The two peroneal tendons are located on the outer side of the back of the ankle, and connect the muscles that allow you to stand on your tip toes. These tendons are susceptible to two similar injuries known as a dislocation or a subluxation. A dislocation occurs when one or both of the tendons is out of alignment and slips completely out of the groove where they normally rest. A subluxation is a lesser but similar injury in which one or both of the tendons slide in and out of normal alignment. The tendons are normally held into place by a ligament-like structure (retinaculum); however, when this structure is injured dislocations and subluxations are common.