Not to be confused with Inflection.
Anatomical planes in a human. Flexion usually occurs in a sagittal plane when the body is in the anatomical position.
In anatomy, flexion (from the Latin word flectere, to bend) is a position that is made possible by the joint angle decreasing. The skeletal (bones, cartilage, and ligaments) and muscular (muscles and tendons) systems work together to move the joint into a “flexed” position. For example the elbow is flexed when the hand is brought closer to the shoulder. The trunk may be flexed toward the legs or the neck to the chest.
The opposite term is extension, or straightening. Flexion decreases the angle between the bones of the limb at a joint, and extension increases it. Except in the shoulder where flexion increases the joint’s angle.
Note that specific flexion activities may occur only along the sagittal plane, i.e. from the forward to backward direction, and not side-to-side direction, which is further discussed in abduction. Contents:
1 Exercises
2 Muscles of flexion
2.1 Upper limb
2.2 Lower limb
2.3 Other
3 See also
4 Additional images
5 References
6 External links
Exercises
These exercises are used after an injury or surgery. They are done by a physical therapist or nurse initially, and may be continued by the patient.
In the healing process, active range of motion exercises should avoid forcing the appendage into the extension or flexion position. The stress induced may re-injure the affected appendage (limb).
Muscles of flexion
Upper limb of forearm at elbow
Brachialis
Brachioradialis
Biceps brachii
of humerus at shoulder
Pectoralis major
Anterior deltoid
Coracobrachialis
of carpus at wrist
flexor carpi radialis
flexor carpi ulnaris
Lower limb
of femur/thigh at hip (L1-L2)
Iliopsoas
Tensor fasciae latae
Rectus femoris
(additional minor contributions from other hip flexors)
of leg at knee (L5-S2)
Posterior compartment of thigh/Hamstrings
Biceps femoris
Semitendinosus
Semimembranosus
Gracilis
Sartorius
Tensor fasciae latae
Gastrocnemius
Popliteus
Plantaris (negligible)
of toes
Posterior compartment of leg
Flexor hallucis longus
Flexor digitorum longus
Flexor digitorum brevis
Quadratus plantae
Flexor hallucis brevis
Flexor digiti minimi brevis
of proximal phalanges at metatarsophalangeal joint[4]
Lumbrical muscle (foot)
Plantar interossei
Dorsal interossei
