abductors

Abductors is a term with two principal uses. In anatomy, it denotes muscles or muscle groups that move a limb away from the midline of the body. In everyday language, abductors refers to persons who abduct or kidnap another person. The word is derived from Latin abductor, “one who leads away.”

Anatomical abductors include several muscle groups. In the shoulder, the supraspinatus initiates arm abduction, with the deltoid continuing the movement as the arm rises. Hip abductors comprise the gluteus medius and gluteus minimus, assisted by the tensor fasciae latae, and they help keep the pelvis level during single-leg stance. In the hand, the abductor pollicis longus and abductor pollicis brevis move the thumb away from the palm and the index finger, while the abductor digiti minimi acts on the little finger. In the foot, the abductor hallucis moves the big toe away from the second toe, and the abductor digiti minimi moves the little toe. Nerve supply varies by muscle and region: shoulder and arm abductors are served by nerves such as the suprascapular and axillary nerves; hip abductors by the superior gluteal nerve; intrinsic hand and foot abductors receive innervation from median, ulnar, or plantar nerves, depending on the muscle.

Clinical significance: Weakness or injury of abductors can impair limb stability and movement. For example, hip abductor weakness may produce a positive Trendelenburg sign and gait abnormalities; shoulder abductor issues can affect arm elevation and shoulder function.

Etymology: from Latin abductor, “one who leads away,” reflecting their role in moving a part away from the midline. See also abduction in anatomy.