THE ELBOW 



1417 



are shown in fig. 1132. The chief points needing attention are: — (1) To leave as much of 

 the lever of the humerus as possible; (2) clean section of the large nerves, the radial (musculo- 

 spiral) in its groove being especially liable to be frayed bj^ the saw; (3) the difference between the 

 amount of retraction of the free biceps in front, and the triceps behind, fixed to the bone and 

 septa. 



THE ELBOW 



The bony points, epicondyles, olecranon, and head of radius, andtheir relation 

 to one another, should be carefully studied. The medial epicondyle is the more 

 prominent of the two, is directed backward as well as medially, and lies a little 

 above its fellow. Above it can be traced upward the supracondyloid ridge and 

 corresponding intermuscular septum. The lateral epicondyle is more rounded, and 

 thus less prominent; below, and a little behind it, the head of the radius can be felt 

 moving under the capitulum when the forearm is supinated and flexed. A depres- 

 sion marks this spot and corresponds to the interval between the anconeus and 

 brachio-radialis and extensor carpi radialis longus; at the back, the upper part 

 of the olecranon is covered by the triceps. The lower part is subcutaneous, and 

 separated from the skin by a bursa. If the thumb and second finger be placed on 

 the epicondyles and the index on the tip of the olecranon, and the forearm com- 

 pletely extended, the tip of the olecranon rises so as to be on the line joining the 

 two epicondyles. In flexion at a right angle, the olecranon is below the line of the 



Fig. 1135. — Longitudinal Section of the Elbow-joint. (One-half.) (Braune.) 



Triceps 



Extensor carpi ulnans 



— Biceps 

 Brachialis 



Radial nerve 

 Brachio-radialis 



Supinator 



Extensor carpi radialis longus 



epicondyles, and in complete flexion quite in front of them. Between the medial 

 epicondyle and olecranon is a pit, in which lie the ulnar nerve and the anastomosis 

 between the inferior ulnar collateral and the posterior ulnar recurrent arteries. 

 The coronoid process is so well covered by muscles, vessels, and nerves that its 

 position cannot be distinctly made out. 



The synovial membrane of the elbow-joint communicates with that of the superior radio- 

 ulnar. Hence the facility with which tuberculous disease may be set up after neglected falls 

 on the hand, in early life. At this time the weakness of the annular (orbicular) ligament leads 

 to its being easily injured. Swelling, due to effusion into the joint, appears on either side of the 

 triceps tendon, and soon obliterates the depression below the lateral epicondyle. The simplest 

 incision for an infected elbow-joint is a vertical one, on the lateral side of the olecranon. A 

 superficial swelling over the tip of the olecranon is due to effusion into the bursa between the 

 soft parts and that bone. A deeper, less easily defined swelling in the same region is due to 

 inflammation of the bursa between the olecranon and the triceps. A swelling on the medial 

 side of the elbow-joint, if painful and accompanied by inflammation of the skin, may be due 

 to mischief in the epitrochlear lymphatic node situated just above the medial epicondyle, and 

 receiving lymphatics from the medial border of the forearm and the two medial fingers. 



The hollow in front of the elbow. — The delicacy of the skin here must always be borne in 

 mind in the application of splints. Owing to the insidious rapidity with which pressure may set 

 up ischaemic paralysis, anterior angular splints are always to be used with caution. The M-like 



