Upper Limb Clinical Gross Anatomy Revisited Flashcards
Brachial Plexus Levels
C5-T1
Ulnar Nerve
C8-T1
Median Nerve
C5-T1
Radial Nerve
C5-T1
Erb-Duchene’s Palsy
MOI is injury to C5 and C6 nerve roots or upper trunk due ti traction placed on neck
Widening of angle of separation between head and shoulders, difficult delivery, etc
Paralysis of flexors of the arm, abductors and lateral rotators of the humerus
Waiter’s Tip
Waiter’s Tip Position
Iconic Erb-Duchenne injury
Adducted = abductors are paralyzed
Extended = elbow flexors are paralyzed
Medially Rotated = lateral rotators are paralyzed
Klumpke Injury
Injury to C8-T1 nerve roots or lower trunk of brachial plexus
Catching onself in a hanging position when falling
Paralysis of intrinsic hand muscles
Claw hand (2-5) appearance due to paralyzed muscles (interossei and lumbricals)
Provides balance between powerful extensor and flexor muscles to the fingers
Claw Hand 2-5
Appearance due to paralysis of muscles
Interossei, lumbricals
Provides balance between powerful extensor and flexor muscles of fingers
Klumpke in New Born
Produces flexion and supination of elbow, extension of wrist, hyperextension of the metacarpophalengeal joints
Flexion of interphalangeal joints with claw hand posture
Radial Nerve Injury
Deep branch of radial nerve
Injury to nerve as it exits the axilla or winds around the humerus in the spiral groove (midshaft humeral fracture)
Poor crutch placement, falling asleep with arm over back of chair
Downward dislocation of glenohumeral joint
Why are triceps spared by radial nerve injury in the middle of the arm?
Occurs because at this point the triceps are already innervated
Wrist Drop?
Radial nerve injury
Occurs because of paralysis of wrist extension
Loss of all sensation over the snuff box region
Chronic loss can cause flexion contractures in upper limb (paralysis of extensors and unopposed action of flexors) with complete loss of limb function
Complete Radial Nerve Lesion
Hand cannot be extended (dorsiflexed) because the forearm extensors are paralyzed
Wrist Drop Testing
Testing deep branch of radial nerve (when lesion is partial) by extending MP joints against resistance
When normal the tendons will become prominent on the dorsum of the hand
Ulnar Nerve Injury Sites
Can be compressed at elbow in the cubital tunnel and at wrist in Guyon’s tunnel
Guyon Tunnel Ulnar Nerve Damage
Compression at elbow
Can cause handlebar neuropathy
Ulnar canal syndrome
Ulnar Nerve Injury MOI
Cuts or falls on outstretched palms
Ulnar Nerve deficits if hit at elbow
Flexion of the hand results in radial deviation (abduction) due to paralysis of flexor carpi ulnaris
Wasting of hypothenar eminence and interosseous spaces if prolonged
Ulnar Claw
Clawing of digits 4/5
Clawing will be less severe than wrist injury to ulnar nerve
Elbow injury FDP tendons to 4/5 are nonfunctional
One of the possible “hand of benediction” causes
Elbow Injury Clawing
Will look worse than at wrist
Will not have innervation to FDP to 4/5 digits
Froment’s Sign
Loss of adduction of the thumb
Loss of adductor pollicis muscle due to ulnar injury
Pt. asked to grip piece of paper between thumb and index finger
If thumb flexion is seen this is a positive sign
Wrist Ulnar Claw
This looks worse than damage at the elbow because FDP is functional
Interossei/Lumbrical function
Able to flex the MP joints and extend the IP joints and counterbalance the strong flexors/extensors of the digits
When interossei/lumbricals act on a paralyzed digit the digit will claw because of unopposed forearm muscles (ED and FD)
Clawing opposite of normal function of muscles
Interossei Functions
Flex MP joints and extend the IP joints and counterbalance the strong flexors/extensors of the digits
Function in adduction/abdunction of the digits
Interossei/Lumbrical Clawing
Opposite of normal action
Hyperextended at MP joint and flexed at PIP and DIP joints
Ulnar Nerve Hand Innervation
Innervates medial 2 lumbricals (digit 4/5)
In this case only 4/5 claw
C8-T1 Nerve Injury
Causes Klumpke’s palsy
Can see clawing in digits 2-5
Tinel’s Sign
Percussion of nerve to replicate symptoms of nerve impingement
Can be median nerve at wrist to replicate carpal tunnel syndrome symptoms
Could do ulnar nerve at elbow to replicate cubital tunnel syndrome symptoms
Replication = positive finding indicative of impingement
Median Nerve Injury
Occurs at the forearm/wrist
Falling through glass door and cutting wrists
Lesion at Forearm
Ask pt to make a fist
Unable to flex radial digits due to paralysis of the radial forearm muscles
Thenar muscles are paralyzed
Ulnar flexors are innervated so they will not be affected
Ape Hand
Paralyzed thenar muscles due to median nerve injury in the forearm
Opposition and Reposition of the thumb do not work!
Injury at elbow due to medial supracondylar humeral fracture or humeroulnar dislocation
Ulnar deviation of the wrist with wrist flexion
Lesion at the Wrist
Ape Hand
Cannot Abduct thumb
Forearm flexors work so digits can be flexed
Dupuytren’s Contracture
Pathological thickening and shortening of the longitudinal bundles of the palmar aponeurosis Draws fingers (digits 4/5) into palm to such a degree that they become useless Can mimic an ulnar claw since it commonly affects digits 4/5 1st of 3 possible interpretations of hand of benediction
Median Nerve
Runs in the medial bicipital groove
In cubital fossa runs medially to the branchial artery
Passes between two heads of pronator teres
Passes between 2 heads of flexor digitorum superficialis
Runs between FDS and FDP in midline
At wrist located between tendons of FDS and FCR
Ulnar Nerve Course
Runs in the medial biceptal groove
In the distal arm pierces the medial intermuscular septum and turns posterior to the medial epicondyle of the humerus
Passes between the 2 heads of the flexor carpi ulnaris
Distal half of the forearm joins to the ulnar artery under the flexor carpi ulnaris
Radial Nerve
Runs behind the humerus
Can be damaged in midshaft fracture of the humerus
Injured if hit in the middle of the arm
Midshaft humerus fracture able to spare triceps
What could cause pain/numbness in the dorsum of the hand but no weakness?
Entrapment of the superficial branch of the radial nerve as it emerges from underneath the brachioradialis
Characterized by pain/numbness on the dorsum of the hand but no weakness
Radial Tunnel Syndrome
Entrapment of posterior interosseous nerve (within supinator canal)
Weakness in extension at the MP joint
Weakness in thumb abduction and extension and weakness in wrist extension ECU affected
ECR and bracioradialis are sparred, no sensory defects
Long Thoracic Nerve Injury
C5-C7 nerve damage
Danger during radical mastectomy
Trauma to lateral chest wall
Winged scapula
Winged Scapula
Significant weakness in abducting the limb beyond 90 degrees (decreased scapular rotation component)
Loss of scapular fixation
Scapula will project posteriorly from posterior thorax in upper limb movements (winging)
Seen when pts are asked to push against wall with outstretched limbs
NPH
Normal pressure hydrocephalus can cause radiculopathies
Bicep MSR
C5-C6 (musculocutaneous nerve)
Brachioradialis MSR
C6 radial nerve
Triceps MSR
C7-C8 radial nerve
C5 Nerve Root
Strength-deltoid, biceps brachii
MSR-biceps brachii
Sensory-lateral shoulder (skin over deltoid) and lateral arm
C6 Nerve Root
Biceps brachii, wrist extension
MSR-brachioradialis
Sensory-lateral forearm, lateral palm including 5th digit and possibly second digit
C7 Nerve Root
Strength-triceps brachii, wrist flexion
MSR-triceps brachii
Sensory-middle finger
C8 Nerve Root
Strength-finger flexion
MSR-none
Sensory-5th digit and medial forearm, maybe 4th digit
T1 Nerve root
Strength-finger adduction/abduction
MSR-none
Sensory-medial forearm
L4 Nerve Root
Strength-tibialis anterior, quadriceps
MSR-patellar tendon
Sensory-medial leg, medial aspect of foot including medial malleolus
L5 nerve Root
Strength-extensor hallucis longus, extensor digitorum longus, walking on heels
MSR-tibialis posterior
Sensory-dorsum of foot
S1 nerve root
Strength-fibularis longus, walking on toes
MSR-calcaneal (achilles)
Sensory-lateral aspect of foot
Dinner Fork Deformity
Colle’s fracture
Transverse fracture of distal radius with dorsal displacement of the hand
Radiographs reveal dorsal angulation of distal radial metaphysis
Rotator Cuff Avulsion
Fracture of humerus
Fall on point of the shoulder
Muscles in greater tubercle pull the tubercle away from the head
Subscapularis muscle remains attached to the humerus and pulls the limb medially
Rotator Cuff Instability
Necessary for glenohumeral stability
Supraspinatus is the most commonly injured rotator cuff muscle
Supraspinatus is the most commonly injured muscle
Can be torn while trying to lift too much weight or catching a heavy falling object
Drop Arm Test
Ask pt. to lower arm from 90 degree abduction
Failure to lower arm in a smooth, controlled fashion or with pain suggests tear of supraspinatus tendon
Carpal Tunnel Syndrome
Contains flexor tendons and median nerve
Covered by flexor retinaculum
Repeated overuse of wrist resulting in edema and inflammation of structures traversing the carpal tunnel
Pain of carpal tunnel syndrome
Parasthesis of lateral 3.5 fingers and distal portion of palm with paresis in flexion, abduction and opposition of the thumb
Phalen’s Test
Dorsum of hands together, flex wrists
Backwards prayer position
Increases pressure in carpal tunnel
Decreases space in carpal tunnel to try to replicate tunnel syndrome symptoms in the pt
Finkelstein’s Test
Tests for De Quervain Tendosynovitis
Place thumb under digits 2/3 in fist and ask patient to medially deviate wrist
Exacerbate pain associated with tenosynovitis of tendons around the snuff box
De Quervain Tendosynovitis
Inflammation of the synovial sheath of the abductor pollicis longus and extensor pollics brevis
AC Separation
Injury to AC joint
Complete separation involves rupture of AC and coracoclavicular ligaments
Glenohumeral Dislocation
Stability of joint is sacrificed for mobility
Tendious and ligamentous support
Majority of dislocations occur inferiorly
Humeral head however may come to lie anterior or posteriorly
Anterior Shoulder Dislocation
Tears joint capsule and detaches labrum
Results in a compression fracture of the humeral head
Ruptured Tendon of Long Head of Biceps
Intracapsular portion of the tendon can become inflamed and erodes over time
Snuff Box Borders
APL, EPB and EPL
Covered by extensor retinaculum
Think Brevis Sandwich!
Snuffbox Floor
Radial artery—>dorsal carpal branch
Tendon of ECRL
Tendon of ECRB
Snuffbox Roof
Superficial branch of radial nerve
Tributaries of cephalic vein
Dupuytren’s Contracture
Pathological thickening and contraction of the palmar aponeurosis due to mechanical microtraumas
Shortening of longitudinal bundles of palmar aponeurosis
Draws fingers 4/5 into plam to such a degree that they become useless
Tapping a Tendon Reflex Action
Results in stretching of the tendon and muscle
Extrafusal fibers and intrafusal fibers
Muscle Spindle
Receives GSE and GSA
Stretching increases GSA axon innervation
Signal relayed to spinal cord–>fires GSE in anterior horn
GSE–>innervate skeletal muscle
Flexor Digitorum Superficiales
Innervated by median nerve C5-T1 Flexes proximal interphalangeal joints Assists flexion of distal IP joints MP joints Wrist Forearm
Flexor Digitorum Profundus
Innervated by median and ulnar nerves
Flexes distal IP joints 2-5
Assists flexion of digits 2-5 and wrist
Avulsion Fracture of Medial Epicondyle
Ulnar nerve at risk
Muscle/ligament can pull out a small piece of bone
Leads to compromised flexor function
Forearm flexors originate at medial epicondyle
Subluxation/Dislocation of Radial Head
Sudden yank on the arm of young child (extension or pronation)
Can tear the annular ligament resulting in partial subluxation or complete dislocation
Nurse Maid’s elbow
Babysitter’s elbow
