506 



DISSECTION OF THE HEAD. 



Great auri- 

 cular nerve. 



Great occipi 

 tal nerve : 



junctions. 



Small occi- 

 pital nerve 



has an 



auricular 



branch. 



How to see 



temporal 



fascia. 



Temporal 

 fascia : 



attach- 

 ments, 



relations, 



and layers. 



To see tem- 

 poral 

 muscle. 



Temporal 

 muscle : 



origin, 



The GREAT AURICULAR NERVE, from the anterior divisions of the 

 second and third cervical nerves in the cervical plexus (fig. 186), is 

 seen to some extent at the lower part of the ear, but its anatomy 

 will be afterwards given with the description 'of the cervical plexus. 



The GREAT OCCIPITAL (fig. 186) is the largest cutaneous nerve 

 at the back of the head, and lies close to the occipital artery. It 

 is the internal branch of the posterior primary branch of the 

 second cervical nerve ; it perforates the muscles of the back of the 

 neck, and divides on the occiput into numerous large offsets ; these 

 spread over the posterior part of the head, and terminate in the 

 integument. As soon as the nerve pierces the trapezius, it is joined 

 by an offset from the third cervical nerve ; and on the back of the 

 head it communicates with the small occipital nerve. 



The SMALL OCCIPITAL NERVE, from the anterior divisions of the 

 second and third cervical nerves in the cervical plexus (fig. 186), 

 lies midway between the ear and the preceding nerve, and is con- 

 tinued upwards in the integuments higher than the level of the 

 ear. It communicates with the nerve on each side, viz., the 

 posterior auricular and the great occipital. Usually this nerve 

 furnishes an auricular branch to the upper part of the pinna on its 

 cranial aspect. 



Dissection. The upper auricular muscles and the temporal 

 vessels, together with the epicranial aponeurosis and its lateral 

 prolongation, will now be removed in order that the attachment 

 of the temporal fascia on the side of the head may be seen. 



The temporal fascia is a white, shining membrane, which is 

 stronger than the epicranial aponeurosis, and gives attachment to 

 the subjacent temporal muscle. Superiorly it is inserted into the 

 curved line that limits the temporal fossa on the side of the skull ; 

 and inferiorly, where it is narrower and thicker, it is fixed to the 

 zygomatic arch. By its cutaneous surface the fascia is in contact 

 with the muscles already examined, and with the superficial 

 temporal vessels and nerves. 



An incision in the fascia, a little above the zygoma, will show it 

 to consist there of two layers, which are fixed to the edges of the 

 upper border of the zygomatic arch. Between the layers is some 

 fatty tissue, with a small branch of the superficial temporal artery, 

 and a slender twig of the orbital branch of the superior maxillary 

 nerve with an accompanying artery. 



Dissection. The temporal fascia is now to be detached from the 

 skull, and to be thrown down to the zygomatic arch, in order that 

 the origin of the underlying temporal muscle may be examined. 

 The soft areolar tissue which lies beneath it near the zygoma is to be 

 taken away. The difference in thickness of the parts of the fascia 

 will be evident. 



The TEMPORAL MUSCLE is laid bare only in part. Wide and 

 thin above, it becomes narrower and thicker below. It arises 

 from the temporal fascia, and from the surface of the impres- 

 sion on the side of the skull, which is named the temporal fossa. 

 From this origin the fibres descend and converge to a tendon, 



