Chapter 20, Problem 1GAQ

Summary Introduction

To describe: The ankle (talotibial) joint.

Introduction: The bones of the skeletal system serve as a supporting framework on which the body is assembled. Bones are the safeguard and support system of the internal organs.

Answer to Problem 1GAQ

1. a. Number of axes: One.
2. b. Shape of joint: Hinge.
3. c. Type of muscle action allowed: Plantar flexion, dorsiflexion.
4. d. Bones involved: Tibia and talus (primarily).

Explanation of Solution

The ankle joint is formed of the distal tibia, fibula, and talus. The ankle joint is also called as the talotibial joint. In the ankle joint, only one axis is present. The orientation of this axis is oblique and can pass through all the three planes. The ankle joint is a type of a hinge joint. This type of joint is formed when the bones can move only in a single axis. The two types of ankle movement are the planar flexion and dorsiflexion. The movement toward the planar surface of the foot is known as the planar flexion. When the movement of the dorsal foot is toward the anterior, it is known as dorsiflexion. The ankle joint comprises of the tibia and talus and they are involved in the ankle movement.