Posterior Forearm Flashcards
superficial group of posterior forearm compartment (6)
brachioradialis extensor carpi radialis longus extensor carpi radialis brevis extensor digitorum longus extensor digiti minimi extensor carpi ulnaris
deep group of posterior forearm compartment
supinator
abductor pollicis longus
extensor pollicis longus
extensor indicies
the superficial group and deep group of extensor muscles are separated by
the radial nerve
all muscles of the posterior forearm are innervated by the ______ nerve by either the _____ branch or _______ -______ nerve branch
radial nerve by the
deep branch or
posterior interosseous nerve branch
origin of brachioradialis m
supra-epicondylar ridge of humerus
insertion of brachioradilis m
lateral distal radius proximal styloid process
innervation of brachioradialis m
superficial branch of radial n
action of brachioradialis m
weak arm flexion
maximal when mid-pronated
brahcioradialis
extensor carpi radialis longus
extensor carpi radialis brevis
are all in what group of extensor muscles
the radialis group is all superficial
extensor carpi ulnaris
extensor digitorum
extensor digiti minimi
along with the radialis group make up the
superficial layer
supinator extensor pollicis longus abductor pollicis longus extensor pollicis brevis extensor indicis are all in what layer of the posterior forearm
all are in the deep layer
superficial lateral group of posterior forearm consists of
extensor carpi radialis longus
extensor carpi radialis brevis
origin/insertion of extensor carpi radialis longus
lateral supraepicondylar ridge of humerus to dorsal side of 2nd metacarpal
action of extensor radialis longus
extend/abduct hand at wrist
innervation of extensor radialis longus
radial n
origin/insertion of extensor carpi radialis brevis
lateral epicondyle of humerus to dorsal base of 3rd metacarpal
action of extensor carpi radialis brevis
extend/abduct hand at wrist
origin/insertion of extensor carpi ulnaris
lateral epicondyle;posterior ulna via shared aponeurosis to dorsal base of 5th metatarsal
extensor carpi ulnaris innervation
posterior interosseous nerve
branch of deep branch of the radial nerve
extensor carpi ulnaris action
extend and adducts hand at wrist
origin/insertion of extensor digitorum
lateral epicondyle to extensor expansion of medial 4 digits
action of extensor digitorum
extends primarily at MPJ but also IPJ
innervation of extensor digitorum m
posterior interosseous n
origin/insertion of extensor digiti minimi
lateral epicondyle to extensor expansion of 5th digit
action of extensor digiti minimi
extends 5th digit at MPJ but also IPJ
innervation of extensor digiti minimi
posterior interosseous n
Supinator extensor indices abductor pollicis longus extensor pollicis longus extensor pollicis brevis are part of the
deep group of extensor muscles
origin/insertion supinator
deep part - ulna
superficial part - lateral condyle to radial tubercle; oblique line of radius
action of supinator
supinates forearm
innervation of supinator
deep branch of radial n
origin/insertion of extensor indices
posterior surface distal ulna and IO membrane to extensor expansion of 2nd digit
action of extensor indices
extend 2nd digit; assists extending hand at wrist
innervation of extensor indices
posterior interosseous n
origin/insertion of abductor pollicis longus
posterior half of ulna, radius IO to base of 1st metacarpal
action of abductor pollicis longus
abduct thumb and extends at carpometacarpal joint
innervation of abductor pollicis longus
posterior interosseous n
origin/insertion extensor pollicis longus
posterior middle third ulna and IO to dorsal base of distal phalanx of thumb
action of extensor pollicis longus
extend distal phalanx of thumb at PIJ; extends at MPJ and carpometacarpal joints
innervation of extensor pollicis longus m
posterior interosseous n
origin/insertion of extensor pollicis brevis
posterior distal radius and IO membrane to dorsal base of proximal phalanx of thumb
action of extensor pollicis brevis
extend proximal phalanx of thumb at MPJ; extends carpometacarpal joints
innervation of extensor pollicis brevis
posterior interosseous n
extensor digitorum pulls on what structure causing the IP joint to extend
extensor expansion (a tendenous structure that extends from the proximal phalanx to the distal phalanx) connected to the extensor hood
lumbricals are able to extend the IP joints by their insertion in what structure
the extensor hood
describe the extensor expansion
tendonous structure that extends across the dorsal aspect of the phalanges that allows for extension of phalanges (even during flexion of MCP joint)
the common interosseous artery gives rise to what two arteries of the forearm
the anterior interosseous a
(the perforating branch of the anterior interosseous)
posterior interosseous a
what a supply the posterior forearm and hand
common interosseous and its branches (A and P) perforating branch of anterior interosseous radial a (deep palmar, dorsal palmar arches)
innervation to the posterior forearm is performed by what n
radial n and its branches
(superficial branch)
(deep branch –> posterior interosseous n)
the deep branch of the radial n becomes the posterior interosseous after it crosses what muscle
becomes posterior interosseous as it begins passing through supinator
radial n injuries subsequent to a proximal humerus injury may result in what lack of function
no elbow extension; weak supination
radial n injuries subsequent to a a mid-humerus injury may result in what lack of function (in the radial groove)
muscle weakness depends on locaiton
distal humerus injuries, such as repetitive forearm rotation, tennis elbow, compression, may result in what symptoms
wrist drop: inability to extend the hand, MCP joint and fully extend forearm
trauma to the raidal n in the wrist may result in what symptoms
no sensory innervation to dorsal hand
causes and symptoms of wrist drop
radial n injury in the distal humerus
paralysis of extensors of wrist and fingers results in inability to extend
flexors overrepresented
lateral epicondylitis symptoms and primary muscles involved
overuse injury of extensors from lateral epicondyle
swelling, tenderness, pain in wrist extension
Ext. Carpi radialis brevis
ext. digitorum
testing the radial n involves
testing resistance to extension by extensor digitorum
radial n only nerve to extend MCP joint
contents of the anatomical snuffbox
superficial radial n
radial a
borders of anatomical snuffbox
Extensor pollicis brevis extensor pollicis longus abductor pollicis longus floor - scaphoid bone roof - superficial radial nerve branches
DeQuervain’s disease
tenosynovitis of first compartment of thumb to Abductor pollicis longus, extensor pollicis brevis
+ Finkelsteins test
