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Tibialis posterior tendon (metatarsal insertions)

The tibialis posterior tendon (TPT) is the most significant dynamic stabilizer of the medial longitudinal arch of the foot. It originates from the tibialis posterior muscle in the deep posterior compartment of the leg and courses behind the medial malleolus before dividing into multiple slips of insertion.

Among its numerous attachments to tarsal bones, the tendon also provides important insertions to the bases of the second, third, and fourth metatarsals. These insertions contribute to arch support, load distribution, and stabilization of the midfoot. Dysfunction or rupture of the tendon, especially near its metatarsal attachments, is a hallmark of adult-acquired flatfoot deformity (AAFD).

Synonyms

  • Posterior tibial tendon (PTT)

  • Tibialis posterior tendon slip insertions

Course and Insertion (Metatarsal Focus)

  • The tendon runs posterior to the medial malleolus, secured in its sheath beneath the flexor retinaculum.

  • After crossing the ankle, the tendon fans out into multiple slips.

  • Metatarsal insertions:

    • Second metatarsal base (via slip from medial cuneiform)

    • Third metatarsal base (via slip from lateral cuneiform)

    • Fourth metatarsal base (via slip from cuboid/lateral cuneiform)

  • These slips help tether the metatarsals together and support the transverse and longitudinal arches.

Relations

  • Medially: Flexor digitorum longus tendon

  • Laterally: Flexor hallucis longus tendon

  • Anteriorly: Medial malleolus, talus

  • Posteriorly: Calcaneus and ankle joint capsule

  • Inferiorly: Plantar aponeurosis and intrinsic foot muscles

Function

  • Arch support: Primary dynamic stabilizer of the medial longitudinal arch

  • Metatarsal stabilization: Maintains alignment of the 2nd–4th metatarsal bases

  • Load distribution: Transfers forces from hindfoot to forefoot

  • Supination and inversion: Contributes to foot inversion and plantarflexion with tibialis anterior

  • Clinical relevance: Weakness or rupture leads to progressive flatfoot deformity and midfoot collapse

MRI images

Tibialis posterior tendon (metatarsal insertions) axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000