Anatomical variations in the first extensor compartment of the wrist. A clinical and anatomical study.

We studied 300 wrists from cadavera and the wrists of forty patients with de Quervain disease to determine the variation in the pattern of the tendons and septa in the first extensor compartment. In 75 per cent of the wrists from cadavera, we found that the number of tendons within the compartment differed from what is considered standard; there was complete or partial septation in 40 per cent. In about a third of the specimens from cadavera, the first extensor compartment was divided by a septum and two tendons or more were present within the major subcompartment. These features might readily result in inadequate decompression of the compartment in the treatment of de Quervain disease. In our prospective study of forty patients with de Quervain disease, septation was found in twenty-seven. There was no significant difference between the number of patients and the number of specimens from cadavera that had no, one, or two accessory abductor tendons.