Peripheral Nerve Injuries of the Upper Limb www.fisiokinesiterapia.biz
Definitions
Radiculopathy Process affecting the nerve root, most commonly by a herniated disc Weakness in muscles supplied by the nerve root (myotome) Sensory loss in the area of the skin supplied by the nerve root (dermatome)
Mononeuropathy Dysfunction of a single peripheral nerve Weakness in muscles supplied by the nerve Sensory loss in the area of the skin supplied by the cutaneous branches of the nerve
Brachial Plexopathy Can refer to involvement of the entire plexus, or parts of the plexus Trunk lesion Cord lesion Distribution of weakness and numbness depends upon the part of the plexus affected
Sensory Supply to the Arm Because fibers from different nerve roots come together and then split apart in the plexus A dermatome may include areas of the skin supplied by different peripheral nerves A single nerve may supply sensation to skin covered by more than one dermatome
Sensory Supply to the Arm Because of the pattern of root contribution to the plexus: An upper trunk lesion has sensory loss in the combined C5,6 dermatomes A middle trunk lesion has sensory loss in the C7 dermatome A lower trunk lesion has sensory loss in the combined C8T1 dermatomes
Dermatomes of the Posterior Arm
Dermatomes of the Anterior Arm
Principles of Localization Certain sites are prone to nerve entrapments/injuries Nerve opposing bone Ulnar nerve at the elbow Closed spaces Carpal tunnel Adjacent structures Median nerve at the elbow, adjacent to the brachial artery
Principles of localization, cont Order in which branches arise Movements at specific joints Single nerve Elbow extension Radial Multiple nerves Elbow flexion Musculocutaneous Radial
Case 1 A 38 yo woman was the restrained passenger in a car struck head on She braced her hands on the dashboard immediately prior to impact She suffered bilateral fractures of the humerus at the spiral (radial) groove She complains of diffuse aches in her arms and neck and weakness in her arms
Case 1, cont On exam she has: Bilateral wrist and finger drop (ie profound weakness of wrist and finger extension at the MCPs) Weakness of supination Weakness of elbow flexion with forearm held so that thumb is toward shoulder, but not with hand held in supination Remainder of strength exam is normal She has numbness in the posterior forearm extending into dorsum of hand into thumb and proximal index finger
Case 1, cont FINDING MUSCLE ROOT PLEXUS P N WR DROP ECR, ECU C7, C8 POST C RADIAL MT, LT FING DRP EDC,EI C7, C8 POST C RADIAL MT, LT ELB FLX BR C5,C6 POST C RADIAL UT SENS ---- C6 LAT C RADIAL UT
Triceps, long head Triceps, lateral head Triceps, med hd Brachioradialis ECRL ECRB Supinator Ext Digit Abd Pol Longus Ext Pol Longus Ext Pol Br Ext Indicies Superficial Radial sens Post Interosseous
Sensory loss in a high radial nerve lesion (Signficant variability b/w patients)
Final Diagnosis Bilateral radial nerve palsies at the spiral (radial) groove related to fractures
Case 2 A 25 year old man gets involved in a fist fight and the police arrest him When he is released on bail, he goes to see his doctor because he has numbness in the hand On exam he had a number of scratches and bruises on both arms normal strength sensory loss on the dorsum of the hand
Patient s sensory loss
Case 2, cont FINDING ROOT PLEXUS PN SENS LOSS < C6 < LAT CORD SUP RAD SENS
Triceps, long head Triceps, lateral head Triceps, med hd Brachioradialis ECRL ECRB Supinator Ext Digit Abd Pol Longus Ext Pol Longus Ext Pol Br Ext Indicies Superficial Radial sens Post Interosseous
Final Diagnosis Superficial radial neuropathy secondary to handcuffs
Case 3 15 yo football player is hit be another player, with the helmet striking him in the axilla On getting up, he is aware of shoulder weakness and pain and is taken to the ER
Case 3, cont On exam he has: Normal elbow flexion Normal elbow extension Normal shoulder adduction Ability to initiate shoulder abduction, but he cannot raise his arm more than 15 degrees Mild weakness of external (lateral) rotation of the arm A patch of sensory loss over his upper arm
Case 3, sensory loss
Case 3, cont FINDING MUSCLE ROOT PLEXUS PN Abd>15 Deltoid C5,6 Post C Axillary UT Ext Rot T. Minor C5,6 Post C Axillary Infrasp C5,6 UT Suprascap Sens ------- <C5 <POST C Axillary <UT
C5 C6 C7 C8 T1
Case 3, cont If it s at the posterior cord Radial innervated muscles should be affected But elbow extension is spared If it s at the upper trunk Musculocutaneous innervated muscles should be affected But elbow flexion is spared Pattern of sensory loss
Case 3, Final diagnosis Axillary Neuropathy in the Axilla
Case 4 A 55 yo hospital worker comes to see you with a 2 week history of pain in her neck, shoulder, and upper arm Symptoms began when she tried to help restrain a combative patient
Case 4, cont On exam she she: Weakness of shoulder abduction Weakness of elbow flexion Mild weakness of pronation Sensory loss in her lateral forearm and thumb both posteriorly and anteriorly
Case 4, cont FINDING MUSCLE ROOT PLEXUS PN ARM ABD DELTOID Suprasp C5,6 POST C, UT AXIL SUPRASC ELB FLX BC, BRACH BR C5,6 MED C, UT POST C, UT MUSC RAD PRON PT C6,7 LAT C MED SENS ------ C6 LAT C, UT MULT
Case 4, Final Diagnosis C6 Radiculopathy secondary to a herniated disc
Case 5 40 yo woman comes to see you because she has noticed weakness and numbness in her right hand This started 2 months ago and is slowly worsening She is otherwise healthy, and rides her bike at lease 40 miles per week
Case 5, cont On exam she has: Atrophy of the interosseous muscles of the right hand Mild weakness of abducting and adducting the fingers Normal thumb abduction, opposition and extension Normal wrist flexion, abduction and adduction
Case 5, sensory loss
CASE 5, cont FINDING MUSCLE ROOT PLEXUS PN FING AD FING ABD PALM INT DORSAL INT C8T1 MED C, LT ULNAR C8T1 MED C, LT ULNAR Sens loss ---- <C8 LT/Med Cd Uln
Case 5, cont If it s the lower trunk, C8/T1, or medial cord other muscles affected should include: APB and Opponens pollicus (median) EPL and EPB (radial) Can it be localized further to a specific site of the ulnar nerve?
Ulnar sensory loss in an ulnar lesion proximal to the midforearm
Ulnar nerve Elbow Flexor carpi ulnaris Flex Dig Prof III/IV Dorsal uln cut Wrist Adductor Pollicus Abductor Flex Pollicus Br Opponens Digiti Minimi Flexor Dorsal/palmar Interosseous 3rd/4th lumbricals
Case 5, final diagnosis Ulnar neuropathy at the wrist