Health & Medicine

Terms of Anatomical Movement

Anatomical terms of movement are used to describe the actions of the skeleton muscles. Muscles contracted to produce joint movement and subsequent movements can be precisely described using the following terminology.

As for the anatomical location, the terms used assume that the body starts in an anatomical position. Most of the movements have an opposite movement, otherwise known as an antagonistic movement. The terms are described herein as antagonistic pairs for ease of understanding.

Flexion and Extension

Flexion and extension are movements that occur in the sagittal plane. They refer to increasing and decreasing the angle between two body parts:

Flexion refers to a movement that reduces the angle between the two parts of the body. Flexion at the elbow lowers the angle between the ulna and the humerus. When the knee flexes, the ankle moves closer to the buttock, and the angle between the femur and the tibia becomes smaller.

Extension refers to a movement that increases the angle between two body parts. Extension at the elbow is increasing the angle between the ulna and the humerus. Extension of the knee straightens the lower limb.

 

Abduction and Adduction

Abduction and adduction are two terms used to describe movements towards or away from the midline of the body.

Abduction is a movement away from the midline – just as abducting someone is to take them away. For example, the abduction of the shoulder raises the arms out to the sides of the body.

Adduction is a movement towards the midline. The adduction of the hip squeezes the legs together.

The midline used in fingers and toes is not the midline of the body but of the hand and the foot, respectively. Therefore, the finger abduction spreads them out.

Medial and Lateral Rotation

Medial and lateral rotation describes the movement of the limbs around their long axis:

The medial rotation is a rotational movement toward the midline. It’s sometimes referred to as internal rotation. We have two scenarios to imagine in order to understand this. First, rotate it with a straight leg to point the toes inward. It’s the medial rotation of the hip. Second, imagine that you’re carrying a tea tray in front of you, with an elbow at 90 degrees. Now rotate your arm and bring your hand to the opposite hip (the elbow is still at 90 degrees). This is the inside rotation of the shoulder.

Lateral rotation is a rotating movement away from the midline. This is in the opposite direction to the movements described above.

Pronation and Supination

This can be easily confused with medial and lateral rotation, but the difference is subtle. With your hand resting on a table in front of you, and keeping your shoulder and elbow still, turn your hand onto its back, palm up. This is the supine position, and this is the supine position.

Again, keep your elbow and shoulder still, turn your hand on your forehead, turn your palm down. This is the prone position, and so this movement is called the pronation.

These terms also apply to the whole body – when lying flat on the back, the body is supine. When lying flat on the front, the body is prone.

Elevation and Depression

Elevation refers to movement in a superior direction (e.g. shoulder shrug), depression refers to movement in an inferior direction.

Pronation and Supination

This is easily confused with medial and lateral rotation, but the difference is subtle. With your hand resting on a table in front of you, and keeping your shoulder and elbow still, turn your hand onto its back, palm up. This is the supine position, and so this movement is supination.

Again, keeping the elbow and shoulder still, flip your hand onto its front, palm down. This is the prone position, and so this movement is named pronation.

These terms also apply to the whole body – when lying flat on the back, the body is supine. When lying flat on the front, the body is prone.

Dorsiflexion and Plantarflexion

Dorsiflexion and plantarflexion are terms used to describe movements at the ankle. They refer to the two surfaces of the foot; the dorsum (superior surface) and the plantar surface (the sole).

Dorsiflexion refers to flexion at the ankle so that the foot points higher. Dorsiflexion of the hand is a confusing term, which is rarely used. The back of the hand is the posterior surface, so moving in that direction is an extension. We can, therefore, say that the dorsiflexion of the wrist is the same as the extension.

Plantarflexion refers to extension at the ankle so that the foot points inferiorly. Similarly, there is a term for the hand, which is palmarflexion.

Inversion and Eversion

Inversion and eversion are movements that occur at the ankle joint, referring to the rotation of the foot around its long axis.

Inversion involves the movement of the sole towards the median plane – so that the sole faces in a medial direction.

Eversion involves the movement of the sole away from the median plane – so that the sole faces in a lateral direction.

Opposition and Reposition

A pair of movements limited to humans and some great apes, these terms apply to additional movements that the hand and the thumb can perform in these species.

Opposition brings the thumb and little finger together.

Reposition is a movement that moves the thumb and the little finger away from each other, effectively reversing opposition.

Circumduction

Circumduction can be defined as a conical movement of a limb extending from the joint at which the movement is controlled.

It is sometimes talked about as circular motion but is more accurately conical due to the ‘cone’ formed by the moving limb.

Protraction and Retraction

Protraction describes the anterolateral movement of the scapula on the thoracic wall that allows the shoulder to move anteriorly. In practice, this is the movement of ‘reaching out’ to something.

Retraction refers to the posteromedial movement of the scapula on the thoracic wall, which causes the shoulder region to move posteriorly i.e. picking something up.

See Also

The Inner Ear Anatomy

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