Upper Extremity Nerves

1/15/2019 Upper Extremity Nerves Learning Objectives Upper Extremity Nerves At the completion of the course, the learner will be able to 1. describe the neuroanatomy from brain to fingertip. 2. describe current concepts of peripheral nerve biology and healing. 3. collect a good history & exam for common peripheral nerve conditions. 4. educate patients regarding their condition and treatments. 5. participate more effectively in the patients’ care Course Content Meets These AOTA Classification Codes for CE activities Category 1: Domain of OT METHODS Areas of occupation: ADLs Performance skills: motor skills • 12 lectures Activity demands: required actions, body functions and • 2 question and answer sessions structures • networking Category 2: OT Process Develop intervention plan/approaches • some repetition between talks Implement intervention bad news: unavoidable because of multiple speakers Category 3: Professional Issues good news: repetition is a good learning tool OT education: teaching theory and methods Supervision: competence Contemporary issues/trends: professional development/continuing competence Upper Extremity Nerves for OTs and PTs For Your Questions during the Discussion Sessions: Write them on notecards as you think of them Practical Matters Can everybody see? Hear? MACRO ANATOMY Room temperature? Cell phones, beepers From Brain to Fingertips Auditorium’s policy on food/beverage Restrooms Evaluation forms and certificates Naveed Nosrati, MD Ready, set, go…… 1 1/15/2019 Motor Pathways: Major Elements Outline Central Nervous System • Motor pathways (cortex to finger tip) cerebral cortex • Sensory pathways (finger tip to cortex) brain stem • 6 major nerves spinal cord • Anatomic anomalies Peripheral Nervous System • Sympathetic nervous system root plexus branch/periph n. end organ Motor Strip Sensory Strip Motor Impulses • Motor Impulses • travel through the internal capsule • originate in (white matter) parietal cortex gray matter • cross in the brainstem – each • originate in the side of the cortex “motor strip” controls the opposite side of the body spinal cord (CNS) gives off nerve roots (PNS) brachial plexus is formed from: -inferior 4 cervical nerve roots (C5-C8) -superior thoracic nerve root (T1) Anterior: Dorsal: posterior anterior Motor Sensory Roots Roots Cell bodies Cell bodies in anterior In dorsal horn of root ganglia spinal cord 2 1/15/2019 The Brachial Plexus Has 5 Anatomical Parts Bony Landmarks and the Parts of the Brachialroots Plexus Randy Travis Drinks Cold Beer Brachial Plexus Brachial Plexus and Axillary Artery • emerges And between anterior Muscles/Bones and medial scalene muscles Medial, lateral, • passes beneath and posterior clavicle cords • passes deep to •Closely pectoralis major associated with and minor AA •Named for their relationships to the AA The brachial plexus is complicated… Its major components can be learned and drawn as easy as 1,2,3 (x8)… 3 1/15/2019 4 1/15/2019 dorsal scapular c5 suprascapular c5,6 C5 lateral pectoral c5,6,7 musculocutaneous c5,6,7 axillary C6 c5,6 median C7 c678t1 lower subscap c6,7 thoracodorsal c6,7,8 long upper radial c5,6,7,8 thoracic C8 subscap ulnar c8,t1 c5,6 c5,6,7 It is important to know the nerves, their routes medial antebrach cutan c8 through the brachial plexus, AND from which medial brachial cutan t1 T1 spinal roots they arise… medial pectoral c8,t1 How to begin making sense out of which muscles often get innervation from same nerve roots supply which muscles? root that supplies overlying skin 1. Know the sensory dermatomes Start with C6 it works for deltoid Bang! C5 C5 C5 T1 T1 C6 C7 C8 C8 It works for biceps, brachialis How to begin making sense out of which and sort of for triceps nerve roots supply which muscles? 2. Make a “7” with your fingers, wrist and elbow C5 C5 C7: T1 C6 elbow extension C5,6 wrist flexion finger extension C7 C8 C7,8 5 1/15/2019 dorsal scapular c5 suprascapular c5,6 C5 lateral pectoral c5,6,7 Major components labeled musculocutaneous c5,6,7 IN OUT 1. Long Thoracic axillary C6 C5-8 c5,6 2. Musc Cut N. median T1 C7 3. Axillary N. c678t1 lower subscap c6,7 thoracodorsal c6,7,8 long 4. Median N. upper radial c5,6,7,8 thoracic C8 subscap 5. Radial N. ulnar c8,t1 c5,6 c5,6,7 medial antebrach cutan c8 6. Ulnar N. medial brachial cutan t1 T1 medial pectoral c8,t1 1) Long Thoracic Nerve 16 nerves exit the brachial plexus We will look at 6 major ones •courses (more detail to follow later today) inferiorly on anterior lateral 1) Long Thoracic chest wall 2) Axillary •innervates 3) Musculocutaneous SERRATUS 4) Radial ANTERIOR 5) Median 6) Ulnar •prevents scapular Quiz follows! winging 2) Axillary Nerve 3) Musculocutaneous Nerve posterior view •exits brachial plexus •Innervates the “BBC muscles” posteriorly • BICEPS • BRACIHALIS •courses through • CORACOBRACHIALIS “quadrilateral •Continues as the lateral space” antebrachial cutaneous nerve •innervates DELTOID. 6 1/15/2019 4) Radial Nerve 4) Radial Nerve •Leaves brachial plexus Lateral View posteriorly Posterior View Passes medial •Passes laterally behind the to lateral behind humerus the humerus •Crosses anterior to lateral epicondyle •Pierces supinator Passes •Passes along anteriorly over dorsolateral forearm lateral aspect of •Innervates triceps, wrist humerus and finger extensors posterior view 5) Median Nerve 6) Ulnar Nerve • arm: medial, with brachial artery • arm: medial; posterior to median nerve and brachial artery • elbow: central, medial to biceps tendon • elbow: posterior to medial epicondyle • forearm: central, beneath fds innervates fds, ½ fdp, fcr, • forearm: medial, beneath fcu pronator teres innervates fcu and ½ fdp • palm: central, through carpal • palm: Guyon’s canal; innervates tunnel innervates thenar hypothenars, interossei, add muscles, 2 lumbricals pollicis, 2 lumbricals 6) Ulnar Nerve QUIZ! Name that palsy! Posterior Views • passes posterior to medial epicondyle of the humerus 7 1/15/2019 Motor Impulses Terminate at the Sensory Impulses Neuromuscular Junction Nerve • Motor impulses move distally away from CNS • Sensory impulses move proximally toward the CNS Muscle – share nerves with motor system, use different fibers • Sensory nerves innervate skin in the area of their motor counterpart – (i.e. axillary nerve transmits sensory information from the skin of the On to sensory nerves….. shoulder) Sensation in the Hand Differences in Sensory Nerve Pathways • S. nerves enter spinal cord thru Median: palmar aspect of lateral 3 ½ digits + dorsal roots nail beds of same • S. nerves cross to opposite side Ulnar: palmar/dorsal aspects of medial 1 ½ in brain stem or spinal cord fingers + hand continuous with same • Pass through the thalamus • Terminate in the sensory strip Radial: volar aspect of lateral 3 ½ digits and hand continuous with same (excluding nail beds). The Sympathetic Nervous System Stellate in the Upper Extremity Ganglion = Inferior 2 parellel Cervical + chains of Superior GANGLIA Thoracic along sides of spinal cord. Ganglia 8 1/15/2019 References Sympathetic Fibers • Falconer, Spinner: Anatomic variations in the motor in the Upper Extremity and sensory supply of the thumb. Clin Orthop 1985;195:83-96. •pass through stellate ganglion • Russomano et al: Riche-Cannieu anastomosis with partial transection of the median nerve. Muscle •travel along arteries Nerve 1995;18:120-2. • Sachs, Raynor, Shefner: The all ulnar motor hand •control vessel without forearm anastomosis. Muscle Nerve constriction/relaxation; sweat; 1995;18:309-13. piloerection • Meals, R, Shaner: Variations in digital sensory patterns: a study of the ulnar nerve-median nerve •implicated in some chronic palmar communicating ramus. J Hand Surgery, regional pain syndromes 1983;8:411-414 Outline Microanatomy Nerve Micro-Anatomy Biology and Biology Nerve Injuries Physiology Classification Adam Martin, MD UCLA Hand Fellow Nerve response to injury no relevant disclosures Anatomy of Neuron Cell body Dendrites Sensory neuron Receive incoming impulses Axon Conducts outgoing impulses Motor neuron Schwann Cells 9 1/15/2019 Anatomy of a Peripheral Nerve Nerve Fiber (Axon) Counts 1. Axon: basic subunit Electric lamp cord: ~60 copper strands . Nerve fiber = Digital nerve: ~1500 nerve fibers axon + Schwann cell + Median nerve: ~25,000 nerve fibers myelin Brachial plexus: ~145,000 nerve fibers 2. Fascicle: groups of axons 3. Peripheral nerve: groups of fascicles Connective tissue layers Cross-section of peripheral nerve Epineurium 1. Epineurium Cushions nerve 2. Perineurium Nerve gliding 3. Endoneurium Perineurium Surrounds fascicle Vascular supply Tight junctions Intrinsic + extrinsic Fascicle Mitchell adapted from www.CDNPA.com Endoneurium Surrounds axons External epineurium Internal epineurium Fascicle Axon + Endoneurium 10 1/15/2019 Nerve Physiology Nerve Injury Axonal transport Mechanical injuries Secondary injury Protein synthesis in cell body Distance too long for diffusion Compression Infection Products motored along Traction Scarring microtubules Laceration Fracture callus Retrograde transport Combination Ischemia Returns waste products for (e.g. GSWs) recycling Transports growth factors to nucleus Implications with injury Response to Injury Nerve Injury Classification Limited repertoire of responses to nerve Seddon H: Three types of nerve injury. Brain, injury 1943. 1. Mild injury 1. Neurapraxia schwann cells/myelin sheath 2. Axonotmesis Focal demyelination 3. Neurotmesis 2. Severe injury axons Axonal degeneration Neurapraxia Neurapraxia

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