Lower limb
Common Tendon Sheath of the Fibularis Muscles
Vagina tendinum musculorum fibularium communis
- Origin
- Surrounds the tendons of the fibularis longus and brevis muscles behind the lateral malleolus
- Insertion
- Extends distally past the lateral malleolus, where the tendons each acquire their own sheath
- Function
- Reduces friction and holds the tendons of the fibularis longus and brevis muscles in place behind the lateral malleolus during movement of the foot
- Innervation
- No independent innervation; synovial connective tissue
- Movement & chain
- Enables frictionless retro-malleolar gliding of fibularis longus and brevis tendons during foot eversion and plantarflexion.
- Palpation
- Easily palpated immediately posterior and inferior to the lateral malleolus; tightens during resisted foot eversion.
- Clinical
- Peroneal tenosynovitis, peroneal tendon subluxation/dislocation following superior peroneal retinaculum tear, and chronic lateral ankle instability.
- Segmental innervation
- L5–S1 (superficial fibular nerve)
- In clinical practice
- Diabetic foot inspection and pressure ulcer prevention; monitor for friction points from footwear or bedding and ensure correct anti-embolism stocking fit.
- Region in the model
- Lower limb