. Cunningham's Text-book of anatomy. Anatomy. METACAEPO-PHALANGEAL JOINTS. 333 The synovial stratum (Fig. 311) is usually single and lines the fibrous stratum, but, as already explained, it has prolongations into the intermetacarpal and inter- carpal series of joints. In connexion with the intercarpal series, the frequent absence of the interosseous ligament between the greater and lesser multangular bones permits the free communication of this joint cavity with that of the transverse carpal joint. ARTICULATIONES Metacarpophalangeal Joints.—In the case of the pollex this j
. Cunningham's Text-book of anatomy. Anatomy. METACAEPO-PHALANGEAL JOINTS. 333 The synovial stratum (Fig. 311) is usually single and lines the fibrous stratum, but, as already explained, it has prolongations into the intermetacarpal and inter- carpal series of joints. In connexion with the intercarpal series, the frequent absence of the interosseous ligament between the greater and lesser multangular bones permits the free communication of this joint cavity with that of the transverse carpal joint. ARTICULATIONES Metacarpophalangeal Joints.—In the case of the pollex this joint is con- structed on the plan of a ginglymus diarthrosis; the four corresponding joints of the fingers are also diarthroses of a slightly modified ball-and-socket variety. With the exception of the metacarpal bone of the pollex, each metacarpal bone has a somewhat spherical head articulating with a shallow oval cup upon the base of the first phalanx. It is important to note that the articular surface upon the head of each of these metacarpal bones is wider on the volar aspect and narrower on the dorsal aspect. The articulation in the thumb presents features similar to those of an interphalangeal joint. Each joint possesses a capsula articularis (Fig. 312) which presents very different degrees of strength in different aspects of the articulation. Thus, on the dorsal aspect, it cannot be demonstrated as an independent structure, but the necessity for dorsal ligaments is to a large extent obviated by the presence of the strong flattened expansions of the extensor tendons. The epiphyseal lines are extra-capsular. Ligamenta Collateralia.—The collateral ligaments ( internal and external lateral) (Fig. 312) are strong cord-like bands which pass from the tubercles and adjacent depressions on the sides of the heads of the metacarpal bones to the contiguous non-articular areas on the bases of the proximal phalanges. They are intimately connected on their volar aspects with th
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
