THE MUSCLES 53 



converge to a long band-like tendon which is attached to the dorsal 

 margin of the pre-articular, immediately anterior to the articulation 

 of the jaw. It is largely covered by the superficial portion, the fibres 

 of which tend to mingle with it near its insertion. 



Innervation: Both portions of the muscle are innervated by a 

 special branch of the trigeminus nerve which leaves it either just 

 before, or just after it emerges from the antrum petrosum laterale. 



Function: Both portions assist in closing the mouth. 



M. levator mandibulae posterior (Edgeworth). 



Cranio-mandibularis (partim) .... Lubosch (19 14). 



Adductor mandibulae posterior .... Luther (19 14). 



A somewhat triangular-shaped muscle arising from the free anterior 

 edge of the squamosal^ the anterior face of the quadrate^ and the 

 ■pterygoid. It is traversed by the mandibular nerve (V3) so that, while 

 some of its fibres lie mesial, the greater portion of the muscle lies 

 posterior to that nerve. A portion of the muscle has a fleshy inser- 

 tion on the articular portion of Meckel's cartilage, while a tendon 

 passes forwards from the anterior fibres to a point immediately in 

 front of the tendon of the M. levator mandibulae anterior (superficial 

 portion), some of the mesial fibres being actually inserted on the 

 tendon of this muscle. The general direction of the fibres is, there- 

 fore, antero-ventral, the most anterior fibres being of moderate 

 length and the most posterior extremely short. 



Innervation: By fine twigs from the mandibular nerve. 



Function: To assist in closing the jaws. 



M. levator mandibulae externus (Edgeworth). 



Masseter Funk (1827); v. Siebold (1828); Fischer (1843); Rusconi 



(1854); Schmidt, Goddard and van d. Hoeven (1864); 

 Owen (1866); Mivart (1869); v. Plessen & Rabinowicz 

 (1891); Druner (1901); Coghill (1901-6); Osawa (1902). 



Temporal, portion posterieur courte . . . Cuvier (1835). 



Pre-temporo-maxillaire ...... Duges (1834). 



Petro-tympano-maxillaris .... Hoffmann (1873-8). 



Mandibularis externus . ..... Lubosch (19 14). 



Adductor mandibulae externus .... Luther (1914). 



This muscle lies anterior to the one just described and entirely 

 lateral to the mandibular nerve, the direction of its fibres being 

 parallel with those of the M. lev. mand. post. It takes its origin 

 from the antero-lateral edge of the squamosal and from the anterior 

 wall of the ear capsule, and is inserted on the posterior end of 

 the dentary and the lateral face of the coronoid process of the 



