What is the Difference Between Abduction and Adduction

The main difference between abduction and adduction is the direction of the movement of the body with respect to the midline. That is; abduction is the motion of an anatomical structure away from the midline. In contrast, adduction is the motion of an anatomical structure towards the midline. For example, the abduction of the shoulder raises the arms out to the sides of the body. On the other hand, the adduction of the hip squeezes the legs together.  

In brief, abduction and adduction are anatomical movements of the body. Generally, joints, limbs, and other specific sections of the body perform such movements.  

Key Areas Covered 

1. What is the Midline of the Body
     – Definition, Significance
2. What is Abduction
     – Definition, Type of Movement, Examples
3. What is Adduction
     – Definition, Type of Movement, Examples
4. What are the Similarities Between Abduction and Adduction
     – Outline of Common Features
5. What is the Difference Between Abduction and Adduction
     – Comparison of Key Differences

Key Terms 

Abduction, Adduction, Hip, Midline, Shoulder, Vocal Cords, Wrist

What is the Midline of the Body 

Midline refers to an imaginary line which splits the body, head-to-toe, into two halves: the left and right. It is also the center of the body and is called the midsagittal plane.  

What is Abduction  

Abduction is any movement which pulls the anatomical structure of the body out of the midline. For example, swinging of the body from the side of the body up to the shoulder or higher is abduction. Also, in the hip, abduction is the raising the legs laterally, which move knees away from the midline.

Figure 1: Abduction and Adduction

Moreover, abduction spreads the digits away from the hand or foot’s centerline of hand or foot. It also moves the hand away from the body at the wrist. Thus, it is also called as radial deviation. Any muscle that creates this type of movement is an abductor. 

What is Adduction 

Adduction is any movement that moves anatomical structures of the body towards the midline. Therefore,  bringing arms down to the sides of the body at the shoulders is adduction. Also, in fingers and toes, adduction brings the digits toward the center of the hand or foot.  In legs, adduction is bringing the knees together.  The ulnar deviation is the adduction of the wrist, moving a hand toward the body at the wrist when that arm is at the person’s side. Any muscles which create such movements is called an adductor. 

Similarities Between Abduction and Adduction 

• Abduction and adduction are two anatomical movements of the body.  
• They take place around the midline of the body.  
• Joints,  limbs, and other specific sections of the body perform such movements.    
• They are important for the maintenance of different anatomical positions of the body. 

Difference Between Abduction and Adduction 

Definition 

Abduction refers to the anatomical movement away from the midline, while adduction refers to the anatomical movement towards the midline. 

Movement of the Shoulders 

Abduction of the shoulder raises the arms out to the sides of the body. But, the adduction of the shoulder lowers down the arms towards the side of the body. 

Movement of the Hips 

Moreover, the abduction of the hip raises the legs out to the sides of the body. But, the adduction of the hip lowers the legs towards the midline of the body. 

Movement of the Wrist 

The abduction of the wrist is called radial deviation, in which the hand moves towards the radial styloid. Meanwhile, the adduction of the wrist is called ulnar deviation, in which the hand moves towards the ulnar styloid. 

Movement of the Face 

Abduction is the movement of the face away from the midline. Meanwhile, adduction is the movement of the face towards the midline. 

Movement of the Fingers and Toes 

Moreover, abduction spreads the digits away from the hand or foot’s midline of hand or foot, while adduction brings the digits toward the center of the hand or foot. 

Movement of Vocal Cords 

When not speaking, abduction pulls vocal cords out to the side, making it easier to breathe. But, when speaking, adduction moves vocal cords to the center of the larynx, allowing the movement of the air fast to create sounds. 

Type of Muscles 

Furthermore, abductors are the type of muscles that undergo abduction. Meanwhile, adductors are the type of muscles that undergo adduction. 

Conclusion 

Abduction is the movement of the anatomical structures away from the midline. For example, in the shoulder, abduction raises the arms out to the sides of the body. In contrast, adduction is the movement of the anatomical structures towards the midline. Therefore, in the shoulder, adduction lowers the arms towards the body. Thus, the main difference between abduction and adduction is the direction of the movement with respect to the midline of the body. 

References:

1. “Anatomy and Physiology I.” Types of Body Movements | Anatomy and Physiology I, Available Here.

Image Courtesy:

1. “Body Movements I (cropped AbAd)” By Tonye Ogele CNX (CC BY-SA 3.0) via Commons Wikimedia   

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