The gluteus medius and gluteus minimus muscles are the smaller two muscles of the gluteal muscle group. The gluteus maximus is the largest of the group. These other two muscles lie underneath the gluteus maximus and are important in movements of the hip and pelvis.
The gluteus medius muscle is the middle muscle in position and in size. It originates from the border of the posterior lateral aspect of the ilium (pelvis) and inserts into the greater trochanter of the femur (hip/thigh bone).
The gluteus minimus muscle is the smallest of the gluteal muscles. It lies underneath both of the other gluteal muscles. It originates from the anteriolateral (front and side) of the ilium. It also, like the gluteus medius, inserts into the greater trochanter of the femur next to the gluteus medius insertion.
The nerve supply of both the gluteus medius and minimus is the superior gluteal nerve that comes from the lumbar 4th and 5th nerve roots and the 1st sacral nerve root.
Both muscles function very similarly to abduct (move out from the body) the thigh at the hip joint. Since the gluteus medius muscle is larger, it plays a larger role in the abduction of the hip, and can also help to rotate the hip both directions. The gluteus minimus aids in a small amount of internal rotation of the hip as well. One way to test weakness between the two muscles is to check internal rotation of the hip while it is flexed to 90 degrees. If this is weak or painful it is more likely that the gluteus medius muscle is injured.
Just as important is their function to stabilize the pelvis when one leg is lifted. This plays a very important role in gait biomechanics. Weakness of the gluteus medius and/or minimus will cause the pelvis to drop when standing on one leg. This is called a Trendelenburg Sign, and is a test to check for injury, weakness, or inhibition of these gluteal muscles. Chronic problems of these muscles can lead to other lower extremity pain issues in the knees or ankles. Its critical role in proper gait makes it important for any running, dancing, and skating athletes. If you love these activities make sure to take good care of these muscles.
Rehabilitation exercises for the gluteus medius and minimus include strengthening exercises such as clam shells, side planks, banded side steps, and single leg squats. Many exercises that include balancing on one foot will strengthen these muscles. To stretch the gluteus medius and minimus muscles foam rolling, lacrosse ball trigger point therapy, or figure four stretches are the most effective.
Shah A, Bordoni B. Anatomy, Bony Pelvis and Lower Limb, Gluteus Medius Muscle. [Updated 2020 Apr 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557509/