular vein. In the Drawing 



3. Anterior belly of the omo-hyoideus. from which this cut is copied the sterno-mas- 



4. Thyro-hyoideus. toid is partly cut through. 

 6. Common carotid artery dividing. 



In laborious respiration the two muscles will assist in elevating the ster- 

 num. 



The OMO-HYOID MUSCLE crosses beneath the sterno-mastoideus, and 

 consists of two fleshy bellies united by a small round intermediate tendon 

 (tig. 14, 3 ). The origin of the muscle from the scapula, and the connec- 

 tions of the posterior part, are to be studied in the dissection of the Back. 

 From the intervening tendon the anterior fleshy belly (fig. 15, 3 ) is directed 

 upwards along the outer border of the sterno-hyoid muscle, and is inserted 

 into the lower part of the body of the hyoid bone, close to the great cornu. 



The anterior belly is in contact with the fascia, after escaping from be- 

 neath the sterno-mastoid ; and rests on the sterno-thyroideus. This part 

 of the muscle crosses the common carotid artery and internal jugular vein 

 on a level with the cvicoid cartilage. 



Action. The anterior belly depresses the hyoid bone ; and the posterior 



