Human anatomy

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Muscles Abductors Adductors Depressors Elevators Extensors Flexors Rotators external internal
See also Glossary of medicine Epithelia Anatomical terminology Index of anatomy articles Outline of anatomy Cell types by origin
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A flexor is a muscle that flexes a joint. In anatomy, flexion (from the Latin verb flectere, to bend)^[1] is a joint movement that decreases the angle between the bones that converge at the joint. For example, one's elbow joint flexes when one brings their hand closer to the shoulder. Flexion is typically instigated by muscle contraction of a flexor.

Flexors

Upper limb

of the humerus bone (the bone in the upper arm) at the shoulder
of the forearm at the elbow
of carpus (the carpal bones) at the wrist
of the hand

Lower limb

Hip

The hip flexors are (in descending order of importance to the action of flexing the hip joint):^[2]

Collectively known as the iliopsoas or inner hip muscles:
- Psoas major
- Iliacus muscle
Anterior compartment of thigh
- Rectus femoris (part of the quadriceps muscle group)
- Sartorius
One of the gluteal muscles:
- Tensor fasciae latae
Medial compartment of thigh

Without the iliopsoas muscles, flexion in sitting position is not possible across the horizontal plane.^[2]

Thigh

of thigh at knee (L5-S2)^[3]
- Biceps femoris
- Semitendinosus
- Semimembranosus
- Gracilis
- Sartorius
- Gastrocnemius
- Popliteus
- Plantaris (negligible)

Other

References

^ Anderson, Kenneth N.; et al., eds. (1994). Mosby's Medical, Nursing, & Allied Health Dictionary (4th ed.). St. Louis: Mosby-Year Book. p. 624. ISBN 9780801672255. OCLC 312496360.
^ ^a ^b Platzer (2004), p 246
^ Knee Articulations
^ Foot Articulations

v t e Joints
Types	Fibrous Gomphosis Suture Syndesmosis Interosseous membrane Cartilaginous Synchondrosis Symphysis synovial: Plane joint 1° Hinge joint Pivot joint 2° Condyloid joint Saddle joint 3° Ball and socket joint synostosis by range of motion: Synarthrosis Amphiarthrosis Diarthrosis
Terminology	Kinesiology Anatomical terms of motion Agonist/Antagonist
Motions	general: Flexion/Extension Adduction/Abduction Internal rotation/External rotation Elevation/Depression specialized/upper limbs: Protraction/Retraction Supination/Pronation specialized/lower limbs: Plantarflexion/Dorsiflexion Eversion/Inversion
Components	capsular: Joint capsule Synovial membrane Fibrous membrane Synovial fluid Synovial bursa Articular disk/Meniscus extracapsular: Ligament Enthesis