The talocrural joint's primary motion is which of the following?

The talocrural joint's primary motion is which of the following?

• A. Eversion
• B. Inversion
• C. Horizontal rotation
• D. Dorsiflexion

Answer: (D)

The talocrural joint functions mainly as a hinge that moves in the sagittal plane, permitting dorsiflexion and plantarflexion. Dorsiflexion—bringing the top of the foot toward the shin—is the primary motion because the joint’s geometry (the tibia and fibula forming a mortise around the talus) allows the talus to rock forward during dorsiflexion and the leg to advance over a relatively fixed foot. Inversion and eversion occur largely at the subtalar joints, not at the talocrural joint, and horizontal rotation is not a primary motion here. So, dorsiflexion is the best answer, with plantarflexion as the complementary motion.

The talocrural joint functions mainly as a hinge that moves in the sagittal plane, permitting dorsiflexion and plantarflexion. Dorsiflexion—bringing the top of the foot toward the shin—is the primary motion because the joint’s geometry (the tibia and fibula forming a mortise around the talus) allows the talus to rock forward during dorsiflexion and the leg to advance over a relatively fixed foot. Inversion and eversion occur largely at the subtalar joints, not at the talocrural joint, and horizontal rotation is not a primary motion here. So, dorsiflexion is the best answer, with plantarflexion as the complementary motion.