Module 35: Lower Extremity III – Leg, Ankle, and Foot
Module 35: Lower Extremity III – Leg, Ankle, and Foot
Learning Objectives:
By the end of this class, students will be able to:
- Describe the thigh and leg muscles that act on the knee.
- Describe the bones and joints of the ankle and foot.
- Describe the muscles of the leg and foot.
- Group the muscles of the leg and foot by their location and/or function.
- Review the anatomy of the lower extremity using clinical application, grouping, and other review methods.
Terms to Know
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Bones of the Lower Extremity
Joints of the Lower Extremity
Other Lower Extremity Terms
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Muscles of the Lower Extremity
*Covered only in lecture, not in this text |
Tibia
This content will be covered in the assignment and briefly reviewed in lecture.
The shaft of the tibia is triangular in shape. Both the anterior tibial border and the medial side of the triangular shaft are located immediately under the skin and can be easily palpated along the entire length of the tibia. The interosseous membrane of the leg is the sheet of dense connective tissue that holds the tibia and fibula bones together.
The large expansion found on the medial side of the distal tibia is the medial malleolus. This forms the large bony bump found on the medial side of the ankle region. Both the smooth surface on the inside of the medial malleolus and the smooth area at the distal end of the tibia articulate with the talus bone of the foot as part of the ankle joint. The lateral side of the distal tibia articulates with the distal end of the fibula, forming the distal tibiofibular joint.
Fibula
This content will be covered in the assignment and briefly reviewed in lecture.
The medial border of the thin shaft of the fibula attaches to the interosseous membrane. The distal end of the fibula forms the lateral malleolus, which forms the easily palpated bony bump on the lateral side of the ankle. The medial side of the lateral malleolus articulates with the talus of the foot as part of the ankle joint. The distal fibula also articulates with the tibia.
Bones and Joints of the foot
Tarsal Bones
This content will be covered in the assignment and briefly reviewed in lecture.
The posterior half of the foot is formed by seven tarsal bones. The most superior bone is the talus. This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint. Inferiorly, the talus articulates with the calcaneus, the largest bone of the foot, which forms the heel. Body weight is transferred from the tibia to the talus to the calcaneus, which rests on the ground.
The cuboid articulates with the anterior end of the calcaneus bone. The talus articulates anteriorly with the navicular, which in turn articulates anteriorly with the three cuneiform (“wedge-shaped”) bones. These bones are the medial cuneiform, the intermediate cuneiform, and the lateral cuneiform. Each of these bones has a broad superior surface and a narrow inferior surface, which together produce the transverse (med