MRI of anatomical variants of the wrist in women.

In the analysis of magnetic resonance (MR) images of the wrist joint, some structural variations may lead to misinterpretation. Our aim was to search for different anatomical variants and their MR characteristics on axial images. Two groups of patients with rheumatoid arthritis (thirty one) and carpal tunnel syndrome (sixty two), and a group of asymptomatic controls (fifty four) underwent bilateral MR axial wrist imaging from the metacarpal bases to the distal radiocarpal joint. The imaging techniques included spin echo (SE), turbo spin echo (TSE) and fast field echo (FFE) sequences, using 3 mm-slice thickness. Different anatomical variants including hypoplasia of the hamulus or hook of the hamate bone (4 cases), anomalous muscles (lumbricals) inside the carpal tunnel (2 cases), unusual location (5 cases) and double branching of the median nerve (14 cases), and aberrant median artery (one case) were detected. These variants, if unfamiliar to MR readers, may be misinterpreted as pathological features.