The RADIAL nerve Profunda brachii Golden Rules of Motor Supply Arm: Posterior compartment Forearm: Posterior compartment Hand: Nothing
The RADIAL nerve All function lost No elbow extension Wristdrop No digit extension Sensory loss on dorsolateral forearm & hand Injured: “Saturday night palsy” Falling asleep on a chair with limb over the back rest Crutches
The RADIAL nerve Damage in spiral groove Elbow extension preserved but weaker Wristdrop No digit extension Sensory loss on dorsolateral forearm & hand Why is some of the elbow extension preserved? Injured: Fractured shaft of humerus
The RADIAL nerve Damage at radial head/neck Elbow extension normal Minimal wristdrop (ECR supplied earlier) No sensory loss - motor nerve Injured: Fracture head of radius
The MEDIAN nerve A B How would you get injured in these two places? A) Cubital fossa puncture wound B) Forearm prior to carpal tunnel (defence wound, suicide attempt) Carpal tunnel (compression)
A Can’t make fist with digits 2&3 (hand of ‘benediction’) Digits 2&3 = No active flexion of IP joints Digits 4&5 = weaker flexion (lacking FDS but FDP = ulnar nerve) No forearm pronation Weak wrist flexion that deviates to adduction (FCU = ulnar nerve) 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) The MEDIAN nerve
B 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)
The ULNAR nerve A B How is this nerve injured here? A) Medial epicondyle fracture B) Wrist, superficial to retinaculum
A 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 Clawing of digits 4 & 5 worse in low lesion as FDP remains innervated and exacerbates IP joint flexion The ULNAR nerve
B 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 The ULNAR nerve
Upper trunk damage Erb’s Palsy How can this injury occur and which roots are effected? C5 and C6 Which nerves are affected? Suprascapula Lateral Pectoral Axillary Musculocutaneous Dorsal Scapula What is the resulting appearance of a patient with Erb’s Palsy? 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
Patient falls from a tree grabbing a branch on the way down injuring themselves. Given the history just presented to you, what king of injury is it likely that the patient will have sustained to his arm/hand. What are other ways he may be able to cause the same injury? Klumpke’s Palsy Shoulder dystocia, Pancoast tumour. What trunks of the brachial plexus have been injured (1 mark). What will be the result of this injury (2 marks)? C8 & T1. Clawing of digits 2-5. Loss of ALL small muscles of the hand.
You are asked to perform a venepuncture on a patient for routine blood tests. Fresh and keen you take a “stab” at it. Name two common places for venepuncture on the upper limb, the veins you will access here and the structures that are at risk of damage in these areas. Which of these is the preferred site? Anatomical snuff box – Cephalic Vein. Superficial branch of the radial nerve. Bicep Barachii Artery. Cubital fossa – Median Cubital Vein, cephalic, basilic. Median Nerve. Radial Artery. On this occasion you decide to go for the cubital fossa. All going well so far, you have cleaned the area, got gloves on, applied the tourniquet, approach the vein at the right angle… Unfortunately you miss the vein and damages the nerve in this area. Complete Severe!! What nerve is injured and what is the resulting motor and sensory loss? Median Nerve Injury: Cannot make fist with digits 2&3. (Hand of Benediction) No active flexion of Interphalangeal joints of digits 2&3. No forearm pronation Weak wrist flexion deviates to the ulna. Ulnar deviation on wrist flexion. Thenar wasting Opposition not possible
You panic and don’t want to get in trouble and so blame this median nerve damage on something else. How and where else can this nerve be damaged? Supracondylar fracture In the carpal tunnel: Self defence wounds Suicide attempt Carpal tunnel compression You are feeling brave and tell your consultant that your patient tried to attempt suicide and has been left with median nerve damage. Your consultant, Dr Doom, doesn’t quite believe you. He assess the patient and concludes that you are lying. Aside from the fact that there are no signs of suicide attempts, how else can Dr Doom tell that the median nerve damage was not done at the carpal tunnel as explained? The patient will be unable to make a fist: Hand of benediction, loss of FDS and FDP to digits 2&3. Unable to pronate: Loss of pronator teres. Ulnar deviation on wrist flexion: Loss of Flexor Carpi Radialis Digits 4 & 5 have weaker flexion: Loss of FDS
Where will Dr Doom have tested for sensory innervation of this nerve? Thenar Eminance Where would he test for ulnar nerve damage? Hypothenar Eminance What is the difference between Ulnar Claw Hand and the Hand of Benediction? Hand of benediction: You will only see this sign on active flexion of digits. Ulnar claw hand is visible at rest/passive.
Meanwhile Anne is finally getting over her LTN injury, unfortunately she fell over due to being unstable because of her breast reduction and fractured her humerus. What nerves are at risk of damage in a fracture of the humerus. Axillary Nerve: Fracture of the surgical neck of the humerus Radial Nerve: Mid-shaft fracture of the humerus, spiral groove. Supracondylar Fracture: Median Nerve Medial Epcondyle: Ulnar Nerve Anne was unfortunate, she had a mid-shaft fracture of the humerus. What travels in the spiral groove/radial sulcus (2 marks)? Profunda brachii Radial Nerve Unfortunately she damaged the nerve running in the region. What will be the resulting clinical appearance? Wrist Drop Flexed arm “Swan Like” apprearance How and where can the radial nerve be injured? Axilla: Shoulder dislocation, crutches, Saturday night palsy Radial Sulcus: Midshaft fracture of the humerous Head/Neck of radius: Fracture
What is the motor loss and weakness following this injury? Elbow extension: Weak (Some of the triceps innervated proximal to injury) Digit Extension: Absent (Complete loss of forearm extensors) Sensory Loss: Dorsolateral forearm & hand You try to console her, she is inconsolable. “How could this be worse?” she cries. “Well, I’m glad you asked, because if you damaged the redial nerve you would have the symptoms you have now plus…..” Finish the sentence. Complete function loss. On top of what she experienced she will also have No Elbow Extension Anne is somewhat comforted by this. Great, it worked. You are amazed at how much you remembered from Dr. T’s lectures goes on to describe what loss there would have been had she have damaged the radial nerve at the head/neck of the radius. What would her signs/symptoms be? Normal Elbow Extension Minimal wrist drop: Extensor Carpi Radialis supplied earlier. No sensory loss Where will you test sensory innervation of the radial nerve in the arm? First dorsal interosseos
A few weeks after her injury your patient Anne comes to you explaining she is having trouble gripping things. Explain why Pamela has no 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 This means that they are mechanically unable to flex the digits tightly. Furious she returns to you! What can you do to help her? Splint the wrist into a neutral position, thus enabling a better use of the digits, especially for a power grip.
Anne has just had a surgical resection of her axilla for removal of axillary lymph nodes. What is the axilla (1 mark) and what are its borders (4 marks)? The axilla is a fat filled region superior to the armpit. Anterior: Pec Major, Anterior axillary fold Posterior: Subscapularis, Scapula, Posterior axillary fold: Lat Dorsi, Teres Major Medial: Lateral thoracic wall, serratus anterior Lateral: Intertubercular groove
What nerve is at risk of damage during this surgery (1 marks)? How else may it get damaged (3 marks)? The Long Thoracic Nerve (C5-7) Trauma Brachial plexus injury Root of neck injury (Posterior triangle)
What muscle is innervated by the long thoracic nerve (1 mark), what is its location (1 mark)? What is the function of this muscle? The serratus anterior. Passes from ribs 1-8 in the mid axillary region, deep to the scapula to insert into its medial border. Prevents the medial scapula border from lifting away from the thorax (winging) when a posterior force applied to an outstretched upper limb.
Unfortunately Mr. Baig was not as careful as he should have been in surgery and has unfortunately injured Pamela’s LTN. What movements will Pamela find difficult? Punching out Combing hair There may be some instabilty
How can you test the functioning of the LTN? If there is damage, what sign will be present? Patient faces a wall, places palms of hands on the wall. Lock their arms in an extended position and then lean into the wall (almost like doing the first stage of press up into the wall). Serratus anterior contraction should prevent scapula winging WINGING OF THE SCAPULA
Vishal has been martial arts training recently and has just learnt how to use a samurai sword with deadly accuracy. He wants to test out his new skills so he cuts Charli’s Cranial Nerve XI on the left side. What is the name of this nerve (1 mark)? What does it innervate (2 marks)? State any abnormalities in Charli’s appearance. What will be the changes/abnormalities of function as a result of this horrific injury (4 marks)? Name of the nerve: Accessory nerve Innervates: Trapezius, Sternocliedomastoid Appearance: The shoulder on the affected side (left) would appear lower than the right (unaffected) due to the paralysis of trapezius. On the left side (affected side) he would not be able to: Shrug his shoulders There would be limited shoulder abduction (loss of pectoral girdle rotation) Pectoral gridle stabilisation and movement would be abnormal Ask the patient to turn their head to the right against resistance, there will be weakness in doing this
What will happen to him over time (2 marks)? After several months there would be wasting of trapezius and loss of the curved contour of the lower lateral neck
Peter is so horny, but he is having trouble wanking. He is suffering from carpal tunnel syndrome. Name the symptoms of carpal tunnel syndrome (2 marks) What might Spunk Master Pete find difficult (1 mark)? If this had been going on for some time, what sign may you be able to see? Tingling in the lateral 3.5digits Nocturnal pain in lateral 3.5 digits Buttoning up his trousers after wanking. Note: Patients who have carpal tunnel syndrome report difficulty closing buttons on their clothes. Thenar wasting would be evident if carpal tunnel has been chronic
Which nerve is involved in Carpal Tunnel Syndrome (1 mark)? What else passes through the carpal tunnel (3 marks)? Median Nerve 4 tendons of the Flexor Digitorum Profundus 4 tendons of the Flexor Digitorum Superficialis 1 tendon of the Flexor Pollicus Longus
Describe the anatomy of the carpal tunnel. 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 Attaches to the hook of hamate and pisiform medially and tubercle of the tripezium and scaphoid laterally.
What causes carpal tunnel syndrome? What conditions are associated with carpal tunnel syndrome? Anything that occupies space in the carpal tunnel: Ganglion cyst, Giant cell tumour, Neuroma, Lipoma, Soft tissue thickening, fluid retention.. Hypothyroidism Pregnancy
What test might you perform to confirm the diagnosis of carpal tunnel (2 marks)? Tinnels Phalen’s
Cubital Fossa Superior: Inter-epicondyle line Medial: Pronator teres Lateral: Brachioradialis Roof: Fascia and bicipital aponeurosis Floor: Fascia of the bicipital aponeurosis (Fascia of the biceps)