MYOLOGY: 



THE Muscles are connected with the bones, cartilages, ligaments, and skin, 

 either directly, or through the intervention of fibrous structures called tendons 

 or aponeuroses. Where a muscle is attached to bone or cartilage, the fibers end 

 in blunt extremities upon the periosteum or perichondrium, and do not come into 

 direct relation with the osseous or cartilaginous tissue. Where muscles are con- 

 nected with its skin, they lie as a flattened layer beneath it, and are connected 

 with its areolar tissue by larger or smaller bundles of fibers, as in the muscles of 

 the face. 



The muscles vary extremely in their form. In the limbs, they are of considerable 

 length, especially the more superficial ones; they surround the bones, and constitute 

 an important protection to the various joints. In the trunk, they are broad, 

 flattened, and expanded, and assist in forming the walls of the trunk cavities. 

 Hence the reason of the terms, long, broad, short, etc., used in the description of a 

 muscle. 



There is considerable variation in the arrangement of the fibers of certain muscles 

 with reference to the tendons to which they are attached. In some muscles the 

 fibers are parallel and run directly from their origin to their insertion; these are 

 quadrilateral muscles, such as the Thyreohyoideus. A modification of these is 

 found in the fusiform muscles, in which the fibers are not quite parallel, but slightly 

 curved, so that the muscle tapers at either end; in their actions, however, they 

 resemble the quadrilateral muscles. Secondly, in other muscles the fibers are 

 convergent; arising by a broad origin, they converge to a narrow or pointed inser- 

 tion. This arrangement of fibers is found in the triangular muscles e. g., the 

 Temporalis. In some muscles, which otherwise would belong to the quadrilateral 

 or triangular type, the origin and insertion are not in the same plane, but the plane 

 of the line of origin intersects that of the line of insertion; such is the case in the 

 Pectineus. Thirdly, in some muscles (e. g., the Peronei) the fibers are oblique and 

 converge, like the plumes of a quill pen, to one side of a tendon which runs the entire 

 length of the muscle; such muscles are termed unipennate. A modification of this 

 condition is found where oblique fibers converge to both sides of a central tendon; 

 these are called bipennate, and an example is afforded in the Rectus femoris. 

 Finally, there are muscles in which the fibers are arranged in curved bundles in 

 one or more planes, as in the Sphincters. The arrangement of the fibers is of con- 

 siderable importance in respect to the relative strength and range of movement 

 of the muscle. Those muscles where the fibers are long and few in number have 

 great range, but diminished strength; where, on the other hand, the fibers are 

 short and more numerous, there is great power, but lessened range. 



The names applied to the various muscles have been derived: (1) from their 

 situation, as the Tibialis, Radialis, Ulnaris, Peronaeus; (2) from their direction, as 

 the Rectus abdominis, Obliqui capitis, Transversus abdominis; (3) from their uses, 

 as Flexors, Extensors, Abductors, etc.; (4) from their shape, as the Deltoideus, 



1 The muscles and fascise are described conjointly, in order that the student may consider the arrangement of the 

 latter in his dissection of the former. It is rare for the student of anatomy in this country to have the opportunity 

 of dissecting the fasciae separately; and it is for this reason, as well as from the close connection that exists between 

 the muscles and their investing sheaths, that they are considered together. Some general observations are first made 

 on the anatomy of the muscles and fasciae, the special descriptions being given in connection with the different regions. 



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