Carpal Angle Abnormalities

► [Variations in the relative position of proximal carpals (scaphoid, lunate and triquetrum)]

The carpal bones in the proximal row articulate with the distal radius and ulna. The articular surface of the radius is divided by a central ridge of bone into a lateral portion, articulating with the scaphoid, and a medial portion, articulating with the lunate. The distal ulna articulates with the os triquetrum through the triangular fibrocartilage. The os pisiform, which is located lateral to the triquetrum, does not enter the wrist joint. The carpal bones in the distal row articulate with the bases of the metacarpals (the trapezium with the 1st metacarpal, the trapezoid with the 2nd, the capitate mainly with the 3rd, and the hamate with the 4th and 5th). The carpal angle, a measure of the relative position of the three carpal bones in the proximal row, is formed by the intersection of two

Turner Syndrome Drumstick Phalanges

Fig. 6.51. Turner syndrome. Radiodermatography of left hand, showing marked sloping of distal radius, widening of distance between radius and ulna, and wedging of the carpal bones between deformed radius and protruding ulna, with the lunate at the apex of the wedge. Note also relative shortening of the 4th metacarpal, drumstick-like distal phalanges, and abnormal creases

Fig. 6.51. Turner syndrome. Radiodermatography of left hand, showing marked sloping of distal radius, widening of distance between radius and ulna, and wedging of the carpal bones between deformed radius and protruding ulna, with the lunate at the apex of the wedge. Note also relative shortening of the 4th metacarpal, drumstick-like distal phalanges, and abnormal creases lines, the first tangent to the proximal surfaces of the scaphoid and lunate and the second tangent to the proximal margin of the triquetrum and lunate. This angle is subject to interracial differences (e.g., it is smaller in Whites than in Blacks) and can be decreased or increased in various pathologic conditions. The close interrelation between distal radius-ulna and proximal carpals at the wrist is such that changes in one compartment cause modifications in the other. For example, the increased carpal angle in arthrogryposis is often associated with hypoplasia of the scaphoid (Poznanski 1984). Significant disarrangement of the carpal bones with a changed carpal angle can occur in several acquired conditions, notably trauma with dislocation and rheumatoid arthritis. Varying degrees of loss of wrist motion occur in association with carpal angle changes.

Rheumatoid Arthritis Pisiform Bone

Fig. 6.52. Mucopolysaccharidosis type I-H (Hurler syndrome) in a 2-year-old boy. The distal articular surfaces of the ulna (arrow) and, to a lesser extent, of the radius are slanted toward each other. The tubular bones of the hand are short and wide. The proximal and middle phalanges are wide and deformed at their base and are bullet shaped. The 2nd through 5th metacarpals are pointed proximally. Bone trabeculation is prominent

Fig. 6.52. Mucopolysaccharidosis type I-H (Hurler syndrome) in a 2-year-old boy. The distal articular surfaces of the ulna (arrow) and, to a lesser extent, of the radius are slanted toward each other. The tubular bones of the hand are short and wide. The proximal and middle phalanges are wide and deformed at their base and are bullet shaped. The 2nd through 5th metacarpals are pointed proximally. Bone trabeculation is prominent

Decreased (more acute) carpal angle typically occurs with the Madelung deformity, a condition involving disturbed radial growth resulting in dorsal bowing of the radius, medial sloping of its epiphysis, and tri-angularization of the carpus with the lunate at the vertex of the triangle. The ulna is displaced dorsally. Madelung deformity is a prominent and constant feature in dyschondrosteosis (Leri-Weill disease, OMIM 127300), a form of mesomelic dwarfism caused by mutations in the pseudoautosomal SHOX genes (Langer 1965; Belin et al. 1998). Another condition with a triangular shape of the distal radial epiphysis and reduced carpal angle is Turner syndrome (Kosowicz 1962, 1965). Additional features in the carpus include a coarse, reticular pattern (Bercu et al. 1976), delayed maturation, and overall carpal smallness as assessed by either linear measurement (Poznanski eta l. 1978) or surface area measurement (Cleveland et al. 1985) (Fig. 6.51). In hereditary multiple exostoses (OMIM 133700) and Ollier disease (OMIM 166000), a wrist deformity reminiscent of Madelung deformity can result from restriction to longitudinal bone growth and/or direct impaction of a growing exostosis (or enchon-droma, respectively) on a contiguous bone. Lateral bowing of the radius and medial slanting of its articular surface lead to wedging of the carpus. In contrast to Madelung deformity, shortening of the distal ulna with ulnar deviation of the hand is a common feature in these conditions (Pritchett 1986). In mucopolysac-charidoses type I (Hurler syndrome, OMIM 252800) and type IV (Morquio disease, OMIM 253000,253010), changes in the carpal angle are secondary to distal tapering of radius and ulna (Fig. 6.52).

Increased (more obtuse) carpal angle occurs in several disorders, including frontometaphyseal dysplasia, oto-palato-digital syndrome, epiphyseal dys-plasias, diastrophic dysplasia, Down syndrome, arthrogryposis, spondyloepiphyseal dysplasia, and Pfeiffer syndrome. Again, the primary defect can be in the carpus (various deformations, extra-carpals, etc.), with widening of the carpal angle occurring secondarily. One such an example is diastrophic dys-plasia (OMIM 222600), a disorder that is characterized by extensive rearrangement of the carpal bones.

Arthritis Joint Pain

Arthritis Joint Pain

Arthritis is a general term which is commonly associated with a number of painful conditions affecting the joints and bones. The term arthritis literally translates to joint inflammation.

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