*n/.SCL 



T A/OO/V 



Reproduced by permission from Keith's " The Engines of the Human 

 Body" (Williams & Norgate). 



A DRAWING OF THE BICEPS OF THE UPPER PART OF THE 



RIGHT ARM, SHOWING ITS TENDON, ITS BLOOD-VESSELS, 



AND ITS NERVE 



A tendon or sinew fastens a muscle to a bone; the artery brings 

 oxygen and food-material for the muscle; the vein carries away car- 

 bon dioxide and waste; the nerve conveys the stimulus which pro- 

 vokes the muscle to contract. The biceps lies along the upper arm 

 or humerus; its upper end is connected by two tendons with the 

 shoulder-blade or scapula; its lower end is connected by a tendon 

 with the radius, one of the bones of the lower arm; when the biceps 

 contracts, becoming shorter and broader, as we can feel it doing, 

 it raises the lower arm nearer the upper arm. 



THE ELBOW-JOINT 



The elbow is a fine example of a simple hinge-joint. The lower 

 end of the humerus works on the upper end of the ulna, which 

 bears an elbow process or olecranon, which prevents the arm 

 being bent back. The biceps muscle, which is fixed above to the 

 shoulder-blade, is inserted below on the radius, and bends the 

 arm when it contracts. At the back of the elbow-joint is seen 

 the triceps which straightens the arm when it contracts. 



THE HIP-JOINT 



The thigh-bone or femur 

 is shown with its rounded head 

 fitted into the socket (ace- 

 tabulum) of the hip-girdle, 

 which, in turn, is fixed to the 

 sacral region of the backbone. 

 This hip- joint is a good 

 example of a " ball and 

 socket " joint with a deep 

 cup; the shoulder- joint is on 

 the same principle, but with a 

 shallow cup. The head of the 

 thigh-bone plays in the cup 

 furnished by the hip-girdle and 

 has considerable freedom of 

 movement, but much less than 

 the arm, which plays in a 

 shallow cup. 



