ARTICULATIONS AND LIGAMENTS. 125 



of the wrist. The internal lateral passes on the ulnar side be- 

 tween the cuneiform and unciform. The external lateral, 

 stronger, passes on the radial side between the scaphoid and 

 trapezium. 



The anterior annular ligament contributes strength to these 

 joints. 



The arteries are: Carpal of anterior interosseous, anterior 

 and posterior carpals of radial and ulnar, carpal of deep palmar 

 arch, interosseous recurrent, and terminal branches of anterior 

 and posterior interosseous. 



The nerves are from median, ulnar, and posterior inter- 

 osseous. 



THE CARPO-METACARPAL ARTICULATIONS are each arthrodial 

 joints, held together by dorsal, palmar, interosseous, and capsular 

 ligaments, except the thumb, which has only capsular. 



The capsular ligament of the thumb surrounds the margins 

 of the articular surfaces of the first metacarpal and trapezium, 

 and is lined by a separate synovial sac. 



The palmar and dorsal carpo-metacarpal connects the carpus 

 and metacarpus on the palmar and dorsal surface. 



The interosseous connect the adjoining inferior angles of 

 os magnum and unciform with the contiguous surfaces, fourth 

 and fifth metacarpal bones. 



The synovial membranes of the wrist consist of five distinct 

 sacs: First, membrana sacciformis lines lower end of ulna, sig- 

 moid cavity of radius, and upper surface of triangular cartilage ; 

 second, lower surface of radius and cartilage and upper surface 

 of first row of carpus; third, between margins of carpus and 

 carpo-metacarpal joints ; fourth, between carpo-metacarpal joint 

 of thumb; and fifth, between pisiform and cuneiform. 



Intermetacarpal Articulation. The bases of the metacarpal 

 bones, except the thumb, articulate with one another by ar- 

 throdial joints, lined by synovial membrane continuous with the 

 carpal sac and connected together by palmar, dorsal, and inter- 

 osseous ligaments. The digital extremities are connected by a 

 transverse ligament across the anterior surface, continuous with 

 anterior metacarpo-phalangeal ligament. 



THE METACARPO-PHALANGEAL and PHALANGEAL are of the 

 condyloid variety, like the wrist-joint, allowing of motion in 

 every direction except laterally. They are each connected by one 

 anterior and two lateral ligaments, the posterior ligament being 

 substituted by the extensor tendon, which crosses the dorsum of 

 the joint. 



The arteries and nerves are from the digitals. 



