Your thigh is made up of several muscle groups that work with your hip and lower leg to produce movement. No single group works by itself in daily activities because all muscles in your body are connected by nerves, blood vessels, and connective tissues called fasciae, according to manual therapist Thomas Myers, author of "Anatomy Trains." If one part of your thigh is weak or damaged, it can affect how your hip, torso, shoulders and lower legs move.
Form and Function
Your thigh muscles are connected by layers of fascia that connect to the muscles in your hip, back and lower leg, according to Myers. They work with the hip to produce locomotion for walking and climbing, and to stabilize your leg and pelvis when you stand and move. They also work together to provide power, strength and speed when you kick a ball or lift a heavy object from a deep squat position.
Your quadriceps and hamstrings are the prime movers for your thigh, and they extend and flex your leg, respectively. Your quadriceps, which are located in the front part of your thigh, consist of the rectus femoris, which is surrounded by the vastus intermedius, medialis and lateralis. The quadriceps originate from the lower parts of your pelvis from several tendons and insert into your knee tendon. Your hamstrings, which are located in the back of your thigh, are made up of the bicep femoris, semimembranosus and semitendonosus. The hamstrings originate from the top and back of the femur and insert into the tendons in the back of your knee.
Several muscles in your thigh connect to your pelvis and rotate your leg left and right. The sartorius muscle runs down and across your thigh from the lower part of your pelvis and into the inner knee. The gracilis muscle runs down the surface of your inner thigh from between your groin and into the inner knee. The tensor fasciae latae, or TFL, is a small muscle that runs from the side of your hip and down to the outer top part of your thigh. These work with the quadriceps, hamstrings, buttocks and deep hip rotators to rotate your leg.
Stabilizing muscles in your thigh maintain proper alignment of your legs, pelvis and feet when you move. These include muscles in your outer and inner thighs. The iliotibial band, or IT band, is not a muscle, but a strong sheath of connective tissues that runs from the top of part of your outer pelvis down to your outer knee. It connects to your TFL, quadriceps and hamstrings to prevent excessive internal rotation when you move. Your inner thigh is made up of the adductor longus, brevis, minimus and magnus. They all work to together to move your leg toward the center of your body and assist in hip and leg rotation. They also prevent excessive external rotation of your leg when you move.
Many people who exercise their legs tend to isolate individual muscle groups, such as quadriceps and hamstrings. Although this isolation technique stimulates the muscle group, it does nothing to improve movement and sports performance. When you do strength-training exercises for your legs, do full-body exercises rather than isolating muscle groups on machines, physical therapist Gray Cook suggests. Exercises such as squats, lunges and step-ups, strengthen all muscles in your thighs, hips, lower leg and upper body.