160 DISSECTION OF THE DOG 



attached to the margins of the temporal fossa, and particularly thick 

 at its attachment to the zygomatic arch. Make an incision along the 

 border of the arch, and turn the fascia upwards. In doing this, some 

 fibres of the muscle which arise from the deep face -of the fascia will 

 have to be divided. The fascia should be removed completely. The 

 superficial temporal vessels will be exposed in the process. 

 With bone forceps snip through the zygomatic arch close to the mandibular 

 articulation, and at its other end as close as possible to the orbit. The 

 piece of bone, with the remains of the masseter muscle attached thereto, 

 must be removed. 



M. TEMPOEALis. — The powerful temporal muscle, mixed with much ten- 

 dinous tissue, arises from the whole of the temporal fossa, which it fills 

 completely. In addition to the bony origin, some fibres spring from the orbital 

 band and the temporal fascia. 



The insertion of the muscle into the coronoid process of the mandible is 

 rendered somewhat indefinite by confusion with the masseter. 



A. TEMPOEALIS STJPEEFiciALis. — The superficial temporal artery is one of 

 the two terminal branches of the external carotid. Crossing the aboral end 

 of the zygomatic process of the temporal bone, it pierces the temporal fascia 

 and runs towards the frontal bone approximately parallel to the zygomatic 

 arch and in close relationship with the temporal muscle. Terminal twgs 

 supply the frontal region and both eyelids. 



The collateral branches of the artery are as follows : (1) Transverse 

 facial artery (a. transversa faciei), a small vessel "already encountered on the 

 surface of the masseter muscle ; (2) anterior auricular artery (a. auricularis 

 anterior), leaving the parent vessel as this crosses the zygomatic arch, and 

 terminating in the muscles and skin over the medial and oral parts of the 

 external ear ; (3) in addition, there are small branches which end in the parotid 

 gland, the masseter and other muscles, and the skin. 



V. TEMPORALIS stTPEEFiciALis . — The superficial temporal vein is arranged 

 in conformity with the artery. 



Dissection. — The following dissection must be performed on one side of 

 the head only. With a saw or bone-forceps separate the coronoid 

 process from the rest of the mandible, and then cut through the bone on 

 a level Avith the first premolar tooth. Liberate the insertion of the 

 digastric muscle from the bone, and carefully pass the knife through 

 the muscles, etc., attached to the medial surface of the mandible, keeping 

 the edge of the knife as close to the bone as possible. Disarticulate 

 the mandibular joint, bearing in mind the close relationship which exists 

 between the joint and the internal maxillary artery. Remove the 

 piece of mandible which the foregoing operations have isolated. 



This dissection involves the partial destruction of the pterygoid muscles and 



