94 THE OSTEOLOGY AND MYOLOGY 



outward (a little backward), to be inserted by a very short tendon into the neck of the 

 mandible, directly underneath the most internal point of the transversely elongated articu- 

 lar surface. Its action is necessarily very feeble and much restricted. 



Muscles of the Neck. 



Under this head I shall describe all the muscles of this region, not confined to the cra- 

 nium, nor attached to the scapular arch, nor forming merely upward prolongations of those 

 of the back. Without going into unnecessary subdivision of the part into " regions," Ave 

 may conveniently recognize three groups of muscles : — The anterior cervical, embracing 

 those muscles not attached to vertebrae; the anterior vertebral, including those lying upon 

 the front of the column ; and the posterior vertebral, containing those upon the back of the 

 same. Excluded from the first group, by reason of attachment to the scapular arch, are 

 the omo-hyoid and cleido-mastoid ; from the second and third, for the same reason, the 

 three levators of the scapula, the trapezius and the rhomboideus ; and from the same two 

 groups, as forming the third exception above taken, the cervicalis ascendens, transversalis 

 and spinalis cervicis, etc. The great similarity of the muscles of all these groups to those 

 of the human subject will appear from the following descriptions. The part that the par- 

 occipital plays as a " styloid process " is worthy of note. Among the more notable fea- 

 tures, as compared with the state of things found in man, are to be observed, the extension 

 of the platysma myoides into a proper panniculus carnosus, as already described, discre- 

 tion of sterno-mastoid and cleido-mastoid, peculiar origin of sterno-hyoid and -thyroid, 

 relation of the latter to thyro-hyoid, expansion of digastricus, etc. 



Sterno-mastoideus. — Perfectly distinct from the cleido-mastoid, though with, the same 

 origin and a parallel and contiguous course. It arises by a short, stout, flat tendon from the 

 mastoid (sometimes from the extremity of the squamosal), and forms a stout fusiform or te- 

 rete belly, that comes a little obliquely down the neck, immediately beneath the panniculus, 

 crossing the omo-hyoid nearly at right angles, to be inserted fleshy, side by side with its 

 fellow, into the side of the top of the manubrium, and frequently, also, the cartilage inter- 

 posed between this and the clavicle, in front of, and close beside, the termination of the 

 cleido-mastoid ; its termination is in contact with the upper corner of the great pectoral. 



Digastricus. — This is the first muscle seen between the jaws upon removal of the integu- 

 ment and panniculus. It is notable for its origin from the paroccipital instead of the mas- 

 toid, its want of a central tendon, and the expansion of its anterior belly to form a flooring 

 to the mouth. It is bound down by the common fascia, and so is virtually attached to the 

 hyoid ; but it is not distinctly drawn to that bone by a fibrous loop. The posterior belly, 

 stout and terete, curves around the angle of the jaw, just internal to the greater pterygoid 

 muscle, becomes constricted and suffers partial tendinous intersection, and then spreads 

 out into a broad, thin plane, that meets its fellow of the opposite side, and completely fills 

 the interramal space. It is attached to the whole of the inner side of the lower jaw, from 

 the anterior border of the pterygoid muscle to the symphysis. Besides depressing the jaw, 

 it thus floors the mouth. 



Mylo-hyoldeus. — The proper floor of the mouth lies upon the digastricus — the lingual 

 vessels running between the two. It has no distinct insertion into the hyoid, being only 



