324 



THE AKTICULATIONS OE JOINTS. 



Humerus 



Ulnar collateral 

 ligament 



ing cartilage covering the capitulum, to the margin of which the cartilage extends in 

 all directions, and thus it presents a convex edge in relation to the radial fossa. 

 The cartilage which lines the semilunar notch of the ulna presents a transverse in- 

 terruption, considerably wider on its medial as compared with its lateral aspect. 

 Thereby the coronoid and olecranon segments of the notch are separated from each 

 other. The cartilage which clothes the coronoid segment is continuous with that 

 which clothes the radial notch of the ulna. The shallow cup-shaped depression on 

 the head of the radius is covered with cartilage which rounds off the margin, and 

 is prolonged without interruption upon the vertical aspect of the head, extending 

 to its most distal level on that part opposed to the radial notch of the ulna. 



Capsula Articularis. 

 Taken as a whole, the liga- 

 ments form a complete 

 fibrous stratum of the 

 articular capsule, which is 

 not defective at any point, 

 although it is not of equal 

 thickness throughout, and 

 certain bands of fibres 

 stand out distinctly because 

 of their greater strength. 



The common epiphyseal 

 line for the trochlea, capit- 

 ulum, and the lateral epi- 

 condyle of the humerus, is 

 partly intra-capsular and 

 partly extra-capsular ; that 

 for the medial epicondyle 

 is extra-capsular. The 

 epiphyseal line of the ole- 

 cranon is intra - capsular 

 only anteriorly, and it may i 

 be altogether extra-cap-! 

 sular. 



Lig. Anterius. The 

 anterior ligament (Fig. 305 

 consists of a layer whos 

 fibres run in several direc 

 tions obliquely, trans 

 versely, and longitudinally 

 and of these the vertica 

 fibres are of most import 

 ance. It is attached proxi 

 mally to the proxima 

 margins of the coronoid and radial fossse ; distally, to the margins of the coronok 

 process and to the annular ligament of the proximal radio-ulnar joint, but som 

 loosely arranged fibres reach as far as the neck of the radius. The marginal portion 

 of this ligament, which are situated in front of the capitulum and the medial margii 

 of the trochlea respectively, are much thinner and weaker than the central parl 

 Fibres of origin of the brachialis muscle are attached to the front of this ligament 

 Lig 1 . Posterius. The posterior ligament is an extremely thin, almost redundan 

 layer. Proximally it is attached, in relation to the margin of the olecranon fossa 

 at a varying distance from the trochlear articular surface, and distally to th 

 summit and sides of the lip of the olecranon. Laterally some of its fibres pass fron 

 the posterior aspect of the capitulum to the posterior border of the radial note! 

 of the ulna. This ligament derives material support from, and participates in th 

 movements of, the triceps brachii muscle, since they are closely adherent to eac 

 other in the region of the olecranon. 



Lig. Collaterale Ulnare. The ulnar collateral ligament (O.T. internal latera] 



Annular 

 ligament 

 of radius 



Radius 



Tendon of insertion of 

 biceps muscle 



Oblique chord 



Ulna 



FIG. 305. ANTERIOR VIEW OP ELBOW-JOINT. 



