THE FORE EXTREMITY. 205 



the liumerus, the inferior to the superior part of the inferior 

 third of the anterior surface of that bone. Between these 

 two heads runs a branch of the humeral artery (with its 

 vein and nerve) to supply flexor brachii. The axillary 

 nerves and vessels will be found in contact with the upper 

 part of this muscle. 



Scapulo- ulnar is runs from the posterior angle of the 

 scapula with caput magnum, and covering the internal 

 surface of the posterior part of the triceps, expands below 

 to become inserted into the inner surface of the olecranon 

 and the faschia covering the internal surface of the arm, 

 foi-ming an aponeurotic expansion which extends upwards 

 to blend with its superior attachment. 



By removal of triceps we expose two muscles, both of 

 which are attached to the capsular ligaments of the joints 

 with which they respectively are in contact. 



Scapulo-humeralis posticus consists of a few fleshy fas- 

 ciculi, which run from immediately behind the glenoid 

 cavity of the scapula, emerging from within the attachment 

 of caput magnum, and after passing over and becoming 

 attached to the capsular ligament of the shoulder- joint, 

 dip between the fibres of humeralis externus to become 

 inserted to the extreme postero- superior part of the hu- 

 merus immediately below the articular cartilage of the head. 



Anconeus arises from the superior part of the ridges 

 which bound the olecranian fossa of the humerus (espe- 

 cially from the outer), becomes attached to the capsular 

 ligament of the elbow-joint, which extends around the 

 articular part of the fossa, and becomes inserted into the 

 antero- superior, inclined to the outer part of the olecranon. 



Humeralis externus arises from the posterior part of 

 the humerus immediately beneath its head, where it covers 

 scapulo-humeralis posticus, and from the back of the bone 

 as far down as the supra - condyloid ridges. It winds 

 around the external surface of the bone in a spiral fossa 

 bounded by ridges (with the spiral nerve), passes beneath 

 the band of white fibrous tissue, mixed with yellow elastic, 

 which runs from the inferior extremity of the humeral 

 ridge to the external ridge of the inferior extremity of the 

 humerus, passes between flexor brachii and extensor meta- 

 carpi magnus beneath the tendinous band connecting 

 these two muscles, and having become attached to the 

 anterior part of the capsular ligament of the elbow-joint, 



