250 



MUSCLES AND FASCIAE. 



fibres pass downwards and backwards, to be inserted into the angle and lower 

 half of the ramus of the jaw. The deep portion is much smaller, and more mus- 

 cular in texture, and arises from the posterior third of the lower border and whole 

 of the inner surface of the zygomatic arch ; its fibres pass downwards and for- 

 wards to be inserted into the upper half of the ramus and outer surface of the 

 coronoid process of the jaw. The deep portion of the muscle is partly concealed, 

 in front, by the superficial portion ; behind, it is covered by the parotid gland. 

 The fibres of the two portions are united at their insertion. 



Relations. By its superficial surface, with the integument; above, with the 

 Orbicularis palpebrarum and Zygomatici ; and has passing across it, transversely, 

 Stenon's duct, the branches of the facial nerve, and the transverse facial vessels. 

 By its deep surface, with the ramus of the jaw, and the Buccinator, from which it 

 is separated by a mass of fat. Its posterior margin is overlapped by the parotid 

 gland. Its anterior margin projects over the Buccinator muscle. 



The temporal fascia is seen, at this stage of the dissection, covering in the Tem- 

 poral muscle. It is a strong aponeurotic investment, affording attachment, by its- 

 inner surface, to the superficial fibres of this muscle. Above, it is a single layer, 

 attached to the entire extent of the temporal ridge ; but below, where it is attached 

 to the zygoma, it consists of two layers, one of which is inserted into the outer, 

 and the other into the inner border of the zygomatic arch. A small quantity of 

 fat, the orbital branch of the temporal artery, and a filament from the orbital 

 branch of the superior maxillary nerve, are contained between these two layers. 

 It is covered, on its outer surface, by the aponeurosis of the Occipito-frontalis, the 

 Orbicularis palpebrarum, and Attollens aurem and Attrahens aurem muscles; 

 the temporal vessels and nerves cross it from below upwards. 



Fig. 151. The Temporal Muscle, the Zygoma and Masseter having been removed. 



Dissection. In order to expose the Temporal muscle, this fascia should be removed ; this may 

 be effected by separating it at its attachment along the upper border of the zygoma, and dissect- 

 ing it upwards from the surface of the muscle. The zygomatic arch should then be divided, in 

 front, at its junction with the malar bone, and, behind, near the external auditory meatus. and 

 drawn downwards with the Masseter, which should be detached from its insertion into the ramus 

 ;iud angle of the jaw. The whole extent of the Temporal muscle is then exposed. 



