B6-011 Nerve Lesions of the Upper Extremity Flashcards
prime supinator at shoulder and elbow
biceps brachii
prime flexor of the forearm
brachialis
forearm flexor when the forearm is in mid pronation
brachioradialis
wrist flexor and abductor (radial deviation)
flexor carpi radialis
wrist flexor and adductor (ulnar deviation)
flexor carpi ulnaris
the muscles that flex the wrist are innervated by [3]
median
anterior interosseous
ulnar
innervates most muscles in the anterior compartment of the forearm
median
innervates the deep muscles of the anterior compartment of forearm
anterior interosseous
innervates the medial half of the FDP and the FCU and the intrinsic muscles of the hand
ulnar
innervates the muscles in the anterior compartment of the arm
musculocutaneous
innervates the posterior compartments of the arm and forearm
radial
the radial nerve is involved in [movement]
extension
lateral rotators of the arm [3]
teres minor
infraspinatus
posterior head of deltoid
medial rotators of arm [4]
latissimus dorsi
pec major
anterior head of deltoid
subscapularis
abductors of the arm [2]
supraspinatus
middle head of deltoid
the radial nerve innervates the […] compartment of the arm
posterior
innervates deltoid and teres minor
axillary
the median nerve innervates the […] compartment of the forearm and thenar muscles
anterior
the musculocutaneous nerve innervates the […] compartment of the arm
anterior
innervates coracobrachialis, biceps, and brachialis
musculocutaneous
the ulnar nerve innervates the […] half of FDP and the FCU and intrinsic muscles of the hand
medial
provides sensation to the medial forearm
medial antebrachial cutaneous
supplies sensation to the medial arm [2]
intercostal-T2
medial brachial cutaneous. - medial cord
supplies sensation to the lateral arm
inferior lateral brachial cutaneous (radial)
provides sensation to lateral forearm
lateral antebrachial cutaneous
the lateral antebrachial cutaneous branches from the
musculocutaneous
the medial antebrachial cutaneous branches from the […]
medial cord
the medial brachial cutaneous branches from the [..]
medial cord
provides sensation to palmar and dorsal hand, 5th digit, half of 4th digit
ulnar
provides sensation to medial palm and digits 1-3, half of 4th, and nail beds
median
provides sensation to dorsum of hand, digits 1-3 and half of 4th on the dorsal side
superficial branch of the radial nerve
what muscles extend the DIP?
interossei and lumbricals
the lumbricals and interossei […] the MCP and […] the DIP/PIP joints
extend MCP
flex DIP/PIP
extends IP joint of thumb
extensor pollicis longus
produces opposition of the thumb
opponens pollicis
flexes DIP joints
flexor digitorum profundus
flexes PIP
flexor digitorum superficialis
abduct fingers
dorsal interossei
adduct fingers
palmar interossei
flex MCP and extend DIP/PIP joints
lumbricals
where is the axillary nerve in contact with bone?
surgical neck of humerus
where is the radial nerve in contact with bone?
radial groove of humerus
where is the suprascapular nerve in contact with bone?
suprascapular notch
where is the ulnar nerve in contact with bone? [2]
between the hook of hamate and the pisiform
medial epicondyle of humerus
what muscle can entrap the medial pectoral nerve?
pectoralis minor
what muscle can entrap the median nerve?
pronator teres
what muscle can entrap the musculocutaneous nerve?
coracobrachialis
what muscle can entrap the posterior interosseus nerve?
supinator
what muscle can entrap the ulnar nerve?
flexor carpi ulnaris
damage to the median nerve results in loss of […] of thumb
opposition
loss of abduction/adduction of the digits results from damage to the
ulnar nerve
loss of extension of the forearm results from damage of the
radial nerve
weakness of supination results from damage to the [2]
musculocutaneous- biceps
radial -supinator
weakness of flexion of the DIPs of digits 4 and 5 results from damage to the
ulnar nerve
innervates the medial portion of flexor digitorum profundus
ulnar nerve
damage to the ulnar nerve at the cubital tunnel would result in
loss of extension of 4 and 5 DIPs
loss of thumb abduction would be due to damage of the
median nerve
abnormal sensation to the anterior lateral palm and first 3.5 digits including nail bed would result from damage to
median nerve
abnormal sensation to the medial forearm would result from damage to the
medial antebrachial cutaneous nerve
(from medial chord of brachial plexus)
abnormal sensation to the posterior lateral hand and first 3.5 digits excluding the nail would result in damage to the
radial nerve
loss of wrist extension is due to damage of the
radial nerve
if pronator teres spasms, […] can become entrapped
median nerve
if coracobrachialis spasms, […] can become entrapped
musculocutaneous n
if flexor carpi ulnaris spasms, […] can become entrapped
ulnar n
if supinator spasms, […] can become entrapped
deep branch of radial n
what is anatomical insurance?
each muscle receives fibers from more than one spinal nerve
[…] division does extensors and abductors
posterior
[…] division does flexors and adductors
anterior
dorsal rami provide motor to
axial muscles
C5 myotome
shoulder
C6 myotome
anterior arm
C7 myotome
posterior arm
C8 myotome
forearm
T1 myotome
hand
dermatomal pattern of C6
deltoid to thumb
axillary, radial, lateral antebrachial, and median all supplied by C6
a peripheral nerve pattern tells you the […] has been damaged
peripheral nerve
a dermatomal pattern tells you the […] has been damaged
anterior rami
(ex. roots of brachial plexus, trunk, or dorsal rami)
C6 is always the [..] for dermatomal patterns
thumb
C8 is always the […] for dermatomal patterns
pinky
C7 usually includes […] for dermatomal patterns
middle finger
a motor deficit in a section of spinal nerve results in
weakness
a motor deficit in a section of peripheral nerve results in
paralysis
[…] of the limb after motor injury depends on antagonistic action of intact muscles
position
loss of vasomotor supply to blood vessel in limbs leads to
flushing of skin
loss of innervation to sweat glands produces
anhidrosis (dry skin)
where is the lesion?
weakness of scapular elevation and retraction
dorsal scapular
where is the lesion?
winged scapula
long thoracic
where is the lesion?
weakness in first 15 degrees of abduction, weakness with lateral rotation
suprascapular
where is the lesion?
weakness of adduction and medial rotation
pectoral
where is the lesion?
weakness of adduction and medial rotation
pectoral
where is the lesion?
weakness of arm extension, adduction, and medial rotation of arm; weakness of scapular depression
thoracodorsal
where is the lesion?
weakened flexion and supination of the forearm, loss of sensation on lateral forearm
musculocutaneous
how would a patient with a lesion in the musculocutanous nerve?
extended and pronated
what nerve/artery are affected by a surgical neck fracture?
axillary nerve
posterior circumflex artery
what motor deficits would a lesion in the axillary nerve present with?
weakness of abduction- loss of deltoid
weakness of external rotation -loss of teres minor and deltoid
weakened shoulder flexion- loss deltoid
weakened arm extension- loss of posterior delt
weakened medial rotation -loss of deltoid
what sensory pattern would a lesion in the axillary nerve present with?
lateral deltoid
“square shoulder” is due to
deltoid atrophy from axillary lesion
what artery and nerve is at risk in a suprachondylar fracture?
median nerve
brachial artery
why does a proximal median nerve lesion cause loss of pronation?
loss of pronator teres and pronator quadratus
why does a proximal median nerve lesion cause weakness of flexion and abduction of the wrist?
FCU still intact
ECR longus and brevis can still abduct
why does a proximal median nerve lesion cause loss of flexion of the IP joints of lateral 2 fingers?
FDS and FDP are out
why does a proximal median nerve lesion cause weakness of flexion of IP joints of medial 2 fingers?
FDP still intact
why does a proximal median nerve lesion cause impairment of thumb movement?
loss of opp
weakness of abduction
Benediction sign indicates […] injury
proximal median nerve
ask patient to [..] to evaluate for benediction sign
make a fist
what sensory pattern would a lesion in the proximal median nerve exibit?
palmar thumb and 2-4.5 fingers, dorsal nail beds of same digits
what position would the arm be in with a proximal median nerve injury?
forearm supinated
lateral 2 fingers extended
ape hand (limited thumb movement)
damage to the distal median nerve would cause what deficits?
loss of opposition
weakness of thumb flexion
weakness of thumb abduction
what deficits would a patient have if the anterior interosseus was damaged?
loss of flexion of DIPs -FDP
weakened pronation -pronator quadratus
**pinched OK sign
what does a “pinched OK sign” indicate?
anterior interosseus nerve damage
where is the nerve damage if a patient presents with weakness of flexion of the wrist?
proximal ulnar
why would damage to the proximal ulnar nerve cause weakness of wrist adduction and flexion?
loss flexor carpi ulnaris, other flexors intact
extensor carpi ulnaris can still adduct
why would damage to the proximal ulnar nerve cause loss of flexion of the DIPs of ulnar 2fingers?
loss of flexor digitorum profundus
why would damage to the proximal ulnar nerve cause weakness of flexion of MCPs?
loss of lumbricals and interossei but flexor digitorum superficialis (innervated by median) still intact
loss of extension of the IP joints of ulnar two fingers and weakness of extension of radial 2 fingers?
loss of lumbricals and interossei, but lumbricals 2 and 3 are innervated by median
why would damage to the proximal ulnar nerve cause loss of ab/adduction of fingers?
loss of interosseus muscles
why would damage to the proximal ulnar nerve cause loss of adduction of the thumb?
loss of adductor pollicis
atrophy of […] is a sign of ulnar nerve damage
1st dorsal interossei
how would the hand look with a proximal ulnar nerve lesion?
ulnar claw
clawing of digits 4 and 5
what sensory pattern is affected in proximal ulnar nerve injury?
4.5-5 digit palmar and dorsal sides
how do you differentiate between ulnar claw and hand of benediction?
hand of benediction is ACTIVE, occurs when you ask the patient to make a fist
ulnar claw is passive
full claw occurs when […] has been damaged
lower brachial plexus
partial claw is due to […] injury
ulnar nerve
artery that travels with median nerve
brachial
why would damage to the radial nerve in the axilla cause loss of forearm extension?
loss of triceps
why would damage to the radial nerve in the axilla cause weakness of arm extension?
loss of triceps
why would damage to the radial nerve in the axilla cause weakness of forearm flexion?
loss brachialis and brachioradialis
why would damage to the radial nerve in the axilla cause loss of wrist extension?
loss of extensors
why would damage to the radial nerve in the axilla cause loss of extension of MCP joints?
loss of extensor digitorum
why would damage to the radial nerve in the axilla cause weakened ab/adduction of the hand? (radial and ulnar deviation)
loss of extensor carpi radialis and ulnaris
but flexors remain
why would damage to the radial nerve in the axilla cause limited thumb movements?
loss of extensor pollicis longus and brevis, and abductor pollicis longus
still have weak abduction from abductor pollicis brevis
why would damage to the radial nerve in the axilla cause weakness of supination?
loss of supinator but biceps still intact
when you see loss of wrist extension think
radial nerve injury
flexor carpi ulnaris does
adduction (ulnar) deviation
flexor carpi radialis does
abduction (radial) deviation
if the damage to the radial nerve occurs in the radial grove, what muscles are spared?
long and lateral head of triceps, forearm extension only weakened
what sensory pattern would a patient with a proximal radial nerve lesion (axillary) exhibit?
posterior arm, posterior forearm, dorsum of hand
**nail beds still intact
wrist drop indicates injury to
radial nerve
caused by downward traction (widen neck angle)
common with birth injuries and falls
Erb’s palsy (upper root injury)
what peripheral nerves are affected by Erb’s palsy?
axillary
musculocutaneous
radial
median
suprascapular
thoracodorsal
what muscles abduct the upper limb?
deltoid and supraspinatus
what muscles externally rotate the arm?
infraspinatus, teres minor
sensory pattern for Erb’s palsy?
shoulder to thumb
**dermatomal pattern indicates roots
what posturing would a patient with Erb’s palsy present with?
waiter’s tip
loss of abduction (arm close to body)
loss of lateral rotation (arm medially rotated)
weakness of forearm flexors (forearm extended)
weakness of supination (forearm pronated)
more common with breech delivery, break fall, or cervical ribs?
Klumpke’s paralysis (lower root injury)
claw hand of all digits can indicate […] paralysis
Klumpke’s
**due to loss of thenar/hypothenar muscles, lumbricals, and interossei
where’s the lesion?
dropped shoulder, weak radial pulse, flat weak hand
spinal accessory
what nerve can be injured during breast biopsy?
spinal accessory
where’s the lesion?
square shoulder, weakness of abduction
axillary
use of crutches can damage the […] nerve
axillary
damage to the […] can weaken biceps and brachialis
musculocutaneous
hand somewhat extended, flat thumb
ulnar deviation on wrist flexion
forearm rests in partial supination
pronator teres syndrome
full claw occurs when […] has been damaged
lower brachial plexus
painful wrist
numbness and tingling in first three digits
cannot oppose thumb
fine motor skill affected
carpal tunnel syndrome
full claw occurs when […] has been damaged
lower brachial plexus
wrist drop indicates damage to the
radial nerve
benediction sign when asked to make a fist indicates damage to the
proximal median nerve
partial claw hand indicates damage to the
ulnar nerve
damage to musculocutaneous n. would present with
waiter’s tip posturing
damage to the […] eventually results in square shoulder
axillary
flexor digitorum profundus is innervated by the […], allowing index and middle digit DIP flexion and is innervated by the […] allowing DIP flexion of the ring and little fingers
median
ulnar
innervates hypothenar muscles
ulnar
innervates the thenar muscles
median
what nerve innervates supinator?
radial
what nerve innervates adductor pollicis?
ulnar
what nerve innervates biceps brachii?
musculocutaneous
what nerve supplies deltoid and teres minor?
axillary
long term injury of the axillary nerve results in
square shoulder
deltoid wasting and loss of rounded contour of shoulder
long term injury of the ulnar nerve results in
partial claw
wasting of third and fourth digits and across body of hand
**thenar eminence is spared
supplies most muscles in the anterior compartment
median nerve
wasting of thenar eminence and a flattened “ape hand” indicate damage to
median nerve
waiter’s tip posturing indicates damage to
musculocutaneous
long standing radial nerve injury is expressed as
wrist drop
stretching of the C5/C6 nerve root can cause
Erb’s palsy
stretching of the C8/T1 nerve root can cause
Klumpke’s palsy
baby lying with arm at side in pronated position
Erb’s
what muscles does musculocutaneous supply?
biceps brachii
coracobrachialis
brachialis
supplies pronator quadratus, flexor pollicis longus, and lateral flexor digitorum profundus
anterior interosseus nerve (median)
damage to […] results in a pinched OK sign
anterior interosseus
weakness of 2nd digit, thumb abduction and loss of thumb extension indicates damage to
posterior interosseus (radial)
provides sensation to dorsum of the lateral hand, digits 1-4.5 without nailbeds
superficial branch of the radial
provides sensation to the palmar side of the medial hand and 4.5-5 digits
ulnar
the radial nerve branches in the cubital fossa to […] and […]
superficial radial nerve
deep radial nerve
superficial radial nerve provides sensory innervation to:
dorsal aspect of proximal lateral hand including digits 1-4.5 except for nail beds
sensation on the ventral aspect of the proximal medial hand is supplied by the [..] n.
ulnar nerve
sensation on the ventral aspect of the central palm is supplied by […] n.
palmar cutaneous branch of the median
thumb extension is done by […] nerve
posterior interosseus (radial)
thumb adduction is done by the … nerve
deep branch of ulnar
entrapment of the musculocutaneous in coracobrachialis would result in what defecits?
weakened arm flexion, forearm flexion, and supination
weakness in arm extension could be caused by [2]
triceps (radial nerve)
latissimus dorsi (thoracodorsal n)
innervates hypothenar muscles
ulnar
full claw occurs when […] has been damaged
lower brachial plexus
