156 HEAD AND NECK 



the zygomatico-temporal branch of the maxillary nerve. Next pull the 

 auricle anteriorly and trace the posterior auricular nerve to its termination 

 in the occipitalis muscle, and in the intrinsic and extrinsic muscles 

 of the auricle, and the posterior auricular artery to its anastomoses with 

 the occipital and superficial temporal arteries. After this part of the 

 dissection is completed, turn to the anterior part of the scalp and find 

 the medial and lateral branches of the supra-orbital nerve. The medial 

 branch pierces the fibres of the frontalis and the lateral branch pierces 

 the galea aponeurotica a little further posteriorly. Trace both branches 

 backwards through the superficial fascia as far as possible ; they extend to 

 the level of the lambdoid suture. Then secure the supra-trochlear nerve, 

 which pierces the frontalis above the medial margin of the orbit, and trace 

 it upwards to its termination. With the branches of the supra-orbital nerve 

 are branches of the supra-orbital artery, and the supra-trochlear nerve is 

 accompanied by the frontal branch of the ophthalmic artery. 



When the nerves and vessels in the anterior region have been cleaned, 

 the head should be turned well over to the opposite side, and the branches 

 of the occipital artery and the great occipital nerve should be sought for in 

 the posterior region ; they radiate upwards and anteriorly from the upper 

 extremity of the trapezius. After they have been secured, the occipitalis 

 muscle must be cleaned. It springs from the lateral part of the superior 

 nuchal line, and after a short course upwards and anteriorly it terminates in 

 the galea aponeurotica. The remains of the superficial fascia should now 

 be removed from the surface of the galea aponeurotica (O.T. epicranial 

 aponeurosis), and then the dissector should make a survey of the vessels 

 and nerves which are met with in the scalp and the superficial fascia of the 

 temporal region. \f 



Nerves and Vessels of the Scalp and the Superficial 

 Temporal Eegion. Branches of ten nerves are found, on each 

 side, in the superficial fascia of the region which lies above 

 the supra-orbital margin, the zygomatic arch and the superior 

 nuchal line. Of these, five lie mainly anterior to the auricle 

 and five posterior to it ; and of each group four are sensory 

 and one is motor. The four sensory nerves anterior to the 

 auricle are all branches of the trigeminal nerve. They are 

 the supra-trochlear and supra-orbital branches of the first or 

 ophthalmic division ; the zygomatico-temporal branch of the 

 maxillary or second division and the auriculo- temporal branch 

 of the mandibular or third division. The motor nerve is the 

 temporal branch of the facial nerve. 



The four sensory nerves, distributed mainly to the scalp 

 area behind the auricle, are the great auricular and the small 

 occipital branches of the cervical plexus ; the great occipital, 

 which is the medial division of the posterior branch of the 

 second cervical nerve ; and the smallest occipital^ not yet seen, 

 but which will be displayed when the body is turned on its 

 face. It lies medial to the great occipital, and is the medial 

 division of the posterior branch of the third cervical nerve. 



