112 SPECIAL ANATOMY. 



2. Extension, to the extent of an obtuse angle, is restrained by 

 the ring which Lig. anterius and the anterior fibres of Ligg. 

 later alia form. In too violent extension the Capitul. os. meta- 

 carp. passes over the ring or tears it, and dislocation of the finger 

 backwards arises, which can only be reduced, if the ring is actu- 

 ally lacerated, but is prevented if it is pushed between the articu- 

 lar surfaces. 



3. Abduction and Adduction. 



B. The phalanges with each other Ginglymus. Articular 

 surfaces : a. At the inferior extremity of the I. phalanx a troch- 

 lea with two small condyles. b. At the superior extremity of 

 phalanx I. and II., two small fossae. 



Ligaments: 1. Ligg. capsularia, on the dorsal surface loose and thin, and 

 formed even here of the fibres of the tendinous sheaths of mm, extensor., the 

 rest like the lig. ant., as in A. 



2. Ligg. late.ra.lia ext. et. int., as in A. 



3. Capsula synoviales* in A and B are, especially on the dorsal surface, 

 very loose, not connected with the tendons, stretch in flexion, and fold up in 

 extension. 



Movements: Flexion. That of the second phalanx is more 

 marked than that of the third. 



Extension is much more restrained than in the metacarpo-pha- 

 langeal articulation. Lateral motion is not possible. 



129. Connections of the Inferior Extremities. 



1. Of the Thigh with the Pelvis, Jirticulatw coxx, hip-joint. 



Articular surfaces : Head of the femur and acetabulum, united 

 in a ball and socket joint, not admitting air, less moveable, but 

 stronger than the shoulder joint. 



Ligaments: 1. Labrum cartilagineum acetabuli, a fibrous ring, of four lines 

 thick, encircling the edge of the acetabulum, which it deepens, passes over 

 the incisura ace'abuli below and bsfore, as lig. transvers. acelabuli, and thus forms 

 theforam. acetabuli, for the vessels of the joint; is thicker above and behind; 

 narrower at its free than at its attached border. Consists entirely of fibrous 

 tissue. See Interarticular Cartilage. 



2. Ligam. capsulare femoris, passes from the border of the bony acetabulum 

 in front, to the linea interirochanter. anter.; behind, as fur downwards as the 

 centre of the neck of the femur; is of a dull whits hue, composed of crossed 

 fibres, two lines thick, strong, solid, and looser at the sides; above and exter- 

 nally, beneath the tendon of the m. recLus femoris, thicker; is strengthened by a 

 bundle of fibres, the Zona nrbicularis seu lig. anterius superius, which passes 

 obliquely from Spina ilei anler. infer, to the: inner part of the basis rolli femoris, 

 around this anteriorly and back to the Spina. Anteriorly, the fibres of the m. 

 Psoas and lliacus, and their synovial sheaths are attached to it. Internally 

 are situated the m. oblurator extern, e* per.lin&us ; externally glatceus fl 

 behind quadratus femor. bigemini, pyramidalis oitur^tor iniernus. 



