Download - Extensor Lab Muscles Elana 2

8/3/2019 Extensor Lab Muscles Elana 2

http://slidepdf.com/reader/full/extensor-lab-muscles-elana-2 1/4

Muscle Origin Insertion Nerve

supply Action

triceps

• long head

• lateral head

• medial head

• infraglenoidtubercle of

scapula• upper lateral

aspect of humerus

• lower medialaspect of

humerus

olecranon process of

ulna

radialextendsarm and

forearm

Anconeus (not

important accessoryextensor)

back of lateral

epicondyle of humerus

olecranon

processof ulna

radialextends

forearm

Superficial: brachioradialislateral supracondylar ridge of humerus

styloid process of

radius

radial

flexesforearm

andsupinates

hand

extensor carpiradialis longus

lateral supracondylar ridge of humerus

base of 2nd

metacarpal

radial

extendsand

abductsthe wrist

extensor carpiradialis brevis

lateral epicondyle of humerus

base of

3rdmetacarpal

radial

extendsand

abductsthe wrist

extensor carpi

ulnaris

lateral epicondyle of

humerus posterior border of

ulna

base of

5thmetacarpal

radial

extends

andadducts

the hand

Intermediate: extensor digitorumlateral epicondyle of

humerus

extensor

expansionover

fingers

radial

extends

fingers,hand and

forearm

extensor digitiminimi

lateral epicondyle of humerus

extensor expansion

of littlefinger

radialextendslittle

finger

Deep: supinator

lateral epicondyle of

humeruscrest of ulna

upper

third of radius

radialsupinates

the hand



abductor pollicis

longus

posterior surface of

ulnar middle aspect of

radius

base of 1st

metacarpalradial

abducts

thumb

extensor pollicis

brevismiddle 1/3rd of radius

base of proximal phalanx of

thumb

radialextends

thumb

extensor pollicislongus

middle 1/3rd ulna &interosseous

membrane

base of distal

phalanx of thumb

radialextendsthumb

extensor indicis

posterior surface of

ulna

extensor expansion

of indexfinger

radial

extends

indexfinger

ImportantInformation:

1. theradialnerveandtheprofundabrachiiarteryrunbetweenthemedialandlateral

headsofthetriceps.Thisiscalledthespiralgrooveortheradialgroove.

2. anconeusisnotimportant,hewillnottagitontheexam.

3. Thecommonextensortendoniswheremostextensorsoriginate.Thetendonis

attachedtothelateralepicondyleofthehumerus.

4. Thebrachioradialisandextensorcarpiradialislongusariseabovethecommonextensor

tendonatthelateralsupracondylarridgeofthehumerus .

5. Therearetwoextensorcarpiradialis,thelongusandthebrevis.Thebrevisoriginates

fromthecommonextensortendon.



6. Thelittlefingerhastwoextensormuscles,theextensordigitorumandtheextensor

digitiminimi.

7. Theindexfingeralsohastwoextensormuscles,theextensorindicisandtheextensor

digitorum.

8. Thethumbhastwoextensors,theextensorpollicislongusandextensorpollicisbrevis,

anditalsohastheabductorpollicislongus!

9. Thedeepbranchofradialnerve(whichisnotcalledtheposteriorinterosseousnerve)

travelsunderneaththesupinatorwherethesuperficialbranchrunsanteriorly.

10. Anatomicalsnuffboxisbetweentheextensorpollicisbrevisandextensorpollicislongus.

11. Eachextensordigitorumtendon(thereare4)goes

throughtheextensorretinaculumandthenbranch

intotheextensorhoods.

12. ALLOFTHESEMUSCLESAREINNERVATEDBYTHERADIALNERVE.