ANATOMY - upper limb p3 Flashcards
what nn roots forms the brachial plexus?
anterior rami C5,6,7,8 + T1
how to remember the parts of the brachial plexus
read that damn cadaver book!
Roots
Trunks
Divisions
Cords
Branches
which mm do the brachial plexus roots pass between after forming from anterior rami
ant + medial scalene mm
what are the 3 trunks of the brachial plexus
superior - C5/6
middle - C7
inferior - C8/T1
into what region of the neck do the trunks of the brachial plexus traverse laterally towards
posterior triangle of the neck
where do the trunks of the brachial plexus become division
in post triangle of neck - divide into ant + post divisions - then leave into axilla to recombine to become the cords
how are the 3 cords of the brachial plexus named?
in relation to the axillary aa
lateral cord brachial plexus consists of
anterior division sup trunk
anterior division middle trunk
posterior cord of brachial plexus consists of
posterior divisions of sup, mid + inf trunks
medial cord of brachial plexus consists of
anterior division of inferior trunk
draw brachial plexus
plz
nn roots musculocutaneous nn
C5,6,7
motor inn musculocutaneous nn
biceps
brachialis
coracobrachialis
sensory inn musculocutaneous nn
lateral cutaneous branch to forearm - lateral 1/2 anterior forearm + small portion post forearm
which cord is the musculocutaneous nn the terminal branch of
lateral
anatomical course musculocutaneous nerve
emerges inferior border pec minor to leave the axilla
pierces coracobrachialis
passes into flexor compartment, superior to brachialis but deep to biceps
pierces deep fascia lateral to biceps –> lateral cutaneous branch
Sx musculocutaneous nn injury
weakness in flexion + supination
axillary nn roots
C5 + 6
motor inn axillary nn
teres minor
deltoid
sensory inn axillary nn
sup lateral cutaneous nn –> regimental badge area
which cord is the axillary nn a continuation of?
posterior cord
anatomical course axillary nn
starts in axilla, post to axillary aa + ant to subscapularis
exits axilla at the inferior border subscapularis via the quadrangular space
passes medially to surgical neck to branch into 3
1) post terminal branch - motor inn post deltoid, teres minor, regimental badge sensory
2) ant terminal branch 0 winds round neck humerus - ant deltoid
3) articular brach to glenohumeral joint
Sx injury axillary nn
can’t abduct arm past 15’
regimental badge area sensory loss
Erbs palsy is 2’ to
damage to C5/6 nn root
axillary, musculocutaneous, suprascapular + nn to subclavius
Sx Erbs palsy
can’t abduct/ext rotate shoulder (axillary nn)
can’t supinate forearm, flex shoulder
–> Waiters tip - medially rotated w/ wrist flexed
median nn roots
C6-T1
motor inn median nn
flexors forearm
thenar mm
lateral 2 lumbricals
flexion wrist+ digits
pronation forearm
flexion at MCPJ
extension at IPJ
sensory inn median nn
palmar cutaneous branch - lateral palm
digital cutaneous branch - lateral 3 1/2 palmar digits
which cords of the brachial plexus does the median nn arise from
medial and lateral cords
anatomical course median nn
descends initially LATERAL to brachial aa
1/2 way - crosses aa –> MEDIAL to brachial aa
enters ant forearm via AC fossa
travels down forearm betw FDP + FPS (gives off 2 branches - ant interossous - deep ant forearm mm + palmar cutaeneous - lat palmar skin)
enters hand via carpal tunnel to terminate as:
- recurrent branch - thenar mm
palmar digital branch - palmar skin lat 3 1/2 digits + 2 lumbricals
cause median nn damage at elbow
usually 2’ to supracondylar fracture
Sx median nn damage at elbow
constant forearm supination
weak wrist flexion
thenar eminence wasting
hand of Benediction
cause median nn damage at wrist
2’ laceration flexor retinaculum
Sx median nn damage at wrist
thenar + lat 2 lumbricals affected
+ hand benediction
radial nn root s
C5-T1
motor inn radial nn
triceps brachii
posterior forearm mm
sensory inn radial nn
posterior forearm + arm
posterolateral dorsal hand
which cord is the radial nn a continuation of
posterior cord
anatomical course radial nn
arises in axilla, posterior the axillary aa
exits via traignular interval to supply lat + long head triceps
descends in radial groove
wraps around humerus laterally - supply med head triceps
3 cutaneous branches - lower lateral (lat arm inf to deltoid insertion), post cutaneous (post arm) - post cutaenous forearm (mid post forearm)
enters forearm anterior to lateral epicondyle @ cubital fossa, then braches to derminate as:
deep branch - post mm forearm
superificial branch - sensation dorsal hand/fingers
after it innervates the supinator, continues as the posterior interosseous nn
Sx of radial nn injury in axilla
wrist drop
loss of sensation
Sx radial nn injury in radial groove
triceps weakened
wrist drop
superficial sensory branch affected
Sx radial nn injury in forearm
superficial branch if 2’ to stabbing - lat 3 1/2 digits + dorsum sensory loss
deep branch (2’ fracture/dislocation) - no wrist drop as ECRL unaffected
ulnar nn roots
C8, T1
motor inn ulnar nn
mm hand except thenar + lat 2 lumbricals
FCU + med ½ FDP
sensory inn ulnar nn
ant + post surface medial 1 ½ fingers
anatomical course ulnar nn
descends in plane between axillary aa (lat) + axillary vv (med)
down med aspect of arm with brachial aa laterally
mid point of the arm - penetrates the emdial fascial septum –> post arm compartment
passes posterior to elbow –> ulnar tunnel (here articular branch to supply elbow joint)
in forearm - pierces FCU, travels deep to mm alongside ulnar
3 main branches in forearm - mm branch - FCU + med ½ FDP, palmar cutaneous branch - med 1 ½ palm + dorsal cutaneous branch - dorsal surface med 1 ½ fingers
travels superficial to flexor retinaculum + medial to ulnar aa –> hand via ulnar canal
terminates into sup (palmaris brevis) + deep (hypothenar mm, med 2 lumbricals, palmar + dorsal interossei) branches
which mm is tested for with Froments
adductor pollicis
What is the ulnar paradox
different manifestation of a high ulnar nerve lesion (at the elbow) and a low ulnar nerve lesion (at the wrist). In a high lesion the clawing is paradoxically more mild than in a low lesion
minor branches from brachial plexus roots (2)
dorsal scapular nn
long thoracic nn
minor branches from the brachial plexus trunks (2)
suprascapular nn
nn to subclavius
minor branches from lateral cord brachial plexus (1)
lateral pectoral nn
minor branches from the medial cord brachial plexus (3)
medial pectoral nn
medial cutaneous nn of arm
medial cutaneous nn of forearm
minor branches from the posterior cord brachial plexus (3)
superior subscapular nn
thoracodorsal nn
inferior subscapular nn
what is Klumpe’s palsy 2’ to
injru to lower roots of brachial plexus C8-T1
assoc w/ dificult vaginal delivery
which nn are most commonly affected in Klumpe’s palsy (2)
ulnar nn
median nn
Sx Klumpe’s palsy
clawed hand 2’ to lumbricals paralysis
what are the 5 main vessels of the UL
SCA
Axillary
brachial
Radial
Ulnar
where does the SCA originate from on the R vs L
R - brachiocephalic trunk
L - arch of aorta
which mm divides the SCA into 3 parts
anterior scalene
1st vs 2nd vs 3rd part SCA location
1st part = origin SCA –> med border ant scalene
2nd part = posterior to ant scalene
3rd part = lat border ant scalene to 1st rib
what does the SCA become once it enters the axilla ?
axillary aa
which mm is the axillary aa deep to
pec minor
what surrounds the axillary aa
axillary sheath
how is the axillary aa divided in 3?
via relation to pec minor
1) proximal to pec minor
2) post to pec minor
3) distal to pec minor
branches in 1st part axillary aa
PROXIMAL TO PEC MINOR
superior thoracic aa
branches in 2nd part axillary aa
POST TO PEC MINOR
thoraco-acromial aa
lateral thoracic aa
branches in 3rd part axillary aa
subscapular aa
ant = post circumflex aa
which mm’s lower border does the axillary aa become the brachial aa
teres major
1st branch brachial aa
profunda brachii
which nn does the profunda brachii travel with
radial nn (hence supplies triceps)
where does the profunda brachii terminate
at an anastomotic network around the elbow
what does the radial aa supply
psterolat forearm
elbow joint + carpals via anastomotic network
thumb, index + palmar arches (after goes through snuffbox)
where can you palpate the radial aa in the arm
lateral to FCR tendon
between which mm head does the radial aa travel through the anatomical snuffbox
Abductor pollicis brevis
what does the ulnar aa supply
anteromed foreoarm
anastomoses - elbow joint
then ant + post interosseous aa
superifical and deep palmar arches
where does the ulnar aa enter the hand
anterior to flexor retinaculum
lateral to ulnar nn
where is the superficial palmar aa arch + what does it supply
anterior to flexor tendons of the hands
deep to the palmar aponeurosis
becomes digital aa to the 4 fingers
where is the deep palmar arch and what does it supply
deep to flexor tendons
blood to digits + wrist joint
what are the 2 main superficial vv of the upper limb
cerphalic vv + basilic vv
what drains into the basilic vv
dorsal vv network
where does the basilic vv ascend on the upper limb
medial aspect
where does the basilic vv leave the arm
border teres major
where does the basilic vv drain into
+ brachial vv –> axillary vv
what drains into the cephalic vv
dorsal vv network
where does the cephalic vv ascend in the UL
anterolateral aspect of the upper limb, anteriorly at elbow
between what 2 muscles does the cephalic vv travel before entering the axillary at the clavicopectoral groove
deltoid
pec minor
where does the cephalic vv drain into
axillary vv
what vv connects the basilic and cephalic vv at the elbow
medial cubital vv
where are the deep vv of the UL
under the deep fascia
which is the largest of the deep vv of the uL
brachial vv
what is vena comitantes
pulsations of the aa (e.g. brachial aa) assist w/ vv return
what connects the superficial and deep vv of the UL
perforating vv
