288 APPLIED ANATOMY. 



head of the radius can be felt turning beneath. Immediately above the head of the 

 radius, lying to the outer side of the olecranon, if the elbow be again flexed to a right 

 angle, can be seen and felt the bony projection of the capitellum covered by the 

 strong expansion from the triceps. By careful palpation a groove can be felt between 

 the lower edge of the capitellum and the head of the radius which marks the limits 

 and point of articulation of the two bones. 



On the posterior aspect of the joint the ulnar nerve is the most important struc- 

 ture; there is, however, a bursa between the upper or posterior surface of the olec- 

 ranon and the skin and also another on its inferior surface, extending downward, 

 which from its exposed position is frequently injured and enlarged. Such an 

 enlargement occurs from chronic irritation in certain occupations, hence the name 

 ' ' miners' elbow. ' ' 



With the elbow flexed at a right angle there is seen on its anterior surface a 

 crease which runs from one condyle across to the other. If a knife were held parallel 

 with the forearm and entered at this crease, it would strike the humerus above the 

 level of the joint line, that is, the line of contact of the bones. This joint line runs 

 from 1.25 cm. (^ in.) below the lateral (external) condyle to 2.5 cm. (i in.) below 

 the medial (internal) condyle. 



Anteriorly the muscular masses form prominent landmarks. In the middle of 

 the crease can be felt the tendon of the biceps muscle. The muscular swell above 

 the crease is formed by the biceps muscle with the brachialis anticus beneath. The 

 sharp upper edge of the bicipital fascia can be distinctly felt when the muscle con- 

 tracts. The limits of the biceps can be felt as two lines, radiating like the letter V 

 from the biceps tendon upward. These are the commencing bicipital furrows or 

 grooves. 



The outer branch marks the depression between the outer edge of the biceps and 

 the swell forming the supinator group of muscles. The inner branch marks the inner 

 edge of the biceps, and between it and the medial condyle can be felt a muscular 

 mass which is formed by the inner portion of the brachialis anticus. In the middle 

 of the flexure of the elbow below the crease is a depression called the antectibital fossa. 

 To its outer side is the muscular prominence of the extensors and supinator. To its 

 inner side is the muscular prominence of the flexors and pronator. The inner mus- 

 cular swell ends at the medial (internal) condyle, but the external one passes well up 

 on the arm. The muscles so prolonged upward are the extensor carpi radialis longior 

 for about 5 cm. (2 in.) above the lateral (external) condyle, and the brachioradialis 

 (supinator longus) for 10 cm. (4 in.) higher. The outer limit of the antecubital fossa 

 is formed by the inner edge of the brachioradialis. The inner side is formed by the 

 pronator radii teres muscle. 



To the inner side of the biceps tendon lies the brachial artery, which bifurcates 

 opposite the neck of the radius, approximately 2 cm. or a finger's breadth below the 

 crease of the elbow. Still farther to the inner side lies the median nerve. In the 

 groove between the biceps and brachialis anticus on the inner side and brachio- 

 radialis (supinator longus) and^extensor carpi radialis longior on the outer side lies 

 the radial (musculospiral) nerve; it divides above or opposite the lateral (external) 

 condyle into the superficial branch and posterior interosseous nerve 



THE VEINS OF THE ELBOW. 



The flexure of the elbow is occupied by a number of veins which are of impor- 

 tance from the fact that they are frequently used for purposes of saline infusion, 

 sometimes for blood-letting, and not infrequently they are wounded and give rise to 

 troublesome hemorrhage. 



They are made more prominent by allowing the arm to hang and by tying a 

 bandage firmly above the elbow. The larger part of the blood from the parts below 

 is carried by the superficial veins; hence the largest veins lie directly beneath the skin 

 and can be seen through it. 



Their arrangement is not always regular but they follow a more or less general 

 plan. The blood from the radial side of the wrist and forearm is carried by the radial 

 vein. The median vein brings the blood from the anterior surface of the wrist and 



