The Muscles and Fasciae. 1 



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 fibres 

 terminate in blunt extremities upon the periosteum or perichondrium, and do 

 not come into direct relation with the osseous or cartilaginous tissue. Where 

 muscles are connected with the skin, they either lie as a flattened layer beneath 

 it, or are connected with its areolar tissue by larger or smaller bundles of fibres, 

 as in the muscles of the face. 



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

 siderable length, especially the more superficial ones, the deep ones being gene- 

 rally broad ; they surround the bones, and form an important protection to the 

 various joints. In the trunk, they are broad, flattened, and expanded, forming 

 the parietes of the cavities which they inclose; 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 fibres of certain 

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

 the fibres are arranged longitudinally, and terminate at either end in a narrow 

 tendon. If the fibres converge, like the plumes of a pen, to one side of a tendon, 

 which runs the entire length of a muscle, the muscle is said to be penniform, as 

 the Peronei; if they converge to both sides of the tendon, the muscle is called 

 bipenniform, as the Eectus Femoris ; if they converge from a broad surface to a 

 narrow tendinous point, the muscle is said to be radiated, as the Temporal and 

 Glutei muscles. 



They differ no less in size ; the Gastrocnemius forms the chief bulk of the 

 back of the leg, and the fibres of the Sartorius are nearly two feet in length, 

 whilst the Stapedius, a small muscle of the internal ear, weighs about a grain, 

 and its fibres are not more than two lines in length. 



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

 situation, as the Tibialis, Eadialis, Ulnaris, Peroneus ; 2, from their direction, 

 as the Eectus Abdominis, Obliqui Capitis, Transversalis ; 3, from their uses, as 

 Flexors, Extensors, Abductors, etc.; 4, from their shape, as the Deltoid, Trape- 

 zius, Ehomboideus; 5, from the number of their divisions, as the Biceps, the 

 Triceps; 6, from their points of attachment, as the Stemo-cleido-mastoid, 

 Sterno-hyoid, Sterno-thyroid. 



In the description of a muscle, the term- origin is meant to imply its more 

 fixed or central attachment ; and the term insertion the movable point upon 

 which the force of the muscle is directed ; but the origin is absolutely fixed in 

 only a very small number of muscles, such as those of the face, which are 

 attached by one extremity to the bone, and by the other to the movable 

 integument ; in the great number, the muscle can be made to act from either 

 extremity. 



In the dissection of the muscles, the student should pay especial attention to 

 the exact origin, insertion, and actions of each, and its more important relations 



1 The Muscles and Fasciae 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 rea- 

 son, as well as from the close connection that exists between the muscles and their investing 

 aponeuroses, that they are considered together. Some general observations are first made on 

 the anatomy of the muscles and fasciae, the special description being given in connection with 

 the different regions. 



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