Which muscle inserts at the base of the first metatarsal?

Which muscle inserts at the base of the first metatarsal?

• A. Gastrocnemius
• B. Soleus
• C. Extensor Digitorum Longus
• D. Tibialis Anterior

Answer: (D)

Understanding where a muscle attaches helps explain what it does. The base of the first metatarsal is the insertion site for the tibialis anterior. This muscle runs in the anterior compartment, crossing the ankle to attach to the medial cuneiform and the base of the first metatarsal. Its tendon positioning lets it pull the foot upward (dorsiflexion) and inward (inversion), which is precisely what inserting on the base of the first metatarsal enables. The other muscles listed attach elsewhere: gastrocnemius and soleus converge on the calcaneus via the Achilles tendon, driving plantarflexion of the foot; extensor digitorum longus extends the other toes (2–5) and inserts on their phalanges, not on the first metatarsal.

Understanding where a muscle attaches helps explain what it does. The base of the first metatarsal is the insertion site for the tibialis anterior. This muscle runs in the anterior compartment, crossing the ankle to attach to the medial cuneiform and the base of the first metatarsal. Its tendon positioning lets it pull the foot upward (dorsiflexion) and inward (inversion), which is precisely what inserting on the base of the first metatarsal enables.

The other muscles listed attach elsewhere: gastrocnemius and soleus converge on the calcaneus via the Achilles tendon, driving plantarflexion of the foot; extensor digitorum longus extends the other toes (2–5) and inserts on their phalanges, not on the first metatarsal.