52 TOPOGRAPHICAL ANATOMY OF THE 



penniform, consisting of fibres that arise from the mandible and maxilla, 

 close to their alveolar border, and join a longitudinal tendinous raphe. 

 Anteriorly the buccal part blends with the orbicular muscle of the lips. 

 (2) The molar part (pars molaris) of the buccinator is partly covered by 

 the buccal part. Its fibres are mainly longitudinal and arise from the 

 coronoid process of the mandible and the alveolar border of the maxilla 

 and mandible on a level with the last cheek-tooth. At the angle of the 

 mouth they blend with the orbicular muscle. 



Dissection. — A portion of the zygomatic arch must now be removed. 

 Saw through it at two points; (1) as close to the mandibular joint as 

 possible ; and (2) as close to the orbit as can be effected without injury to 

 the orbital rim. If now the zygomatic process of the frontal bone be 

 sawn through at its base, a piece of bone is isolated and may be removed. 

 During the removal of the bone, it will be observed that the temporal 

 muscle is covered by a strong slieet of fascia that is thickest where it is 

 attached to the margin of the zygomatic arch. Run the knife along the 

 edge of the arch so as to free the fascia from its attachment. Then 

 remove the fascia completely from the surface of the temporal muscle. 



M. TEMPORALIS. — The strong temporal ^ muscle occupies the whole 

 of the fossa of that name. Its origin is from the frontal crest, external 

 sagittal crest, and the superior nuchal line, and from the parietal, 

 occipital, temporal and sphenoid bones. In addition, some fibres arise 

 from the deep face of the temporal fascia, and have been cut during its 

 removal. 



The converging fibres of the muscle are inserted principally into 

 the coronoid process of the mandible, but some blend with the adjacent 

 part of the masseter and are thus attached to that portion of the 

 mandibular ramus from which the coronoid process springs. 



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

 of the liead only : — With the saw separate the coronoid process from the 

 rest of the mandible and then cut through the bone immediately behind 

 the mental foramen. Liberate the digastric, jugulo-mandibular, and 

 buccinator muscles from the bone, and then carefully pass the knife through 

 the muscles, &c., 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 that exists 

 between the joint and important vessels and nerves. Remove the piece 

 of mandible that the foregoing operations have isolated. 



This dissection involves the partial destruction of the pterygoid 

 muscles and the inferior alveolar vessels and nerve; but the dissector 

 will have an opportunity later of examining these on the other side of 

 the head. 



Note the presence of the mylo-hyoid nerve — a branch of the 



^ Temjyoralis [L.], pertaining to the temple {teinpuSy time, temple), where Time 

 first shows his ravages. 



