Anomalous Innervations

1.  Richie-comeau



- ulna to median in palm

- provides motor to the thenar muscles

- ulna dominate hand

- may be due to RC anastomosis


Clinical significance

- carpal tunnel syndrome with no thenar atrophy


2.  Martin-Gruber 



- median to ulna in forearm

- provides motor function to hypothenar eminence


Clinical significance

- cubital tunnel syndrome with no hypothenar atropy

- may be due to MG anastomosis




Brachial Plexus




C5 - T1

- prefixed: C4 (more common)

- post fixed: T2


Roots (3 Branches / LSD)(Interscalene)

Trunks (1 Branch)(Posterior Triangle)

Division (Clavicle)

Cords (5,5,3)(Axillary Artery)


Nerve roots


Formed by ventral and dorsal nerve rootlets

- in foramen

- DRG has cell bodies of sensory nerves

- rupture proximal to DRG indicates preganglionic


Run between scalenius anterior and medius



- long thoracic nerve (C5/6/7)(serratus anterior)

- nerve to subclavius (C5/6)

- dorsal scapula nerve (C5)(rhomboids)


T1 sympathetic ganglion close to T1 nerve root

- frequently injured together




A.  Upper 

- C 5/6

- merger is Erb's point

- where SSN exits

- injury: SSN, axillary, MCN (lose SS, IS, deltoid, biceps)


B.  Middle

- C7


C.  Lower

- C8/T1



- suprascapular nerve (C5,6) from upper trunk




Trunks divide into anterior and posterior

- behind clavicle




A.  Posterior cord (5)

- all three posterior divisions

- C5 - T1

- posterior to axillary artery



- radial is terminal branch

- axillary

- upper and lower subscapular

- thoracodorsal


B.  Lateral cord (3)

- anterior divisions of upper and middle trunk

- C5/6/7

- lateral to axillary artery



- MCN lateral to artery

- lateral branch of median nerve / runs across artery

- lateral pectoral


C.  Medial cord (5)

- anterior division of lower trunk

- C8 / T1

- medial to axillary artery



- medial median

- medial pectoral

- MCNA, MCNFA (medial cutaneous nerve of arm and forearm)

- ulna nerve is terminal branch (runs medial to artery)




Roots / ASIA


Peripheral nerves


Supraclavicular region  C4


Regimental patch C5

- axillary nerve


Radial forearm C6



Dorsal first web space C6

- radial nerve


Thumb and thenar eminence C6

- median nerve


Middle finger C7

- median nerve


Little finger C8

- ulnar nerve


Ulnar forearm T1



Medial arm T2





Nerve roots / ASIA


C5 / deltoid / bicep

C6 / wrist extensors

C7 / tricep


T1 / interossei


Adjacent nerves


Trapezius (CN Xl)

- patient shrugs shoulders against resistance


Branches from roots


Rhomboid (C5)

- dorsal scapular nerve

- patient retracts scapula

- examiner uses hand to palpate


Serratus anterior (C567)

- long thoracic nerve


A.  Patient pushes against wall

- observe for winging

- patient protracts shoulder against resistance 


B. Some pateints won't be able to get arm up to wall

- raise arm for them

- get them to push arm away


Branches from the trunks


Supraspinatus (C5)

- suprascapular neve

- patient tries to initiate abduction of the arm from the side


Infraspinatus (C5)

- suprascapular nerve

- patient tries to externally rotate shoulder with arm by side


Branches of the posterior cord (C5-T1)


Deltoid (C5)

- axillary nerve

- patient abducts arm against resistance


Latissimus Dorsi (C7)

- thoracodorsal nerve

- patient adducts horizonal arm against resistance



- upper and lower subscapular


Radial nerve


1.  Triceps (C78)

- patient extends elbow against resistance


2.  Brachioradialis (C6)

- patient flexes the elbow with forearm pronated


3.  ECRL (C67)

- radial nerve

- extend IF against resistance


4.  ECRB (C67)


- extend MF


5. Wrist extension (C67-ECR, C67-ECU)

- radial and posterior interosseous nerve

- patient extends wrist


5.  Supinator (C6)

- patient supinates forearm in extension


6.  EDC (C8)


- patient extends MCPJ


7.  ECU (C67)


- extend wrist


8.  Extensor pollicis longus (C7)


- patient extends thumb IPJ against resistance


Branches of the lateral cord (C5,6,7)


Pectoralis major (clavicular fibres) (C6)

- lateral pectoral nerve

- patient pushes arm forwards with arm horizontal


Biceps (C56)

- musculocutaneous nerve

- patient tries to flex elbow with forearm supinated


Lateral median nerve


1.  PT (C6)

- pronate in flexion


2.  FCR (C6)

- wrist extension


Branches of the medial cord (C8 / T1)


Pectoralis major (sternocostal fibres) (C7,8)

- medial pectoral nerve

- patient places hand on hip and pushes in


Medial branch median nerve


Flexor digitorum profundus (C8)


- patient makes fist and resists extension of index finger


Flexor pollicis longus (C8)


- patient flexes distal phalanx of thumb against resistance


Abductor pollicis brevis (TI)

- patient abducts thumb at right angles to palm against resistance


Ulna nerve


Flexor carpi ulnaris (C8)

- patient flexes wrist against resistance


Flexor digitorum profundus (C8)

- patient makes fist and resists extension of little finger


Interossei (TI)




Diagnostic Issues



- nerve root patterns of sensation and motor disturbance



- peripheral nerve root pattern / cord


Supraclavicular preganglionic

- dorsal scapular / long thoracic / suprascapular nerves injured

- Horner's

- lack of sensation supraclavicular

- no tinel's


Supraclavicular postganglionic

- + Tinels

- tender posterior triangle









- suggests C8/T1 root avulsion


Posterior triangle swelling / bruising


Wasting deltoid / biceps / Pecs


Wrist drop




Hand on head

- axillary scars






Supraspinatus/ Infraspinatus

Static winging




Palpate post triangle

- tenderness

- supraclavicular post ganglionic


Tinel's in post triangle

- supraclavicular post ganglionic




Ask patient about sensory loss


Supraclavicular C4 

- suggests preganglionic injury


Axillary nerve C5 


LCNF C6 musculocutaneous


SRN C6 (1st dorsal webspace) 


C6 median n (thumb)


C7 median n (MF)


C8 ulnar n (LF)


C8 MCNF m cord (med forearm)


T1 MCNA m cord







- function of accessory nerve important


Roots / From Behind



- shoulders back

- DSN C5


Rhomboid Testing


Serratus anterior

- push shoulder forward

- LTN C5-7


Suggest preganglionic




Suprascapular Nerve (C5)

- supraspinatous

- infraspinatous


Front / Nerve Root innervation



- C5

- axillary / posterior cord



- C5

- musculocutaneous / lateral cord


Left biceps wasting



- C7

- radial / posterior cord


Wrist extension

- C6

- radial / posterior cord


Finger flexion

- C8

- median / medial and lateral cord


Finger abduction

- T1

- ulna nerve / medial cord


Decide if fits root pattern

- Otherwise consider cord injury




Post Cord

- axillary nerve (deltoid + T minor)

- radial nerve

- subscapularis

- lat dorsi TDN C7 (hand on hip or cough)


Medial Cord

- medial median (FDP, FPL, AbPB)

- medial pectoral (sternal head)

- ulna nerve (interossei, LOAF)

- MCNA / MCNFA (decreased sensation medially)


Lateral Cord

- lateral median (FCR, PT)

- musculocutaneous (biceps, sensation lateral forearm)

- lateral pectoral (clavicular head)




Biceps C5

Triceps C7





Cephalad joint - Neck

Concealed - axilla





Classification Leffert "OCRO"


I Open


II Closed


A  Supraclavicular 

- Preganglionic / Avulsion of Roots

- Postganglionic / Rupture of Trunks


B Infraclavicular

- cords & branches


C.  Post anaesthetic


III Radiation / Other



Iatrogenic e.g. patient positioning



IV Obstetric


A Erb C5/6

B Klumpke C7/8 T1

C Mixed


Narakas Rule of 7's


70% MVA

70% of these MBA

70% associated injuries

70% supraclavicular

70% root avulsions 

70% C8/T1 involvement

70% persistent pain




MBA most common


Gunshot Injury

- deficit 2° nerve concussion

- usually improves

- observe for 3 /12

- explore if no improvement / large residual deficit


Position of arm

- abducted above horizontal (lower lesion)

- abducted below horizontal (upper lesion)


Associated Injuries


Axillary / subclavian artery 10-20%


Fracture humerus / clavicle / scapula / ribs


Dislocations GH / AC / SC joints


Rotator cuff tears




Supraclavicular preganglionic (nerve root patterns)

Supraclavicular postganglionic (trunks)

Infraclavicular (cords)


Can be mixed

- 2 patterns can occur in one nerve root


Supraclavicular Preganglionic / Root avulsion




Severe pain in anaesthetised arm

- starts day 1 in 50%

- constant burning + superimposed `lightning shocks`down limb


Tender & swollen in posterior triangle

- pseudomeningocoeles


Tinel's negative

- dorsal root ganglion intact so no wallerian degeneration of sensory nerve


Horner's if T1


Evidence of injury to branches from roots

- long thoracic / serratus anterior

- dorsal scapular / rhomboids





- SNAP normal (as fibres in continuity with DRG)

- abnormal sensation



- denervation dorsal neck muscles (posterior rami)


Diaphram paralysis

- high nerve root lesion / phrenic nerve


MRI Neck

- pseudomeningocoeles

- empty root sleeves




1.  Erb's Palsy


C5 & 6 +/- 7

- also lose branches from roots and trunk

- long thoracic / dorsal scapular / suprascapular



- shoulder adducted & internally rotated

- elbow extended

- forearm pronated 

- waiter's tip


Brachial Plexus Erbs


Paralysis of 

- deltoid / abductors

- SS / abductor

- IS / external rotator

- biceps / supinator and elbow flexor


Sensory loss

- lateral shoulder

- lateral forearm and hand


2.  Klumpke's palsy


C8 & T1 lesion

- paralysis intrinsics, wrist and finger flexors

- sensory changes medial hand and forearm


Klumpkes Hand 1Klumpkes Hand 2Klumpes Forearm



- ptosis (drooped)

- miosis (small)

- anhidrosis (dry)

- enophthalmos (sunken)


Supraclavicular Postganglionic (trunks)




Tinel's positive


SSN / DSN / LTN intact


No Horners




Erb's Palsy


Klumpke's Palsy

- no Horner's




Peripheral nerve patterns


A.  Lateral cord weak (C5,6,7)



- biceps (C5)


Lateral cord median

- FCR (C6)

- PT (C6)


Lateral pectoral nerve

- clavicular head


B.  Posterior cord weak (C5-T1)


AXN (C5)

- deltoid


Radial nerve

- triceps (C7)

- ECRL / ECRB (C8)

- EDC (C8)

- EPL (C8)


Upper and lower SCN (C5,6)

- SSC, T major


LTN (C5,6,7)

- latissimus dorsi


C. Medial cord weak


Ulna nerve (C7,8 T1)

- FCU (C8)

- LF FDP (C8)

- interossei (T1)


Medial median Nnerve



- Thenar / APb


Medial pectoral

- sternocostal P. major





- elevated diaphragm (phrenic nerve injury)

- fractured 1st rib

- suggests root avulsion


C spine Xray

- avulsion of C7 TP 

- suggests root avulsion


Shoulder Xray

- fracture clavicle / Scapula / GHJ / ACJ / SC




Takes 3 weeks for Wallerian degeneration / denervation to occur



- muscle sample of specific groups of interest

- denervation / sharp waves & fibrillation potentials

- re-innervation / polyphasic AP on volitional activity


Preganglionic lesion



- Skin Anaesthetic 

- SNAP persist because of DRG


EMG Denervation in

- paravertebral muscles

- serratus anterior

- rhomboids


Postganglionic lesion



- skin anaesthetic

- no SNAP as due to wallerian degeneration




MRI C Spine


Nerve root avulsion

- displacement or oedema spinal cord

- empty foramen

- pseudomeningocoeles (takes 5 days to develop)


MRI Shoulder


Difficult to correctly image trunks and cords

- high amount of oedema / hard to define severity of injury


Hems et al J Hand Surg Br 1999

- some usefulness in identifying level of injury in postganglionic




1.  Infraclavicular > Supraclavicular


2.  Upper trunk > Lower trunk


3.  Better in children and young adults







1.  Shoulder abduction and ER

2.  Elbow flexion

3.  Wrist extension

4.  Median nerve / C67 / lateral cord sensation

5.  Finger flexion




1.  Nerve repair / neurorrhaphy

2.  Neurolysis

3.  Nerve graft

4.  Nerve transfer / neurotisation

5.  Tendon / muscle transfer


Open injury / laceration


Immediate surgery

- can tag ends and return later

- primary repair / nerve graft



- can continue to improve over time

- blast injury to plexus


Surgical Approaches




Z incision

- longitudinal along posterior border SCM

- transverse along inferior clavicle

- longitudinal in deltopectoral groove


Supraclavicular approach

- posterior triangle

- SCM / omo-hyoid / clavicle / trapezius


Superficial dissection

- subcutaneous Tissue

- platysma

- elevate clavicular head of SCM


Deep dissection

- may need to divide omo-hyoid

- identify scalenius anterior and medius

- ligate external jugular vein

- suprascapular and transverse cervical arteries



- identify nerve roots / nerve stimulation

- nerve graft C5, C6, C7

- phrenic or accessory to SSN




Deltopectoral approach

- P. major tendon divided

- P. minor reflected from coracoid (leave stump to repair)



- nerve stimulate medial pectoral nerve

- if working transfer to MCN

- or ICN / Oberlin


Pre ganglionic lesion / Nerve root avulsions



- spinal cord level nerve root reimplantation

- nerve transfers


Spinal Cord Level Nerve Root Reimplanation




Carlsted et al Neurosurgical Focus 2004

- reimplanation of nerve root avulsion in 9 year old boy

- C5 - T1

- regained motor function in arm and hand use


Carlsted et al J Neurosurg 2000

- nerve reimplantation in 10 patients

- surgery from 10 days to 9 months

- 3/10 recovered MRC grade 3 power

- better with higher lesions and earlier reimplantation


Shoulder Nerve Transfers


A.  Accessory nerve to SSN



- test trapezius

- surgery performed in the posterior triangle


Suzuki et al J Reconstruct Microsurg 2007

- accessory nerve to SSN in 12 patients

- average shoulder flexion 70o

- average shoulder abduction 77o


B.  Consider ICN to axillary nerve


Biceps Nerve Transfers


Connect to motor unit MCN


A.  Medial pectoral nerve to MCN



- much simpler than ICN

- often not intact

- test with nerve stimulator


B.   ICN to MCN



- problem is disparity in axon number

- T3-6 in males

- T3,4,7,9 in females to avoid breast denervation


Merrell et al J Hand Surg Am 2001

- 90% achieved MRC grade 3 power

- 70% grade 4 power


C.  Motor branch ulna nerve to MCN / Oberlin transfer



- use nerve stimulator

- isolate motor branch to FCU, preserving intrinsics


Sensation median nerve


ICN to lateral median


Hatori et al Plast Reconstr Surg 2009

- 17 patients

- none recovered 2 point discrimination

- 13 had perception of cold, 8 had perception of head


Post ganglionic lesion




A.  Late / 3 months

- evaluate recovery on EMG

- look for renervation potentials


B.  Immediate repair



- neurolysis

- nerve repair

- nerve grafting





- nerve functioning with nerve stimulator

- release nerve


Nerve repair 



- ruptured

- able to perform tensionless repair


Nerve graft



- non functioning on nerve stimulator

- long segment of clearly severely damaged nerve

- rupture unable to be repaired primarily


Graft Options

- sural nerve (30cm)

- saphenous




- C5 to SSN for shoulder abduction

- C5 to posterior division upper trunk (axillary)

- C6 to anterior division upper trunk for elbow flexion

- C7 to posterior division middle trunk (wrist and elbow extension)


Late salvage



- shoulder fusion

- elbow flexion / tendon transfers

- wrist fusion

- amputation


Shoulder fusion


Need functioning serratus anterior and trapezius

- for scapula control


Elbow Flexion


1.  Lat Dorsi transfer

- entire muscle mobilised on NV pedicle

- attached proximally & distally to replace biceps


2.  Triceps to Biceps transfer


3.  Steindler flexorplasty

- transfer of CFO to more proximally on anterior humerus

- need power of wrist flexors

- will often get some pronation deformity

- also need wrist extensors to prevent excessive wrist flexion


4.  Clark Pectoralis major transfer

- transfer of sternocostal P. major


5. Free Gracilis transfer

- innervated by ICN


Wrist arthrodesis


Mid humeral amputation



- flail limb

- limb is a hazard


Shouldn't be performed for pain relief




Nerve Conduction Studies / EMG

Pathological Processes


Two possible types of injury

1.  Axonal

2.  Myelin sheath


Myelin Sheath Damage




Commonly seen in compression

- i.e. CTD, ulna nerve at elbow

- area of focal demyelination


Can progress to a conduction block

- some or all axons simply stop working

- decreases the amplitudes




1.  Usually affects sensory fibres first

- affects motor fibres later


2.  Results in slowing of conduction velocity


3.  Prolonged distal latency

- i.e. long time for stimulation to reach recording electrodes


4.  Effect is focal

- slowed conduction velocity above block

- normal below

- can isolate level of entrapment


5.  If progresses to conduction block

- decreased amplitude


Axonal Damage




Due to severe damage to the axon

- laceration / avulsion / severe contusion i.e. Sunderland type 3 and 4




1.  Decreased amplitude - related to number of axons affected

2.  Normal latency and conduction velocity

3.  In contrast to demyelination, cannot get normal result by stimulating below level of lesion






Sensory nerve action potentials




Stimulate a sensory nerve and measure the action potential distally


Median nerve

- two stimulations over median nerve in forearm (S)

- ring type recording (R) electrodes on index and middle finger (sensory nerves only)


Ulna nerve

- stimulation over ulna nerve at elbow or wrist

- record over little finger





- time to reach distal electrodes


Conduction velocity

- simply measure distance between electrodes

- computer calculates velocity



- number of axons being stimulated

- also need all the axons transmitting at a similar velocity or get a wide, shorter velocity


NCS Sensory




Diagnosis of carpal tunnel syndrome

- measure conduction velocity

- in upper limb is usually > 50 m/s

- compare to ulna nerve / standard charts

- median nerve is slower than ulna, but difference should be < 0.2 ms

- usually use 0.3 ms as cut off


Ulna nerve compression


CPN compression


Radial nerve


Sciatic nerve






Combined motor action potential

- called this because is difficult to stimulate just one muscle

- i.e. on thenar eminence want to stimulate just APB, but would get FPB also




Stimulate a nerve and record from a muscle that it innervates




1.  Distal latency


2.  Conduction velocity

- stimulate at 2 points and measure difference between times

- 50 m/s UL

- 40 m/s LL


3.  Amplitude


NCS Motor




Same as for SNAP

- entrapments

- slowing of conduction velocity and latency with demyelination

- +/- decreased amplitude if any axonal damage (severe entrapment, traumatic contusions, lacerations)





Combine sensory and motor

- measuring electrodes simply in palm in median nerve distribution

- measure sensory and motor components

- see in delayed latency or conduction velocity

- very simple for CTD

- can move onto more specific SNAP and CMAP if needed






Proportional to number of functional axons

- loss of axons causes decrease in response amplitude

- amplitude is a measure of the total number of functioning axons in the nerve


Conduction Velocity


Calculated fro

m the latency values

- reflects only the function of the fastest conducting fibres

- fortunately most compressive or traumatic disorders affect the largest fibres


Calculated by

- dividing the latency by the distance between the stimulating and recording electrodes


Problem in CMAP

- the response is measured over the muscle

- the delay at the motor end plate must be considered

- conduction slowed by the small, unmyelinated terminal branches of the motor axon

- and by the time taken for release of Ach

- typically ~1 mS

- because the delay is fairly constant the terminal latency can be compared with the range of normal values


The Late Responses




Nerve root or proximal nerve lesions 

- cannot use simple NCS

- stimulate a peripheral nerve and recording over a muscle

- wait for a delayed signal

-  has travelled up the nerve to the anterior horn cell then returned to the muscle


F Response




Supramaximal stimulus is applied to a nerve

- motor nerves are directly depolarised

- like all axons they conduct equally well in all directions


2 impulses


- which travels to the muscle and produces the typical M response



- which travels back to the anterior horn cell and depolarizes the cell body

- to be detected, the second muscle contraction has to occur after the first has subsided

- only muscles in which the round trip takes over 15 - 20 mS can be used




Does not measure sensory nerves




Brachial plexus injury

- want to know if nerve roots intact

- look in muscles relevant for each nerve root

- i.e. stimulate median nerve, look in thenar eminence (T1)

- look to see if F wave intact, delayed or absent

- problem is most muscles supplied by more than one nerve root



- use MRI to see if nerve root avulsion


H Reflex


This is the electrical equivalent of the deep tendon reflex

A mixed peripheral nerve is sub maximally stimulated

- stimulates the large myelinated sensory nerves that convey muscle stretch

- they are the most easily depolarised of the axons

- following a relatively weak stimulus these sensory fibres are selectively depolarised

- a signal ascends to the dorsal root ganglion and then through the monosynaptic reflex arc

- depolarises the anterior horn cells 

- causes a secondary signal in the motor axons with a subsequent muscle contraction


Characterised by having a consistent latency 

- is elicited by a stimulus so small that it does not cause a direct muscle contraction.


Unfortunately it can only be elicited in the tibial nerve (and recorded over the gastrocnemius)


Electromyography (EMG)




Needle placed in relevant muscle

- record electrical potential

- at rest and voluntary contraction


NCS Motor


NCS Waveform





- takes 3/52 to see

- amount of time for wallerian degeneration to occur

- if do earlier will get a false negative

- normal muscle electrically silent at rest



- spontaneous depolarisation in muscle

- fibrillations

- positive sharp waves



- takes 3/12 to see

- due to surviving motor axons branching out and recruiting other motor units



- see large polyphasic motor unit potentials




Muscle problems

- specific patterns of EMG
- Duchenne's muscular dystrophy /myotonica dystrophy


Shortfalls of EMG


It is only a sampling technique

- normal areas in an abnormal muscle may have normal potentials


Specific uses of NCS / EMG


Conduction blocks



- median nerve, ulna nerve

- confirm entrapment

- evaluate site of entrapment


Axonal / Nerve damage


1.  Radial nerve palsy with humeral fractures 



- is nerve in continuum or lacerated?


NCS / EMG cannot tell you that

- similar findings for Stage 4 and 5 Sunderland


Can give information regarding severity of injury

- denervation potentials at 3/52

- indicates Sunderland grade 3 or greater


Can give idea of prognosis

- i.e. is there any chance of recovery?

- reinnervation on EMG at 3/12


2.  CPN injury at knee, sciatic nerve injury following THR


Can give you idea of prognosis

- i.e. SNAP intact at 3/12

- neuropraxia




Minimal axonal damage

- demyelinating / conduction block only

- no Wallerian degeneration





- some SNAP and CMAP still seen

- minimal denervation signs i.e. fibrillation

- means nerve is not too badly injured

- prognosis good

- should be just a neuropraxia


Laceration / Neurotmesis


Both conditions will lead to Wallerian degeneration

- severity dependant on number of axons injured



- no SNAP / CMAP

- may be reduced or no amplitudes depending on number of axons injured

- see fibrillations in muscle in EMG due to denervation



- looking for reinnervation

- hoping to see large polyphasic AP due to surviving motor axons branching out and recruiting

- if this is not seen, is a poor sign as means no surviving axons

- can repeat later hoping some axons have sprouted down intact tube


Problems with NCS


1.  Obese patient

2.  Oedema

3.  Electrical inteference

- 50 MHz from fluorescent lights

- need to do in Faraday room

- difficult to do in ICU

4.  Must remove oils / moisturiser

5.  Sweat


Spinal Cord Monitoring


Used to assess spinal cord integrity during spinal instrumentation




Posterior tibial nerve stimulated

- scalp SEP used to monitor for surgical induced changes

- signal monitored is in the posterior column

- relatively immune to compromise of the anterior spinal artery

- motor control is located anteriorly in the descending corticospinal tracts



Nerve Entrapment

Median Nerve

Anatomy Median Nerve



- medial and lateral branches median nerve

- from medial and lateral cords respectively

- C5 - T1

- median branch crosses artery, such that median nerve lies lateral to artery

- no branches in arm

- medial nerve crosses brachial artery to lie medial to it



- nerve medial to artery at elbow

- passes under bicipital aponeurosis then between heads of pronator teres

(sublime tubercle and CFO)

- medial nerve supplies PT, FCR, PL, FDS 



- arises as pass between two heads PT from the dorsal aspect of median nerve

- occasionally passes deep to deep head of PT

- passes beneath arch of FDS

- runs distally along intra-oseous membrane between FDP & FPL

- branch to FDP / FPL ~ 4 cm distal to origin then branch to PQ


Median nerve 

- runs under arch of FDS to run on FDP

- crosses the ulna artery  

- at wrist it is lateral to FDS tendons, medial to FCR with PL above

- palmar cutaneous branch emerges on radial side of PL to run over TCL




1.  Motor recurrent 

- usually arises laterally

- sometimes comes off medial side and runs over distal edge of TCL (danger during endoscopic CTD)

- can pass through TCL


2.  Medial sensory branch

- gives two common digital nerves

- motor to first 2 lumbricals


3.  Lateral branch 

- supplies thumb and lateral index finger




Anterior Interosseous Nerve Palsy



Symptoms & signs due to compression of AIN


Sites of Compression



- Pronator Teres (most common)

- FDS arch

- Fascial bands 

- Bursa



- thrombosis in leash vessels over AIN



- aberrant belly FPL (Gantzer's)

- palmaris profundus

- aberrant FCR ulnar origin

- anomalous FDS origins




1.  Pain in proximal forearm

- vague pain

- most common symptom


2.  Motor deficiency



- PQ


3.  No sensory disturbance




Discomfort over site of compression


Inability to tip-to-tip pinch grip IF &Thumb

- weak pulp-to-pulp pinch possible

- Weak FPL / Index FDP / PQ



- resisted pronation with elbow flexed 90o








Rupture FPL / FDP

Median N entrapment

C8 lesion




Non operative Management


Avoid Aggravating Factors




Operative Management





- as per pronator syndrome




Schantz et al J Hand Surg Br 1992

- 20 cases of AIN compression

- operated on 15 with 12 good results / 3 required tendon transfer

- non operative on 5 / 3 continued palsy at 4 years

- recommended operative release



Carpal Tunnel Syndrome



Symptoms & signs due to compression of median nerve in carpal tunnel




Middle aged female

- F:M   2:1

- peak age 40-50 years

- often bilateral




Underlying process is decreased microvascular perfusion 

- normal press in CT is 2.5mmHg

- most CTS > 30 mmHg & > 90 mmHg with palmar flexion


Commonest cause in tenosynovitis




1. Decreased size

- bony abnormality / thickened TCL


2. Increased contents

- hypertrophic synovium / fracture callus / hematoma

- neuroma / lipoma

- abnormal muscle bellies / persistent median artery




1. Neuropathic Conditions

- diabetes / alcoholism / proximal lesion of median nerve (Double Crush)


2. Inflammatory Conditions

- tenosynovitis / RA / infection / gout


3.  Altered fluid balance

- pregnancy / eclampsia / OCP

- thyroid problems / CRF / acromegaly / obesity


Patterns of Use


1.  Repetitive flexion / extension

- manual labour / typing


2.  Weight bearing with wrist extended

- paraplegia (weight bear on palms) / long-distance cycling


3.  Vibration




Transverse carpal ligament / TCL

- tuberosities of scaphoid and trapezium laterally

- pisiform and hook of hamate medially

- distal volar wrist crease proximal limit

- Kaplan's line (apex of interdigital fold between thumb and IF) distal limit


Carpal tunnel

- FCR in separate tunnel with FPL separate and below

- median nerve radial to 4 FDS

- IF / LF below MF / RF

- 4 FDP at base

- FPL separate 


MRI Wrist Carpal TunnelMRI Wrist Carpal Tunnel 2


Motor Branch of Median nerve


Most important structure at risk / location can vary


1. Extraligamentous Recurrent / 50%

- branches distal to TCL with recurrent course to thenar muscles


2. Subligamentous / 30%

- branches beneath TCL / lies close to median nerve

- recurrent course to thenar muscles distal to TCL


3. Transligamentous/ 20%

- branches beneath TCL and pierces TCL to enter thenar muscles


4. Other

- proximal division

- branch from ulnar border of median nerve

- nerve superficial to TCL


Palmar Cutaneous Branch of Median Nerve

- arises in distal 1/3 of forearm from palmar-radial side of median nerve

- usually 5 cm proximal to wrist

- Pierces deep fascia between FCR & PL




Often diverse 



- pain & numbness radial 3± digits

- nocturnal wakening with relief from shaking

- worse with driving





- thenar wasting



- abnormal thenar sensation suggests higher compression

- decreased sensation lateral 3 1/2 digits



- APB weakness


Augmented Phalen's 

- elbow extended & supinated

- wrist held flexed 60° 2 fingers for 30 seconds

- sensitive 80% / specific 99%



- percussion of the median nerve at wrist 

- paresthesia in distribution of median nerve indicate a positive test   

- sensitive 75% / specific 95%




EJ compression

- more proximal pain / AIN weakness


T1 lesion

- check interossei power


C6/7 lesion 

- similar sensory loss

- check wrist extension / triceps






Stimulate proximally

- measure in IF and MF (sensory only from median)

- measure latency / conduction velocity / amplitude


Conduction velocity

- compare to ulna nerve

- usually > 50 m/s

- median nerve slightly slower

- should be within 0.2 / 0.3 m/s

- can compare to tables or to contralateral median nerve (may be bilateral pathology)



- > 3.5 ms = Abnormal

- > 1 ms between sides




90% sensitive


10% false negative rate

- intact conduction in a small number of fibres will give normal conduction velocity for whole nerve

- normal study does not rule out CTS




Denervation activity (late change)

- spontaneous depolarisation

- fibrillations



- large polyphasic AP




Exclude wrist arthritis / tumour




Non-operative management






Wrist in neutral / Night splints







- must avoid intraneural injection

- can cause chronic pain and disability





- 2%

- most recover 6/52 after delivery

- very rarely require decompression



- splints



Operative Management




Failure non operative management

Permanent numbness / weakness

- indicates nerve damage which may not resolve




Open carpal tunnel release

Endoscopic carpal tunnel release



Open Carpal Tunnel Release 




1.  Increase volume carpal tunnel by 25% 


2.  Increases Guyon's canal

- may relieve compression ulna nerve / LF numbness

- Guyon's canal goes from triangular to circular




LA infiltration over site of release

- incision in line with radial side ring finger

- parallel to and ulna side of thenar crease

- if cross wrist, ulna side of PL to avoid palmar branch of median nerve

- divide palmar aponeurosis which has longitudinal fibres

- divide TCL which has transverse fibres

- ensure released proximally and distally

- inspect for ganglion etc


Endoscopic CTR



- transection of recurrent branch median nerve

- especially with abnormal anatomy and inexperienced surgeons




GA, Tourniquet


Proximal transverse incision at wrist crease

- insert spatula

- under TCL, feel it, clear soft tissue

- insert cannula

- exits in palm through distal incision

- wrist DF over bump with strap


Insert camera looking up at TCL

- must see transverse fibres in full for entire length

- clean with Q tip, or with probe if needed

- ensure nerve branches not crossing plane

- cut with hook knife under vision




Trumble et al JBJS Am 2002

- RCT of 192 patients open v endoscopic

- better grip strength in first 3 months

- less scar tenderness and earlier return to work

- no complications from endoscopic technique




Incorrect diagnosis


Incomplete decompression


Division of palmar branch


Palm dysaesthesia with is difficult to salvage

- sensitivity often precludes use of hand

- avoid by always staying ulnar to thenar crease



- confirmed by LA block



- explore and bury nerve ending


Hypersensitive Scar

- much more common if cross wrist crease


"Pillar Pain" 

- 4% at 10 months post surgery



- decreased with minimal nerve trauma & avoiding neurolysis


Division of recurrent branch 



- operative repair


Tenderness / sensitivity of median nerve



- due to superficial course post op



- if a real problem needs soft tissue to cover

- proximally can use pronator quadratus

- distally use hypothenar fat graft on vascular pedicle


Flexor tendon bowstringing or adhesions

- Bowstring tendons 2% of open CTR


Persistant numbness

- may take 12 months for all symptoms to resolve

- loss of Schwann cells resulting in persistent conduction block





- symptom free interval

- usually due to scar




Pronator Syndrome



Forearm pain caused by compression of median nerve


Sites of Compression


Pronator Teres

- commonest site

- hypertrophied / excess fascia


Ligament of Struthers

- remnant third head Coracobrachialis

- runs from supracondylar spur to medial epicondyle

- median nerve & brachial artery may be deep to it


Bicipital Aponeurosis

- lacertus Fibrosis

- from medial border of biceps to subcutaneous ulna border

- may be thickened


Arch of FDS

- runs from humeroulnar Head (origin CFO & Sublime tubercle medial coronoid) 

- inserts anterior oblique line on radius

- accessory muscle slips and anomalous origins of FDS




Pain in anteromedial EJ / volar aspect of distal arm 

- worse with repetitive pronation / supination eg tennis, tools


May have

- intermittent / nocturnal parasthesia

- some weakness




Tenderness at site of compression

- proximal flexors


Pain with resisted pronation elbow in flexion / PT


Other provocations test

- Ligament of Struthers - resisted flexion of elbow at 135°

- Bicipital aponeurosis - resisted supination flexed elbow 

- Arch of FDS - resisted flexion of FDS of MF





- confirm location 

- exclude CTS



- delayed conduction velocity across elbow 30%

- EMG abnormalities of PT or FCR





- seen with ligament of struthers




May help identify site of compression / ligament of struthers




Non-operative Management



Avoid aggravating activities



Operative Management




Medial incision

- divide bicipital aponeurosis

- release pronator teres

- release FDS

- +/- ligament of struthers if present





Radial Nerve

Pin Syndrome



Loss of PIN motor function with no pain

- multiple potential causes

- may be caused by compression as per radial tunnel

- may be post fracture or surgery

- may be caused by synovits / ganglion / rheumatoid nodules etc




Often heralded by deep aching pain in forearm that resolves

- is followed by PIN weakness


Most commonly is incomplete lesion

- weakness of extension of index and middle or just thumb




No sensory loss


Characteristic radial deviation with wrist extension

- BR & ECRL functioning

- supplied by radial nerve




Can be helpful


EMG of appropriate muscles

- demonstrates denervation




Looking for mass lesion


Site of Compression 




Trauma - Monteggia fracture

Iatrogenic - surgery radial head / radius

Inflammation - RA nodule / synovitis of radio-capitellar joint DRUJ

Masses - lipoma / ganglia


Local injections

Lead poisoning - usually bilateral / motor palsy without sensory

Conversion reaction

Polyarteritis Nodosa

Muscle rupture




Locked trigger finger

Tendon rupture




Non operative


Splint / therapy

- wait 3 months for recovery





- ganglion / rheumatoid nodule / synovitis

- failure to recover post operatively




Operative release

- posterior approach

- between EDC and ECRB

- divide supinator


PIN in radial tunnel release



Radial Nerve Anatomy


- terminal branch posterior cord / C5 - T1

- runs anterior to subscapularis / teres major / lat dorsi

- passes into triangular space (between humerus / long head of triceps / teres major)

- enters posterior compartment of arm



- runs in the radial groove between medial and lateral head of triceps, with profunda brachii

- gives a branch to the long and medial head of triceps (this branch runs with the ulna nerve) before the groove

- also gives the posterior cutaneous nerve of the arm

- in the groove branches to the lateral head  again to the medial head (this branch also supplies anconeus)

- also the lower lateral cutaneous nerve of the arm and the posterior cutaneous nerve of the forearm, which perforates the lateral head



- passes anteriorly through intermuscular septum

- runs between BR / ECRL laterally and brachialis medially

- supplies these muscles and the elbow joint

- at the level of the lateral epicondyle, the radial nerve divides into superficial branch radial and PIN


Superficial branch

- runs under BR until it emerges between it and FCR

- runs superfical to first extensor compartment

- supplies dorsum of hand



- has superficial and deep layers

- originates from the supinator crest of the ulna

- inserts onto the lateral surface of the radius between the anterior and posterior oblique lines



- passes through the radial tunnel which is between the radiohumeral joint and the distal extent of supinator

- passes under a fibrous band of ECRB

- under the radial recurrent leash of vessels

- into supinator (arcade of Frohse)

- then out from under another fibrous band of supinator

- runs over APL

- dips to run on the interosseous membrane

- ending as a small nodule which supplies the wrist joint


PIN then divides

- a superficial branch (supplies EDC, EDM, ECU)

- the deep branch supplies APL, EPB, EI and EPL





Radial Tunnel Syndrome



Dynamic structural compression syndrome of PIN

- causing pain with little or no muscular weakness

- similar presentation to lateral epicondylitis / pain more distal




Radial tunnel begins at radiohumeral joint

Extends to end of supinator muscle


Sites of compression


PIN can be compressed by FREAS in radial tunnel


Fibrous bands

- level of radio-capitellar joint


Recurrent leash of Henry 

- radial recurrent artery

- vessels to mobile wad



- nerve branches caught between ECRB and supinator


Arcade of Frohse 

- free fibrous proximal edge supinator (superficial belly)

- most common site of compression

- thought to be more tendinous in some patients (30 - 80%)

- thought to become more fibrous in some patients with repetitive supination


Supinator distal edge

- occasional cause

- always decompress to here




Pain is similar to tennis elbow

- lateral elbow joint / CEO area often radiating to wrist

- deep ache or similar to muscle cramp

- often at night

- exacerbated by exercise 

- relieved by rest




Point tenderness 5cm distal to CEO 

- more proximal with Tennis Elbow

- Often tender in normal individual --> compare to other side


Provocation test

- Arcade of Frohse 

- resisted supination



- unhelpful / usually normal


Local Anaesthetic block


Best test

- inject LA in most tender spot

- usually distal to CEO

- must produce PIN palsy to confirm diagnosis

- A prior negative injection to lateral condyle for tennis elbow




Tennis Elbow

- failure of HCLA lateral epicondyle to relieve pain

- can have both tennis elbow and radial tunnel syndrome


Radiocapitellar pathology

- OA / RA / OCD / Loose body

- no pain with supination / pronation






Tends to resolve spontaneously







Avoid provocative activities






- anterior (can release all potential sites of compression)

- posterior (can only release supinator)

- brachioradialis muscle splitting


Anterior approach


Henry's approach

- start 4cm proximal to elbow joint

- identify nerve between BR & Brachialis & then follow distally

- release any proximal fibrous bands / divide recurrent vessels

- pronate / supinate and release ECRB if any compression

- fully pronate and divide all fibres of supinator


Posterolateral approach



- incision just distal to lateral condyle for 8cm

- dissection between ECRB & EDC

- identify supinator

- find PIN distally and follow proximally


Trans-brachial approach


Brachioradialis splitting

- direct approach to radial tunnel

- longitudinal incision 6cm long over BR at neck of radius

- incise BR in line of incision

- identify fat covering superficial Radial Nerve

- beneath this branch is arcade of Frohse and PIN

- extend proximally and distally till released




Jebson et al J Hand Surg Am 1997

- surgical release in 31 patients

- excellent or good results in 67%, fair or poor in 33%


Lee et al J Plast Recons Aesthet Surg 2008

- 86% good results in isolated radial tunnel syndrome

- dropped to around 50% if

- other nerve compression / lateral epicondylitis / workers compensation







Wartenberg's Syndrome



Compression of superficial branch radial nerve by ECRB / BR




Parasthesia first dorsal webspace




Up to 50% of patients also Dequervain's




Non operative







Surgical release / neurolysis




Ulna Nerve

Anatomy Ulna Nerve

Nerve supply

- C7, C8, T1 

- nerve picks up some branches of C7 from the lateral cord



- direct continuation medial cord

- runs between the brachial artery and the vein in the arm

- behind MCNFA



- pierces the medial intermuscular septum to run in posterior compartment

- runs anterior to the triceps



- enters the cubital tunnel between the medial epicondyle and the olecranon

- running on MCL 

- covered by osbourne's ligament

- gives articular branches to the elbow


Ulna Nerve MRI Cubital Tunnel



- runs between the two heads of FCU (anterior aspect medial epicondyle and proximal ulna)

- branches to (usually) medial 2 FDP and to FCU

- nerve descends on FDP, under the cover of FCU



- nerve runs with the ulna artery to the wrist

- it emerges on the lateral aspect of FCU

- nerve is ulna to artery

- dorsal sensory branch which runs under FCU and supplies dorsum of hand in region of 1 and 1/2 fingers

- palmar cutaneous branch which supplies sensation over the hypothenar muscles


Guyon's canal 

- superficial to TCL

- under volar carpal / pisohamate ligament

- between hook of hamate and pisiform

- nerve is ulna to the artery

- at the distal edge volar carpal ligament divides into a sensory and motor branch


Motor branch 

- runs between abductor and flexor digiti minimi 

- through opponens 

- crosses the palm within the concavity of the deep palmar arch

- gives branches to the lateral 2 lumbricals, all the interossei and ends by supplying adductor pollicis





Cubital Tunnel Syndrome



Symptoms & signs from compression of ulnar nerve near elbow


Sites of Compression




Arcade of Struthers 

- thick myofascial band, 1.5-2cm wide

- present in 70%

- 8cm proximal to medial epicondyle

- from medial head of triceps to medial intermuscular septum, superficial to nerve


Medial intermuscular septum

- with subluxation, nerve may impinge on it 


Medial head of triceps

- hypertrophied (body builders)


Medial epicondyle


Tardy ulna nerve palsy / cubitus valgus

- compression due to valgus deformity of the bone

- previous supracondylar / lateral condyle fracture


Cubital tunnel / Osbourne's ligament



- walls are humeral & ulna heads of FCU

- floor is MCL

- roof is Osbourne's fascia (continuation of fibro-aponurotic covering of epicondylar groove)


Nerve compression 

- occurs in flexion as Osbourne's fascia tightens

- MCL bulges out and tunnel becomes flattened ellipse




Nerve passes intramuscular for ~5cm

- penetrates fascial layer to lie on FDP

- proximal and distal compression possible




A. Lesions in the groove

- medial epicondyle fracture / arthritic spurs / HO

- lipomas / ganglia / osteochondromas / synovitis / rheumatoid nodule

- infection (TB, leprosy) /bleeding (haemophilia)


B. Conditions outside the groove

- external compression

- anomalous anconeus muscle


C. Subluxation / Dislocation from the groove

- laxity / traumatic tear of fibro-aponurotic roof




Pain on ulnar side of elbow

Pain & numbness in ulnar fingers

Provoked by elbow flexion

Weakness of fine movements





- deformity or carrying angle

- full ROM

- wasting intrinsics dorsum hand


Wasting Adductor Pollicis Right Hand



- tenderness tunnel

- Tinel's

- subluxation ulna nerve

- sensation in hand / involvement of dorsal and palmar branches




A.  Power FCU / FDP LF


B.  Hand

- intrinsics

- abductor digiti minimi

- adductor pollicis / 1st dorsal interossei (Froment's)


Froment's sign



- C spine

- axilla





- symptoms worse with overhead position


C spine

- neck / shoulder pain


T1 nerve root lesion

- thenar muscle power will be reduced

- decreased sensation medial forearm


C8 nerve root lesion

- IF / MF FDP & FPL weakened


Ulna tunnel syndrome

- sensation normal palmar / dorsal branch

- FCU / FDP LF normal


Pancoast tumour


Systemic illness

- DM

- alcohol

- hypothyroid

- vitamin deficiency




High false negative


Test with elbow flexed

- < 50 m/s conduction velocity across elbow




Denervation in hypothenar muscles in severe cases




Non-operative Management




50% resolve with night elbow extension splint

Avoid leaning on elbows


Rest / activity modification


Operative Management




Intrinsic weakness

Failed non-operative > 3/12




1.  Open release

2.  Endoscopic release

3.  Open release + Nerve transposition

4.  Open release + Medial Epicondylectomy


1.  Open release



- mild disease

- normal anatomy

- no subluxation





- 10cm curved incision centred over cubital tunnel

- 1/2 way between olecranon & medial epicondyle

- extended proximally along medial edge of triceps & distally parallel to border of Ulna



- Posterior branch of MCNFA


Superficial dissection

- deepened through deep fascia

- nerve identified in proximal tunnel



- proximally ensure no arcade of Struthers

- release Osbourne ligament

- distally release fibrous band of FCU

- ensure ulna nerve stable at end of case

- if unstable, transpose



- protect distal muscular branches

- 2 branches to FCU 

- branch to FDP


Ulna Nerve ReleaseUlna nerve release test stability




Ziowodzki et al JBJS Am 2007

- meta-analysis of decompression v anterior transposition

- no deformity or previous surgyer

- no evidence of improved outcome with anterior transposition


Vogel et al Br J Plastic Surg 2004

- revision surgery in 22 patients

- combination of simple release and subcutaneous transposition initially

- findings were scarring / incomplete release medial intermuscular septum / incomplete FCU release

- all had submuscular transposition and Z lengthening of CFO

- 78% satisfaction rate


2.  Endoscopic Release



- normal anatomy / simple release

- no SOL / ganglion requiring removal




Small incision over epicondylar groove

- release osbourne's ligament under vision

- lift skin flaps with special retractor proximally and distally

- insert 30scope

- release remainder ulna nerve under endoscopic vision




Watts et al J Hand Surg 2009

- compared results from open and endoscopic release

- greater patient satisfaction in endoscopic with fewer complications


3. Nerve Transposition



- subluxation

- valgus deformity / FFD

- failed decompression / revision surgery



- allows functional lengthening of nerve 3-4cm

- low recurrence rate



- scar formation with possible new proximal site of compression


3 options


A.  Submuscular

- muscles elevated from CFO protecting MCL 

- nerve transposed anteriorly

- muscles reattached


B.  Intra-muscular

- 5 mm trough made in CFO 

- nerve transposed into groove

- superficial fascia closed over nerve


C.  Subcutaneous

- nerve transposed anterior medial epicondyle

- sutcutaneous tissue from skin flap sutured to muscle fascia behind nerve


4. Medial Epicondylectomy



- valgus deformity

- malunited fracture

- bony abnormality



- produces scarring

- protection of medial epicondyle lost / pain if lean on elbows

- weakens flexors (contraindicated in athlete)

- MCL injury can occur



- nerve identified, released & protected

- CFO elevated

- medial condyle & supracondylar ridge removed

- guide is medial border of trochlea

- flexor origin attached to periosteum

- MCL should be left attached as it is deep & lateral




Hypertrophic scar

Neuroma MCNF


Non resolution of parasthesia

Ulna Tunnel Syndrome



Symptoms & signs from compression of ulnar nerve in guyon's canal


May be purely sensory, purely motor or combination


Anatomy Guyon's Canal


4cm long ulnar tunnel


Floor - transverse carpal ligament


Roof - volar carpal ligament and pisohamate ligament


Walls - pisiform (ulna) & hook of hamate (radial)




Ulna nerve and artery

- nerve ulnar to artery


Within canal at distal margin ulna nerve divides into 2

- superficial sensory

- deep motor branch

- separated by common tendinous origin of hypothenar muscles


3 zones


1.  Proximal to bifurcation ulnar nerve - motor and sensory branches

2.  Medial & distal to bifurcation - motor branch

3.  Lateral & distal to bifurcation - sensory branch






Soft tissue masses (including ganglia) 46%

Anomalous Muscles 16%




Repeated blunt trauma 


Can also get

- thrombosis of ulnar artery / hypothenar hammer syndrome

- fracture of hamate (Golfer)

- aneurysm ulnar artery




Pain & paraesthesia in ulnar hand & fingers


Weakness hand

- difficulty fine motor skills





- hypothenar wasting / intrinsic wasting / ulna claw hand



- decreased sensation in LF

- decreased sensation hypothenar eminence / dorsal branch suggest higher lesion



- intrinsic weakness / abd digiti minimi / adductor pollicis / 1st dorsal interossei



- Tinel's over Guyon

- Allen's test 


Cervical spine




Cubital Tunnel Syndrome


Cervical root compression




Confirm Guyon's canal site of compression




Tunnel view

- hamate fracture / pisiform OA








Non-operative Management


Restrict exacerbating activities

Splint in neutral








- radial border of FCU 

- 3 cm proximal to wrist crease 

- across crease and along line of ring finger 


Superficial dissection

- ulnar nerve isolated proximal to  wrist 

- followed into Guyon's canal 


Deep dissection

- divide volar carpal ligament

- divide pisohamate ligament

- resect hook hamate or pisiform if needed 



- injury palmar branch ulna nerve





Peripheral Nerve Injury

Anatomy of the peripheral nerve 



- loose collagenous matrix

- surrounds the individual nerve fibers within the fascicle



- thin, dense connective tissue sheath that surrounds each fascicle



- a loose meshwork of collagen  and elastin fibers 

- provides a supportive and protective framework for the fascicles

- collagen fibers in the epineurium are thicker than those in the endoneurium / perineurium





- focal demyelination 2° ischaemia

- full recovery by 3 months



- axon disrupted



- nerve division


Seddon & Sunderland  Grading


1st Degree / Neuropraxia

- localised conduction block leading to segmental demyelination

- axons are not injured

- remyelination and recovery < 3 months, no Tinel's


2nd Degree / Axonotemesis

- axonal injury with distal segment Wallerian degeneration

- full recovery

- nerve fibres regenerate 1 mm per day

- but > 3 months, advancing Tinel's


3rd Degree / Endoneurium disrupted

- incomplete recovery due to fibrosis

- advancing Tinel's


4th Degree / Perineurium divided / Epineurium intact


Nerve is in continuity but complete block due to scar


Poor prognosis

- perineurium disrupted

- becomes filled with scar

- no recovery, no Tinel's

- no SNAP, denervation potential

- no rennervation at 3/12 (polyphasic AP)


Often needs repair 


5th Degree / Epineurium divided

- 100% divided / neurotmesis


6th Deg (added by Susan McKinnon)

- neuroma in continuity

- mixed recovery


Injury Response 


Wallerian Degeneration


Axon dies distally

- remains intact for 3/24 (until stores depleted)


Schwann cell proliferation and macrophage ingrowth

- clear distal stump of axoplasm & myelin

- prepares way for new axon 


Axon Regeneration


Axon sprouts enter distal endoneural tubes

- 1-2 mm/day

- survive if contact an end organ

- sprouts often enter wrong tube & wrong end organs

- some axons fail to cross repair site & form neuroma


Axon Guidance 


1. Directional Neurotropic Cues 

- target releases tropic factor


2. Survival Neurotropic Cues 

- tube supports correct axon


3. Mechanical Alignment 

- worst


4. Contact Recognition 

- path selection based on surface


Sensory Fibres


Survive years of degeneration

- sensory return order

- pinprick / moving touch / constant touch / vibration


Muscle Fibres


Myofibrils atrophy without nerve

- 50% in 2/12

- fibrotic by 12/12

- need to repair < 9/12


Neuromuscular Junction


Receptor dispersal over 12 months

- needs to be re-innervated prior to 12 months


Receptor becomes more sensitive to ACh

- spontaneous fibrillation start Day 10 

- significant EMG changes > 2/52 


Neuronal Response


Cell body dies if very proximal axon injury

- 2° ion leakage

- if neurone survives body & nucleolus enlarges

- regenerative proteins produced

- responsible for delay in nerve recovery / regeneration


Mechanism Injury


1. Open wounds


2. Compression

- pressures > 30 mmHg impair venular epineural flow

- retards axonal transport

- alteration in intraneural BV permeability

- leads to nerve function deterioration 

- relative to length of compression & absolute pressure 



- UL 200 mmHg / Max 90 min

- LL 300 mmHg/ Max 120 min


3. Traction


4.  Thermal 


5.  Irradiation Neuritis


6.  Injection


Recovery Assessment





- 3 weeks

- fibrillation potentials

- positive sharp waves 

- spontaneous AP



- polyphasic AP  


Tinel's Sign


Percuss along the nerve

- transient tingling in nerve distribution not at injury site

- indicates axonal sprouts progressing along tube that haven't remyelinised

- response fades proximally secondary to progressive myelinization


Sweat Test


Sympathetic fibres very resistant to injury

- sweat preservation 

- 20+ magnification lens 




Outcome Factors 



- age of patient / most important / < 30 best prognosis

- level of injury (proximal worse than distal)

- health of patient

- time delay to repair

- pure sensory nerves do better than mixed nerves



- cut or crush

- single or double level

- surgeon factors

- nil gap, no tension on repair


Contraindications to Repair


Noncompliant patient


Hopeless outcome

Insignificant nerve eg SRN -> surgery to avoid neuroma

Insufficient skills


Types of Repair


1.  Direct


Epineurium repair without tension


Primary repair

- best chance of fascicular matching / best fit

- minimal retraction & gap formation

- historically best results

- 8/0 or 9/0 nylon


Fascicular Repair


Not usually indicated except

- distal 1/3 forearm median nerve

- distal 1/3 forearm ulna nerve

- sciatic nerve in thigh




Median nerve

- release PT and FDS radial insertion

- can transpose anterior to pronator and FDS




Rujis et al Plastic Recon Surg 2005

- meta-analysis

- age > 40 / proximal lesions / delay to repair poor prognostic indicators


2.  Nerve Grafting 



- gaps > 2.5 cm



- cable graft

- vascularised graft


Cable graft


Graft options

- Sural / MCNF / LCFN / Saphenous


Vascularised graft



- mobilise on BV pedicle



- faster recovery


3.  Neural tubes



- absorbable synthetic tubes

- epineurium sutured to each end of tube

- nerve fibrils grow into and along tubue



- tension free repair



Aberg et al J Reconst Plast Aesthet Surg 2009

- RCT of epineural repair v tube in sharp distal median and ulna nerve injures

- no difference between two groups


3. Nerve Transfer 


4. Neuroma 


Resect, diathermy & bury nerve end deeply in good tissue not bone 



Tendon Transfers

Median & Ulna Nerve

IssuesMedian and ulna nerve injury


Extremely difficult

- goals of rehab must be realistic

- limited number of donors

- static procedures more prominent

- fusions, tenodesis and capsulodeses must be used




1.  Thumb Opposition


EIP to APB and EPL 

- via pulley around Pisiform and FCR

- alternative is Palmaris longus or ADM


2.  Thumb Adduction 


BR / ECRB + PL graft to P1

- via base of MC III as Adductor


3.  Thumb to index tip pinch


APL slip with free graft to 1st dorsal interosseous


+/- Arthrodesis thumb MP


4.  Thumb to LF tip pinch


EDM to deep transverse lig

EDC to little must work


5.  Power Flexion of fingers 


ECRL to all 4 fingers



- using 4 tail graft to lateral sheath or A2 pulley via lumbrical path



- free gracilis graft

- into FDP

- insert vascularized ulna graft to power


6.  Sensation median nerve


Superficial radial nerve translocation

Median Nerve



High Lesion

- elbow fracture or dislocation

- forearm fracture

- penetrating forearm wound


Low Lesion

- laceration at wrist

- distal radius fracture

- carpal dislocation

- entrapment in carpal tunnel


Clinical Features


1.  Low Lesion


A.  Loss Thumb function

- paralysis of APB & Opponens 

- variable FPB

- 1/3 have enough opponens power not to need transfer


B.  Parasthesia Radial 3 1/2 fingers and palm


2.  High Lesion


Above +


C.  Loss flexion index and middle finger

- lose FDS IF / MF / RF / LF 

- lose FDP to IF / MF


D.  Unable to flex thumb IPJ



E. FCR + PT 


3.  Anterior Interosseous Nerve Palsy


Benediction sign

- loss FDP & FPL

- index finger and thumb straight

- middle finger is flexed due to quadriga of MF / RF


Weakness of pronation

- pronator quadratus


No thenar weakness or sensory loss



- thumb: BCR to FPL

- IF / MF: FDP buddy to RF / LF / ECRL to FDP / fuse DIPJ






Open injury

- Explore & repair


Closed injury

- Reduce fracture or dislocation

- Explore if fails to improve after 3/12

- NCS / EMG first




Maintain Joint ROM / Prevent Contractures




1.  Flexion IF / MF



2.  Flexion RF / MF

- fusion DIPJ or

- buddy to RF / LF FDP


3.  Thumb IPJ flexion

- BR to FPL


4.  Thumb Opposition

- EI to APB or



4.   Sensation thumb & radial side IF 

- for pinch grip




High median nerve / Extensor indicis to APB


Harvest EIP

- incision over index MCPJ

- EIP divided with some extensor hood

- hood repaired


2nd incision over dorsum of hand 

- free EIP from EDC


Incision over dorsoulnar wrist 

- displace tendon ulnarward

- tendon passed subcutaneously ulnar aspect of wrist to pisiform which acts as a pulley


Tunnel across palm to thumb MCPJ

- interwoven into APB & EPL tendon


Low Median Nerve / Opponensplasty with RF FDS



- have strong Adductor Pollicis / 1st dorsal interosseous / EPL 

- they will overpower a weak transfer



- loop of FCU at pisiform for pulley for donor

- pass donor through loop 

- tunnel subcutaneously across palm & attach to tendon APB


Rule of 13 S's 


In a Sensible patient, I will transfer a

- Strong, Sacrificeable, Synergistic tendon with Sufficient excursion

- Straight through a Scarless, Stable bed, Subcutaneously

- across a Supple, Sensate joint

- to achieve a Single function by Securing distally



- Sensible



- Strong (will lose 1 grade of power)

- Sacrifice able

- Synergistic

- Sufficient excursion



- Straight

- Subcutaneous

- Straight pull

- Secure distally

- Single function



- Supple

- Sensate

- Scarless




Tendon transfer

- tendon of a functioning muscle is mobilised, detached or divided

- reinserted into a bony part or into another tendon

- to supplement or substitute for the action of the recipient tendon



- the detachment of a tendon & its attachment across a joint


Tendon Graft 

- when proximal & distal ends of a tendon are transected

- interposed into another tendon pathology


Indications 3R's


1. Replacement for lost function

- nerve injury 

- neurological disease 


2. Replacement of ruptured or avulsed tendons

- RA

- EPL in wrist fracture


3. Restoration of balance to a deformed limb

- Cerebral palsty

- stroke





Radial Nerve



1. Loss of wrist extension

2. Loss of finger extension

3. Loss of thumb extension




High lesion (loss of wrist extension)

- humeral fracture (Holstein Lewis)

- compression (Saturday night palsy)


Low lesion (PIN - wrist extension intact)

- fracture / dislocation elbow

- trauma / laceration

- iatrogenic - ORIF proximal radius


Clinical Features


High lesion

- triceps weakness uncommon (lesion usually past triceps innervation)

- wrist drop (ECRL, ECRB)

- inability to extend MCPJ (EDC)

- inability to extend thumb (EPL, EPB)

- sensory defect in anatomical snuffbox


Low lesion

- triceps intact

- wrist extension ECRB / ECRL intact

- no sensory deficit

- inability to extend MCPJ (EDC)

- inability to extend thumb (EPL, EPB)




1.  Radial Splint / Lively splint

- rubber bands & outrigger

- bands replace EPL / ECRB / EDC


2.  Simple static extension splint

- passive ROM to maintain supple joints




NCS at 3/52 

- SNAP intact - neuropraxia


EMG at 3/12

- no reinnervation potentials

- poor prognosis




1.  Explore at 4/12 if no recovery


Terzis et al Plast Recon Surg 2011

- surgical repair in 35 radial nerves

- 77% good outcome


Lee J Hand Surg Am 2008

- sural nerve grafting of high radial nerve injury

- 80% good or excellent results in regards motor function


2.  Tendon transfers



- no recovery at 6 - 9/12

- usually 1 mm / day

- should see ECRL by 6 months


Tendon Transfers




1.  Wrist Extension / ECRB


Pronator Teres


2.  Digit Extension / EDC





- is the most important wrist flexor

- only ulnar deviator / may result in radial deviation


B.  FDS middle finger



- many authors favour 

- gives strong grasp 


3.  Thumb Extension / Abduction


A.  PL to EPL 

- line of pull via 1st dorsal compartment

- works well as gives some abduction


B.  FDS to RF (if no PL)

- can pass through intra-osseous membrane or tunnel subcutaneously


High Radial Nerve Transfers


Basis is use of PT for wrist extension


Jones Transfer

1.  PT to ECRL / ECRB

2.  FCU to EDC

3.  FCR to EPL (+ EPB & APL)


Problem is that both wrist flexors are transferred

- loss of FCU may lead to radial deviation


Brand Transfer

1.  PT to ECRB

2.  FCR to EDC

3.  PL to rerouted EPL



- PL absent in 20% 

- alternative FDS RF / MF

- take through interosseous membrane or tunnel subcutaneously



1.  PT to ECRL / ECRB

2.  FCR to EPB & APL

3.  FDS MF / EDC

4.  FDS RF / EPL & EIP


Technique Brand Transfer


Set up

- tourniquet

- arm table




1.  PT incision

- over insertion on midportion radius

- dissect between ECRL and ECRB

- take entire periosteal insertion off radius

- need to keep long


2.  FCR / PL incision

- distal volar incision

- take both tendons as distal as possible



- make incision in palm over A1 pulley of RF

- if need FDS to RF must take proximal to bifurcation


3.  Dorsal incision

- proximal to extensor retinaculum, expose EDC and EPL


Transfers / Tensioning


1.  PL to EPL

- tunnel PL / FDS subcutaneously under SRN to EPL

- place thumb abducted and extended

- pulve taft weave

- through tendon 4 times at 90 degrees to each other 

- 4.0 ticron stitches at each pass

- check tension


2.  FCR to EDC

- pass FCR through all 4 tendons of EDC

- may need to take through EDMB

- check tension

- fingers should be in cascade in wrist flexion

- full extension with wrist extension


3.  PT to ECRB

- PT passed through ECRB with wrist in full extension

- again check tension


Post op


0 - 4 weeks splint

- wrist and MCPJ extension

- active finger extension (DIPJ, PIPJ)


4 - 6 weeks

- active MCPJ extension


Wrist flexor to finger extensor

- teach patient to flex wrist & extend fingers

- after a while they can extend fingers without flexing fingers


Pin Palsy Transfers


Wrist extension not required



- FCR to EDC

- PL to EPL




Ulna Nerve



Low Lesion (Below Elbow)


Injury usually at wrist

- laceration at wrist

- fenetrating forearm wound


Ulna nerve laceration wrist


High lesion / Above elbow


Injury usually at elbow

- elbow fracture / dislocation

- compression (GA) 

- tardy ulna palsy


Low Lesion


1.  Claw hand deformity



- hyperextension all MCPJ 

- flexion of IPJ of Ring & Little fingers


A.  Absent lumbricals - loss of MCPJ flexion / IPJ extension to RF & LF


2.  Unopposed MCPJ extension - EDC 


3.  IPJ flexed by long flexors - less marked in high lesion because ulnar FDP paralysed


2.  Loss of interossei 


Weak finger abduction / adduction

Positive Froment's sign

Hypothenar & Interossei wasting




3.  Numbness of ulnar  1 & 1/2 fingers


May have numbness of ulnar dorsum of hand

- depends on level of lesion

- if forearm, take out dorsal branch ulna nerve


High Lesion

Above +


A.  RF / LF FDP loss

- ulna paradox with less clawing 


B.  FCU weak

- weak wrist flexion




1.  Restore pinch / thumb stability

- thumb adduction (interposition to BR/ECRB)

- index abduction (EPB to 1st Dorsal Interossei)


2.  Correct MCPJ clawing


Management Low Ulna Palsy


1.  Thumb adduction


No donor long enough

- FDP LF tendon to BR / ECRB



- need interposition graft  i.e. FDP to LF)

- graft fixed to base P1 / normal insertion

- tendon passed along a line form base of MC III /  line of pull of Adductor

- bring out through dorsum between III and IV MC's

- attach to donor tendon BR or ECRB


2.  Index Finger abduction


EPB to 1st dorsal interossei


3.  Clawing of MCPJ




Prevent hyperextension of MCPJ's

- Want to create FFD





- Zancolli Capsulodesis / volar plate advancement



- reconstruction lumbricals

- split MF FDS / ECLR into 4


Zancolli Capsulodesis 


Transverse palmar incision

- each A1 pulley opened

- flexor tendons retracted


Volar plate raised as distally based flap & advanced proximally


Finger flexed to 20°

- volar plate sutured to new position

- mild FFD MCPJ created


Management High Ulna Palsy


1. FDP to ring and little


Buddy to middle FDP



- FDP flexes IPJ's before MCPJ's

- this unopposed flexion of IPJ can push object out of palm


2. FCU


Split FCR to FCU