THE REGION OF THE ELBOW 51 



side open into the epitrochlear lymph gland (p. 44), while the 

 median and radial lymph trunks open into lymph glands which 

 lie in the cubital fossa., or, in the absence of these, into the 

 epitrochlear lymph gland. The efferents from these glands 

 follow the course of the basilic vein and terminate in the 

 central group of the axillary lymph glands (p. 35). Some- 

 times the lymph vessels from the lateral three digits pass 

 directly along the radial side of the arm and end in the 

 infra -clavicular (p. 30) or even in the pectoral lymph 

 glands (p. 35). 



The Elbow and Proximal Radio-Ulnar Joints. At 

 the elbow-joint the Trochlea and Capitulum of the humerus 

 articulate with the Semilunar Notch (Greater Sigmoid Cavity) 

 of the ulna and the proximal surface of the head of the radius, 

 respectively. At the proximal radio-ulnar joint the medial 

 side of the head of the radius articulates with the Radial Notch 

 (Lesser Sigmoid Cavity) of the ulna, and the cartilage covering 

 these areas is directly continuous with that which covers the 

 adjoining articular surfaces of the humero-radial and humero- 

 ulnar joints. 



The transverse axis of the trochlea slants distally and 

 medially, and is therefore not at right angles to the long axis of 

 the humerus. The semilunar notch (greater sigmoid cavity) 

 is formed by the anterior surface of the olecranon and by the 

 proximal surface of the coronoid process. The transverse axis 

 of the latter forms an angle of less than 90 with the shaft of the 

 ulna, and so the long axis of the humerus and ulna meet at an 

 angle of less than 180 when the forearm is extended and supine. 

 This lateral angulation (Fig. 16) is termed the " Carrying 

 Angle," and it allows the supinated forearm to swing freely past 

 the pelvis. It is masked in flexion of the supinated forearm 

 and in pronation. The angles which the long axes of the 

 humerus and ulna make with the transverse axis of the elbow 

 are equal to one another. As a result, when the supinated 

 forearm is fully flexed, the anterior surfaces of the arm and 

 forearm are accurately applied to one another. But, when 

 the supinated forearm is fully flexed (the arm being by the side), 

 the palm of the hand lies over the medial half of the clavicle 

 and not over the point of the shoulder, owing to the existing 

 medial rotation of the humerus (p. 44). To obtain the correct 

 alignment of the arm and to reproduce accurately the carrying 

 angle following fractures into the joint, the limb is adjusted 



