THE HEAD AND NECK 



XX05 



from each other and leave between them a triangular interval, 

 called the submental triangle. The base of this triangle is formed 

 by the body of the hyoid bone, and each lateral boundary is con- 

 structed by the anterior belly of the digastric, the apex being 

 placed at the chin. The area of the triangle is occupied by the 

 anterior portions of the mylo-hyoid muscles, which meet at the 

 median line in a tendinous raphe, and superficial to these muscles 

 there are the suprahyoid or submental glands. Immediately 

 underneath the mesial portions of the mylo-hyoid muscles are the 

 genio-hyoid muscles, these two latter muscles being in very close 

 contact at the median line. Beneath each genio-hyoid muscle is 

 the inferior portion of the genio-hyo-glossus. 



Posterior Belly of Digastric 

 and Stylo-hyoid 

 Hyo-glossus Aluscle and 

 Hypoglossal Nerve 



Ster. Head of St.-cleido-mas 



Crico-thyroid Muscle -. 



Cricoid Cartilage 



Lat. Lobe of Thyroid Body 



Trapezius — 



CHavicular Head of-_^> 

 Sterno-cleido-mas. //// 

 Brachial Plexus -_'/.' 

 Subclavian Artery - 

 (third part) 



Clavicle 



In 



. - Anterior Belly of Digastric 

 ■ Mylo-hyoid 



-Body of Hyoid Bone 



.interior Belly of Omo-hyoi( 

 Stemo-hyoid 



Ji'^-.'i '- -iLilX-^?- -Isthmus of Thyroid Cartilai 

 ^ ' • ^mi-nn- -Stemo-thyroid 



-^SSJrJi'i --Anterior Belly of Omo-hyoi 



-rr y SSltlM^n Cricc-thyroid Membrane 



■' ■ ^^'"iSSn- Stemo-hyoid 



Isthmus of Thyroid 

 Body 



Inferior TTiyroid Flex 



of Veins 

 Cla. HeadofSt.-cI.-m; 

 Stemo-thyroid 



Sternal Head of Sterno- 

 deido-mastoid 



Stemo-thyroid 



Fig. 449. 



Sterno-hyoid 



-Dissection of the Front of the Neck. 



(The area bounded on either side bv the Anterior Belly of the Digastric and 

 below by the body of the Hyoid Bone is the Submental Triangle.) 



The relation of structures in the suprahyoid region, from the 

 surface downwards (in a deep direction), is as follows: 



1. Platysma myoides. 3. Genio-hyoid. 



2. Mylo-hyoid. 4. Genio-hyo-glossus. 

 Submental, or Suprahyoid, Lymphatic Glands. — These glands, 



usually two in number. He in the submental triangle, beneath the 



70 



