Computer generated transcript

Warning!
The following transcript was generated automatically from the content and has not been checked or corrected manually.

Year 1 Anatomy Revision Nerves of the Upper Limb Fionán Mac Giolla Bhríde fmcbride06@qub.ac.uk Overview Brachial Plexus Cutaneous Nerves 01 and main branchesvisions, cordsupper limb and dermatomesthe Nerve Anatomy 03 each nerve (except ulnar)bution of 01 Brachial Plexus Brachial Plexus ROOTS C5 C6 C7 C8 T1 Brachial Plexus ROOTS TRUNKS Superior Middle Inferior Brachial Plexus ROOTS TRUNKS DIVISIONS Ant t A n st t Post s o P Ant Brachial Plexus ROOTS TRUNKS DIVISIONS CORDS Lateral Posterior Medial Brachial Plexus ROOTS TRUNKS DIVISIONS CORDS BRANCHES Musculocutaneous Axillary Median Radial Ulnar Brachial Plexus ROOTS TRUNKS DIVISIONS CORDS BRANCHES C5 Superior Ant Lateral t Musculocutaneous A n C6 Axillary Pst C7 Middle Posterior Median Post t s Po Radial C8 Inferior Medial Ulnar Ant T1 Brachial Plexus Dorsal Scapular Suprascapular Nerve to Lateral subclavius pectoral Upper, middle & lower subscapular Medial pectoral Medial cutaneous nerve Long thoracic of arm & forearmBrachial Plexus Moore KL, Dalley AF, Agur AMR. Clinically Orientated Anatomy. Page 722 02 Cutaneous Nerves Cutaneous Nerves Cutaneous Innervation ANTERIOR POSTERIOR ● Cutaneous nerves innervate the skin Axillary ● These arise directly from the brachial Musculocutaneous plexus or as cutaneous branches of the Radial Median musculocutaneous, axillary, median, radial or ulnar nerves Ulnar Cutaneous Nerves ANTERIOR POSTERIOR Axillary Medial cutaneous nerve of arm Posterior cutaneous nerve of arm & forearm Medial cutaneous nerve of forearm Lateral cutaneous nerve of forearm Superficial branch of radial Median Ulnar Cutaneous Nerves ANTERIOR POSTERIOR Dermatomes ● Most superior part of shoulder is C3-C4 dermatome (rarely examined clinically) ● Beginning at C5, dermatomes follow sequentially around the limb from elbow to elbow ● Dermatomes do not match areas of cutaneous nerves Drake RL, Vogl W, Mitchell AWM, Gray H. Gray’s anatomy for students. Page 697 Cutaneous Nerves Upper Limb Neurological Examination ● During sensory examination of the limbs all dermatomes must be assessed ● It is useful to have consistent landmarks that can be used to test each dermatome DERMATOME LANDMARK C5 Lateral aspect of the elbow C6 Tip of the thumb C7 Tip of the middle finger C8 Tip of the little finger T1 Medial aspect of the elbow 03 Nerve Anatomy Nerve Anatomy Axillary Nerve ● Nerve roots C5-C6 ● Arises from posterior cord of brachial plexus ● Travels in quadrangular space with posterior circumflex humeral artery ● Innervates deltoid, teres minor and ‘regimental badge’ area of skin Nerve Anatomy Axillary Nerve NERVE ROOT MUSCULAR INNERVATION CUTANEOUS INNERVATION Axillary C5-C6 deltoid ‘regimental badge’ area teres minor Nerve Anatomy Axillary Nerve Injury ● Axillary nerve can be damaged by shoulder dislocation or a fracture of the surgical neck of the humerus ● Damage to the axillary nerve causes inability to fully abduct the arm due to loss of deltoid and loss of sensation over the regimental badge area Nerve Anatomy Musculocutaneous Nerve ● Nerve roots C5-C7 ● Arises from lateral cord of brachial plexus ● Pierces coracobrachialis and travels between biceps brachii and brachialis in the arm ● Becomes superficial at the elbow and continues as lateral cutaneous nerve of forearm Nerve Anatomy Musculocutaneous Nerve NERVE ROOT MUSCULAR INNERVATION CUTANEOUS INNERVATION biceps brachii MusculocutaneousC5-C7 brachialis lateral forearm coracobrachialis Nerve Anatomy Radial Nerve ● Nerve roots C5-T1 ● Arises from posterior cord of brachial plexus ● Found mostly in the posterior compartment (innervating extensor muscles) but travels anteriorly at the elbow ● Passes through triangular interval with profunda brachii artery ● In the forearm it splits into superficial (sensory) and deep (motor) branches Nerve Anatomy Radial Nerve NERVE ROOT MUSCULAR INNERVATION CUTANEOUS INNERVATION triceps brachii anconeus brachialis brachioradialis extensor carpi radialis longus extensor carpi radialis brevis posterior arm Radial C5-T1 extensor digitorum posterior forearm extensor digiti minimi lateral dorsal aspect of hand extensor carpi ulnaris dorsal aspect of lateral 3 ½ digits supinator extensor indicis abductor pollicis longus extensor pollicis longus extensor pollicis brevis Nerve Anatomy Radial Nerve Injury ● Radial nerve may be damaged by distal radial fracture (eg. Colle’s fracture) or more proximally in a humeral shaft fracture ● Loss of innervation to the extensors of the hand and wrist leads to ‘wrist drop’ ● If the injury is very proximal elbow extension (from triceps) may also be lost Nerve Anatomy Median Nerve ● Nerve roots C5-T1 ● Arises from lateral and medial cords of brachial plexus ● Located medial to the brachial artery in the cubital fossa ● Innervates most muscles of the anterior compartment in the forearm and ‘LOAF muscles’ in the hand ● Travels through carpal tunnel in the wrist Nerve Anatomy Median Nerve NERVE ROOT MUSCULAR INNERVATION CUTANEOUS INNERVATION pronator teres flexor carpi radialis palmaris longus flexor digitorum superficialis lateral ½ flexor digitorum profundus lateral palmar aspect of hand Median C5-T1 flexor pollicis longus palmar aspect of lateral 3 ½ digits pronator quadratus nailbeds of lateral 3 ½ digits abductor pollicis brevis flexor pollicis brevis opponens pollicis st nd 1 & 2 lumbricals Nerve Anatomy Carpal Tunnel Syndrome ● Compression of the median nerve in the carpal tunnel ● Associated with diabetes, female sex and pregnancy ● Inability to oppose the thumb and weakness in thumb flexion/abduction due to loss of thenar muscles ● Palmar sensation unaffected because palmar cutaneous branch arises proximal to carpal tunnelMCQ’s MCQ’s 1.A 42-year-old male was injured at work. He received a laceration midway along the anterior aspect of his right arm that severed all tissue to the bone. Following neurological examination by the F1 in A&E it is noted that the man has severe weakness in elbow flexion and loss of sensation over the lateral aspect of his forearm. What nerve is most likely affected? A. Median nerve B. Axillary nerve C. Lateral cutaneous nerve of forearm D. Anterior interosseus nerve E. Musculocutaneous nerve MCQ’s 2.A 32-year-old female presented to her GP with pain and heaviness in her left hand. She also mentions that she has noticed herself dropping things around the house. She is 26-weeks pregnant and has a past medical history of eczema. The GP suspects carpal tunnel syndrome. Which of the following muscles would notbe affected by this condition? A. Abductor pollicis brevis B. Flexor pollicis brevis C. Opponens pollicis D. Abductor pollicis longus E. 2ndlumbrical MCQ’s 3.A 20-year-old medical student has presented to A&E following a night of heavy drinking. They are unable to extend their wrist and fear the alcohol they consumed the night before may have accelerated the onset of multiple sclerosis. After a thorough examination the F2 assures them that they have a very proximal radial nerve palsy. Which of the following movements will the student still be able to perform in the affected limb despite their injury? A. Extension of the elbow B. Extension of the IP joints of the fingers C. Extension of the IP joint of the thumb D. Extension of the MCP joint of the fingers E. Extension of the MCP joint of the thumbQuestions?