THE MUSCLES OF THE HEAD. 19 



then be easily dissected up,above, to its origin; below, to its 

 insertion. 



The relations of this group, the openers and closers 

 of the jaw, to the surrounding structures, as the ear, 

 the dermo-temporalis muscle, and the quadrate, should 

 be carefully examined. 



To expose the next set, divide the biventer maxillse as 

 already directed, say on the right side ; cut the corre- 

 sponding tendon of insertion of the temporal ; divide the 

 masseter as its origin ; and finally disarticulate the man- 



p I e 



biventer maxilho 

 rectus capitis posticus major 



Fig. 4. — Posterior view of skull of Raven. Life-size. Shows the origin of the 

 muscles upon this aspect. After nature, by the writer. 



dible, lifting the cranium so that we have a plain view of 

 its under side. Matters may be somewhat improved, 

 too, by severing the zygoma at its middle, and pulling 

 the extremities upwards. 



17. The entotympanic is a small, spindle-shaped 

 muscle, which arises quite fleshy from the side of the 

 basisphenoid, and to a limited extent from the base 

 of the rostrum immediately beyond it. As it passes 

 backwards and downwards, it rapidly contracts to form 



C 2 



