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The intra- and interobserver variability of 3 techniques for measuring the humpback deformity of 37 scaphoids using longitudinal computed tomography was assessed. The 3 measuring techniques were the lateral intrascaphoid angle, the dorsal cortical angle, and the height-to-length ratio. The intraobserver reliability of the intrascaphoid angle was poor; the dorsal cortical angle was moderate to excellent, and the height-to-length ratio was excellent. The interobserver reliability of the intrascaphoid angle was poor to moderate, the dorsal cortical angle was moderate to excellent, and the height-to-length ratio was moderate to excellent. For all 3 observers, the intra- and interobserver reliability was the best for the height-to-length ratio and worst for the intrascaphoid angle. The height-to-length ratio is the most reproducible method of assessing the humpback deformity. Clinical correlation is required to establish whether the height-to-length ratio will be of value in predicting the outcome of fractures of the scaphoid.

The hook of the hamate is an important landmark in endoscopic carpal tunnel release. We studied the incidence of abnormalities of the hook of the hamate in patients with carpal tunnel syndrome. One hundred thirty-one consecutive patients presenting with carpal tunnel syndrome underwent carpal tunnel radiography. Abnormalities of the hook of the hamate were present in 6 of 131 patients (4.6%). The hook of the hamate was aplastic in 3 of 131 patients (2.3%). A bipartite hook of the hamate was present in 1 patient (0.8%). A nonunion of an old fracture of the hook of the hamate was found in two patients (1.6%). The previously reported incidence of an aplastic hook of the hamate in the general population is 1 of 1,452 (0.06%). The odds ratio revealed a 34-fold increase in the risk of hamate abnormalities in the carpal tunnel population (p < 0.001). Hook of the hamate abnormalities may be more common than previously reported.

Computed tomography is increasingly utilized for the evaluation of scaphoid fracture, nonunion, and deformity. We have developed a new technique of positioning patients while performing longitudinal computed tomography of the scaphoid. With the wrist positioned in radial deviation and neutral flexion, greater patient comfort is provided and immobilization of the wrist is not required. A reproducible image can be obtained with attention to the alignment of the scanning plane to the longitudinal axis of the scaphoid on the scout image, and verified with the "target sign". High resolution images, which clearly demonstrate the abnormalities of the scaphoid, can be produced even if the patient has a cast on the wrist or if there is hardware in situ.