Extensor Lab Muscles Elana 2
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Muscle Origin Insertion Nerve supply Action triceps • long head • lateral head • medial head • infraglenoid tubercle of scapula • upper lateral aspect of humerus • lower medial aspect of humerus olecranon process of ulna radial extends arm and forearm Anconeus (not important accessory extensor) back of lateral epicondyle of humerus olecranon process of ulna radial extends forearm Superficial: brachioradialis lateral supracondylar ridge of humerus styloid process of radius radial flexes forearm and supinates hand extensor carpi radialis longus lateral supracondylar ridge of humerus base of 2nd metacarpal radial extends and abducts the wrist extensor carpi radialis brevis lateral epicondyle of humerus base of 3rd metacarpal radial extends and abducts the wrist extensor carpi ulnaris lateral epicondyle of humerus posterior border of ulna base of 5th metacarpal radial extends and adducts the hand Intermediate: extensor digitorum lateral epicondyle of humerus extensor expansion over fingers radial extends fingers, hand and forearm extensor digiti minimi lateral epicondyle of humerus extensor expansion of little finger radial extends little finger Deep: supinator lateral epicondyle of humerus crest of ulna upper third of radius radial supinates the hand
Transcript of Extensor Lab Muscles Elana 2
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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
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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.
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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.
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