Upper and lower limb nerve injuries Brogan Spencer and Millie Fern

Upper limb nerve injuries

Golden rule of posterior forearm innervation: The Golden Rules Posterior forearm Golden rule of posterior forearm innervation: - Everything is radial nerve supplied Hand Golden rule of hand muscle innervation Everything is ulnar nerve supplied except: - Thenar muscles - Lumbricals to digits 2 & 3 Everything is C8 & T1 supplied Anterior forearm Golden rule of anterior forearm innervation Everything is median nerve supplied except: - Flexor carpi ulnaris - Flexor digitorum profundus to digits 4 & 5 (the muscle on the ulnar side)

X X X The RADIAL nerve Mechanism of injury: “Saturday night palsy”, Crutches, surgery in the axilla Result: All function lost No elbow extension Wristdrop No digit extension Sensory loss on dorsolateral forearm & hand X Mechanism of injury: Fractured shaft of humerus X Result: Elbow extension preserved but weaker Wristdrop No digit extension Sensory loss on dorsolateral forearm & hand Mechanism of injury: Fractured head of radius Result: Elbow extension normal Minimal wristdrop (ECR supplied earlier) No sensory loss - motor nerve

X X The MEDIAN nerve Mechanism of injury: MEDICAL STUDENTS! Cubital fossa puncture wounds Result: 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 Mechanism of injury: Forearm prior to carpal tunnel (defence wound, suicide attempt) Carpal tunnel (compression) X Result: 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 X The ULNA nerve Mechanism of injury: Medial epicondyle fracture Result: 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 OK Loss of most intrinsic hand muscles…. Hypothenar & interosseous wasting X X Mechanism of injury: Wrist, superficial to retinaculum Result: X 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

A 45 yr male patient with a history of diabetes presents to his GP 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? What is the likely diagnosis? Carpal Tunnel syndrome Apart from diabetes, what else can increase the chance of carpal tunnel syndrome? Pregnancy Hypothyroidism Occupation What can directly cause carpal tunnel syndrome? Anything that occupies space in the carpal tunnel: Ganglion cyst, Giant cell tumour, Neuroma, Lipoma, Soft tissue thickening, fluid retention.. What passes through the carpal tunnel? 4 tendons of flexor digitorum superficialis 4 tendons of flexor digitorum profundus Flexor policis longus Median nerve What tests can you perform to confirm your diagnosis Phalen’s test Tinnels 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 How can this injury occur REMEMBER: SLAMeD into floor (Supascapula, lt.pectoral, Axillary, Musculocutaneous, Erbs palsy, Dorsal scapula) Stab wounds Iatrogenic Shoulder dystocia Forced separation of neck from shoulder Which nerves are affected? Suprascapula Lateral Pectoral Axillary Musculocutaneous Dorsal Scapula Which roots are effected? C5 and C6 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 nerves Medially rotated shoulder: Loss of supra- & infraspinatus & unopposed medial rotation action from sternal head of pec major Limp & loss of shoulder contour: Loss of deltoid Pronated forearm: Loss of biceps brachii Partial wrist drop/flexion at rest: Loss of extensor carpi radialis Anaesthesia: Over C5 & C6 dermatomes

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 Which roots are affected? C8 and T1 What is the name for this type of injury? Klumpke’s Palsy How can this injury occur Shoulder dystocia Pancoast tumour 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 joints Anaesthesia = medial elbow, forearm & arm

* What pattern of sensory loss would be seen in carpal tunnel syndrome? 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. Why do we care? This can help separate carpal tunnel syndrome from thoracic outlet syndrome, or pronator teres syndrome. Describe the surface anatomy of the carpal tunnel. Hook of hamate Pisiform Tubercle of Scaphoid Tubercle of trapezium 2cm distal to the most distal wrist crease Lateral and Medial walls formed by the U-shaped bones of the carpal tunnel. Roof: Flexor retinaculum What are the attachments of the flexor retinaculum Attaches to the hook of hamate and pisiform medially and tubercle of the trapezium and scaphoid laterally.

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. Which muscles are affected? Glut. Minimus & Medius What is the name for this type of walk? Trendelenburgs Describe why the patient looks like this when he walks Pelvis will tilt towards opposite side. (Due to weakness of the abductor muscles) You suspect the patient has damaged his gluteal muscles how do you test this and what would you expect to see? Trendelenburg’s test Place your hands on the ASIS and ask the patient to stand on one leg If 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… Which muscle is responsible for powerful hip/trunk extension and describe the nerve supply? Gluteus maximus – nerve supply = inferior gluteal L5/S1 Describe why the patient looks like this when she walks Gluteus maximus prevents the pelvis tipping forward while walking Damage/paralysis can lead to patient lurching backwards when the affected limb is on the floor during walking What other activities may she complain of finding difficult during your thorough history? Climbing the stairs Struggling to get out a chair

Betty, a 78 year old lady presents to her GP with pain in her left leg 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? SQITAS Hx. of trauma What major nerve could be the source of Betty’s pain? Sciatic What is the nerve root of he sciatic nerve and therefore what pattern of distribution could be expected? L4,5 and S1,2,3 Spine, buttock, thigh, calf and heel List some causes of Betty’s sciatica Spinal disc herniation Degenerative disk disease Lumbar 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. What is the clinical sign seen in compression of the deep fibular nerve? Equine Gait 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, or Circumduct the limb in order to prevent the affected foot dragging on the floor. 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….)