The details of forearm muscles are given in tables 5-8. The relation of the epicondyles to the olecranon is best seen posteriorly (figure 46a,b); the shape of the triangle joining these structures changes in height in extension and flexion.
Table 5 Superficial muscles of the anterior (flexor) compartment of the forearm
Table 6 Deep muscles of the anterior (flexor) compartment of the forearm
Table 7 Superficial muscles of the lateral and posterior (extensor) compartment of the forearm
Table 8 Deep muscles of the lateral and posterior (extensor) compartment of the forearm
A number of bony points in the elbow and superior radioulnar joints are palpable. These include the lateral and medial epicodyles, the supracondylar ridges, the olecranon and the head of the radius. The coronoid process can be palpated with deep pressure in the cubital fossa. The ulnar nerve can be palpated behind the medial epicondyle; the ulna has a palpable posterior subcutaneous border (figure 47a–e).
Figure 48a–c shows the normal lateral radiograph of the elbow, and the disruption that occurs in a dislocation or a comminuted fracture.
The common extensor origin, from the lateral epicondyle is injected for the condition of tennis elbow (figure 49a) and the olecranon bursa over the proximal ulna (figure 49b). The elbow joint can be injected through a posterolateral approach, lateral to the tendon of triceps (figure 50).
The elbow is a hinge joint and the zero position is when the arm is fully extended (figure 51a,b); normal flexion is to approximately 150 degrees (figure 51c,d). Early synovitis may limit these movements.
Pronation (figure 52a,b) and supination (figure 52c,d) may be tested with the elbow flexed to 90 degrees; about 80 degrees of supination and 80 degrees of pronation are possible. Pronation and supination take place at both the superior and inferior radioulnar joints