Upper and lower limb nerve injuries

BROGAN SPENCER AND MILLIE FERN

Upper limb nerve injuries

The Golden Rules

Golden rule of hand muscle innervation

Everything is ulnar nerve supplied except:

- Thenar muscles

- Lumbricals to digits 2 & 3

Everything is C8 & T1 supplied

Golden rule of anterior forearm innervationEverything is median nerve supplied except:

- Flexor carpi ulnaris

- Flexor digitorum profundus to digits 4 & 5 (the muscle on the ulnar side)

Golden rule of posterior forearm innervation:

- Everything is radial nerve supplied

Posterior forearm

Anterior forearm

Hand

Mechanism of injury:“Saturday night palsy”, Crutches, surgery in the axilla

All function lostNo elbow extensionWristdrop No digit extensionSensory loss on dorsolateral forearm & hand

Result:

Mechanism of injury:

Result:Fractured shaft of humerus

Elbow extension preserved but weaker Wristdrop No digit extension Sensory loss on dorsolateral forearm & hand

XX

XMechanism of injury:

Result:Fractured head of radius

Elbow extension normal Minimal wristdrop (ECR supplied earlier) No sensory loss - motor nerve

The RADIAL nerve

The MEDIAN nerve

Mechanism of injury:MEDICAL STUDENTS!Cubital fossa puncture wounds

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......

Result:

Mechanism of injury:

Result:

Forearm prior to carpal tunnel (defence wound, suicide attempt)Carpal tunnel (compression)

Thenar wasting & opposition not possible

Thumb laterally rotated & adducted

Lumbricals 1 & 2 paralysed = digits lag in fist making (4+5 go

down first the others follow)

X

X

Mechanism of injury:Medial epicondyle fracture

Digits 4 & 5 = no flexion of distal IP joint of (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 (less than wrist level injury) (loss of lumbricals & interossei, & unopposed extensor action) Lumbricals 1 & 2 OK = no clawing of digits 2 & 3 Thenar muscles OKLoss of most intrinsic hand muscles…. Hypothenar & interosseous wasting

Result:

Mechanism of injury:

Result:

Wrist, superficial to retinaculum

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

The ULNA nerve

X

A 45 yr male patient with a history of diabetes presents to his GP. He complains of pain and parathesia in his hand. The pain is worst at night and starting to keep him awake?

Apart from diabetes, what else can increase the chance of carpal tunnel syndrome?PregnancyHypothyroidismOccupation

What passes through the carpal tunnel?

What is the likely diagnosis?

What tests can you perform to confirm your diagnosis

4 tendons of flexor digitorum superficialis4 tendons of flexor digitorum profundusFlexor policis longusMedian nerve

Carpal Tunnel syndrome

Anything that occupies space in the carpal tunnel:Ganglion cyst, Giant cell tumour, Neuroma, Lipoma, Soft tissue thickening, fluid retention..

What can directly cause carpal tunnel syndrome?

Tinnels test

Phalen’s test

A 63yr old skateboarder presents to you at clinic after having fallen whilst doing a jump.

What is the name for this type of injury?Erbs Palsy

Which nerves are affected?

How can this injury occur

Which roots are effected?

You are asked by your consultant to describe the resulting appearance of your patient?

Loss of C5 & 6: Axillary, suprascapular, dorsal scapula, lateral pectoral & musculocutaneous nervesMedially rotated shoulder: Loss of supra- & infraspinatus & unopposed medial rotation action from sternal head of pec majorLimp & loss of shoulder contour: Loss of deltoidPronated forearm: Loss of biceps brachiiPartial wrist drop/flexion at rest: Loss of extensor carpi radialisAnaesthesia: Over C5 & C6 dermatomes

Stab woundsIatrogenicShoulder dystocia Forced separation of neck from shoulder

SuprascapulaLateral PectoralAxillaryMusculocutaneousDorsal Scapula

REMEMBER: SLAMeD into floor(Supascapula, lt.pectoral, Axillary, Musculocutaneous, Erbs palsy, Dorsal scapula)

C5 and C6

A mom brings her 8yr son into A&E reporting that he was playing in a tree in the garden when he fell grabbing a branch on the way down

What is the name for this type of injury?Klumpke’s Palsy

How can this injury occur

Which roots are affected?

How might Klumpke’s Palsy present

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 jointsAnaesthesia = medial elbow, forearm & arm

Shoulder dystocia Pancoast tumour

C8 and T1

What pattern of sensory loss would be seen in carpal tunnel syndrome?

Describe the surface anatomy of the carpal tunnel.2cm distal to the most distal wrist creaseLateral and Medial walls formed by the U-shaped bones of the carpal tunnel.Roof: Flexor retinaculum

What are the attachments of the flexor retinaculumAttaches to the hook of hamate and pisiform medially and tubercle of the trapezium and scaphoid laterally.

Hook of hamate

Pisiform

Tubercle of Scaphoid

Tubercle of trapezium

Why is the palm spared in true carpal tunnel syndrome? The palmar branch of the median nerve, branch before the median n. enters the carpal tunnel and passes over it.

This can help separate carpal tunnel syndrome from thoracic outlet syndrome, or pronator teres syndrome.Why do we care?

*

Lower limb nerve injuries

You are the duty doctor on call and a 22yr man attends your surgery, as you watch him approach your room you observe he leans to the side when he walks and it looks like his hip drops on one side.

What is the name for this type of walk?Trendelenburgs

Describe why the patient looks like this when he walks

Which muscles are affected?

You suspect the patient has damaged his gluteal muscles how do you test this and what would you expect to see?

Pelvis will tilt towards opposite side. (Due to weakness of the abductor muscles)

Glut. Minimus & Medius

Trendelenburg’s test

Place your hands on the ASIS and ask the patient to stand on one legIf the pelvis drops on the unsupported side - positive Trendelenburg sign - the hip on which the patient is standing is painful or has a weak or mechanically-disadvantaged gluteus medius.

You are the orthopaedic registrar in charge of a very long new patient clinic. In between patients you run out to grab a much needed coffee, and notice a lady in her mid 40’s struggling to get out of the chair. She lurches down the hall towards your consulting room and you’re excited to finally have an interesting case…

Describe why the patient looks like this when she walks

Which muscle is responsible for powerful hip/trunk extension and describe the nerve supply?

What other activities may she complain of finding difficult during your thorough history?

Gluteus maximus prevents the pelvis tipping forward while walkingDamage/paralysis can lead to patient lurching backwards when the affected limb is on the floor during walking

Gluteus maximus – nerve supply = inferior gluteal L5/S1

Climbing the stairsStruggling to get out a chair

Betty, a 78 year old lady presents to her GP with pain in her left leg. She is already on regular co-codamol for severe OA and is very concerned that this may mean she is finally requiring a hip replacement, which she would rather not have.

What else from the history would you like to know?

SQITASHx. of trauma

What major nerve could be the source of Betty’s pain?

Sciatic

List some causes of Betty’s sciatica

What is the nerve root of he sciatic nerve and therefore what pattern of distribution could be expected?

L4,5 and S1,2,3Spine, buttock, thigh, calf and heel

Spinal disc herniationDegenerative disk diseaseLumbar spinal stenosis Piriformis syndrome

You are the FY1 in A&E and a 17 yr old female patient in brought in after having been involved in an accident. You are told the car struck her on the lateral side of her knee.

What lower limb nerve injury is she at risk of?

Foot drop

Why?Common fibular nerve is subcutaneous at the head of the fibula and at risk of damage/compression. Therefore she will no be able to dorsiflex her foot during heel strike and swing phase.

Foot drop occurs during heel strike and swing phases of walking when the foot would normal dorsiflex.No dorsiflexion = foot drop

Patient will either: lift leg higher to prevent foot dragging on floor (foot lands first) = equine gait, orCircumduct the limb in order to prevent the affected foot dragging on the floor.

What is the clinical sign seen in compression of the deep fibular nerve?Equine Gait

What other ways can the common fibular nerve be damaged?

Fibula head fracture Anterior Tibial artery occlusion/Aneurysm(but it doesn’t have to be local damage: MND, Sciatic n. damage, Lumbosacral plexus, spinal cord trauma, stroke etc….)