Leg anatomy: An overview
Each of your legs relies on a complex construc¬tion that includes not just bones, but also ligaments, muscles, tendons, nerves, blood vessels, and more.
Bones provide the framework to which the other parts of the leg attach (see Figure 1). There are three major bones in your legs: the thighbone (femur) in the upper leg, and the shin bone (tibia) and calf bone (fibula) in the lower leg. In addition, the kneecap (patella) is a small bone that protects the knee joint. The bones of the upper and lower legs connect to additional bones in the hips and ankles.
Without other important structures in the leg, however, bones would collapse into a useless heap:
- Ligaments are the tough bands of tissue that connect bones to other bones. They link the thighbone and shin bone at the knee joint and connect the thighbone to the pelvis at the hip joint. Ligaments also stabilize joints, restricting movement to a range that will not cause damage.
- Muscles provide the force to move bones at the joints. In the upper leg, multiple muscles help lift the thigh. These hip flexors include the powerful quadriceps muscles on the front of the thigh and the iliopsoas muscles, which link the spine and the legs. Meanwhile, the hamstrings at the back of the thigh help with hip extension and knee flexion. In the calf, the gastrocnemius and soleus muscles help you point and flex your foot, walk, jump, and run. The gluteus maximus, medius, and minimus muscles of the buttocks support your lower body and allow your hips to rotate.
- Tendons are the strong bands of connective tissue that attach muscles to bones. One of the best-known tendons in the body is the Achilles tendon, which connects your calf muscles to your heel.
- Bursae are small, liquid-filled sacs where tendons, muscles, and bones meet that reduce friction between bones and soft tissue.