A flexor is a

muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...

that flexes a joint. In anatomy, flexion (from the Latin verb ''flectere'', to bend) 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 A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each "h ...

closer to the shoulder. Flexion is typically instigated by muscle contraction of a flexor.

Flexors

Upper limb

*of the

humerus bone The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a round ...

(the bone in the upper arm) at the shoulder **

Pectoralis major The pectoralis major () is a thick, fan-shaped or triangular convergent muscle, situated at the chest of the human body. It makes up the bulk of the chest muscles and lies under the breast. Beneath the pectoralis major is the pectoralis minor, a ...

** Anterior deltoid ** Coracobrachialis **

Biceps brachii The biceps or biceps brachii ( la, musculus biceps brachii, "two-headed muscle of the arm") is a large muscle that lies on the front of the upper arm between the shoulder and the elbow. Both heads of the muscle arise on the scapula and join t ...

* of the forearm at the elbow **

Brachialis The brachialis (brachialis anticus), also known as the Teichmann muscle, is a muscle in the upper arm that flexes the elbow. It lies deeper than the biceps brachii, and makes up part of the floor of the region known as the cubital fossa (elbow pi ...

** Brachioradialis **

*of carpus (the carpal bones) at the wrist ** flexor carpi radialis ** flexor carpi ulnaris ** palmaris longus *of the

** flexor pollicis longus muscle ** flexor pollicis brevis muscle ** flexor digitorum profundus muscle ** flexor digitorum superficialis muscle

Lower limb

Hip

The hip flexors are (in descending order of importance to the action of flexing the hip joint):Platzer (2004), p 246 *Collectively known as the iliopsoas or inner hip muscles: ** Psoas major ** Iliacus muscle *

Anterior compartment of thigh The anterior compartment of thigh contains muscles which extend the knee and flex the hip. Structure The anterior compartment is one of the fascial compartments of the thigh that contains groups of muscles together with their nerves and blood s ...

** Rectus femoris (part of the quadriceps muscle group) ** Sartorius * One of the gluteal muscles: **

Tensor fasciae latae The tensor fasciae latae (or tensor fasciæ latæ or, formerly, tensor vaginae femoris) is a muscle of the thigh. Together with the gluteus maximus, it acts on the iliotibial band and is continuous with the iliotibial tract, which attaches to the ...

Medial compartment of thigh The medial compartment of thigh is one of the fascial compartments of the thigh and contains the hip adductor muscles and the gracilis muscle. The obturator nerve is the primary nerve supplying this compartment. The obturator artery is the bloo ...

Pectineus The pectineus muscle (, from the Latin word ''pecten'', meaning comb) is a flat, quadrangular muscle, situated at the anterior (front) part of the upper and medial (inner) aspect of the thigh. The pectineus muscle is the most anterior adductor o ...

** Adductor longus ** Adductor brevis ** Gracilis Without the iliopsoas muscles, flexion in sitting position is not possible across the

horizontal plane In astronomy, geography, and related sciences and contexts, a '' direction'' or ''plane'' passing by a given point is said to be vertical if it contains the local gravity direction at that point. Conversely, a direction or plane is said to be hor ...

Thigh

* of thigh at

knee In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...

(L5-S2) **

Biceps femoris The biceps femoris () is a muscle of the thigh located to the posterior, or back. As its name implies, it has two parts, one of which (the long head) forms part of the hamstrings muscle group. Structure It has two heads of origin: *the ''long h ...

** Semitendinosus ** Semimembranosus ** Gracilis ** Sartorius ** Gastrocnemius ** Popliteus ** Plantaris (negligible) * of

toes Toes are the digits (fingers) of the foot of a tetrapod. Animal species such as cats that walk on their toes are described as being ''digitigrade''. Humans, and other animals that walk on the soles of their feet, are described as being ''plant ...

** Posterior compartment of leg *** Flexor hallucis longus *** Flexor digitorum longus ** Flexor digitorum brevis **

Quadratus plantae The quadratus plantae (flexor accessorius) is separated from the muscles of the first layer by the lateral plantar vessels and nerve. It acts to aid in flexing the 2nd to 5th toes (offsetting the oblique pull of the flexor digitorum longus) and is ...

** Flexor hallucis brevis ** Flexor digiti minimi brevis * of proximal phalanges at metatarsophalangeal jointFoot Articulations
/ref> **

Lumbrical muscle (foot) The lumbricals are four small skeletal muscles, accessory to the tendons of the flexor digitorum longus muscle. They are numbered from the medial side of the foot. Structure The lumbricals arise from the tendons of the flexor digitorum long ...

Plantar interossei In human anatomy, plantar interossei muscles are three muscles located between the metatarsal bones in the foot. Structure The three plantar interosseous muscles are unipennate, as opposed to the bipennate structure of dorsal interosseous muscl ...

** Dorsal interossei

Other

* torso/ lumbar vertebrae ** Rectus abdominis muscle *

neck The neck is the part of the body on many vertebrates that connects the head with the torso. The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In ...

at atlanto-occipital joint ** Longus capitis muscle **

Longus colli muscle The longus colli muscle (Latin for ''long muscle of the neck'') is a muscle of the human body. The longus colli is situated on the anterior surface of the vertebral column, between the atlas and the third thoracic vertebra. It is broad in the mid ...

References

{{Joints Anatomical terms of motion