SECTION lY 



THE xMUSCULATUEE 



Revised for the Fifth Edition 

 By C. R. BARDEEN, A.B., M.D. 



PROFESSOR OP AXATOMY IN THE UNIVERSITY OF WISCON SIN 



MUSCLES, the movements of which are under the control of the will, almost 

 completely envelope the skeletal framework of the body; close in the oral, 

 abdominal, and pelvic cavities; separate the thoracic from the abdominal 

 cavity; surround the pharj-nx and the upper portion of the oesophagus; and are 

 found connected lA-ith the eye, ear, larj^nx, and other organs. The}- constitute 

 about two-fifths to three-sevenths of the weight of the body. 



In this section an account is given of the gross anatom}^ of the musculature 

 attached to the skeleton and the skin, with the exception of certain of the 

 muscles which are more conveniently treated in connection with the organs to 

 which they are appended. Thus, the muscles of the eye, the ear, the pharynx, 

 the larynx, and the intrinsic muscles of the tongue are described in the sections 

 devoted to those structures. 



Relations to the skin. — Beneath the skin is a sheet of connective tissue, the 

 tela subcutanea. In this, in some regions of the body (the head, neck, and palm), 

 thin, flat, subcutaneous muscles are embedded. Superficial muscles of this kind 

 constitute a panniculus carnosus, much more extensive in the lower mammals than 

 in man. The tela subcutanea is separated from the more deepty seated muscu- 

 lature by areolar tissue, which, in most places, is loose in texture over the muscles. 

 In some regions, as over the upper part of the back, the tela subcutanea is firmly 

 united to the underlying musculature and is less freely movable. In the tela sub- 

 cutanea more or less fat is usually embedded. This constitutes the panniculus 

 adiposus, which varies greatly in thickness in different parts of the body. As a 

 rule, it is much more developed over muscles than over those regions where bone 

 and joints lie beneath the skin. From the tela subcutanea of the ej^elids, penis, 

 and scrotum fat is absent. The deeper layer of the tela subcutanea is more or less 

 free from fat, and in it run the main trunks of the cutaneous nerves and vessels. 

 In some regions, as over the lower part of the abdomen, one or more fibrous mem- 

 branes are differentiated in this deeper layer. 



To the tela subcutanea the term superficial fascia has been commonly applied, but since 

 this leads to a confusion with the superficial fascia; which immediately invest the muscles, it 

 seems better to restrict the term fascia to the membranes connected with the muscular system, 

 and to use the term tela subcutanea for the la}'er of connective tissue which underlies the skin 

 and is continuous over the whole surface of the body. 



In several places where the skin overlies bony prominences well-marked 

 synovial bursae, or sacs (bursas mucosae), are developed in the tela subcutanea. 



Since the skin and the subcutaneous tissue must be removed in order to study 

 the muscles of various regions, the tela subcutanea and subcutaneous bursae may 

 be conveniently described in connection with the muscles, and brief references wdll, 

 therefore, be made to them in connection with the musculature of various regions. 



Muscle fasciae. — The musculature of the body, 'wdth the exception of some of 

 the subcutaneous muscles, is ensheathed by fibrous tissue, which, in certain regions 

 forms distinct membranes, while in other regions it is delicate and not clearh' to be 

 distinguished from the superficial connective tissue of the muscles, the perimy- 



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