Rarely do movements of one body segment with respect to another take place in a single plane. They almost invariably occur in two or three planes simultaneously, producing a complex pattern of movement. However, it is convenient to consider movements about each of the three defined axes separately. Movement about a transverse axis occurring in the paramedian plane is referred to as flexion and extension; that about an anteroposterior axis in a coronal plane is termed abduction and adduction; and finally, that about a vertical axis in a transverse plane is termed medial and lateral rotation.
All movements are described, unless otherwise stated, with respect to the anatomical position, this being the position of reference. In this position joints are often referred to as being in a ‘neutral position’.
- Flexion. The bending of adjacent body segments in a paramedian plane so that their two anterior/posterior surfaces are brought together, e.g. bending the elbow so that the anterior surfaces of the forearm and arm move towards each other. (For flexion of the knee joint the posterior surfaces of the leg and thigh move towards each other.)
- Extension. The moving apart of two opposing surfaces in a paramedian plane, e.g. the straightening of the flexed knee or elbow. Extension also refers to movement beyond the neutral position in a direction opposite to flexion, e.g. extension at the wrist occurs when the posterior surfaces of the hand and forearm move towards each other.
Flexion and extension of the foot at the ankle joint may be referred to as plantarflexion and dorsiflexion respectively.
- Plantarflexion. Moving the top (dorsum) of the foot away from the anterior surface of the leg.
- Dorsiflexion. Bringing the dorsum of the foot towards the anterior surface of the leg.
- Abduction. The movement of a body segment in a coronal plane such that it moves away from the midline of the body, e.g. movement of the upper limb away from the side of the trunk.
- Adduction. The movement of a body segment in a coronal plane such that it moves towards the midline of the body, e.g. movement of the upper limb back towards the side of the trunk.
- Lateral flexion (bending). A term used to denote bending of the trunk (vertebral column) to one side, e.g. lateral bending of the trunk to the left. The movement occurs in the coronal plane.
- Medial rotation. Rotation of a limb segment about its longitudinal axis such that the anterior surface comes to face towards the midline of the body, e.g. turning the lower limb inwards so that the toes point towards the midline.
- Lateral rotation. Rotation of a limb segment about its longitudinal axis so that its anterior surface faces away from the midline plane, e.g. turning the lower limb so that the toes point away from the midline.
Supination and pronation are terms used in conjunction with the movements of the forearm and foot.
- Supination. Movement of the forearm so that the palm of the hand faces forwards. In the foot it is the movement whereby the forefoot is turned so that the sole faces medially; it is always accompanied by adduction of the forefoot.
- Pronation. Movement of the forearm that makes the palm of the hand face backwards. In the foot it is a movement of the forefoot which causes the sole to face laterally; it is always accompanied by abduction of the forefoot.
Inversion and eversion are terms used to describe composite movements of the foot.
- Inversion. Movement of the whole foot to make the sole face medially. It consists of supination and adduction of the forefoot.
- Eversion. Movement of the whole foot so that the sole comes to face laterally. It consists of pronation and abduction of the forefoot.
- Specific terms refer to different types of movement between body parts/segments and/or regions.
- Flexion/extension occur about a transverse axis in a paramedian plane; abduction/adduction occur about an anteroposterior axis in a coronal plane; medial/lateral rotation occur about a vertical axis in a transverse plane.
- More specific terms are used for movements associated with some segments/regions: plantarflexion/dorsiflexion of the foot at the ankle joint; supination/pronation of the forearm; supination/pronation/inversion/eversion within the foot; lateral flexion of the vertebral column.