THE MUSCLES IN GENERAL. 1S3 



Section IIL— MYOLOGY. 



THE MUSCLES IN GENERAL, 



Under this section will be brought the description of the Voluntary 

 Muscles, and along with it that of the Fascias and Aponeuroses by 

 which they are invested. 



The voluntary muscles are for the most part placed in close relation 

 Avith the Endo-skeleton, being attached to the bones or other hard parts, 

 and moving these in different directions by their contractions. There 

 are, however, some muscles which may be looked upon as belonging to 

 the cutaneous system, or Exo-skeleton, and there are a few others which 

 are connected with the viscera at the places where parts of these reach 

 the surface of the body. The muscles are all symmetrical, and, 

 Avith the exception of the sphincters and one or two others, are in pairs. 



The number of voluntary muscles to which distinct names have been 

 given in the systems of Albinus and Soemmering, Avhich are mainly fol- 

 lowed in this work, amounts to about 240, there being some variation 

 above or below that number according as certain muscular parts are 

 regarded as separate and independent muscles or only as portions of 

 others. They naturally iall under the following four great divisions, 

 and in the numerical proportions stated under each, viz. : — 



A. In the axial part of the body. 



1. The muscles of the head and neck = 75. 



2. The muscles of the vertebral column and trunk =51. 



B. In the limbs. J^ 



3. The muscles of the upper limb = 58. 



4. The muscles of the lower limb = 59. 



In the detailed description of the muscles, however, while the fore- 

 going general divisions will be followed, it may be expedient occasion- 

 ally to deviate from the strictly systematic arrangement, in so far as 

 may conduce to facility in study and convenience in dissection. 



Each muscle constitutes a separate organ, composed chiefly of 

 a mass of the contractile fibrous tissue which is called muscular, 

 and of other tissues and parts which may be regarded as accessory. 

 Thus the muscular fibres are connected together in bundles or fasciculi 

 (see General Anatomy), and these fasciculi are again embedded in and 

 united together by a quantity of connective tissue, forming the perimi/- 

 sitim, and the whole muscle is usually enclosed in an external sheath of 

 the same material. Many of the muscles are connected at their more 

 or less tapering extremities with tendons by which they are attached to 

 the bones or hard parts ; and tendinous bands frequently run to a con- 

 siderable length either on the surface of a mtiscle or between its fibres. 

 Thu^'c is indeed great variety in the relation of the muscular and 

 tendinous portions, but few muscles are entirely destitute of some 

 tendinous element in their composition. 



Farther, blood-vessels are largely distributed in the substance of a 

 muscle, carrying the materials necessary for its nourishment and chemico- 

 vital ehanges, and there are also lymphatic vessels, as in other vascular 

 parts of the body. Nerves are ramified through every muscle, by which 

 the muscular contractions are called forth and a low degree of sensi- 

 bility is conferred upon the muscular substance. 



Tlie muscles vary much in their individual forms. Some are broad and 



