Difference between Abduction and Adduction

Abduction and adduction are two fundamental terms used to describe the movements of body parts. These terms are often used in anatomy, kinesiology, and physical therapy to describe the movements of the limbs, fingers, toes, and other body parts. Abduction refers to the movement of a limb or body part away from the midline of the body, while adduction refers to the movement of a limb or body part towards the midline of the body. In this essay, we will explore the differences between abduction and adduction and how they relate to the body's movements and functions.

What is Abduction?

Abduction refers to the movement of structures or limbs away from the middle of the body by the contraction of abductor muscles. Toes and fingers are pulled apart by contraction of the abductor muscles.

• Anatomical structure involved in Abduction − The physiological function of a muscle is related to fiber length and cross-sectional area. It has been found that abductors usually have a shorter muscle fiber length (in general) than an adductor muscle.

• Abductors of the hand − There are many examples of abductor muscles in the human body. Some are even partly named for the action they perform. For instance, abductor pollicis brevis and abductor pollicis longus which are two muscles acting on the thumb, causing the abduction of the thumb. The abductor pollicis longus, as the name implies, is a long muscle that attaches to the bones of the forearm and thumb. The dorsal interossei are muscles found between the long bones that bring about abduction of the fingers.

• Abductors of the arm − Part of the deltoid muscle is responsible for abduction of the arm, as is the supraspinatus muscle. The deltoid muscle covers the shoulder region. The supraspinatus is attached to the shoulder blade (scapula) and the upper arm bone (humerus).

• Abductors of the leg − These muscles are often called abductors of the hip. They include the following muscles: gluteus minimus and gluteus medius which are found in the gluteal region. The gluteus medius is the larger of these two muscles and is very important in keeping the hip stable during walking. Abduction muscles allow you to move your legs sideways, and also function in stabilizing the hip joint. Abductor muscles found in the hip region contract to produce a lateral movement of the pelvic region of the body. Any weakness of abductor muscles that are found in the hip region can cause an abnormal gait.

• Abductors of the foot − Abductor movement of the big toe is brought about by the abductor hallucis and movement of the little toe is brought about by the digiti minimi pedis. The dorsal interossei bring about some abduction of the toes.

What is Adduction?

Adduction refers to the movement of structures or limbs towards the middle of the body by the contraction of adductor muscles. Toes and fingers are moved closer together by contraction of the adductor muscles.

• Anatomical structure for Adduction − Adductor muscles generally have a longer average muscle fiber length when compared with an abductor muscle. Longer fibers and fibers with greater cross-sectional area produce greater force, even within a type of muscle. Research has shown therefore that the adductor magnus, which is longer and has greater cross-sectional area than adductor longus and adductor brevis, also has greater force.

• Adductors of the hand − The adductor pollicis is a muscle that acts on the thumb. The palmar interossei are muscles found between the long bones that bring about adduction of the fingers.

• Adductors of the arm − The latissimus dorsi is a back muscle that helps in adduction of the arm. The pectoralis major is a very large chest muscle that is involved in adduction of the arms.

• Adductors of the leg − There are three very important adductor muscles that are found on the human thigh. These are the adductor magnus, adductor longus and adductor brevis. These muscles attach to the lower parts of the pelvic bones and to the long bone (femur) of the upper leg. The contraction of the adduction muscles moves the leg inwards towards the middle of the body, allowing you to move your thighs together.

• Adductors of the foot − Adductor movement of the big toe is brought about by the adductor hallucis. The plantar interossei are also important in the adduction and spreading of the toes.

Differences: Abduction and Adduction

In summary, the main difference between abduction and adduction is the direction of movement. Abduction refers to the movement of a limb or body part away from the midline of the body, while adduction refers to the movement of a limb or body part towards the midline of the body. Both movements are important for many physical activities and for maintaining balance and stability during movement.

It is worth noting that both abduction and adduction can be performed by various muscles throughout the body. For example, the abductor muscles of the hip are responsible for abducting the leg, while the adductor muscles of the hip are responsible for adducting the leg. Similarly, the deltoid muscle of the shoulder is responsible for abducting the arm, while the pectoralis major muscle of the chest is responsible for adducting the arm.

The following table highlights the major differences between Abduction and Adduction −

Conclusion

In conclusion, understanding the differences between abduction and adduction is important for anyone studying anatomy, kinesiology, or physical therapy. These terms are fundamental to describing the movements of the body and are essential for many physical activities.

By understanding these movements and the muscles that control them, we can better understand the mechanics of the body and how to optimize our movements for improved performance and injury prevention

Vineet Nanda

Updated on: 25-Apr-2023

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