376 HUMAN ANATOMY. 



The pneumogastric, superior laryngeal, external laryngeal, 

 descendens noni, spinal accessory, hypoglossal, and sympathetic 

 nerves. 



The submaxillary triangle is the most superior of the sub- 

 divisions of the anterior triangle, and has the following bound- 

 aries : 



Above, the lower border of the body of the jaw, and the 

 imaginary line behind ; 



In front, the median line of the neck ; 



Behind, the posterior belly of the digastricus. 



It contains the following structures : 



External carotid, internal carotid, facial, submental, mylo- 

 hyoidean arteries; 



The internal jugular, the commencement of the external 

 jugular, branches of the anterior jugular, and the facial vein and 

 its branches; 



The inframaxillary branches of the facial nerve, the ascend- 

 ing- branches of the superficial cervical nerve, and the pneumo- 

 gastric and glosso-pharyngeal and mylo-hyoid nerves; 



Portions of the parotid and submaxillary glands, and also 

 submaxillary lymphatic glands and vessels. 



The posterior triangle of the neck occupies the space behind 

 the posterior border of the sterno-mastoideus, and is bounded 

 as follows : 



Front, posterior border of the sterno-mastoideus; 



Behind, anterior border of the trape/ius; 



Below, upper border of the middle third of the clavicle, 

 forming its base; 



Above, the occiput, forming the apex. 



Its floor is formed from above downward, by the following 

 muscles : 



Splenius capitis, levator anguli scapuli, scalenius medius, 

 scalenius posticus, and the upper portion of the serratus magnus. 



Its roof is formed by the superficial and deep fascia, and 

 below by the platysma myoides. 



It contains the following structures : 



The transversalis colli artery and vein; 



Spinal accessory and superficial plexus of the cervical nerve; 



Lymphatic glands and vessels. 



The subclavian triangle, or the inferior division of the poste- 

 rior triangle, is bounded 



In front by the margin of the sterno-mastoideus, behind by 

 the posterior belly of the omo-hyoideus, below by the clavicle. 



It contains the following structures : 



The subclavian, transversalis colli, and transversalis humeri 

 or suprascapular arteries; 



