Anterior tarsal tendon sheaths
Vaginae tarseae anteriores tendinum
- Latin synonym: Vaginae tendinum tarsales anteriores
- Related terms: Anterior tarsal tendinous sheaths
Definition
The anterior tarsal tendon sheaths are synovial structures that envelop the extensor tendons as they traverse the anterior aspect of the ankle and dorsum of the foot:
These sheaths facilitate smooth gliding of the tendons beneath the extensor retinacula and reduce friction during movement. The principal tendons in this region include the extensor hallucis longus (EHL), extensor digitorum longus (EDL), and tibialis anterior, each with its own sheath as they pass under the superior and inferior extensor retinacula.
The tendon sheaths of the EHL and EDL typically begin proximal to the ankle joint and extend distally onto the dorsum of the foot, terminating near the metatarsophalangeal joints. The tibialis anterior tendon sheath is more limited, ending near its insertion on the medial cuneiform and first metatarsal. These sheaths are clinically significant, as inflammation or adhesions can impair tendon function and contribute to conditions such as anterior tarsal tunnel syndrome : the inferior extensor retinaculum forms the roof of the anterior tarsal tunnel, while the floor is composed of the fascia overlying the talus and navicular. Within this compartment, the tendon sheaths are closely associated with the deep peroneal nerve, dorsalis pedis artery, and accompanying veins.
The sheaths are lined by synovial membrane, which is continuous with the synovial lining of the tendons, and are surrounded externally by a thin layer of areolar connective tissue (paratenon) that provides vascular supply and facilitates healing.
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