142 HEAD AND NECK 



nose. Medially , the medial part of the cartilage is in the 

 form of a narrow strip which lies upon the lower part of the 

 septal cartilage, and projects slightly below it so as to support 

 the margin of the nostril upon this side. Its extremity is 

 turned slightly laterally. 



SIDE OF THE NECK. 



On the fourth day after the body is brought into the room 

 it is placed upon its back, and the dissectors of the head and 

 neck should examine the side of the neck and commence the 

 dissection of the posterior triangle. 



The side of the neck is bounded below by the clavicle, 

 above by the lower border of the mandible, the mastoid 

 portion of the temporal bone, and the superior nuchal line of 

 the occipital bone. Anteriorly it extends to the median plane, 

 and posteriorly to the anterior border of the trapezius muscle. 

 It is divided into anterior and posterior parts, the anterior 

 and posterior triangles^ by the sterno- mastoid muscle. If 

 the head is pulled over towards the opposite side, the sterno- 

 mastoid muscle will be seen descending from the mastoid 

 portion of the temporal bone and the superior nuchal line of 

 the occipital bone, to the upper border of the sternal third 

 of the clavicle and the anterior surface of the manubrium 

 sterni. 



In the lower part of the posterior region, posterior to the 

 sterno -mastoid and above the convex middle third of the 

 clavicle, there is a depression called the fossa supradavicularis 

 major, to distinguish it from the fossa supradavicularis minor 

 which lies above the sternal end of the clavicle between the 

 sternal and clavicular heads of the sterno-mastoid. The 

 brachial plexus, the third part of the subclavian artery, and 

 the supra -clavicular lymph glands lie in the region of the 

 fossa supra-clavicularis major, and the fossa supra-clavicularis 

 minor indicates the position of the internal jugular vein near 

 its lower end. 



POSTERIOR TRIANGLE. 



Dissection. To expose the boundaries and contents of the posterior 

 triangle make the following three incisions through the skin, (i) From 

 the back of the auricle along the upper border of the mastoid part of the 



