MSK Revision

Nerve Palsies

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Have a plan and stick to it!!

Rest – take regular breaks and get your sleep

If you can easily turn it into an exam question Warwick have probably thought of it too!

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Covering…

Nerve palsiesSensory innervation

Hopefully:Blood supply (arterial and venous)Clinical landmarks

NOT covered:AnatomyHand signs of diseaseCompartmentsJointsShoulder – Dislocation, rotator cuff, pathologiesElbow – nurse maids, anatomy, tennis/golfer’s elbowWrist – Carpal bones

What is a dermatome?

a) Area of skin innervated by a single spinal nerveb) Group of muscles innervated by a single nerve rootc) A branching network of vessels or nervesd) Nerve cell cluster or a group of nerve cell bodies located in the peripheral nervous

system

What is a dermatome?

a) Area of skin innervated by a single spinal nerve - Dermatomeb) Group of muscles innervated by a single nerve root - Myotomec) A branching network of vessels or nerves - Plexusd) Nerve cell cluster or a group of nerve cell bodies located in the peripheral nervous

system – Ganglion

The Upper Limb

Axilary Nerve

Musculocutaneous

Median Nerve

Radial Nerve

Ulnar Nerve

(Long thoracic nerve)

Axillary Nerve (C5)

Innervates:Deltoid Teres minor

Vulnerable during: Shoulder dislocationFracture of the surgical neck of the humerus Intramuscular injection (Runs 5cm below the aromiom)

Damage can result in:Paralysis of deltoid and teres minorLimb hang limp by sideLoss of shoulder contourSensory Loss over lateral shoulder (regimental badge area)

Musculotaneous nerve (C5 – 7)

InnervationBBCBiceps BrachiiBrachialisCoracobrachialis

Vulnerable during:‘Stretch’ injury during dislocation

Damage results in:Weakness of flexionWeakness of supinationSensory loss over the lateral forearm

Why in musculocutaneous nerve damage is it still possible to flex the elbow?Flexion is still possible as the brachioradialis also performs this function and it is innervated by the radial nerve

Thenar wasting is a sign of damage to which nerve?

a) Ulnar nerveb) Median nervec) Radial nerved) Axillary nerve

Thenar wasting is a sign of damage to which nerve?

a) Ulnar nerveb) Median nervec) Radial nerved) Axillary nerve

Median nerve (C6 – T1)

Innervates:Pronator teresFlexor carpia radialisPalmaris longus

Flexor digitorum superficialis

Flexor digitorum profundusFlexor pollicis longusPronator quadratus

LOAF:Lumbricals 1 & 2 (Digits 2 & 3)Opponens pollicis Abductor pollicis brevisFlexor pollicis brevis

Superficial

Intermediate

Deep

Hand

Damage at the Elbow or proximal

Can’t make fist with digits 2&3 (hand of ‘benediction’)

No active flexion of IP joints of digits 2&3

Weaker flexion of digits 4&5 = No FDS but FDP from ulnar

nerve

No forearm pronation

Weak wrist flexion that deviates to adduction (FCU = ulnar

nerve)

Plus damage seen with wrist injury below......

X

X

Median Nerve Injury

Damage at the Wrist

Thenar wasting & opposition not possible

Thumb laterally rotated & adducted

Digits 2 & 3 lag in fist making as lumbricals 1 & 2

paralysedR G Tunstall 2014

Carpal Tunnel Syndrome“Compression of the median nerve in the carpal tunnel”

What are the symptoms a patient may complain of with carpal tunnel?Sensory loss in the lateral 3.5 digitsNocturnal pain in the lateral 3.5 digitsThenar wasting

What conditions can increase the chance/are associated with carpal tunnel syndrome?PregnancyHypothyroidism

What passes through the carpal tunnel?4 tendons of flexor digitorum superficialis4 tendons of flexor digitorum profundusFlexor policis longusMedian nerve

Describe the surface anatomy of the carpal tunnel.The canal starts at the distal wrist crease and passes distally by about 2cm

What make the roof of the carpal tunnel?a) Extensor retinaculumb) Flexor retinaculumc) Biceps aponeurosisd) Carpal bones

What make the roof of the carpal tunnel?a) Extensor retinaculumb) Flexor retinaculumc) Biceps aponeurosisd) Carpal bones

“Wrist drop” is a sign of damage to which nerve?a) Axillaryb) Medianc) Radiald) Ulnare) Musculocutaneous

“Wrist drop” is a sign of damage to which nerve?a) Axillaryb) Medianc) Radiald) Ulnare) Musculocutaneous

Radial Nerve (C5 – T1)

What does the radial nerve supply?All of the posterior compartments of the arm and forearmPLUS brachioradialis

Where is the radial nerve injured?Axilla – Shoulder dislocation, crutches, falling asleep over upper limb ‘Saturday night palsy’ Spiral groove - Humeral fracture (sleeping on the arm)Head/neck of the radius - #

What travels with the radial nerve in the radial groove?a) Brachial arteryb) Profunda brachii arteryc) Axillary artery d) Cutaneous branch of the radial nerve

What travels with the radial nerve in the radial groove?a) Brachial arteryb) Profunda brachii arteryc) Axillary artery d) Cutaneous branch of the radial nerve

Damage in axilla All function lost No elbow extension Wristdrop No digit extension Sensory loss on dorsolateral forearm & hand

Damage in spiral groove Elbow extension preserved but weaker Wristdrop No digit extension Sensory loss on dorsolateral forearm & hand

Damage at radial head/neck Elbow extension normal Minimal wristdrop (ECR supplied earlier) No sensory loss - motor nerve

XX

X

Radial Nerve Injury

R G Tunstall 2014

Why do patient with wrist drop lose their power grip?The wrist needs to be held in the neutral (anatomical) position by extensors in order to bring about a power grip.

Lack of extensor action means wrist flexion occurs when FDP & FDS contract, thus rendering them mechanically unable to flex the digits tightly.

Explain why forearm supination is still possible in the damaged limb following radial nerve damage (2 marks)?Supination is brought about by two muscles, supinator (radial nerve innervated and therefore paralysed) and biceps brachii (musculocutaneous nerve innervated and therefore working).

Wasting of the 1st dorsal interosseous is a sign of damage to which nerve?

a) Axillaryb) Medianc) Ulnard) Radiale) Musculocutaneous

Wasting of the 1st dorsal interosseous is a sign of damage to which nerve?

a) Axillaryb) Medianc) Ulnard) Radiale) Musculocutaneous

Ulnar nerveC8 – T1

What does this nerve innervate?Flexor carpi ulnarisFlexor digitorum profundus to digits 4 & 5All intrinsic muscles in the hand EXCEPT thenar and lumbrical 1 & 2

Where can damage to this nerve occur?Medial epicondyle – fracture or compressionGuyon’s canal – compression

Damage at the elbow or proximal

No flexion of distal IP joint of Digits 4 & 5 = Lack of

FDP

Wrist abducts on flexion = Lack of FCU

No digit ab-or adduction (except thumb abduction)

Some clawing of digits 4 & 5 at rest = loss of

lumbricals &

interossei

No clawing of digits 2 & 3 as lumbricals 1 & 2 OK

Plus damage seen with wrist injury below.....Damage at the wrist

Loss of most intrinsic hand muscles

Hypothenar & interosseous wasting

Clawing of digits 4 & 5 worse in low lesion as FDP

remains

innervated and exacerbates IP joint flexion

X

X

Ulnar Nerve Injury

R G Tunstall 2014

Describe the resting appearance of someone with ulnar claw.This is extension of the MCP and flexion of the corresponding IP joints

Describe the ulnar paradoxIf you damage the ulnar nerve at the wrist you will get more clawing and more damage than if you damaged the ulnar nerve more proximally.

The reason this happens is because if you damage the ulnar nerve at elbow you also paralyse the flexor digitorum profundus for digits 4 & 5 and therefore get far less clawing of digits 4 & 5.If you damage the ulnar nerve at the wrist the flexor digitorum profundus for digits 4 & 5 is still innervated and will produce greater clawing.

Where do you test for sensory loss following damage to the:

a) Axillary nerveb) Radial nervec) Ulnar nerved) Median nerve

Where do you test for sensory loss following damage to the:

a) Axillary nerve – Regimental badge area b) Radial nerve – First dorsal interosseousc) Ulnar nerve – Hypothenar eminanced) Median nerve – Thenar eminance

Winging of the scapula is a sign of damage to which nerve?

a) Axillary nerveb) Musculocutaneous nervec) Long thoracic nerved) Lateral cutaneous nerve of the

Winging of the scapula is a sign of damage to which nerve?

a) Axillary nerveb) Musculocutaneous nervec) Long thoracic nerved) Lateral cutaneous nerve of the

Long Thoracic Nerve (C5 – 7)

What muscle does this nerve supply?

Which ribs does this muscle attach to?

How can this nerve be damaged?

What movements may a patient find difficult?

Long Thoracic Nerve (C5 – 7)

What muscle does this nerve supply?Serratus anterior

Which ribs does this muscle attach to?Ribs 1 – 8Inserts into medial border of the scapula

How can this nerve be damaged?At risk during axillary surgery.This is because the LTN lies on the superficial layer of muscle as opposed to the deep layer as most other nerves are.

What movements may a patient find difficult?Punching out Reaching out

What is a painful arc indicative of?a) Supraspinatus impingementb) Calcific tendonosis c) Adhesive capsulitisd) Axillary nerve damage

What is a painful arc indicative of?a) Supraspinatus impingementb) Calcific tendonosis c) Adhesive capsulitisd) Axillary nerve damage

Erb’s Palsy

C5 – 6

Stab woundsIatrogenicShoulder dystocia -

SuprascapularLateral pectoral AxillaryMusculocutaneousDorsal scapula

Klumpke’s Palsy

C8 – T1

Traction injuryCancer at lung apex****Compession via cervical rib

Ulnar nerve and Median nerve effected

Erb’s Palsy

Medially Rotated Shoulder: loss of supra and infraspinatis resulting in unopposed medial rotation from the sternal head of pec majorLimp & loss of shoulder contour: Result of loss of deltoidPronated forarm: Loss of biceps brachiiPartial wrist drop: Loss of extensor carpi radialis

Erb’s Palsy

Medially Rotated Shoulder: loss of supra and infraspinatis resulting in unopposed medial rotation from the sternal head of pec major

Limp & loss of shoulder contour: Result of loss of deltoid

Pronated forarm: Loss of biceps brachii

Partial wrist drop: Loss of extensor carpi radialis

SuprascapulaLateral PectoralAxillaryMusculocutaneousDorsal Scapula

Klumpke’s PalsyC8 – T1

How does Klumpke’s Palsy present (3 marks)?Paralysis & wasting of ALL small muscles of hand

Clawing of digits 2-5 at rest due to unopposed action of extensors on MCP joint & long flexors on IP joints

Anaesthesia = medial elbow, forearm & arm

Horner’s Syndrome

What are the signs of Horner’s syndrome?Ptosis – Droopy eyelidMiosis – Constricted pupilEnophtalmos – Sunken eyesAnhydrosis – Lack of sweatingRed flush skin - Vasodilation

What are the causes of Horner’s syndrome?Pancoast tumour Tumour of skull baseLymphadenopathyIatrogenicTrauma

What are the anatomical boundaries of the anatomical snuff box?

Ventro-lateral: abductor pollicis longus & extensor pollicis brevisDorso-medial: Extensor pollicis longusFloor :formed by the scaphoid and trapezium

What are the contents of the anatomical snuff box (3 marks)?Radial arteryCutaneous branch of the radial nerveCephalic Vein

What should pain in the anatomical snuff box arouse suspicion of?a) Superficial radial nerve damageb) De Quervain’sc) Scaphoid fractured) Ulnar nerve damage

What should pain in the anatomical snuff box arouse suspicion of?a) Superficial radial nerve damageb) De Quervain’sc) Scaphoid fractured) Ulnar nerve damage

What is the most common method of fracturing your scaphoid?Falling on an outstretched arm

What is a big concern in fractures of the scaphoid, explain why this is so anatomically.A fraccture of the scaphoid may result in avascular necrosis, however this is more common in the proximal 1/3 as blood supply is retrograde from branches of the radial artery supplying the distal part of the bone first and then the more proximal part.

What are the borders of the cubital fossa?

Lateral: BrachioradialisMedial: Pronator TeresSuperior Border: Inter-epicondyle lineRoof: Aponeurosis of biceps

What are the contents of the cubital fossa from lateral to medial (3 marks)?Biceps TendonBrachial ArteryMedian Nerve

Which veins are accessed in this area (3 marks)?Cephalic Basilic Median cubital vein

What are the borders of the axilla?Anterior: Pectoral Muscles - Anterior Axillary foldPosterior: Subscapularis and scapula, Posterior Axillary fold (Lat dorsi and teres major)Medial: Serratus Anterior and lateral thoracic wallLateral: Intertubercular groove

What are the names of the axillary lymph nodes?CentralHumeralApicalPectoralSubscapular(NOTE: Think CHAPS)

An F1 is performing an injection in a patient’s butt! To ensure that the needle is placed in a safe area they draw a vertical line through highest point of crest and another line from PSIS to the greater trochanter and inject into the upper outer quadrant of the patient's gluteal region.What nerve is the Dr trying to avoid by employing this method?

a) Pudendal nerveb) Superior gluteal nervec) Inferior gluteal nerved) Sciatic nerve

An F1 is performing an injection in a patient’s butt! To ensure that the needle is placed in a safe area they draw a vertical line through highest point of crest and another line from PSIS to the greater trochanter and inject into the upper outer quadrant of the patient's gluteal region.What nerve is the Dr trying to avoid by employing this method?

a) Pudendal nerveb) Superior gluteal nervec) Inferior gluteal nerved) Sciatic nerve

What are the nerve roots of the sciatic nerve?

L4 – S3

Which nerve do you suspect is damaged based on the following observation of a patient’s gait?

“Gait in which trunk lurches back on heel strike to prevent it from toppling forward”

a) Inferior gluteal nerveb) Superior gluteal nervec) Sciatic nerved) Femoral nerve

Which nerve do you suspect is damaged based on the following observation of a patient’s gait?

“Gait in which trunk lurches back on heel strike to prevent it from toppling forward”

a) Inferior gluteal nerveb) Superior gluteal nervec) Sciatic nerved) Femoral nerve

A 35 year old male tears his medial collateral ligament during a football match. What else might be damaged and with what consequence?

A 17 year old female is hit by a moving car on the lateral side of her knee. Why is she at risk of foot drop?

A 76 year old man presents to you with a deep laceration to the region behind his medial malleolus. Examination reveals that crude flexion-extension movement of his toes is possible, but they splay whilst weight-bearing and he is unable to curl/scrunch his toes up. Why?

A 56 year old male suffers a supracondylar fracture of the femur. 30 minutes later the pain is considerably worse and the back of his thigh is swollen, and he was loosing sensation in, and functioning of, his leg and foot. What might be damaged and with what consequence?