inferior extensor retinaculum of the foot

{{short description|Y-shaped band placed in front of the ankle-joint}}

{{See also|Superior extensor retinaculum of foot}}

{{Infobox ligament

| Name = Inferior extensor retinaculum of foot

| Latin = retinaculum musculorum extensorum inferius pedis, ligamentum cruciatum cruris

| Image = Gray441.png

| Caption = The mucous sheaths of the tendons around the ankle. Lateral aspect.

| Image2 = Gray442.png

| Caption2 = The mucous sheaths of the tendons around the ankle. Medial aspect.

| From =

| To =

}}

The inferior extensor retinaculum of the foot (cruciate crural ligament, lower part of anterior annular ligament) is a Y-shaped band placed in front of the ankle-joint, the stem of the Y being attached laterally to the upper surface of the calcaneus, in front of the depression for the interosseous talocalcaneal ligament; it is directed medialward as a double layer, one lamina passing in front of, and the other behind, the tendons of the peroneus tertius and extensor digitorum longus.{{Cite book |title=Gray's Anatomy: the anatomical basis of clinical practice |date=2021 |publisher=Elsevier |isbn=978-0-7020-7705-0 |editor-last=Gray |editor-first=Henry |edition=42nd |location=Amsterdam |page=1430 |chapter=Chapter 79 Ankle and foot |editor-last2=Standring |editor-first2=Susan |editor-last3=Anhand |editor-first3=Neel}}{{Cite journal |last=Dalmau-Pastor |first=M. |last2=Yasui |first2=Y. |last3=Calder |first3=J. D. |last4=Karlsson |first4=J. |last5=Kerkhoffs |first5=G. M. M. J. |last6=Kennedy |first6=J. G. |date=2016-05-29 |title=Anatomy of the inferior extensor retinaculum and its role in lateral ankle ligament reconstruction: a pictorial essay |url=http://link.springer.com/10.1007/s00167-016-4082-5 |journal=Knee Surgery, Sports Traumatology, Arthroscopy |language=en |volume=24 |issue=4 |pages=957–962 |doi=10.1007/s00167-016-4082-5 |issn=0942-2056 |via=Springer|hdl=2445/110811 |hdl-access=free }}

At the medial border of the latter tendon, these two layers join, forming a compartment in which the tendons are enclosed.

From the medial extremity of this sheath, the two limbs of the Y diverge: one is directed upward and medialward, to be attached to the tibial malleolus, passing over the extensor hallucis longus and the vessels and nerves but enclosing the tibialis anterior by a splitting of its fibers.

The other limb extends downward and medialward, to be attached to the border of the plantar aponeurosis, and passes over the tendons of the extensor hallucis longus and tibialis anterior and also the vessels and nerves.