{{Short description|none}} {{Anatomical lists}} In anatomy, '''extension''' is a movement of a joint that increases the 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 (bent) elbow. Straightening of the arm would require extension at the elbow joint. If the head is tilted all the way back, the neck is said to be extended.
==Extensor muscles== {{Anchor|Extensor muscle|Muscles of extension}}
===Upper limb=== *of arm at shoulder<ref>[http://www.exrx.net/Articulations/Shoulder.html#anchor764495 Shoulder Articulations<!-- Bot generated title -->], ExRx.net</ref> **Axilla and shoulder ***Latissimus dorsi ***Posterior fibres of deltoid ***Teres major *of forearm at elbow<ref>[http://www.exrx.net/Articulations/Elbow.html#anchor764495 Elbow Articulations<!-- Bot generated title -->], ExRx.net</ref> **Posterior compartment of the arm ***Triceps brachii ***Anconeus *of hand at wrist<ref>[http://www.exrx.net/Articulations/Wrist.html#anchor261877 Wrist Articulations<!-- Bot generated title -->], ExRx.net</ref> **Posterior compartment of the forearm ***Extensor carpi radialis longus ***Extensor carpi radialis brevis ***Extensor carpi ulnaris ***Extensor digitorum *of phalanges, at all joints **Posterior compartment of the forearm ***Extensor digitorum ***Extensor digiti minimi (little finger only) ***Extensor indicis (index finger only) *of phalanges, at interphalangeal joints<ref>[http://www.exrx.net/Articulations/Fingers.html#anchor783765 Finger Articulations<!-- Bot generated title -->], ExRx.net</ref> **Lumbricals of the hand **Dorsal interossei of the hand **Palmar interossei *of thumb<ref>[http://www.exrx.net/Articulations/Thumb.html#anchor206622 Thumb Articulations<!-- Bot generated title -->], ExRx.net</ref> **Extensor pollicis brevis (proximal phalange) **Extensor pollicis longus (distal phalange)
===Lower limb===
====Hip==== *of thigh/femur at hip<ref>[http://www.exrx.net/Articulations/Hip.html#anchor845621 Hip Articulations<!-- Bot generated title -->], ExRx.net</ref> **Gluteus maximus **Posterior compartment of thigh ***Biceps femoris ***Semitendinosus ***Semimembranosus
====Knee==== *of leg at knee (L3-L4)<ref>[http://www.exrx.net/Articulations/Knee.html#anchor22459 Knee Articulations<!-- Bot generated title -->], ExRx.net</ref> **Quadriceps ***Rectus femoris muscle ***Vastus medialis ***Vastus lateralis ***Vastus intermedius
====Toes==== *of toes<ref>[http://www.exrx.net/Articulations/Toes.html#anchor231444 Foot Articulations<!-- Bot generated title -->], ExRx.net</ref> **Extensor hallucis longus **Extensor digitorum longus **Extensor digitorum brevis **Extensor hallucis brevis
==See also== {{Anatomy-terms}} *List of flexors of the human body
==References== {{reflist}}
{{Joints}}
Category:Anatomical terms of motion *