3 Golden rule of posterior forearm innervation: The Golden RulesPosterior forearmGolden rule of posterior forearm innervation:- Everything is radial nerve suppliedHandGolden rule of hand muscle innervationEverything is ulnar nerve supplied except:- Thenar muscles- Lumbricals to digits 2 & 3Everything is C8 & T1 suppliedAnterior forearmGolden 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)
4 X X X The RADIAL nerve Mechanism of injury: “Saturday night palsy”, Crutches, surgery in the axillaResult:All function lostNo elbow extensionWristdropNo digit extensionSensory loss on dorsolateral forearm & handXMechanism of injury:Fractured shaft of humerusXResult:Elbow extension preserved but weakerWristdropNo digit extensionSensory loss on dorsolateral forearm & handMechanism of injury:Fractured head of radiusResult:Elbow extension normalMinimal wristdrop (ECR supplied earlier)No sensory loss - motor nerve
5 X X The MEDIAN nerve Mechanism of injury: MEDICAL STUDENTS! Cubital fossa puncture woundsResult:Can’t make fist with digits 2&3 (hand of ‘benediction’)No active flexion of IP joints of digits 2&3Weaker flexion of digits 4&5 = No FDS but FDP from ulnar nerveNo forearm pronationWeak wrist flexion that deviates to adduction (FCU = ulnar nerve)Plus damage seen with wrist injury below......XMechanism of injury:Forearm prior to carpal tunnel (defence wound, suicide attempt)Carpal tunnel (compression)XResult:Thenar wasting & opposition not possibleThumb laterally rotated & adductedLumbricals 1 & 2 paralysed = digits lag in fist making (4+5 go down first the others follow)
6 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 & 3Thenar muscles OKLoss of most intrinsic hand muscles….Hypothenar & interosseous wastingXXMechanism of injury:Wrist, superficial to retinaculumResult:XLoss of most intrinsic hand muscles….Hypothenar & interosseous wastingClawing of digits 4 & 5 worse in low lesion as FDP remains innervated and exacerbates IP joint flexion
7 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 syndromeApart from diabetes, what else can increase the chance of carpal tunnel syndrome?PregnancyHypothyroidismOccupationWhat 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 superficialis4 tendons of flexor digitorum profundusFlexor policis longusMedian nerveWhat tests can you perform to confirm your diagnosisPhalen’s testTinnels test
8 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 PalsyHow can this injury occurREMEMBER: SLAMeD into floor(Supascapula, lt.pectoral, Axillary, Musculocutaneous, Erbs palsy, Dorsal scapula)Stab woundsIatrogenicShoulder dystociaForced separation of neck from shoulderWhich nerves are affected?SuprascapulaLateral PectoralAxillaryMusculocutaneousDorsal ScapulaWhich roots are effected?C5 and C6You 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
9 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 downWhich roots are affected?C8 and T1What is the name for this type of injury?Klumpke’s PalsyHow can this injury occurShoulder dystociaPancoast tumourHow might Klumpke’s Palsy presentParalysis & wasting of ALL small muscles of handClawing of digits 2-5 at rest due to unopposed action of extensors on MCP joint & long flexors on IP jointsAnaesthesia = medial elbow, forearm & arm
10 *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 hamatePisiformTubercle of ScaphoidTubercle of trapezium2cm distal to the most distal wrist creaseLateral and Medial walls formed by the U-shaped bones of the carpal tunnel.Roof: Flexor retinaculumWhat are the attachments of the flexor retinaculumAttaches to the hook of hamate and pisiform medially and tubercle of the trapezium and scaphoid laterally.
12 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 & MediusWhat is the name for this type of walk?TrendelenburgsDescribe why the patient looks like this when he walksPelvis 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 testPlace 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.
13 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/S1Describe why the patient looks like this when she walksGluteus maximus prevents the pelvis tipping forward while walkingDamage/paralysis can lead to patient lurching backwards when the affected limb is on the floor during walkingWhat other activities may she complain of finding difficult during your thorough history?Climbing the stairsStruggling to get out a chair
14 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?SQITASHx. of traumaWhat major nerve could be the source of Betty’s pain?SciaticWhat 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 heelList some causes of Betty’s sciaticaSpinal disc herniationDegenerative disk diseaseLumbar spinal stenosisPiriformis syndrome
15 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 dropWhy?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 GaitFoot drop occurs during heel strike and swing phases of walking when the foot would normal dorsiflex.No dorsiflexion = foot dropPatient 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 other ways can the common fibular nerve be damaged?Fibula head fractureAnterior Tibial artery occlusion/Aneurysm(but it doesn’t have to be local damage: MND, Sciatic n. damage, Lumbosacral plexus, spinal cord trauma, stroke etc….)