O&T SC062: I Cut My Finger: Hand Injury, Industrial Safety And Compensation Flashcards
Anatomy of hand
High demand for function
Prone to complicated injuries:
1. Contact to outside world
2. Different varieties of work
3. Complex anatomy
4 important anatomic tissue layers:
1. Skin + SC tissue + Vascular structures (Circulation)
2. Nerve (Sensation)
3. Muscle + Tendon (Active movement)
4. Bone + Joint (Passive movement)
Rehabilitation damands ***gliding of tissue layers (not stick together)
Volar side:
1. Bone
2. Muscle (Intrinsic)
3. Tendon (Flexor tendons of extrinsic muscles)
4. Joints (Synovium)
5. Peripheral nerves
Dorsal side:
1. Tendon (Extensor tendons of extrinsic muscles)
Classification of Hand injuries
- Closed (usually blunt injury, no immediate risk of infection, can wait)
- Fracture
- Dislocation
- Tendon avulsion (e.g. mallet finger) - Open
- Sharp cut —> Skin, SC tissue, ***Neurovascular bundle (check motor + sensory), Tendon, Bone, Amputation
- Crush
Finger tip injury
Small: Keep wound clean to allow spontaneous healing
Large: Wound coverage + repair
Urgent management of amputated part
- Remove amputated part atraumatically to prevent further tissue trauma (e.g. if trapped under bus) —> preserve as much as possible
- Wrap in sterile gauze (if available) with saline
- Put in plastic bag
- Submerged in ice cold water (4oC) to decrease warm ischaemic time (limit to 6 hours for parts with muscles) (X ice: ∵ water content in finger expand —> cell membrane damage)
Types of injuries
- Sharp cuts
- Usually circulation is good except amputation
- Not too much damaged tissue —> not much fibrosis (undesirable: impair mobility) - Crush injury
- Much devitalisation (a lot of dead cells in injured part)
- Result in fibrosis
—> Relatively poorer outcome than sharp cut injury
Other types:
3. Burnt (flame, scald, electrical, chemical)
4. Frostbite
***Approach in Hand injury (History taking, P/E)
Severe life-threatening injury before less severe injury (hand injury alone often not life-threatening)
History:
1. How to get the injury?
2. When
3. Associated injury
4. Relevant medical history + medication
P/E:
1. Inspection
- External wound
- Deformity / Abnormal posture (indicate bone, tendon, joint injury)
- Palpation
- Temp
- ***Pulse - ROM
- Active + Passive - Sensation
- Pain (Spinothalamic)
- Light touch (Dorsal column)
Treatment:
1. Identify injuries to other body systems (multiple trauma patient)
2. Assessment of hand injuries (extent + structures involved) + Documentation
3. Determine treatment method (single stage / multiple stages)
4. Rehabilitation always
***First aid management
- ***Removal of possible limb constriction (∵ can get edematous after injury, e.g. ring, watch, bracelet) (e.g. Ribbon method)
- ***Pressure to stop bleeding —> Direct to wound / digital artery
- ***Clean wound with detergent + copious amount of fluid
- ***Wound dressing
- Bandaging + ***Splinting
Emergency medication:
1. **Tetanus + **Antibiotics prophylaxis (in open wound)
2. Analgesics
Conservative treatment:
1. Minor cut
2. Small finger tips injuries
Treatment in Bleeding laceration
- Lie patient down
- Hand elevated
- Sterile dressing to cover the wound
- Gentle direct pressure applied
Finger pressure dressing:
1. Sterile dressing pack
2. Non-adherent absorbent dressing
3. Adhesive tape
4. Cotton tubular bandage
5. Applicator for cotton tubular bandage
Procedure:
- Wound toilet / suture
—> Place non-adherent dressing onto the wound
—> Place absorbent gauze to form a pressure pad
—> Apply tapes (ensure tape not complete encircle finger)
—> Selective appropriate width of cotton tubular bandage and cut a length 10x as long as injured finger
—> Thread bandage over applicator
—> Pass applicator over finger and ease off the end of bandage
—> Twist applicator around the base of finger to anchor the bandage
—> Twist applicator continuously while withdrawing it to the end of finger
—> At the end of finger twist bandage through 2 complete turns
—> Preferably tip of finger is exposed for observation of circulation
(If tip need to be covered up —> no tight circumferential taping should be applied —> split remaining piece of bandage into 2 and use the 2 ends to tie the dressing loosely in position at base of finger)
Life threatening condition in Hand injury
ONLY one:
- Uncontrolled haemorrhage from a partially transected vessel (vessel does NOT spasm —> continual haemorrhage)
Emergency control of arterial bleeding:
1. Direct pressure
2. Apply arm tourniquet
3. Elevation
4. Inflating cuff of sphygmomanometer to 100-150 mmHg (above SBP)
Subungual haematoma
- Nail hit by heavy object —> Very painful
- Bleeding inside soft tissue, haematoma collected underneath nail
Treatment:
Small: Resolve on its own
Moderate:
Light spirit lamp
—> Straighten out paper clip + Heat in flam until red hot
—> Apply red hot tip to central point of haematoma
—> Burn a hole in nail
—> Allow blood to escape through hole
Large: Need drainage (with incision in soft tissue / remove strip of nail)
Open hand injuries
Treat as **emergencies (cleansing + operation within 6 hours —> prevent bacterial contamination / infection)
1. **Tetanus + ***Antibiotics prophylaxis
- Assess + Documentation
- ***Exploration
- Adequate anaesthesia
- Surgical toilet (copious of detergent + fluid) -
**Repair
- Primary repair if possible
- Set priority if not possible (tourniquet time is limited ~2 hours)
- **Skin coverage is highest priority to prevent infection
- Secondary repair / reconstruction
- Late reconstruction (for residual problem)
—> Skin: Insufficient skin
—> Bone: Malunion / Non-union
—> Tendon: Adhesion
—> Nerve: Poor regeneration
—> Composite tissue transfer (e.g. toe hand transplant)
Rehabilitation always:
1. **Edema control
- Elevation
- Pressure dressing (e.g. Boxing glove)
2. **Immobilisation in functional position if necessary (e.g. flexed MPJ, extended IPJ, thumb abducted + extended)
3. ***Early mobilisation (ensure bone, joints, muscles, tendons are stable)
- Prevent joint stiffness of involved joints
- Maintain gliding of tissue layers
- Mobilisation of joints of whole body
- Maintain cardio-thoracic fitness
- Maintain muscle strength + endurance
4. Mental rehabilitation
- Adjustment problem
- Depression
- Body image
- Stamina to go back to original work
Case managers for Work-related injuries
- Close observation of rehabilitation
- Arrange best rehabilitation + Follow up for patients
- Liaise with multi-disciplines (PT, OT, MSW, Psychi, Psycho) for best patient management
- Target to shorten duration out of work, maximise recovery
Work-related hand injury
- 75% work-related injury involve hand
- Poor management leads to functional disability
- Loss of earning capacity of patient
- Decrease family income —> affect life of family
Types of work:
1. Department stores
2. Restaurants
3. Hospitals
4. Hotels
5. Motor vehicle manufacturing
6. Nursing / personal care facilities
7. Retail grocery stores
8. Trucking industries
Fatalities:
1. Construction
2. Transportation
3. Public utilities industries
Upper limb work-related injuries
- More common due to chronic overuse now
- Not life-threatening but pain + decrease in work capacities
- Office workers
- ***Notifiable disease
Diseases:
- Carpal tunnel syndrome
- De Quervain’s disease
- Trigger finger
- Tennis elbow
Cause:
- Multifactorial
Occupational safety charter
- Safety is a shared responsibility of employers + employees
Employers:
- Safety organisation to ensure each person’s role + responsibilities are understood
- Safety training to equip all staff with knowledge, skills, attitudes
- Risk assessment programme which identify actual + potential risks
- Safe working environment
- Healthy assurance programme
- Safety committee
- Safety promotion
Employees:
- Follow safety rules + work procedures set out in safety management system
- Take active part in attending safety + health training
- Report to employer any potential job hazards
- Make suggestions on safety improvement to supervisor / employer
- Cooperative with relevant authorities in reporting breaches of statutory requirements
Industrial safety in high risk work
- Protective shield to cover press mould
- Safe use of electric saw
- Research to find out causes of industrial accidents
Compensation
Sick leave:
- ***80% of salary up to 3 years
Permanent disability:
- Rated according to loss of earning capacity
—> Under 40: 96 months’ earnings / minimum amount of compensation x % of PDC
—> 40-56: 72 months’ earnings / minimum amount of compensation x % of PDC
—> >56: 48 months’ earnings / minimum amount of compensation x % of PDC
Decrease social cost of industrial accident
- Government policy / law
- Employers’ responsibility
- Workmen’s awareness
SpC O/T Seminar: Hand injuries
Hand injuries Case 1: Avulsed nail
Distal hand:
- Most prone to injury
- Volar / Dorsal injury
P/E (Nail plate + Nail bed + Distal phalanx):
1. Digit involved
2. Perforation of nailbed
- Outside-in / Inside-out injury (indicate underlying fracture fragment of distal phalanx)
—> communicate with atmosphere in open fracture
—> possible complication: Infection, Osteomyelitis
Investigations:
1. X-ray
- Comminuted fractures caused by crush injury
Treatment:
1. ***Wound management
- Proper wound care
- **Antibiotic + **Tetanus prophylaxis
Hand injuries: Distal phalanx fracture
DIP joint motion does NOT put loading on tuft fracture of distal phalanx
- Pinching will put loading to fracture fragment and should be avoided
- Active joint motion should be encouraged to prevent stiffness + continue original motor program
Hand injuries Case 2: Volar distal injuries
P/E:
1. Exposed tissue?
- Tendon
- Bone
Treatment:
1. Conservative: ***Wound dressing
- if Small surface, Superficial cut
- Body can regenerate skin layer by re-epithelialisation, granulation tissue formation —> restore bulk of pulp
- Urgency to cover (otherwise may be desiccated —> necrotic)
- if Large surface, Deep cut
- Skin layer most important to replenish for protective surface for exposed tendons / bones
- **Skin graft / **Skin flap (with skin, SC tissue, blood supply, nerve supply)
—> V-Y plasty (for transverse cut)
—> Volar advancement flap for thumb
—> Flap from dorsum of index finger to thumb tip defect —> index finger defect then covered with skin graft
—> Partial toe transfer (need arterial, venous, nerve anastomosis) - Debridement of dead tissue + Suturing of viable tissue
Nerve problems Case 3: Carpal tunnel syndrome
Most common nerve problem: **Nerve entrapment
Most common nerve entrapment in upper limb: **Carpal tunnel syndrome
History:
1. Middle age women
2. Repetitive stress injury
3. ***Worse at night (∵ accumulation of interstitial fluid at night)
4. Numbness + Clumsiness in hand
Causes:
1. **Overuse (majority)
2. Local causes: **Fracture, Dislocation, **Space-occupying lesion (e.g. gouty tophi)
3. General causes: **Myxedema, ***Amyloidosis in chronic renal failure
(4. Pregnancy?)
P/E:
Motor:
1. Atrophy / Weakness of thenar muscles
- only **abduction is affected (i.e. Abductor pollicis brevis) (∵ Flexor pollicis brevis, Opponens pollicis may be innervated by **Ulnar nerve)
- indicate chronic —> motor fibres also involved
- Supinated posture of thumb (***Adducted thumb)
- indicate chronic —> motor fibres also involved
Sensation
3. Decreased sensation of radial 3.5 fingers
- ***Palm spared
- ∵ palmar cutaneous nerve not enter carpal tunnel -
**Tinel’s sign positive
- tap on median nerve in carpal tunnel —> numbness over radial 3.5 fingers —> ∵ median nerve compressed —> axons become necrotic —> **regeneration of nerve endings —> local sensitivity of median nerve over carpal tunnel —> tap on nerve endings —> sensitive - ***Phalen’s test positive
- palmar flex wrist —> kinking of median nerve
Treatment:
1. Conservative (***Splint at night time —> keep median nerve in smooth course)
- early cases (only numbness)
- Surgery (Open / Endoscopic release)
- advanced case
Nerve problems Case 4: Ulnar nerve neuropathy
Causes:
1. **Cubital tunnel syndrome (most common)
2. **Tardive ulnar nerve palsy (valgus deformity of elbow stretching ulnar nerve)
3. ***Subluxable ulnar nerve with frictional injury
P/E:
Motor:
1. Thenar: Froment’s sign positive
- Weak **Adductor pollicis —> need to compensate by flexion of IP of thumb (*Flexor pollicis longus by Median nerve) to pinch paper
- Hypothenar: ***Hypothenar atrophy
- Weak hypothenar muscles
—> Weak abductor digiti minimi - Lumbricals: ***Ulnar claw hand
(- Unopposed long extensor at MCP by Radial nerve
- Unopposed long flexors at IP by Median nerve) - Interossei: ***Web space muscle atrophy
- Weak adduction of fingers (test by gripping paper between fingers)
- Weak abduction of fingers (by spreading fingers apart) (Weak 1st dorsal interossei)
Sensory:
1. Ulnar 1.5 fingers with corresponding area of palm + hand dorsum
Treatment:
- **Surgery mainly (not much room for Conservative)
—> **Decompression (open / endoscopic)
—> **Anterior transposition of ulnar nerve (move ulnar nerve to volar side of elbow joint to decrease tension + release compression)
—> **Medial epicondylectomy
Nerve problems Case 5: Radial nerve compression
Radial nerve palsy (aka Saturday night palsy)
Causes:
- **Displaced fracture of humerus
- **Falling asleep with one’s arm hanging over the arm rest of a chair —> Compression of radial nerve
P/E:
Motor:
1. ***Drop wrist + Drop finger (MCPJ)
- Weak wrist extensors
- Weak long finger + thumb extensors by testing extension at MCPJ (NOT IPJ —> ∵ supplied by intrinsic muscle by ulnar nerve)
Sensation:
2. ↓ Sensation at ***anatomical snuffbox (but much overlapped by median nerve —> ∴ small area of deficit)
Treatment:
- **Splintage to lift up fingers and wrist while waiting for recovery of radial nerve
- Iatrogenic / Laceration wound: **Exploration + Repair
- Humerus fracture: ***Monitor (mostly Neurapraxia: 90% recover)
- Radial tunnel syndrome (Entrapment neuropathy): Rare
Hand rehabilitation
Regain maximal function after injury / illness
1. Start at ***time of injury —> Prevent edema (∵ edema fluid induce adhesion between tissue layers)
2. Encourage gliding of tissue layers to prevent adhesion
3. Passive mobilisation whenever safe
4. Active mobilisation whenever safe
Severe hand edema:
- Volar tissue are bound to deeper tissue by fascial layer so edema cannot occur
—> Fluid collected in **dorsum of hand + digits
—> **Claw hand deformity (MPJ extended, IPJ flexed, Thumb adducted)
—> Non-functional (∵ space of motion very limited)
Role of treating surgeon / hand therapist:
- Good operation + Good rehabilitation —> Good outcome
Early phase:
1. Edema control
- **Compression Boxing glove —> **Functional position of hand: MPJ flexed, IPJ extended, Thumb abducted to open up 1st web (exactly opposite to Claw hand)
- ***Elevation of hand
- Protect damaged tissue + Improve function during recovery phase
- ***Splintage to lift up fingers and wrist while waiting for recovery of radial nerve - Maintain gliding of tissue layers
- Active / Passive / Dynamic passive motion of mobilisation to maintain gliding of tissue layers
Late phase (after recovery of damaged tissue):
1. Sensory / Motor re-education
- Strengthening exercise + Work hardening
- e.g. Carpal tunnel syndrome: hand and wrist exercise to increase nerve mobility + active ROM + strength of hand / upper limb - Work rehabilitation
- Train up tasks of their job demand
Management of claw hand:
- Vigorous mobilisation execise
Miscellaneous common conditions: Dinner fork deformity
***Colles fracture:
- Osteoporosis
- Elderly
- Fall on outstretched hand
Distal fracture fragment:
1. Dorsal angulation + displacement
2. Radial angulation + displacement
3. Shortening of radius
Treatment:
- Extra-articular fracture: Conservative with CR + POP
Miscellaneous common conditions: Scaphoid fracture
Causes:
- Falling on outstretched hand
Scaphoid:
- Blood supply from dorsal scaphoid to proximal scaphoid (retrograde bloodflow)
—> Fracture
—> Proximal part of scaphoid will lack blood supply
—> Must have fracture healing in order to regain blood supply to proximal pole
—> Risk of ***AVN of proximal part of Scaphoid (if fracture not treated properly / no fracture healing)
Clinical features:
1. Local tenderness at **anatomical snuffbox + **scaphoid tubercle (Classical sign: but can also appear in sprained wrist)
Other signs not reliable:
2. Pain over scaphoid area on radial-dorsiflexion (impingement of scaphoid)
3. Pain on forced radial-dorsiflexion + forced ulnar deviation
4. Pain over scaphoid when patient pinches thumb against index finger while examiner tries to pull against it
Management:
1. ***MUST identify the fracture (esp. in undisplaced fracture)
- X-ray may not show fracture initially —> require CT / MRI
- Immobilise wrist with ***Scaphoid cast
- to avoid displacement of fracture
- treat as displaced fracture if cannot see on X-ray
Miscellaneous common conditions: De Quervain’s disease
Inflammation of tendon in ***1st extensor compartment —> APL + EPB
Causes:
1. Excessive use of thumb
2. Sustained posture in lifting heavy objects
—> Overuse of tendon —> Inflamed
S/S:
- Pain over radial styloid —> ***Finkelstein test positive
—> Put thumb and hold it in hand then ulnar deviate wrist
- Pain in both wrist neutral and flexed position during active extension and abduction of thumb against resistance
Treatment:
1. Conservative
- NSAID
- Splint
Miscellaneous common conditions: Mallet finger deformity and Boutonniere deformity
Mallet finger deformity:
- Most common extensor injury
- **Hyperflexion injury of DIP during ballgames (篤魚蛋)
—> Rupture of **distal extensor tendon
Treatment:
1. ***Mallet finger splint: Oppose tendon ends in normal position
2. Mobilisation exercise after recovery
Prognosis:
- Healing in 6 weeks
Boutonniere deformity:
- Rupture central slip of extensor system
- Treatment: Long mallet splint / Surgery
Miscellaneous common conditions: Loss of flexor tone
Normal hand posture: Flexor tone predominant —> flexed digits
Loss of flexor tone: Flexor problem (Flexor digitorum superficialis + profundus)
SpC O/T Seminar: Peripheral nerve injuries
Structure of nerve + Nerve injury types
Epineurium:
- Covering peripheral nerve
- Cushion against external pressure
Perineurium:
- Around one fascicle
- Tensile strength and elasticity
Endoneurium:
- Around each axon
Nerve injury types:
1. Traumatic
- Stretching (15% elongation can already cause axonal disruption)
- Laceration
2. Compression
- Chronic compression
—> Local ischaemia + Endoneural edema + Fibrosis —> more ischaemia —> Segmental demyelination + Wallerian degeneration
—> Low threshold (30mmHg: Paresthesia, 60mmHg: Complete nerve block)
3. Vascular
4. Vibration
5. Radiation
6. Chemical / Biochemical
Neurapraxia:
- Myelin sheath (Sunderland 1)
- No Wallerian degeneration —> EMG: No muscle fibres fibrillation
- Reversible
- Full recovery
- NCS: Conduction block at lesion but distal conduction preserved
Axonotmesis:
- Axon involved (Sunderland 2)
- Have Wallerian degeneration —> EMG: Have muscle fibre fibrillation
- Variable reversibility
- Incomplete recovery
- NCS: Loss of conduction both at + distal to lesion
Neurotmesis:
- Endoneurium (Sunderland 3), Perineurium (Sunderland 4), Epineurium (Sunderland 5)
- Have Wallerian degeneration —> EMG: Have muscle fibre fibrillation
- Variable / No reversibility
- Incomplete / Poor recovery
- NCS: Loss of conduction both at + distal to lesion
Nerve fibre transection:
- Distal segment —> Wallerian degeneration —> Schwann cells proliferation + line up in bands of Bungner
- Proximal segment —> Atrophy + degeneration to nearest node of Ranvier —> Axon spouting at 1 mm/day down endoneurial tubes —> “Axonal” connection with periphery + maturation of nerve fibre
Nerve regeneration:
- Yes: advancing Tinel sign
- No: time-dependent permanent atrophic changes to target organ
—> motor end plates disappear after 3 months —> followed by muscle spindles + cutaneous sensory organs
Prognostic factors:
1. Age (most important factor)
2. Mechanism of injury
- Sharp cut better, Crush injury poorer
- Low velocity injury better, High velocity injury poorer
- Associated arterial / bony injuries poorer (poor wound environment)
3. Level of injury
- Distal better
Nerve repair
- Direct muscular neurotisation
- inserting proximal nerve stump into affected muscle belly: resulting in less-than-normal function - Epineural repair
- preparation of nerve ends (resecting neuroma / scar) —> suture epineurium together —> approximate 2 ends
- need to ensure proper rotation + lack of tension - Grouped fascicular repair
- for large nerves (e.g. Sciatic nerve)
- suture perineurium together
- more scarring due to more sutures
- no significant difference in outcome compared to epineural repair
Limitations:
1. Slow growth velocity (1 mm/day)
2. Chronic denervation —> target muscle atrophy —> cannot be dealt by surgery
3. Neural atrophy only partially reversible for delayed repair
4. Misalignment of motor and sensory axons in large nerves
Other options:
4. Nerve grafting
- if defect too large to perform tension-free repair
- options:
—> **Nerve graft (Autograft e.g. Sural nerve / Allograft)
—> **Nerve conduit (act as scaffold for nerve to grow back) (Artificial e.g. silicon / Non-artificial e.g. vein graft, muscle)
5. Nerve transfer / Neurotisation
6. Gene therapy
Sural nerve: lateral side of foot, sensory only, less donor site morbidity
Median nerve
Motor supply:
1. Volar forearm (Extrinsic muscles)
- PT, FCR, PL, **FDS
- **Anterior interosseous nerve (AIN) (branch off at proximal forearm): FPL, ***Radial half of FDP, PQ
- Intrinsic muscles of hand
- LOAF
—> Lateral 2 lumbricals
—> Thenar muscles (Recurrent motor branch): OP, APB, FPB
Sensory supply:
1. 3.5 fingers sensation (Common + Proper digital nerves)
2. **Thenar sensation (Palmar cutaneous branch: branches off **before entering carpal tunnel —> NOT affected in CTS)
—> ***Need to check Thenar sensation to determine whether it is CTS / Higher palsy
Common sites of compression:
1. **Pronator teres syndrome (High palsy: more functional disturbance)
2. **Carpal tunnel syndrome (Low palsy) (more common)
Causes of Median nerve palsy:
1. **Idiopathic CTS
2. **Secondary CTS
- **Trauma (e.g. **Distal radius fracture, Carpal injury, **Supracondylar humerus fracture: **AIN palsy) —> Acute CTS
- **Inflammatory joint disease (e.g. RA, Gout, Pseudogout)
- **Systemic (e.g. Myxedema, Amyloidosis)
- **SOL within carpal tunnel (e.g. Ganglion cyst, gouty tophi)
- Tenosynovitis
(- **Pregnancy
- ***Acromegaly
- Diabetic neuropathy)
P/E of Median nerve
Intrinsic muscles:
1. Thenar wasting
2. Weak thumb opposition (Weak OP)
3. Weak thumb abduction (Weak APB) (a specific muscle innervated by Median nerve ONLY)
Extrinsic muscles:
4. Square sign / Failure to do OK sign
- ***AIN palsy (esp. in supracondylar fracture in children): Weak FPL + FDP
- FPS is intact —> Can flex PIP
- Benediction sign / Cannot make a fist (Cannot flex 1 + 2 + 3 finger)
- ***High median nerve palsy: Weak extrinsic + intrinsic muscles: FPL + Radial FDP + Radial lumbricals
- 4 + 5th digit can flex: intact Ulnar FDP + Ulnar lumbricals
- vs Claw hand: Cannot extend 4 + 5th finger
Provocative tests:
1. Tinel’s sign (percuss from distal to proximal)
2. Phalen test (30s)
3. Durkan’s test (direct compression test)
Differentiate high vs low palsy:
Motor:
- Intrinsic LOAF = Low (carpal tunnel)
- OK sign (FPL + FDP) = AIN
- Both = Median nerve
Sensory:
- Radial 3.5 digit = Low (carpal tunnel)
- Thenar eminence = Palmar cutaneous nerve = High (proximal to carpal tunnel)
Tinel sign:
- Area of nerve injury
Ulnar nerve
Motor supply:
1. Volar forearm (Extrinsic muscles)
- FCU
- Ulnar half of FDP
- Intrinsic muscles of hand
- ALL except LOAF
—> Adductor pollicis
—> Interossei (Palmar + Dorsal)
—> Medial 2 lumbricals
—> Hypothenar (ADM, FDMB, ODM)
Sensory supply:
1. 1.5 fingers sensation
- Superficial terminal branch
- Hypothenar sensation
- **Palmar cutaneous branch: branches off **proximal to wrist —> High palsy
- **Dorsal cutaneous branch: branches off **proximal to wrist —> High palsy
Common sites of compression:
1. **Cubital tunnel syndrome (High palsy) (more common)
- associated with Cubitus valgus, Elbow OA —> check **elbow ROM
2. ***Guyon’s canal / Ulnar tunnel syndrome / Cyclist’s palsy (Low palsy)
- chronic compression of ulnar wrist
Causes of Ulnar nerve palsy:
1. **Elbow deformity (Cubitus valgus, varus)
2. **Elbow arthritis (e.g. OA / RA elbow)
3. Entrapment neuropathy (e.g. **Cubital tunnel syndrome, **Guyon’s canal)
4. Trauma
5. Muscle anomaly
DDx:
- T1 radiculopathy (but have thenar muscle wasting)
P/E of Ulnar nerve
Intrinsic muscles:
(記: Adductor pollicis, Interossei, Lumbricals, Hypothenar)
Adductor pollicis:
1. Froment’s sign
- Compensated by IPJ flexion: FPL by median nerve
- Jeanne sign (Weak Adductor pollicis)
- Compensated by MCP hyperextension: EPL by radial nerve
Interossei:
3. Weakness in Abduction / Adduction of fingers
- **Diamond hand sign unable to do (1st dorsal interossei (adduction): strong side push against weak side)
- **Cross finger test (1st palmar (adduction) + 2nd dorsal interossei (abduction))
Lumbricals:
4. Claw hand / Duchenne sign (Weak Lumbricals)
- **Intrinsic-extrinsic imbalance (weak intrinsic + strong extrinsic (long flexor + long extensor))
—> **MCP hyperextension (EDC by Radial nerve) + ***IP flexion (FDS by Median nerve + FDP not affected in low palsy)
Hypothenar:
5. Abductor digiti minimi (ADM)
- Push little finger against each other
- Wartenberg sign (~finger escape sign in cervical myelopathy)
- Little finger kept in abduction + slight extension (unopposed action of EDM by Radial nerve)
- ***Intrinsic-extrinsic imbalance - Masse sign / Rectangular palm
- Wasting of hypothenar —> flattened metacarpal arch
Extrinsic muscles:
1. Weak wrist ulnar deviation + flexion (Weak FCU)
2. Pollock test (FDP of ring + little finger —> DIP flexion)
- ***Need to immobilise PIP (FDS)
Cubital tunnel:
1. Ulnar nerve subluxation around medial epicondyle
2. Elbow flexion test
3. Tinel sign
Differentiate high vs low palsy:
Motor:
- Intrinsics = Low
- FDP (Pollock test), FCU = High
Sensory:
- Ulnar 1.5 digit = Low
- + Ulnar hand dorsum (Dorsal cutaneous branch) = High
Tinel sign:
- Area of nerve injury
**Ulnar paradox:
- High palsy = more muscles paralysed but **less clawing = actually less disabling (∵ FDP also involved in high palsy —> less clawing)
Radial nerve
Motor supply:
1. Arm
- Triceps
- Anconeus
- Elbow
- BR
- ECRL
- Supinator - Posterior interosseous nerve (PIN) (posterior to interosseous membrane)
- ECRB
- EDC
- APL / EPB
- EPL
- EIP
- EDM
- ECU
Sensory supply:
1. Posterior arm
2. Posterior forearm
3. Hand dorsum (superficial radial nerve branch)
Common sites of compression:
1. **Axilla (Saturday nigh palsy)
2. **Lateral intermuscular septum (common in Distal 1/3 **humerus fracture (Holstein-Lewis fracture) —> rigid septum render immobility of radial nerve —> easily injured during by fractured bony segments —> cannot do closed reduction)
3. **Radial tunnel
P/E of Radial nerve
- Wrist + Finger drop
- ***EDC
- Extend MCP against examiner with IPJ flexed —> eliminate effects of lumbricals (IPJ extension)
Differentiate high vs low palsy:
Motor:
- Finger drop (EDC, EPL, EI, EDM) = Low (PIN palsy) —> ECRL still present: wrist extension present but **weak with **radial deviation (weak ECU)
- Finger + Wrist drop (BR, ECRL) = High (Proximal to forearm)
- Triceps involved = Very high (Arm / Axilla)
Sensory:
- More proximal —> More sensory area deficit
DDx of PIN palsy Finger drop (SpC Revision):
1. Extensor tendon rupture
2. Extensor dislocation
3. MCPJ dislocation
Decompression vs Reconstruction
Decompression:
- Early cases to prevent target organ atrophy (will be irreversible once atrophy developed)
Reconstruction of tendon / muscle function:
1. Severe chronic compression
2. Incomplete nerve regeneration
3. Target organ atrophy (Motor end plate / Sensory organ: irreversible even after decompression)
Tendon transfer:
- Donor tendon (dispensable tendon without functional impairment) —> Recipient tendon (e.g. Camitz opponensplasty for median nerve (Palmaris longus tendon (not much function in adult) to APB))
Nerve transfer / Neurotisation:
- Donor nerve (e.g. AIN supplying PQ, even if PQ function loss, still have PT for pronation) —> Recipient nerve (e.g. transfer Ulnar nerve to get axons growing distally —> try to recover intrinsic muscles motor function)
Foot drop
Deep peroneal nerve:
- Motor:
—> Tibialis anterior (Ankle dorsiflexion)
—> EHL, EDL (Toe extension)
- Sensory: Dorsal 1st web
Common peroneal nerve:
- Motor: Deep peroneal nerve + Superficial peroneal nerve (Peroneal longus + brevis, Lateral calf) (Ankle eversion)
- Sensory: Deep peroneal nerve + Superficial peroneal nerve (Foot dorsum sensory)
Sciatic nerve:
- Motor:
—> Common peroneal nerve + Tibial nerve (Gastrocsoleus (Ankle plantar flexion), FHL, FDL (Toe flexor), Tibialis posterior)
—> Sciatic nerve itself: Hamstring
- Sensory: Common peroneal nerve + Tibial nerve (Sole sensory)
L5 nerve root:
- **Intact peroneal longus + brevis (Intact ankle eversion)
- **Weak hip abductor (Gluteus medius)
