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
Upper limb
- of arm at shoulder1
- Axilla and shoulder
- of forearm at elbow2
- of hand at wrist3
- of phalanges, at all joints
- Posterior compartment of the forearm
- Extensor digitorum
- Extensor digiti minimi (little finger only)
- Extensor indicis (index finger only)
- Posterior compartment of the forearm
- of phalanges, at interphalangeal joints4
- of thumb5
- Extensor pollicis brevis (proximal phalange)
- Extensor pollicis longus (distal phalange)
Lower limb
Hip
Knee
Toes
See also
This article uses anatomical terminology.
References
Shoulder Articulations, ExRx.net http://www.exrx.net/Articulations/Shoulder.html#anchor764495 ↩
Elbow Articulations, ExRx.net http://www.exrx.net/Articulations/Elbow.html#anchor764495 ↩
Wrist Articulations, ExRx.net http://www.exrx.net/Articulations/Wrist.html#anchor261877 ↩
Finger Articulations, ExRx.net http://www.exrx.net/Articulations/Fingers.html#anchor783765 ↩
Thumb Articulations, ExRx.net http://www.exrx.net/Articulations/Thumb.html#anchor206622 ↩
Hip Articulations, ExRx.net http://www.exrx.net/Articulations/Hip.html#anchor845621 ↩
Knee Articulations, ExRx.net http://www.exrx.net/Articulations/Knee.html#anchor22459 ↩
Foot Articulations, ExRx.net http://www.exrx.net/Articulations/Toes.html#anchor231444 ↩