168 MYOLOGY. 



stood that it is sufficient, as in the bones and joints, to describe those 

 occupying one side of the body. 



The description of the involuntary and unstriped muscles connected with 

 internal organs is excluded from the present section, as is also that of 

 some small striped muscles situated in certain complicated organs, such as 

 the larynx and ear, as it is more expedient that those muscles should be 

 treated of under the several organs to which they belong. In the arrange- 

 ment to be adopted in the anatomical description of the external and volun- 

 tary muscles, it is almost impossible to follow a strictly systematic order 

 founded exclusively, either upon their position in the several regions of the 

 body, or upon their actions : in the following section, therefore, an arrange- 

 ment is adopted which is based in part on both of these considerations, and 

 which seems to be the most simple and advantageous to the student. 



FASCLE. The term Fascia includes all the membranous dispositions of 

 reticulated or felted fibrous tissue. These structures have usually been 

 distinguished as the superficial and the deep ; the former consisting of looser 

 and finer substances, and passing by their slenderer kinds into the finer 

 varieties of connective tissue ; while the latter, denser in character, fre- 

 quently exhibit more or less regular arrangements of strong white fibres, 

 giving them a shining appearance, and are often termed aponeuroses. 



The connective tissue of the body being that in which all others are em- 

 bedded, may be considered as forming a continuous meshwork of fasciae of 

 various degrees of firmness arranged so as to enclose shut spaces, within which 

 the other parts are contained. Thus each fasciculus of muscle is surrounded 

 by connective tissue ; the larger fasciculi are separated by stronger par- 

 titions, and the whole muscle is invested with a layer of such distinctness, 

 that it may appropriately be styled a fascia. So also the sheaths of vessels 

 are formed of this substance ; and in certain parts stronger septa, having 

 attachment to bone, and continuous with the periosteum, which likewise 

 belongs to the series of white fibrous membranes, form partitions between 

 dissimilar structures. 



Superficial Fascia. Under this name, or as subcutaneous fascia, is described 

 the layer of loose tissue of varying density, which is placed immediately 

 below the skin, all over the body. It is the web which contains the sub- 

 cutaneous fat, the panniculus adiposus, and in some regions superficial 

 muscles, as the panniculus carnosus. From the subcutaneous tissue of 

 the eyelids, however, as well as from that of the penis and scrotum, adipose 

 matter is entirely absent. It is to be noticed also that between the muscles 

 and the subcutaneous fat there is always a certain amount of fascia devoid 

 of adipose matter, and that it is in this stratum that the trunks of the 

 subcutaneous vessels and nerves are found. But when the fat becomes 

 absorbed, the stroma in which it was deposited is still left, and its meshes 

 approach one another, so that in lean subjects a more fibrous condition of 

 the subcutaneous fascia is often found than in others. 



Deep Fascice and Aponeuroses. Under the name of deep fascia is com- 

 prehended that stronger layer of fibrous or connective tissue which, lying 

 more close to the muscles, gives them a general investment or dips between 

 them, and forms a nearly continuous covering of the body beneath the 

 superficial fascia. It is chiefly to the stronger parts of this fascia that the 

 name of aponeuroses has been given. Those covering the muscles have 

 been named aponeuroses of investment (Bichat), to distinguish them from 

 proper tendinous expansions, or aponeuroses of insertion, of muscles. This 

 distinction, however, is far from being universally applicable : aponeuroses 



