48 PRACTICAL ANATOMY. 



4. The deep fascia determines the course taken by pus and missiles, hence a 

 thorough knowledge of the architecture of the deep fascial envelopes of the 

 neck is just as important as any fascial area in the body. 



Figure 24 represents schematically a transverse section of the neck. From 

 this it will be seen there are two spaces: (i) Those formed by delamina- 

 tion of the four layers, including certain structures and their nerve -supply and 

 blood-supply. (2) The interfascial spaces containing fat and connective tissue. 

 It will be seen that the first layer delaminates to unsheath the sterno-mastoid 

 muscle. The second layer delaminates to enclose the omo-hyoid, sterno-hyoid, 

 sterno-thyroid, and thyro-hyoid muscles, with their nerve-supply and blood- 

 supply. The third layer delaminates to enclose the larynx and trachea and 

 thyroid, the pharynx and oesophagus, the carotid sheath and its contents. The 

 fourth layer delaminates to ensheath the rectus capitis anticus major and minor 

 and longus colli muscles. 



First layer 



Second layer 



Third layer 



Fourth layer 



First layer 



Second layer 



Fourth layer 



FIG. 24. DEEP CERVICAL FASCIA TRANSVKKSK SECTION. (Schematic.) 



Dissection : 



1. The temporal muscle and its aponeurosis or fascia. 



2. The masseter muscle and its aponeurosis or fascia. 



3. The sterno-cleido-mastoid and its fascial covering. 



4. The trapezius muscle and its aponeurosis. 



5. The zygoma, and its relations. 



6. The temporal fossa and its contents. 



7. The temporal ridge, its formation of three parts. 



Examine your work and answer this quiz : 



1. Name the deep fascia covering the temporal muscle and give all its attach- 

 ments. 



It is called the temporal fascia. It is attached to the linea suprema of the 

 complete temporal ridge, and to the superior border of the zygomatic arch. 



2. What does the complete temporal ridge consist of? 



It consists of two parallel' lines, having a frontal, a parietal, and a temporal 

 portion. The aponeurosis of the muscle arises from the upper, the muscle itself 

 from the lower line. 



3. What structures occupy the superficial fascia, covering the temporal muscle .' 

 The superficial temporal arteries and their veins ; the aitrieulo-temporal nerve, a 



branch of the fifth cranial ; some temporal branches of the seventh or facial nerve, 

 and the lesser occipital nerve. 



