The abductors represent muscles of the human body that have the purpose of abducting a certain extremity from the body. We commonly use the term abductors for the abducting muscles of the leg. To be more specific this muscle group abducts the thigh via the hip joint. This group includes the butt muscles that contain one of the biggest muscles of the human body, the musculus gluteus maximus.
Abductors – different muscles
The abductors further consist of the musculus gluteus medius and the gluteus minimus, which, together with the musculus gluteus maximus, represent the butt muscles, the musculus rectus femoris, the musculus tensor fasciae latae, the musculus sartorius, and the musculus piriformis. The abduction just represents one function that all mentioned muscles have in common.
Abductors – location and function
Musculus gluteus maximus
The musculus gluteus maximus originates from the iliac crest (ala ossis ilii), the sacral and tail bone (os sacrum and os coccygis), the ligamentum sacrotuberale and the fascia thoracolumbalis. It inserts into the tractus iliotibialis at the proximal portion of the thigh bone (femur).
The functions of the musculus gluteus maximus are:
- the extension of the hip joint,
- the external rotation of the hip joint,
- the abduction and adduction of the hip joint (depending on the respective muscle portion),
- the prevention of falling over to the front when the centre of gravity of the body shifts before the hip,
- the erection of the pelvis (in closed system, e.g. with closed legs), and
- the tilting of the pelvis (in open system, e.g. with open legs).
Musculus gluteus medius and minimus
The musculus gluteus medius and the musculus gluteus minimus represent a functional unit. They originate from the iliac crest (ala ossis ilii) and insert into the trochanter major of the femur. The gluteus minimus is covered by the gluteus medius. Their functions are:
- the abduction of the hip joint,
- the flexion (bending) and internal rotation of the hip joint (ventral muscle parts),
- the extension and external rotation of the hip joint (dorsal muscle parts), and
- the prevention of the tilting of the pelvis toward the side of the raised leg (in one leg stand).
Musculus rectus femoris
The musculus rectus femoris belongs to the front thigh muscles. It originates from the lower front iliac spine (Spina iliaca anterior inferior) and the hip socket (Acetabulum). From here it runs all the way down the thigh until it inserts the patellar tendon above the knee. The functions of the straight front thigh muscle are:
- the extension of the knee,
- the flexion and abduction of the hip joint, and
- the tilting of the pelvis.
Musculus tensor fasciae latae
The musculus tensor fasciae latae originates from the Spina iliaca anterior superior of the iliac crest and inserts into the lateral Condylus of the shinbone (tibia). Its functions are:
- the tension of the fascia lata and the tractus iliotibialis,
- the flexion and abduction of the hip joint,
- the internal rotation of the thigh (supportive),
- the flexion (and extension) of the knee joint (supportive), and
- the stabilization of the extended knee.
The musculus sartorius originates from the spina iliaca anterior superior of the iliac crest and the ala ossis ilii. Together with the tendons musculus gracilis and the musculus semitendinosus the sartorius tendon creates the pes anserinus what inserts into the condylus medialis tibiae of the shinbone. The functions of the musculus sartorius are:
- the flexion of hip and knee joint,
- the external rotation and abduction of the thigh, and
- the internal rotation of the lower leg.
The musculus piriformis originates from the facies pelvica of the os sacrum, the incisura ischiadica major, the ligamentum sacrotuberale, and the articulatio sacroiliaca. It inserts into the trochanter major of the femur. Its tendon quite often unifies with the tendons of the musculus gemellus superior, the musculus gemellus inferior, and the musculus obturator internus. The functions of the musculus piriformis are:
- the external rotation and abduction of the hip joint,
- the backward movement of the opposite side of the pelvis (when leg is fixated), and
- the internal rotation of the hip joint at a hip angle of greater than 80°.
Abductors – importance
From an aesthetic point of view among all abductors most importance can be attached to the musculus gluteus maximus. This muscle shapes the butt considerably. Together with the musculus rectus femoris it is involved in many essential movements, like walking, running, jumping, climbing stairs, or squats.
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