plantardorsiflexion

Plantardorsiflexion is not a standard anatomical term; instead, anatomy describes two opposite movements at the ankle: plantarflexion and dorsiflexion. Plantarflexion points the foot downward (standing on tiptoe), while dorsiflexion lifts the foot upward toward the shin. Together, they define the range of motion of the ankle in the sagittal plane.

Anatomy and function. The primary joint involved is the talocrural joint. Plantarflexion is produced by the strong calf muscles—the gastrocnemius and soleus (often called the triceps surae)—with support from the plantaris, tibialis posterior, flexor digitorum longus, and flexor hallucis longus. Dorsiflexion is mainly driven by the tibialis anterior and, to a lesser extent, by the extensor hallucis longus and extensor digitorum longus, with the fibularis tertius contributing a small assist. Nerve supply follows muscle groups: tibial nerve for most plantarflexors and deep peroneal (fibular) nerve for the primary dorsiflexors.

Range of motion and measurement. Normal dorsiflexion is about 20 degrees with the knee extended, and plantarflexion is roughly 50 degrees. Clinicians assess ankle mobility using a goniometer, positioning the fulcrum at the lateral malleolus and the axis parallel to the fifth metatarsal, to quantify ROM and track changes over time.

Clinical significance. Adequate plantarflexion and dorsiflexion are essential for gait, balance, and push-off during walking or running. Restricted dorsiflexion or excessive plantarflexion can contribute to altered gait mechanics, ankle instability, or compensatory movements. Weakness or nerve injury affecting the dorsiflexors can lead to foot drop, while tight plantarflexors can limit dorsiflexion.

See also: plantarflexion, dorsiflexion.