Lower limb
Tendon sheath of tibialis posterior
Vagina tendinis musculi tibialis posterioris
- Origin
- Begins ~4-5 cm proximal to the medial malleolus on the posterior distal tibia
- Insertion
- Passes through the anterior compartment of the tarsal tunnel deep to the flexor retinaculum to terminate near the navicular tuberosity
- Function
- Ensures frictionless gliding for the tibialis posterior tendon, the primary dynamic stabilizer of the medial longitudinal arch
- Innervation
- Branches from the tibial nerve
- Movement & chain
- Displaces during foot inversion, adduction, and arch elevation
- Palpation
- Palpable immediately posterior and inferior to the medial malleolus down to the navicular tuberosity
- Clinical
- Posterior tibial tendon dysfunction (PTTD) / tenosynovitis; progressive degeneration causes adult-acquired flatfoot deformity (AAFD); 'too many toes' sign
- Segmental innervation
- L4, L5 spinal segments
- In clinical practice
- Single-leg heel rise test (failure to invert calcaneus on tip-toe); custom orthotic arch support with medial posting, physical therapy, and tendon reconstruction
- Region in the model
- Lower limb