Arm Anatomy Flashcards
Where does the brachial plexus run on a person
Roots - posterior triangle of neck
Trunks - posterior to the middle third of the clavicle
Divisions - apex of the axilla
Cords - related to the axillary artery
Where are the parts of the brachial plexus found in relation to other structures
Origin: Anterior rami C5-T1
Roots: Posterior triangle, between anterior and median scalenes
Trunks related to subclavian artery middle third of the clavicle. upper and middle above and the lower trunk over the 1st rib posterior to subvlacian artery
Divisions: apex of axilla
Cords: axillary artery
Branches: arm
What is Erb’s paralysis
damage to the upper nerve roots of the brachail plexus - C5/6
gives rise to what is described as the waiter’s tip deformity
Paralysis of the arm abductors (supraspin and delt) leads to arm adduction
Paralysis of the external rotators (infraspin adn teres minor) leads to internal rotation
Paralysis of the flexors and supinators (bcieps, brachialis and brachioradialis) leads to forearm extension and pronation
sensory changes: radial side of the arm and forearm
what is klumpke’s paralysis
injury to the lower trunk of the brachial plexus
C8 T1
gives rise to what is called the claw hand deformity
paralysis of all intkrinsic muscles in the hand
paralysis of the wrist flexors except FCR
hyperextenstion of the MCPJs and flexion of the IPJs
sensory: ulnar border of forearm and hand
you loose the lumbricals which flex the mcpj and extend the IPJs
tell me about the axillary artery
divided by the pec minor into three parts
part 1 - one branch - superior thoracic (runs medial to serratus anterior and pec muscles)
part 2 - two branches - thoracoacromial (branches to deltoid, acromial, pectoralis, clavicular) and lateral thoracic (descends to serratus anterior)
part 3 - three branches - subscapular (largest, thoracodorsal branch and circumflex scapula which travels in the triangular space) anterior circumflex humeral (supplies humeral head: arcuate artery lateral to bicipital groove) and posterior circumflex humeral (in the quadrangular space with the axillary nerve)
mneumonic: screw the lawyer, save a patient
triangular space
borders:
superir teres minor
inferior teres major
lateral long hea dof triceps
contains circumflex scapular artery
quadrangular space
superior teres minor
inferior teres major
lateral humerus
medial long head of triceps
contains axillary nerve
posterior circumflex humeral artyert
triangular interval
superior terest major
lateral humerus
medial long head of triceps
contains profunda brachii and radial nerve
innervation of the rotator cuff
subscapularis - upper and lower subscapular nerves
supraspinatus - suprascapular nerve
infra spinatus - suprascapular nerve
teres minor - axillary nerve
surface marking of th coracoid
2cm inferior to the junction between the middle and lateral thirds of the clavicle
structures attached to the coracoid
ligaments
- coracoclavicular (trapezoid and conoid)
- coracoacromial
- coracohumeral
muscles
- pec minor insertion
- coracobrachailis origin
- short head of biceps origin
muscles inserted in the bicipital groove
PLT sandwich - lady between two majors
Pec major - lateral
latissimus dorsi - floor
teres major - medial
tendon of the long head of bicep runs in the groove
muscles responsible for should abduction
0-15 - supraspinatus
15-90 middle fibres of deltoid
over 90 - trapezius and serratus anterior as need upward rotation of the scapular and lateral rotation of the huerus
fractors decreasing stability of the shoulder joint
shallow glenoid
lax capsule with few ligaments
inferior aspect is not supported due to the quadrangualr space
what is the main stabilizer of the shoulder
rotator cuff
static restraints of the shoudler
unidirectional limitations to translatiion
labrm
version
conformity
negative intrarticular pressure
capsule
glenohumeral ligametns
dynamic restraints of the shoulder
syndrocnised contaction of the rotator cuff causing joint concavity compression. direct attachment fo the cuff to the capsule increases capuslar tensoin
what is a synovial joint
freely moving joint with the articulating surfacies covered in hyaline carticalge and seperated by a film of synovial fluid to act as a lubricant
fibrous capsule provides stability
synovial fluid is a trnasport medium and is produced by the synovial membrane
axillary nerve motor supply
deltoid
teres minor
axillary nerve sensory supply
skin to eh lower half of th edeloitd (badge patch)
INJURY to axillary nerve
inability to abduct the shoulder past 15 degrees
loss of sensation over the badgepatch
upper limb reflexes
c5/6 biceps
c7 triceps
supinator c6
myotomes upper limb
c5 flexion elbow
c6 wrist extensors
c7 elbow extensors
c8 long finger flexion and thumb extension
t1 small finger abductors
muscles flexing the elbow
biceps
brachialis
bacioradials
pronanor teres
FCR
FCR and pronator teres cross the elbow joint (common felxor orgin on the medial epicondyle) so weakly support elbow flexion
articulations at the elbow
capitulum of humerus and radial head
trochlea of humerus and trochlear notch of ulna
olecranon of ulna and olecranon fossa of humerus
structures in the spiral groove
radial nerve profunda brachi vessels
run in triangula interal
clinical picture of radial nerve injury at spinal groove
wrist drop
finger drop
loss of senstion to the first webspace
origin of biceps brachii
coracoid short head
supraglenoid long head
insertion of biceps
radial tubersoty
origin of triceps
long head infraglenoid
lateral head and medial head posterior humerus
structure running between heads of triceps
radial nerve and profunda brachii run between the medial and lateral heads
superficial flexors of the forearm
pronator teres
FCR
palmaris longus
FCU
FDS
innervation of superfical flexors of the forearm
PT, FCR, PL, FDS - median nerve
FCU - ulnar
what attaches to the pisiform
FCU
what hooks around listers tuberle
EPL
deep flexors of the forearm
flexor digitorum profundus
flexor pollicus longus
pronator quadrarus
innervation of the deep flexors of the forearm
AIN
superficial extensors of the forearm
brachioradialis
extensor carpi radialis longus
extensor carpi radialis brevis
anconeus
exteensor digitorum
extensor digiti minimi
extensor carpi ulnaris
Boundaries of the cubital fossa
Lateral: brachioradialis
Medial: pronator teres
Floor: Brachialis
contents of the cubital fossa
median nerve
brachial artery
biceps tendon
veins the ACF medial to lateral
basilic vein
median cubital vein
cephalic vein
Forearm arteries
brachial
radial and ulnar
deep and superficial palmar arches
median nerve relation to pronator teres and FDS
superficial to the deep head of pronator teres and then deep to the radial head of flexor digitorum superficialis
median nerve sensory distribution in the hand
lateral 2/3 of the palm of the hand
lateral (radial) 3.5 digits
dorsum of the tip of the index, middle and thumb
median nerve motor distribution in the hand
LOAF
lateral 2 lumbricals
opponens pollicus
abductor pollicus brevis
flexor pollicus brevis
clinical picture of median nerve injury at the elbow
hyperextended thumb due to paralysis of FPB
Adducted thumb (APB paralysis)
flat thenal eminence
loss of median nerve sensory region
clinical picture of ulnar nerve injury at the wrist
complete claw
clawing of 4th and 5th digits (median lumbricals and interossei paralysis)
loss of sensation inthe ulnar nerve distrubution
ulnar paradox
proximal injury = less clawing
Only the intrinsic muscles of the hand are affected at the wrist.
Lumbricals flex MCPJs and Extend IPJs and interosei have an indirect role of stbilising the mcjs. threrefore with these paralysed the MCPJs are hyperextended and the IPJs are flexed.
Flexion fo the DIPJs is by FDP and flexion of PIPJs is by FDS.
Loss of FDP and FDS in a higher injury means you lose the flexion of the IPJs, making the claw less pronounced.
blood supply to the scaphoid
primarily from palmar and dorsal branches of radial artery
proximal portion relies on retrograde flow
how to test the ulnar artery
allen’s test
elevate the hand and make a fist for 30 seconds
occlude oth radial and ulnar arteries
open the hand whilst still elevated - blanched
release the ulnar artery pressure
colour should return in 7 seconds
attachment of the flexor retinaculum
laterally - scaphoid tubercle ad hook of hamate
medially - trapezium and pisiform
proximal - pisiform and tubercle of scaphoid
distal -hook of hamate and trapezium
structures passing through carpal tunnel
4 tendons of FDS
4 tendons of FDP
1 tendon of FPL
1 tendon of FCR (retincaculum wraps aorund it)
median nerve
Movements of the thumb
MCP/IPJ flexion - FPL and FPB (AIN)
MCP/ICJ extension - EPL, EPB (PIN)
Flexion - FPB, adductor pollicus (median and ulnar)
Extension - Abductor pollicus longus, EPB (PIN)
Abduction - abductor pollicus longus and brevis (Radial, median)
Adduction - adductor pollicus (ulnar)
opposition - opponens pollicus, flexor pollicus brevis, abductor pollicus brevis (median recurrent)H
How to test FDP
Fip PIPJ
How to test FDS
hold adjacent digits in extension to eliminate the FDP motion in adjacent digits
where do FDS and FDP tendons insert
FDS: split tendon on both sides of the middle phalynx
FDP passes through the split tendon of FDS to insert into the distal phalynx
What tendon is attached to pisiform?
FCU
What attaches extensor tendons to phalanges
extensor expansion
what is the function of the intertendinous connections?
create space between the extensor tendons
redistribute the force between tendons
coordinate extension of fingers
stabilize MCP
what is the insertion of the entensor digitorum
extensor expansion of the phalanges of 2,3,4,5th fingers
two extensor tendons inserting into index finger
extensor digitorum (lateral)
enxtenosr indices (medial = ulnar side)
first dorsal interosseous
origin: 1st metacarpal
insertion: lateral side of the extensor expansion of index finger
action: abduction of index finger
supplied by deep branch of ulnar nerve
what is the role of the rdial nerve in power grip?
wrist extension to give a mechanical advantage by synergistic activity causing more efficient flexion of the digits
why is hand grip more powerful in extension than flexion
flexor muscles in the extension position are under tension so contraction is more powerful
boundaries of anatomical snuffbox
medial: EPL
lateral: Abductor pollicus longus, EPB
proximal: styloid process
distal: apex
floor: trapezium and scaphoid
content: radial artery
Insertion of EPL
dorsum of the base of the terminal phalynx of thumb
insertion of EPB
dorsum of the base of the proximal phalynx
