8 Muscles of Head and Neck 



are the buccinator and the lower jaw. The parotid gland is 

 hind it. 



The temporal fascia binds down, and gives origin to, the temporal 

 muscle. It is attached above to the temporal ridge, and below, in 

 two layers, to the zygomatic arch ; between these layers, and running 

 in a little fat, are the orbital branch of the temporal artery (p. 31) and 

 a twig of the temporo-malar nerve. 



Upon the fascia are fibres of the orbicularis palpebrarum ; the 

 aponeurosis of the occipito-frontalis; the attollens and attrahens aurem ; 

 and the superficial temporal vessels and nerves. 



The temporal muscle arises from the temporal fossa and also 

 from the temporal fascia, and, passing beneath the zygomatic arch, is 

 inserted into the coronoid process down to the last molar tooth. Its 

 action is to raise the jaw and draw it backwards. Its nerve supply is 

 from the third division of the fifth. 



Relations. It is covered by the temporal fascia and the structures 

 lying thereon. Behind it are the masseteric vessels and nerves passing 

 through the sigmoid notch, and beneath is the floor of the temporal 

 fossa, with the deep temporal vessels and nerves. 



The external pteryg-oid, pyramidal, arises from the outer side of 

 the external pterygoid plate and the great wing of the sphenoid, and, 

 running outwards and backwards, is inserted into the condyle of the 

 jaw and into the inter-articular fibre-cartilage. When the jaw is dislo- 

 cated the cartilage follows the condyle. 



Action. To advance and depress the jaw, and to carry it towards 

 the opposite side. 



Relations. Below it are the internal pterygoid, the inferior dental 

 vessels and nerve, and the gustatory nerve. The internal maxillary 

 artery winds round the muscle to enter the pterygo-maxillary fossa 

 between its heads. 



T*he internal pterygoid arises from the inner surface of the external 

 pterygoid plate, and passes downwards, outwards, and backwards to 

 its insertion on the inner side of the angle of the jaw. Thus its action 

 is to raise the jaw, to thrust it towards the opposite side, and to 

 bring it forwards. Both pterygoid muscles are supplied by the thii 

 division of the fifth nerve. 



Relations. With the ramus of the jaw and the external pterygoi< 

 it roughly forms a triangular space through which pass the interne 

 maxillary vessels, the inferior dental vessels and nerve, and the gustatory 

 nerve. 



Tetanus (re'rai/or, rfiW, strain}, a continuous spasm of the muscles 

 of the body, often begins in the maxillary region, so that the patient 

 cannot separate the teeth or swallow without great effort or choking. 

 This local tetanus is Mock-jaw 'or trismits (rpio>, creak, gnash A 

 teeth}. 



IV* 



; 



: 



Md 





