Final answer:
The primary insertion for the tibialis posterior muscle is the navicular bone which plays a key role in the movement and stabilization of the foot.
Step-by-step explanation:
The primary insertion for the tibialis posterior muscle is the navicular bone of the foot. This muscle plays a crucial role in plantar flexion and inversion of the foot.
The tarsal bones of the posterior foot, including the calcaneus, talus, navicular, cuboid, and the medial, intermediate, and lateral cuneiform bones, form the structural framework of the foot. The tibialis posterior, which is critical for stabilizing the foot arch during locomotion, inserts mainly on the navicular bone but also sends fibres to the medial, intermediate, and lateral cuneiform bones, and to the bases of the second, third, and fourth metatarsal bones. The talus bone receives the weight from the tibia and transfers it to the calcaneus, or heel bone. The articulation of the tarsal bones forms the ankle joint and supports the various movements of the foot.