To clarify the morphological patterns of the extensor tendon and juncturae tendinum on the dorsum of the hand.

Fifty eight hands of cadavers were dissected to evaluate the morphological patterns of the extensor tendon and juncturae tendinum.

The tendon of extensor indicis proprius and extensor digitorum communis (EDC) to the index finger arose and terminated at a single tendon. The EDC to the long finger arose as a single tendon, divided into two slips and then converged again to form a single tendon. The EDC to the ring finger arose as double tendons, divided into three or four slips and converged again into double tendons. The EDC to the little finger was usually absent (72%). The extensor digiti minimi arose and terminated as double tendons. The juncturae tendinum (JT) between the EDC tendons to the index finger and those to the long finger were of type I (thin filamentous type). The JT between EDC tendon to the long finger and those to the ring finger consisted of 16% in type I, 31% in type II (thick filamentous type) and 53% in type III (tendinous type). There were 14% of type II JT and 86% of type III JT between the ring and small fingers.

A knowledge of both the usual and possible variations of the extensor tendon and the juncturae tendinum is useful in the identification and repair of these structures.