6.62. Ossification: In the first year of life the ossification centres for the capitate (C) and hamate (H) appear at 2 months, the radius (R) at 6 months, and the triquetral (T) at 10 months. After the first year, the lunate (L) appears at about 2. the trapezium (Tr) at 21/:. the trapezoid (Tz) and scaphoid (S) at 3. and the distal ulna (U) at 4>/i years.
6.63. Wrist radiographs: examples of pathology (1): the radiograph shows a deformity of the upper limb in which there is absence of the radius and thumb, along with failure of carpal differentiation. Diagnosis: congenital deformity.
6.64. Pathology (2): The radiographs show an upper and lower limb where the width of the bones is normal but they are proportionately short, contributing to the dwarfism associated with this hereditary abnormally. The metaphyses are wide, and there is defective modelling of the shafts. Diagnosis: achondroplasia.
6.65. Pathology (3): In this radiograph of a child's forearm there is a little metaphyseal widening and irregularity, with ulnar metaphyseal cupping (said to be due to pressure transmitted in crawling). Diagnosis: rickets.
6.66. Pathology (4): There are deformities of the distal radius and ulna, which are splayed. There is relative lengthening of the ulna, which is unduly prominent at the side and back of the wrist.
Diagnosis: Madelung deformity of the wrist.
6.67. Pathology (5): There is gross distortion and collapse of the lunate. Diagnosis: Kienbock's disease.
6.68. Pathology (6): The history is of weakness and instability of the wrist, with clicking sensations and pain occurring with certain movements.
Diagnosis: carpal instability secondary to scapholunate dissociation.
6.69. Pathology (7): The radiograph shows a defect in the continuity of the scaphoid, with increased density of its proximal pole. Diagnosis: there has been a fracture of the scaphoid, followed by non-union and avascular necrosis.
6.70. Pathology (8): The radiograph shows a long-established defect situated in the waist of the scaphoid. There is some narrowing of the joint space between the scaphoid and the radius. Diagnosis: established non-union of the scaphoid following fracture, with early secondary radiocarpal osteoarthritis.
6.71. Pathology (9): There is gross destruction of the carpal and wrist joints, with fibrous ankylosis.
Diagnosis: the findings are typical of the late appearances of an infective arthritis (in this case due to tuberculosis).
6.72. Pathology (10): The radiograph was taken shortly after a fall on the outstretched hand, when there was complaint of pain in the wrist and paraesthesia over the ball of the thumb.
Diagnosis: the lateral projection shows two bones lying proud of the rest of the carpus at the front of the wrist: one is the normally situated pisiform; the other, semilunar in shape and lying more proximal, is a dislocated lunate. The symptoms suggest involvement of the median nerve.
6.73. Pathology (11): The radiograph shows an abnormality of the distal radius. There is rounding of the proximal part of the small bone fragment in the region of the styloid process.
Diagnosis: fracture of the styloid process of the radius, which has failed to unite. The appearances are of a long-standing lesion. Such a condition may be symptom free, or give pain if secondary arthritic changes develop between the radius and scaphoid.
16.74. Pathology (12): This radiograph of a ' child's wrist and forearm shows gross distortion of the distal radius. There are apparently cystic spaces in the radial shaft, with extensive new bone formation. Diagnosis: the appearances are typical of gross osteitis, with bone abscess formation. In this case the causal organism was, unusually, the tubercle bacillus. (NB: Most tuberculous infections have their principal effects on the joints, rather than the shafts of the long bones.)
6.75. Pathology (13): There is widespread ► decalcification of the carpus and adjacent long bones, with loss of radiological carpal detail. There was complaint of pain and stiffness following a minor injury. Diagnosis: Sudeck's atrophy (complex regional pain syndrome). The radiological appearances are similar to those found in rheumatoid arthritis.
6.76. Pathology (14): This anteroposterior radiograph shows distortion of the inferior radioulnar joint, relative lengthening and prominence of the ulna, and widening of the radius. The patient complained of pain in the wrist (in the radioulnar joint) and restriction of pronation/supination movements. Diagnosis: malunion of a Colles' fracture.
6.77. Pathology (15): The lateral radiograph of the same case shows marked alteration in the plane of the radiocarpal joint, again due to malunion; this, apart from the deformed appearance, has the effect of seriously restricting palmar flexion.
6.78. Aspiration of the wrist joint:
Using your thumb, feel for the depression at the back of the wrist which lies between the distal end of the radius and scaphoid, and which is bordered by extensor digitorum communis and extensor carpi radialis brevis. Infiltrate this area with local anaesthetic before introducing the aspirating needle. The tip of the needle should be directed cranially at an angle of 30° from the vertical.
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