Mid-foot retinaculum: an unrecognized entity

Area of Science:

• Anatomy
• Orthopedics
• Biomechanics

Background:

• Retinacula are fascial thickenings stabilizing tendons around joints.
• Known retinacula in the ankle region include superior and inferior extensor retinacula.
• The function of extensor tendons at distal joints necessitates secure tendon fixation.

Purpose of the Study:

• To investigate the presence of an additional extensor retinaculum in the mid-foot.
• To identify the attachments and structures passing beneath this potential mid-foot retinaculum.
• To understand the functional and clinical implications of a mid-foot retinaculum.

Main Methods:

• Dissection of 50 cadaveric feet.
• Detailed examination of the mid-foot region.
• Identification and documentation of anatomical structures.

Main Results:

• An additional extensor retinaculum was identified distal to the inferior extensor retinaculum in 22 out of 50 feet (44%).
• This mid-foot retinaculum, partially or completely present in about half the specimens, covered tarsometatarsal joints.
• Structures found beneath the retinaculum included extensor tendons, the medial terminal branch of the deep peroneal nerve, and the dorsalis pedis artery.

Conclusions:

• A partial or complete mid-foot retinaculum exists, potentially stabilizing extensor tendons.
• This anatomical variation may contribute to deep peroneal nerve entrapment, mimicking anterior tarsal tunnel syndrome.
• Further research is warranted to fully elucidate the biomechanical role and clinical significance.