THE REGION OF THE ELBOW 



53 



The Annular (Orbicular) Ligament surrounds the head of 

 the radius and is attached to the anterior and posterior 

 extremities of the radial notch. Its proximal border blends 

 with the capsule of the elbow, but its distal margin is not attached 

 to bone, and therefore the distal part of the capsule of the elbow 

 and proximal radio-ulnar joints is incomplete. Through the 

 gap left between the neck of the radius and the distal border 

 of the annular ligament the synovial membrane pouches distally 

 for a varying distance (Fig. 17). 



The Anterior and Posterior Ligaments of the elbow are 



paM: 

 m- '^^ : ' 



Medial epicondyle-jf-'fif' - 

 Epiphyseal lines 



Distal epiphysis 



of humerus 



Ulnar col lateral - 



ligament 



Radial collateral 

 ligament 



Annular ligament 

 Head of radius 

 Epiphyseal line 



Protrusion of 

 ynovial membrane 



FIG. 17. Frontal Section through the Elbow and Proximal 

 Radio-Ulnar Joints. 



Light blue = articular cartilage. 

 Striped blue = ligaments. 



Green = periosteum. 



Red = synovial membrane. 



simply thickenings of the capsule in front and behind. They 

 do not possess great strength, but they are supported by the 

 tendons of the brachialis and the triceps respectively. 



The Radial Collateral (External Lateral) Ligament is 

 narrow at its attachment to the lateral epicondyle but is wider 

 distally, where it blends with the annular ligament. 



The Ulnar Collateral (Internal Lateral) Ligament is 

 attached to the distal aspect of the medial epicondyle. Its 

 anterior fibres pass to the medial border of the coronoid process 

 and its posterior fibres to the medial border of the olecranon, 

 while the intermediate fibres are attached to a strong transverse 

 band which bridges the interval between the two processes. 



4a 



