Chapter 4 The Skeletal System 149 the medial center of the bottom of the foot to be slightly elevated. It is these arches that compress somewhat during the weight-bearing phase of your gait, but then act as springs when they rebound to their original shape during the propulsive (push-off) phase of the gait. Check Your Understanding 1. Which bones make up the pelvic girdle? 2. Which three bones fuse to form each coxal bone? 3. What is the longest and strongest bone in the body? 4. Although relatively small bones, the bones of the toes serve what important function? 5. What is the purpose of the two arches formed by the metatarsal bones? © Body Scientific International Figure 4.28 Superior (A) and inferior (B) views of the bones of the right foot. A Superior view B Inferior view Distal phalanx 1 Proximal phalanx 1 Metatarsal Medial cuneiform Intermediate cuneiform Lateral cuneiform Navicular Talus Trochlear surface of talus Distal phalanx 5 Middle phalanx 5 Proximal phalanx 5 Cuboid Calcaneus Tuberosity of calcaneus Phalanges Metatarsal bones Tarsal bones 1 2 3 4 5 1 2 3 4 5 Head Body Base © Body Scientific International Figure 4.29 Arches of the foot, inferior view. How do these arches contribute to the ability to walk with a smooth, easy gait? Medial longitudinal arch Lateral longitudinal arch Transverse arch Copyright Goodheart-Willcox Co., Inc.