578 



DISSECTION OF THE NECK. 



Occipital 

 triangle 



contains 

 nerves and 

 lymphatics 



also spinal 



accessory 



nerve. 



Nerves of 

 the cervical 

 plexus 



that ascend, 

 viz. 



Small 

 occipital. 



Great 

 auricular 



supplies 

 facial, 



auricular, 



and mastoid 

 branches. 



Superficial 



cervical 



nerve. 



Nerves that 

 descend are 



usually three 

 branches. 



The occipital triangle is larger than the supraclavicular. Its 

 boundaries in front and behind are the sterno-mastoid and the 

 trapezius, and below the posterior belly of the omo-hyoid muscle. 



In it are contained chiefly the ramifications of the cervical 

 plexus ; and a chain of lymphatic glands lies along the sterno- 

 mastoid muscle. The spinal accessory nerve ( 10 ) is directed 

 obliquely across this interval from the sterno-mastoid muscle, 

 which it pierces, to the under surface of the trapezius ; and a 

 communication takes place between it and the spinal nerves in the 

 space. 



SUPERFICIAL BRANCHES OF THE CERVICAL PLEXUS. These 

 nerves emerge from beneath the sterno-mastoid muscle about the 

 middle of its hinder border, and are thence directed both upwards 

 and downwards. 



The ASCENDING SET (fig. 210) are three in number, viz., small 

 occipital, great auricular, and superficial cervical. 



The small occipital nerve (fig. 205, p. 562) comes from the 

 second, and in most cases also from the third cervical nerves, and 

 is directed upwards to the head along the posterior border of the 

 sterno-mastoid muscle. It perforates the fascia near the skull, and 

 is distributed between the ear and the great occipital nerve, as 

 already seen. Occasionally there is a second cutaneous nerve to 

 the back of the head. 



The great auricular nerve (fig. 205) is derived from the second 

 and third cervical nerves. Perforating the deep fascia at the pos- 

 terior border of the sterno-mastoid muscle, the nerve is directed 

 upwards between the platysma towards the lobule of the ear, and 

 ends in the following branches : 



The facial branches are sent forwards to the integuments over the 

 parotid, and a few slender filaments pass into the gland to join the 

 facial nerve. 



The auricular branches ascend to the external ear, and are chiefly 

 distributed on its cranial aspect, but one or more reach the lower 

 part of the outer surface. On the pinna they communicate with 

 branches furnished from the facial and pneumo-gastric nerves. 



The mastoid branch is directed backwards to the skin over the 

 mastoid process, where it joins the posterior auricular branch of the 

 facial nerve. 



The superficial cervical nerve (fig. 205, ) arises from the cervical 

 plexus in common with the preceding, and turns forward round 

 the sterno-mastoid muscle about the middle. Afterwards it pierces 

 the fascia, and ramifies over the anterior triangle. There may 

 be more than one branch to represent this nerve. 



The DESCENDING SET of branches (fig. 2 10) are derived from the 

 third and fourth nerves of the plexus, and are directed towards the 

 clavicle over the lower part of the triangular space. Their number 

 is somewhat uncertain, but usually there are about three near the 

 clavicle. 



The most internal branch (sternal] crosses the clavicle near its 

 inner end ; the middle branch (clavicular] lies about the middle of 



