DISSECTING MANUAL. 



metacarpal bones, viz.: the ligamenta basium volaria, dorsalia, 

 et inter ossea. [287] 



Carpo-metacarpal Joints. Articulatio carpo-metacarpea pol- 

 licis : The joint between the trapezium and first metacarpal is 

 one of mutual coaptation of saddle-shaped surfaces. It has a 

 complete capsule with palmar, dorsal, external lateral, and 

 internal lateral bands; and a separate synovial membrane. 

 Articulationes carpo-metacarpcce digitorum : These are arthro- 

 dial diarthroses between the distal carpal row and the four 

 inner metacarpals. There is a common capsule with special 

 oblique bands, viz. : Oblique palmar ligaments; one or two slips 

 running to each metacarpal from the carpal bones, but the third 

 may get three. Oblique dorsal ligaments; similar stronger 

 bands joining the second metacarpal to the trapezium and 

 trapezoid ; the middle metacarpal to the os magnum and (often) 

 trapezoid; the fourth metacarpal to the os magnum and 

 unciform; and the fifth metacarpal to the unciform. One or 

 two interosseous ligaments lie within the capsule, usually in 

 relation to the contiguous margins of the bases of the third 

 and fourth metacarpals, and extending thence to the adjacent 

 margins of the os magnum and unciform. A synovial mem- 

 brane lines the capsule and has prolongations into the inter- 

 metacarpal and intercarpal joints. [287] 



Metacarpo-phalangeal Joints. The thumb is a ginglymus 

 diarthrosis ; the others are slightly modified enarthrodial diar- 

 throses. Each joint has a capsule (which cannot be demon- 

 strated dorsally) with its separate synovial membrane. Strong 

 cord-like external lateral and internal lateral ligaments run, 

 from the tubercles and adjacent depressions on the sides of the 

 heads of the metacarpals, to the contiguous non-articular areas 

 on the bases of the proximal phalanges. The palmar ligaments 

 are plates of fibre-cartilage placed between and connected 

 with the lateral ligaments, and grooved ventrally for ten- 

 dons. [288] 



Transverse Metacarpal Ligament. This structure unites 



[156] 



