Extensor (posterior) compartment of the forearm Flashcards
What are the 5 superficial extensors that originate from the lateral epicondyle?
- Extensor Carpi Radialis Longus
- Extensor Carpi Radialis brevis
- Extensor Digitorum (communis)
- Extensor digiti minimi
- Extensor Carpi Ulnaris
Which 3 muscles are wrist extendors?
- Extensor Carpi radialis longus
- Extensor Carpi Radialis Brevis
- Extensor Carpi Ulnaris
What is the origin and insertion of extensor carpi radialis LONGUS?
ORIGIN : Lateral epicondyle (of humerus)
INSERTION : 2nd metacarpal
What is the innervation of extensor carpi radialis LONGUS?
Radial nerve (C6, C7) , (before division into superficial and deep branches)
What is the function of Extensor carpi radialis longus?
Extends and Abducts the wrist
What is the origin and insertion of Extensor Carpi Radialis Brevis?
ORIGIN : Lateral EPICONDYLE of humerus
INSERTION : base of metacarpal 2 and 3
What is the innervation of Extensor Carpi Radialis Brevis?
Deep branch of RADIAL nerve (C7, C8)
what is the function of extensor carpi Radialis brevis?
extends and abducts wrist
what is the origin and insertion of extensor digitorum (communis)
ORIGIN : Lateral epicondyle of the humerus
INSERTION : 4 tendons insert onto the bases of the middle and distal phalanges of digits 2 - 5
What is the innervation of extensor digitorum ?
Posterior Interosseous Nerve ( C7, C8)
*continuation of the deep branch of the Radial Nerve
what is the function of extensor digitorum?
extends digits 2 - 5.
Also extends wrist
what is the origin and insertion of Extensor digiti minimi?
ORIGIN : Lateral epicondyle of humerus
INSERTION : extensor hood of little finger
What is the innervation of extensor digiti minimi?
Posterior interosseous nerve (C7, C8)
*continutation of the deep branch of the radial nerve
What is the origin and insertion on anconeus?
Origin = Lateral Epicondyle Insertion = Olecranon(ulna) and Proximal prosterior surface of Ulna
What is the nerve supply of anconeus?
Radial Nerve (C7, C8 and T1)
What is the fucntion of anconeus?
- abduction of Ulna in pronation
- accessory extensor of elbow joint
what is the function of extensor digiti minimi?
extend little finger
what is the origin and insertion of Extensor Carpi Ulnaris?
Origin = Lateral Epicondyle of humerus Insertion = Tubercle on base of medial side of metacarpal 5
What is the innervation of extensor carpi ulnaris?
Posterior interosseous nerve (C7, C8)
What is the function of extensor carpi ulnaris?
extends and ADDucts wrist
What are the 5 deep muscles of the posterior (extensor) compartment of the forearm?
- Supinator
- Abductor Pollicis Longus
- Extensor Pollicis Brevis
- Extensor Pollicis Longus
- Extensor Indices
What is the origin, insertion and function of Supinator muscle?
ORIGIN : Superficial head = -Lateral Epicondyle of humerus, -radial collateral -and ulnar ligaments.
Deep Head =
-Supinator crest of ulna
INSERTION :
Lateral surface of radius (superior to anterior oblique line)
FUNCTION :
Supination
What is the innervation of Supinator?
Posterior Interosseous Nerve ( C6, C7)
What is the origin and insertion of Abductor Pollicis Longus?
ORIGIN : Posterior surface of ULNA and RADIUS + Interosseous membrane.
INSERTION : Lateral side of base of metacarpal 1 (thumb)
What is the innervation of Abductor Pollicis Longus?
Posterior Interosseous Nerve (C7, C8)
What is the function of abductor pollicis longus?
Abducts thumb
accessory extendor of thumb
What is the origin and insertion of extensor pollicis brevis?
ORIGIN :
Posterior surface of RADIUS (+ interosseous membrane)
INSERTION :
base of PROXIMAL phalanx of thumb (dorsal side)
What is the innervation and function of extensor pollicis brevis?
nerve : POSTERIOR INTEROSSEOUS (C7, C8)
function : extends thumb
What is the origin and insertion of extensor pollicis longus?
ORIGIN : Posterior surface of ULNA and (interosseous membrane)
INSERTION : base of distal phalanx of thumb (dorsal surface)
What is innervation and function of extensor pollicis longus?
Innervation : POSTERIOR INTEROSSEOUS (C7, C8)
Function : extends thumb
What is origin and insertion of Extensor Indices?
ORIGIN :
Posterior surface of Ulna + interosseous membrane
INSERTION :
Extensor hood of index finger
What is the innervation and function of Extensor Indices?
Innervation : Posterior Interosseous Nerve (C7, C8)
Function : Extension of index finger
What 3 tendons form the boundaries of the anatomical snuff box?
superior = Extensor pollicis longus Inferior = Extensor pollicis brevis and Abductor pollicis longus
What are the contents of the anatomical snuff box?
- Radial artery
- Cephalic Vein
What bony elements can be palpated in the floor of the snuffbox?
Scaphoid and Trapezium
