In anatomy

Anatomy

Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...

, flexion (from the Latin word flectere, to bend) is a position that is made possible by the joint angle decreasing. The skeletal (bone

Bone

Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

s, cartilage

Cartilage

Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...

, and ligaments) and muscular (muscle

Muscle

Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

s and tendons) systems work together to move the joint into a "flexed" position. For example the elbow

Elbow

The human elbow is the region surrounding the elbow-joint—the ginglymus or hinge joint in the middle of the arm. Three bones form the elbow joint: the humerus of the upper arm, and the paired radius and ulna of the forearm....

 is flexed when the hand

Hand

A hand is a prehensile, multi-fingered extremity located at the end of an arm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs...

 is brought closer to the shoulder

Shoulder

The human shoulder is made up of three bones: the clavicle , the scapula , and the humerus as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder make up the shoulder joints. The major joint of the shoulder is the glenohumeral joint, which...

. The trunk

Torso

Trunk or torso is an anatomical term for the central part of the many animal bodies from which extend the neck and limbs. The trunk includes the thorax and abdomen.-Major organs:...

 may be flexed toward the leg

Leg

Łęg may refer to the following places in Poland:*A former name for the town of Ełk *Part of the Czyżyny district of Kraków*Łęg, Pleszew County in Greater Poland Voivodeship...

s or the neck

Neck

The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...

 to the chest

Chest

The chest is a part of the anatomy of humans and various other animals. It is sometimes referred to as the thorax or the bosom.-Chest anatomy - Humans and other hominids:...

.

The opposite term is extension

Extension (kinesiology)

In kinesiology, extension is a movement of a joint that results in increased angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed elbow. Straightening of...

, or straightening. Flexion decreases the angle between the bones of the limb at a joint, and extension increases it.

Note that specific flexion activities may occur only along the sagittal plane

Sagittal plane

Sagittal plane is a vertical plane which passes from front to rear dividing the body into right and left sections.-Variations:Examples include:...

, i.e. from the forward to backward direction, and not side-to-side direction, which is further discussed in abduction

Abduction (kinesiology)

Abduction, in functional anatomy, is a movement which draws a limb away from the median plane of the body. It is thus opposed to adduction.-Upper limb:* of arm at shoulder ** Supraspinatus** Deltoid* of hand at wrist...

.

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).

Lower limb

• of femur
  Femur
  The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
  
  /thigh
  Thigh
  In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...
  
   at hip (L1-L2)
  • Iliopsoas
    Iliopsoas
    -External links:*...
    
    
  • Tensor fasciae latae
    Tensor fasciae latae
    The tensor fasciae latae or tensor fasciæ latæ is a muscle of the thigh. The English name for this muscle is the muscle that stretches the band on the side...
    
    
  • Rectus femoris
  • (additional minor contributions from other hip flexors
    Hip flexors
    In human anatomy, the hip flexors are a group of skeletal muscles that act to flex the femur onto the lumbo-pelvic complex, i.e., pull the knee upward....
    
    )

• of leg
  Leg
  Łęg may refer to the following places in Poland:*A former name for the town of Ełk *Part of the Czyżyny district of Kraków*Łęg, Pleszew County in Greater Poland Voivodeship...
  
   at knee
  Knee
  The knee joint joins the thigh with the leg and consists of two articulations: one between the fibula and tibia, and one between the femur and patella. It is the largest joint in the human body and is very complicated. The knee is a mobile trocho-ginglymus , which permits flexion and extension as...
  
   (L5-S2)
  • Posterior compartment of thigh
    Posterior compartment of thigh
    The posterior fascial compartment of the thigh contains the knee flexors and hip extensors.It consists of the following muscles:* biceps femoris* semitendinosus* semimembranosus...
    
    /Hamstring
    Hamstring
    In human anatomy, the hamstring refers to any one of the three posterior thigh muscles, or to the tendons that make up the borders of the space behind the knee. In modern anatomical contexts, however, they usually refer to the posterior thigh muscles, or the tendons of the semitendinosus, the...
    
    s
    • Biceps femoris
      Biceps femoris muscle
      The biceps femoris is a muscle of the posterior thigh. As its name implies, it has two parts, one of which forms part of the hamstrings muscle group.-Origin and insertion:It has two heads of origin;...
      
      
    • Semitendinosus
      Semitendinosus muscle
      The semitendinosus is a muscle in the back of the thigh; it is one of the hamstrings.-Structure:The semitendinosus, remarkable for the great length of its tendon of insertion, is situated at the posterior and medial aspect of the thigh ....
      
      
    • Semimembranosus
      Semimembranosus muscle
      The semimembranosus is a muscle in the back of the thigh. It is the most medial of the three hamstring muscles.-Structure:The semimembranosus, so called from its membranous tendon of origin, is situated at the back and medial side of the thigh....
      
      
  • Gracilis
    Gracilis muscle
    The gracilis is the most superficial muscle on the medial side of the thigh. It is thin and flattened, broad above, narrow and tapering below.-Origin and insertion:...
    
    
  • Sartorius
    Sartorius muscle
    The Sartorius muscle – the longest muscle in the human body – is a long thin muscle that runs down the length of the thigh. Its upper portion forms the lateral border of the femoral triangle.-Origin and insertion:...
    
    
  • Tensor fasciae latae
    Tensor fasciae latae
    The tensor fasciae latae or tensor fasciæ latæ is a muscle of the thigh. The English name for this muscle is the muscle that stretches the band on the side...
    
    
  • Gastrocnemius
    Gastrocnemius muscle
    In humans, the gastrocnemius muscle is a very powerful superficial pennate muscle that is in the back part of the lower leg. It runs from its two heads just above the knee to the heel, and is involved in standing, walking, running and jumping. Along with the soleus muscle it forms the calf muscle...
    
    
  • Popliteus
    Popliteus muscle
    The popliteus muscle in the leg is used to unlock the knee during walking/running by laterally rotating the femur on the tibia during a closed chain movement ....
    
    
  • Plantaris
    Plantaris muscle
    Plantaris is a vestigial structure and one of the superficial muscles of the posterior crural compartment of the leg.It is innervated by the tibial nerve ....
    
     (negligible)

• of toes
  • Posterior compartment of leg
    Posterior compartment of leg
    The posterior compartment of the leg is supplied by the tibial nerve.It contains the plantar flexors:* deep: popliteus, flexor hallucis longus, flexor digitorum longus, tibialis posterior* superficial/calf: gastrocnemius, soleus, plantaris...
    
    
    • Flexor hallucis longus
    • Flexor digitorum longus
  • Flexor digitorum brevis
  • Quadratus plantae
  • Flexor hallucis brevis
  • Flexor digiti minimi brevis
    Flexor digiti minimi brevis muscle (foot)
    The Flexor digiti minimi brevis lies under the metatarsal bone of the little toe, and resembles one of the Interossei....
    
    

• of proximal phalanges
  Proximal phalanges
  Proximal phalanges are bones found in the limbs of most vertebrates. In humans, they are the bones at the base of a toe or finger, the prominent, knobby ends of which are often called the knuckles....
  
   at metatarsophalangeal joint
  • Lumbrical muscle (foot)
    Lumbrical muscle (foot)
    The lumbricals are four small skeletal muscles, accessory to the tendons of the flexor digitorum longus and numbered from the medial side of the foot; they arise from these tendons, as far back as their angles of division, each springing from two tendons, except the first.The muscles end in...
    
    
  • Plantar interossei
  • Dorsal interossei

Other

• torso
  Torso
  Trunk or torso is an anatomical term for the central part of the many animal bodies from which extend the neck and limbs. The trunk includes the thorax and abdomen.-Major organs:...
  
  /lumbar vertebrae
  Lumbar vertebrae
  The lumbar vertebrae are the largest segments of the movable part of the vertebral column, and are characterized by the absence of the foramen transversarium within the transverse process, and by the absence of facets on the sides of the body...
  
  
  • Rectus abdominis muscle
    Rectus abdominis muscle
    The rectus abdominis muscle, also known as the "six pack", is a paired muscle running vertically on each side of the anterior wall of the human abdomen . There are two parallel muscles, separated by a midline band of connective tissue called the linea alba...
    
    

• neck
  Neck
  The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...
  
   at atlanto-occipital joint
  Atlanto-occipital joint
  The Atlanto-occipital joint consists of a pair of condyloid joints. The atlanto-occipital joint is a synovial joint.-Ligaments:The ligaments connecting the bones are:* Two Articular capsules...
  
  
  • Longus capitis muscle
    Longus capitis muscle
    The longus capitis muscle , broad and thick above, narrow below, arises by four tendinous slips, from the anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth cervical vertebræ, and ascends, converging toward its fellow of the opposite side, to be inserted into the...