402 



THE MUSCULAK SYSTEM. 



and extension (occurring at the carpo-metacarpal, metacarpo-phalangeal, and inter-phalangeal 

 joints) ; abduction and adduction, together with circumduction (occurring at the carpo-metacarpal 

 joint). 



The muscles and their respective actions are given in the following table : 





The characteristic features of the movements of the upper limb are their range and 

 refinement. The hand, in addition to its intrinsic powers, can be moved through a 

 wide range and in several planes by the muscles acting on the wrist and radio-ulnar 

 joints ; this range is increased by the fore and aft movements at the elbow- joint, and the 

 extensive movements of which the shoulder and clavicular joints are capable. The 

 result is that the hand can be brought into a position to cover and guard any portion 

 of the body. The precision and refinement of movement is made possible by the co- 

 ordinate movements of the various muscles acting upon the several joints, so that 

 actions can be performed (as raising the food to the mouth) in which all the articulations of 

 the limb are brought into play ; while others (such as writing) are possible by movements 

 at the joints of the wrist and ringers along with fixation of the elbow- joint. 



THE LOWER LIMB. 



FASCI/E AND MUSCLES OF THE THIGH 

 AND BUTTOCK. 



FASCLffi. 



The superficial fascia of the thigh and buttock is continuous above with the 

 fascia of the abdomen and back, medially with that of the perineum, and distally 

 with that of the leg. It presents noticeable features in the buttock and groin. 



In the buttock the superficial fascia is of considerable thickness, and is usually 

 loaded with fat, whereby it assists in forming the contour of the buttock and the 

 fold of the nates. 



In the groin it is divisible into two layers : a superficial fatty layer, continuous 

 with a similar layer on the anterior surface of the abdominal wall above, and over 

 the perineum medially, and a deeper membranous layer, which is attached above to 

 the medial half of the inguinal ligament, and to the deep fascia of the thigh just 

 distal to the lateral half of that ligament. Medially it is attached to the pubic 

 arch, and below the level of the femoral triangle it blends inseparably with the 

 superficial fatty layer. The separation of these two layers of the superficial fascia 

 is occasioned by the presence between them of the inguinal and superficial 

 subinguinal lymph glands, the great saphenous vein and its tributaries, and some 

 small arteries. The attachment of the deeper layer of the fascia to the pubic arch 

 and the inguinal ligament 'cuts off the superficial tissues of the thigh from the 

 perineum and the abdominal wall, and prevents the passage into the thigh of fluid 

 collected in the perineum or beneath the fascia of the abdominal wall. 



