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SECTIOISr III 



THE MUSCLES 



By J. N. C. DAVIP]8 COLLEY. M.A., M.C.Cantab., F.R.C.S. 



SURGEON TO AND LECTURER ON SURGERY AT GUY'S HOSPITAL ; MEMBER OF THE COURT OF EXAMINERS OF THE 

 KOVAL COLLEGE OF SURGEONS OF ENGLAND; FORMERLY LECTURER ON ANATOMY AT GUY'.S HOSPITAL 



THE Muscles consist chiefly of transversely striated fibres arranged in fasciculi 

 or bundles of various sizes; and also of white fibrous tissue, which forms the 

 flattened cords or sheets, the tendons and aponeuroses, as they are called, by 

 which most of the muscles at one or both ends are attached to the bones or 

 cartilages. 



In the account of each individual muscle, it is convenient to divide the descri]>- 

 tion into seven heads, viz.: — 1. the name; 2. the shape; 3. the attachments; 4. 

 the structure: 5. the nerve-supply; 6. the action; and 7. the relations. A short 

 account also of the more important variations will be added. 



1. The name is given for various causes, and frequently when it consists of 

 more than one word, for two or even three causes, viz. : (a) the supposed action, 

 e.g. adductor and sartorius; (&) the shape, e.g. triangularis and lumbricalis; (c) 

 the direction, e.g. rectus (straight), obliquus (slanting); (c?) the position, e.g. 

 subliniis (near the surface), profundus (far from it), gluteus (in connection with 

 the nates); (e) its divisions and complexity, e.g. biceps, triceps, multifidus; (/) 

 its size, as magnus, minimus, &c. ; (gr) its attachments, e.g. sterno - cleido- 

 mastoideus. 



2. The shape is sometimes difficult to define on account of the irregularity of 

 the outline, and curvature of the surfaces of the muscle. Some are narrow and 

 of a flattened cylindrical form, which may be designated riblwn-shaped. Many of 

 these are diminished at their extremities, and mav be called fusiform or spindle- 

 shaped. Others are broad, and form sheets of various thicknesses, which, according 

 to their outline, may be described as fan-shaped, rhomboidal, triangular, or quadri- 

 lateral. Many, again, are compound muscles with double or multiple origins or 

 insertions, which are called, from this cause, bicipital, trifid, &c. This is often the 

 case when a strong muscle arises from many points of bone, or when a muscle 

 divides into many tendons below to move several small levers, such as the bones of 

 the fingers and toes. A few have tendons intercalated in their length, and are 

 called biventral or digastric muscles. It is in some cases diflicult to comprehend 

 why certain nuiscles, on the one hand, which appear to be separate, are grou])ed 

 under one name as a compound muscle; and, on the other hand, muscles which 

 might very well be combined are distinguished by separate names. The principle 

 of distinction appears to have been to group muscles which combine to form one 

 belly, and to separate those in which the tendons alone are united. 



3. Of the attachments, the more fixed end of the muscle is usually called the 

 origin, the mure iiioval)le the insertion. In enumerating the various points of 



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