Your leg muscles are a large powerful group of muscles that act on the hip, knee and ankle joints. You rely on them to stand and walk, sometimes run and jump, maybe even hop or skip. Understanding their complex anatomy will give you a new appreciation of the lower half of your body.
Quadriceps
A group of four muscles combine to form the quadriceps, hence the name, which give the front of your leg its shape and strength. They are known as the rectus femoris, vastus medialis, vastus intermedius and vastus lateralis. Their primary function is to extend or straighten the leg. You use them every time you climb stairs or stand up from a chair.
Hamstrings
The back of your leg is composed of a group of three muscles known as the hamstrings. The function of the biceps femoris, semitendinosus and semimembranosus is to flex or curl the leg. They have a tendency to be weaker than the quads, which can lead to knee problems and low back pain.
Pes Anserine
The lesser-known, but equally important pes anserine muscle group contains the sartorius, the longest muscle in your body, and the gracilis, which flex and rotate your leg. The sartorius runs from your outer hip, crosses over the top of your leg and joins the inner part of the knee. The gracilis is a long, narrow muscle located in the inner thigh that extends from the pubic bone to the tibia in the lower leg.
Adductors
Inner thigh muscles are named for their function and size. The adductor magnus, adductor longus and adductor brevis all work to adduct the leg, or move it sideways, toward the body's midpoint. Painful groin pulls usually involve these muscles, along with the gracilis.
Abductors
These muscles are located in upper most part of the legs, the outer part of the glutes, the "saddle bag" area. They control the abduction movement of the leg. The gluteus medius and minimus muscles function to move the leg sideways, away from your body's midpoint.
Calves
The calf muscles are a powerful group of muscles that control your feet and ankles. Composed of the gastrocnemius, the soleus and the plantaris, the calves power every step you take. Whenever you are on your feet, your calves muscles are being stimulated.
References
- Inner Body: Muscular System
- University of Minnesota: Muscles
- "Personal Trainer Manual"; American Council on Exercise; 1997
