Extensor Retinacula Revisited

In 2007 Abu-Hijleh, M. F. and Harris, P. F. published a paper on the deep fascia of the distal leg, ankle and dorsal foot. Dissecting 14 limbs they examined arrangement, fiber orientation and collagen content.

Among other findings they list the following.

The deep fascia of the distal leg, ankle and dorsal foot forms a continuous sheet containing thickened bands or retinacula. It is anchored to the subcutaneous surface, the tibia and fibula (both malleoli), the tarsal and metatarsal bones.

The Superior Extensor Retinaculum (SER) seems variable in width and thickness. A clearly defined band as generally illustrated is not found. The observed thin bands, possibly representing the SER, run from the tibia to the fibula, crossing the anterior compartment of the distal leg.

Instead of the familiar Y shape the Inferior Extensor Retinaculum (IER) is observed to have an X shape (9 out of 14) or is formed by a central thick node-like band (5 out of 14). Based on dissection findings Abu-Hijleh suggests a physical connection between the IER and the spring ligament.

Several additional bands are consistently found.

The Extensor Digitorum Brevis Retinaculum (EDBR), a band crossing the belly of the muscle connecting with the IER and fascia over the abductor digiti minimi.

The Proximal Extensor Hallucis Retinaculum (PEHR), a band crossing the distal tendons of the extensor hallucis longus and brevis and the distal tibialis anterior attachment (specifics are not given) at the tarsal/metatarsal level. This band connects with the abductor hallucis (its fascia) and the (dorsal) interosseous fascia of the foot.

The Distal Extensor Hallucis Retinaculum (DEHR), a band crossing the distal tendons of the extensor hallucis longus and brevis at the distal metatarsal level. This band also connects with the abductor hallucis (its fascia), the (dorsal) interosseous fascia of the foot and the DLPF.

The Disto-Lateral Pedal Fascia (DLPF), a band crossing the distal tendons of the extensor digitorum longus and brevis at a distal metatarsal level. This band connects with the abductor digiti minimi (its fascia), the (dorsal) interosseous fascia of the foot and the DEHR.

Malleolar Fascia (MF), oblique transverse bands on the tibial and fibular sides, crossing over the malleoli. Both bands connect with the SER.

In regard to collagen fiber disposition, using polarized light a “crisscrossing or woven mesh pattern” is observed. This pattern is observed in all specimens from the distal lower leg to the dorsum of the foot. Histological sections show collagen fibers with elongated nuclei and confirm the “crisscrossing or woven mesh pattern”.

From Theory to Practice
Based on Abu-Hijleh’s research we can opt to consider the individual thickened bands (retinacula) and fiber orientation when treating the deep fascia of the distal lower leg, ankle, dorsum of the foot and its related organs.

Because of the PEHR and DEHR, abductor hallucis, extensor hallucis longus connections we can, for example, consider the abductor hallucis when addressing a flexor hallucis related problem. And the “crisscrossing or woven mesh pattern” might require us to “aim” our therapy and exercises in more than a single direction.

For more details and first hand details please read:
Abu-Hijleh MF, Harris PF. Deep fascia on the dorsum of the ankle and foot: extensor retinacula revisited. Clin Anat. 2007 Mar;20(2):186-95.