THE LIGAMENTS. 107 



Ligaments : 



1. Lig. capsulare cubiti from the inferior extremity of the Hwmerus to the 

 Olecranon, the fossa sigmoid. major, proc. coronoid., and lig. annulate radii; 

 loose and wide, behind and on the sides weaker than before ; behind, the ten- 

 don of the Triceps muscle. 



2. Lig. laterale internum, three portions from the internal condyle of the hu- 

 merus to a point below the Coronoid process of the Ulna on the inner side. 



3. Lig. laterale externurii, triangular, from the external condyle to the lig. an- 

 nulare radii, below the tendon of the Supinator breuis. The Synovial Capsule 

 lies behind the anterior wall of the capsular ligament, reflected from the fossa 

 anterior to the fossa posterior, where it is the widest ; it terminates below in 

 a blind prolongation on the inner margin of the lig. annulare radii. 



Movements : 



1. Flexion, flexio. The entire fore-arm moves upon the 

 Trochlea and rotula humeri from behind, forwards, so that the 

 finger-points may touch the mouth. Proc. coronoid. lies in the 

 fossa anterior, and prevents farther flexion. 



2. Extension, extensio. The reverse of the preceding, from 

 before backwards, until the axes of the fore-arm and humerus lie 

 in the same line. Proc. olecrani lies in the fossa posterior, and 

 prevents farther extension. 



19.9.. Connections of the Ulna with the Radius. 



A. Articulatio radio-cubit alls superior. Rotatio. 

 Articular surfaces : 



1. On the Radius, circumferentia articularis capituli. 



2. On the Ulna, fossa sigmoidea minor, elongated from before 

 to behind, forms the osseous portion of the ring in which Capitul. 

 radii rolls. 



Ligaments: 1. Lig. annulare radii, strong, dense, three-fourths of a ring, 

 surrounds a synovial capsule and capitul. radii ; attaches itself to the anterior 

 and posterior extremity of the fosssa sigmoid. minor and unites externally with 

 lig. laterale externum; above, with lig. capsulare cubiti; is anteriorly much 

 thinner, and therefore easily lacerates. 



2. Lig. teres s. chorda transversalis cubiti, Weitbrecht, passes obliquely from 

 below, outwards, from the most external aspect of the Proc. Coronoid. to the 

 inferior portion of the Tuberost. (bicipit.) radii; compensates for the lig. inter- 

 osscum at the superior part. 



19.9. bu. B. Articulatio radio-cubitalis inferior. Rotatio. 

 Articular surfaces : 



1. On the radius: incisura ulnaris. 



2. On the ulna: capitulum, of the external circumference. 



Ligaments : 1. Lig. capsulare sacciforme, broad and loose, proceeds from the 



