Intertendinous connections

The intertendinous connections are fibrous or tendinous bands that link the adjacent tendons of the extensor digitorum muscle on the back (dorsum) of the hand in the metacarpal region. These connections are most commonly found between the tendons going to the middle, ring, and little fingers.

The strongest of these connections are usually between the tendons of the middle and ring fingers. We can also frequently find a connection between the little finger tendon and the ring finger tendon. Connections between the index and middle fingers are more variable.

These intertendinous connections have a significant functional impact. They redistribute force among the extensor tendons and limit the independent extension of the fingers. Because force from one extensor tendon is partially transferred to its neighbors, it explains why we often can't fully extend just one finger in isolation.