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Entrapment neuropathies
- 1. BRACHIAL PLEXUS ANATOMY AND ENTRAPMENT NEUROPATHIES OF UPPER LIMB Dr Ankit Kumar Garg Moderator : Dr Md Zackariya Sir
- 2. Past Year DNB Questions • Define entrapment syndrome. (June2018) Enumerate various entrapment syndromes. (June2018) • Anatomy & contents of carpal tunnel with suitable diagram(s). (June-2017) Etiopathogenesis, clinical features. diagnosis and management of carpal tunnel syndrome. (2+2+3+3) (Dec2015) Clinical features and management of carpel tunnel syndrome.(6) (June2018) Clinical features, diagnosis, treatment of Carpal tunnel syndrome. (2+2+2) (June 2015) • Anterior Interosseous Nerve Syndrome(5) (June 2016-2B2), (5) (Dec 2013) Enumerate its etiology and clinical features (4) (Dec 2017) What are the diagnostic tests for it? (3) (Dec 2017) Its treatment protocol? (3) (Dec 2017)
- 3. BRACHIAL PLEXUS • The brachial plexus is a network of nerves formed by the union of the anterior rami (branches) of C5 – C8 & T1 spinal nerves. • It originates in the neck, passes laterally & inferiorly over the first rib & enters the axilla. • All major nerves of the upper limb originate from parts of the brachial plexus
- 4. PREFIX / POST FIX • C5 usually receives some fibers from C4, and T1 usually receives fibers from T2. • The formation of the brachial plexus begins just distal to the scalene muscles.
- 6. Roots • Long thoracic nerve (C5, C6, C7)- supplies serratus anterior • Dorsal scapular nerve (C5)- supplies levator scapulae, rhomboidus major and minor Trunks • Suprascapular nerve(C5,C6)- branch of upper trunk; supplies supra and infraspinatus • Nerve to subclavius(C5,C6)- Supplies subclavius Division No Branch
- 7. Branches of lateral cord (LML) • Lateral pectoral n.(C5-C7) • Pectoralis major and minor • Musculocutaneous n.(C5-C7) • Biceps • Brachialis • Coracobrachialis • Lateral root of median nerve(C5-C7)
- 8. Branches of medial cord (M4U) • Medial pectoral nerve(C8,T1)-sternoclavicular head of pectoralis major • Medial cutaneous nerve of arm(C8,T1) • Medial cutaneous nerve of forearm • Medial root of median nerve(C8,T1) • Ulnar nerve(C7,C8,T1)
- 9. Branches from Posterior cord (ULNAR) • Upper subscapular nerves(C5,C6) • Lower subscapular nerves supply subscapularis and teres major • Nerve to Latissimus dorsi. (C6,C7,C8) (thoracodorsal nerve) • Axillary nerve(C5,C6) • teres minor • deltoid muscles • patch of skin over deltoid • Radial nerve(C5-C8,T1) • continuity of posterior cord
- 10. ENTRAPMENT NEUROPATHIES MEDIAN NERVE CARPAL TUNNEL SYNDROME ANTERIOR INTEROSSEOUS SYNDROME PRONATOR TERES SYNDROME ULNAR NERVE CUBITAL TUNNEL SYNDROME ULNAR TUNNEL SYNDROME RADIAL NERVE RADIAL TUNNEL SYNDROME WARTENBERG SYNDROME POSTERIOR INTEROSSEOUS SYNDROME SUPRASCAPULAR NERVE SYNDROME QUADRILATERAL SPACE SYNDROME
- 11. Pathophysiology of compression neuropathies • Hampers intraneural blood flow & transfer of oxygen and micronutrients Venous flow stops at 20-30 mm Hg Frank ischemia at 60-80 mm Hg Ischemia impairs myelination ; demyelination seen • Direct injury to axons • Interferes with axoplasmic flow- at 50 mm Hg, metabolites distribution is disturbed, complete conduction block at 130 mm Hg
- 12. Median Nerve • Root Valve : C5-T1 • Median Nerve : Flexor Digitorum Superficialis Flexor Carpi Radialis Longus Palmaris Longus • Ain : Flexor Pollicis Longus Fdp Of Index , Middle Finger Pronator Quadratus • Motor Branch: Thenar Muscles( Only Sup.Fpb) Lateral 2 Lumbricals
- 14. Median Nerve • Root Valve : C5-T1 • Median Nerve : Flexor Digitorum Superficialis Flexor Carpi Radialis Longus Palmaris Longus • Ain : Flexor Pollicis Longus Fdp Of Index , Middle Finger Pronator Quadratus • Motor Branch: Thenar Muscles( Only Sup.Fpb) Lateral 2 Lumbricals
- 15. Median Nerve
- 16. MEDIAN NERVE(LABOURERS NERVE) • ROOT VALVE : C5-T1 • MEDIAN NERVE : FLEXOR DIGITORUM SUPERFICIALIS FLEXOR CARPI RADIALIS LONGUS PALMARIS LONGUS • AIN : FLEXOR POLLICIS LONGUS FDP OF INDEX , MIDDLE FINGER PRONATOR QUADRATUS • MOTOR BRANCH: THENAR MUSCLES( ONLY SUP.FPB) LATERAL 2 LUMBRICALS
- 18. BOUNDARIES: ROOF : TRANSVERSE CARPAL LIGAMENT FLOOR: CARPAL BONES MEDIAL: PISIFORM LATERAL : SCAPHOID CONTENTS : 9 TENDONS ( 4FDS + 4 FDP) , 1 NERVE CARPAL TUNNEL SYNDROME
- 19. Carpal tunnel pressure • Normal – 2.5 mm Hg • 20-30 mm Hg- reduces venule flow in epineurium, nerve oedema • > 30 mm Hg- decreases nerve conduction • In chronic CTS- higher compression needed to produce symptoms
- 20. Types of presentation Acute onset • Trauma, • infection, • Hematoma, • Injections Needs urgent decompression Chronic • MC idiopathic • hypertrophy of fibrous tissue+ chronic edema+ minimal inflammation of nerve • MC site of compression 1cm distal to proximal edge of ligament (thickest part) • female predominant
- 21. FACTORS AFFECTING CARPAL TUNNEL Anatomy Decrease in Size of Carpal Tunnel ■ Bony abnormalities of the carpal bones ■ Acromegaly ■ Flexion or extension of wrist Increase in Contents of Canal ■ Forearm and wrist fractures (Colles fracture, scaphoid fracture) ■ Dislocations and subluxations (scaphoid rotary subluxation, lunate volar dislocation) ■ Posttraumatic arthritis (osteophytes)
- 22. ■ Musculotendinous variants ■ Aberrant muscles (lumbrical, palmaris longus,palmaris profundus) ■ Local tumors (neuroma, lipoma, multiple myeloma, ganglion cysts) ■ Persistent medial artery (thrombosed or patent) ■ Hypertrophic synovium ■ Hematoma (hemophilia, anticoagulation therapy, trauma) FACTORS AFFECTING CARPAL TUNNEL
- 23. • Physiology Neuropathic Conditions ■ Diabetes mellitus ■ Alcoholism ■ Double-crush syndrome ■ Exposure to industrial solvents • Inflammatory Conditions ■ Rheumatoid arthritis ■ Gout ■ Non-specifc tenosynovitis ■ Infection • External Forces ■ Vibration ■ Direct pressure & extreme wrist flexion or extension FACTORS AFFECTING CARPAL TUNNEL
- 24. • Alterations of Fluid Balance ■ Pregnancy (20-45% incidence, self limiting, 3rd trimester) ■ Menopause ■ Eclampsia ■ Thyroid disorders (especially hypothyroidism) ■ Renal failure ■ Long-term haemodialysis ■ Raynaud disease ■ Obesity ■ Lupus erythematosus ■ Scleroderma ■ Amyloidosis ■ Paget disease FACTORS AFFECTING CARPAL TUNNEL
- 26. Diagnosis- mainly clinical • “Nocturnal acroparesthesia”- disturbs sleep also in daytime by provocative postures- keyboard, hyperflexion of wrist, praying, sewing • Bilateral common – 87%, but mostly one side predominant • Chronic cases- grip & pinch loss • Autonomic dysfunction • Thenar atrophy- very late KATZ AND STIRRAT HAND DIAGRAMS
- 27. Differential diagnosis • Median nerve contusion • Cervical radiculopathy • Cervical syringomyelia • Thoracic outlet syndrome • Pronator syndrome • Idiopathic brachioplexitis ( Parsonage Turner syndrome) • Intracranial tumor • Pancoast syndrome • Systemic neuropathy • Peripheral nv tumors
- 28. Provocative tests 60 seconds • Sign of regeneration • Doesn’t correlate with an ongoing damaging process
- 29. DURKANS COMPRESSION/ REVERSE PHALEN TEST • 30 seconds • Increased sensitivity post Phalens
- 30. •Tourniquet test (Gilliat & Wilson)- above SBP for 60 s •Closed fist sign- Tight fist 60 s
- 31. Investigations Electrodiagnostic studies- NCV • Sensitive in clinically silent patients • Rule out other causes • Quantifies severity of damage, and recovery • In early irritative stage- false negative due to excess excitability & ectopic impulse generation Diagnostic criteria for CTS • Sensory fiber compression- Delayed/ absent motor nerve sensory action potential(SAP) >3.4ms latency Increased median to ulnar latency difference 4th finger SAP >0.5ms • Motor fiber compression – Distal motor latency >4.2ms. Denervation signs in APB muscle
- 32. MRI • Flattening of median nerve at hook of hamate level • Cross sectional diameter ratio of median nv at level of pisiform : distal radius – Normal is 1, Increases in CTS • Inflammatory fluid • Fatty infiltration • Space occupying lesions • Scarring
- 33. Management • Non surgical Injections Surgical CTR including arthroscopy • Poor outcome indicators Diabetics Workman compensation No response to steroid injections and orthosis Prolonged duration >3 years Thenar atrophy
- 34. Non surgical • 80 % respond to night wrist splinting and intermittent day splinting • Lowest pressure in 2 ± 9ᵒ extension and 2 ± 6ᵒ ulnar deviation : keeps lumbricals out of tunnel • Most helpful in Phalen positive • NSAIDS, Pyridoxine, Methylcobalamine • Oral steroids and diuretics for fluid retention • Laser, UST,
- 35. • Starting point- 4th finger flexed towards distal wrist crease • Incision ulnar to thenar crease and 2mm ulnar to 4th ray • Keep dissection lateral to avoid injury to thenar and palmar cutaneous branch • No internal neurolysis- leads to neurodermodesis & algoparesthesia
- 36. Surgical release • Open Mini-open Endoscopic • Endoscopic release allows earlier return to work and improved strength during the early postoperative period. • Results at 6 months or later were similar according to current data except that patients with endoscopic release are at greater risk of nerve injury and lower risk of scar tenderness compared with open release.
- 38. • Pure motor • AIN arises 4cm distal to medial epicondyle beneath the fibrous arch of FDS • Descends on anterior aspect of interosseous membrane along with artery • Between FDP and FPL ANTERIOR INTEROSSEOUS SYNDROME
- 39. ENTRAPMENT SITES • Between 2 heads of pronator teres • FDS arcade • Edge of lacertus fibrosus • Anomalous structures- Supracondylar spur with accessory bicipital aponeurosis Gantzers muscle – accessory head of FPL Anomalous heads of PT
- 40. Clinical features • Complete/ Incomplete • Motor palsy • Fatigue pain and dyskinesia in proximal volar forearm after repititve work • Martin Gruber anastomosis- incomplete palsy
- 41. Management • EMG- FPL, index FDP, middle FDP, pronator quadratus • Non operative Splint in supination Correct DM, hypothyroid, alcohol Pyridoxine • Operative Failed conservative Anatomical causes- spurs, SOL
- 44. • Between 2 heads of PT • Females in 5th decade • Males- atheletes, bodybuilders • Fibrous bands between 2 heads • Thickened or tight bicipital aponeurosis (lacertus fibrosus)- lacertus fibrosus syndrome in venepuncture/ exercise • Supracondylar process + Ligament of Struthers • FDS aponeurotic arch • Anomalous heads of PT • Iatrogenic- tight casts
- 45. Clinical features • Aching pain in volar proximal forearm aggravated by pronation, elbow flexion • Paraesthesia's and hypesthesia's in median nv sensory distribution similar to CTS • Tenderness on median nerve in proximal forearm • Weakness of all muscles supplied by median nv • Tinel's sign in proximal forearm- after 4-5 mths • Resisted elbow flexion in supination – at bicipital aponeurosis • Resisted pronation in elbow flexion- between 2 heads of PT • Resisted middle finger FDS contraction- at FDS arch • Pressure over pronator teres increases paraesthesia • Associated medial epicondylitis
- 46. Carpal Tunnel Syndrome vs Pronator teres syndrome CTS PTS Forearm painfree Aching over proximal volar forearm Palmar cutaneous nerve spared Palmar cutaneous territory affected Night paresthesia Lack of night symptoms Symptoms aggravate by wrist hyperflexion By forearm flexion and repititive prono-supination
- 47. Management CTS PTS • Nonoperative- successful in 50 % • Rest, splinting and NSAIDs for 3- 6 months • Avoid forearm pronation • Operative-successful in 90 % • Decompress all possible sites
- 48. ULNAR NERVE ( MUSICIAN NERVE) • ROOT VALUE : C7,C8,T1 • MUSCLE SUPPLY : FLEXOR CARPI ULNARIS FLEXOR DIGITORUM PROFUNDUS 4 PALMAR + 4 DORSAL INTEROSSEI MEDIAL 2 LUMBRICALS HYOTHENAR MUSCLES ADDUCTOR POLLICIS DEEP HEAD OF FLEXOR POLLICIS BREVIS
- 51. • 55 % cross sectional area reduction in flexion • Olecranon advances 5 mm / 45ᵒ flexion • Elongation stretch of 47 mm in flexion • Pressure 9mm Hg to 63 mm Hg, + FCU contraction= 209 mm Hg
- 52. Common sites of compression • Between 2 heads of FCU/ aponeurosis- Most common • Arcade of Struthers- 70 % incidence; 8-10 cm prox to medial epicondyle; medial head triceps medial intermuscular septum • Hiatus in medial intermuscular septum • Between Osborne ligament and MCL • Medial head triceps • Anconeus epitrochlearis- medial olecranon medial epicondyle • Fractures, malunions, Cubitus varus/valgus, Tardy ulnar palsy • Osteophytes, myositis ossificans • Tumors, cysts, medial epicondylitis • Iatrogenic- Intercondylar fixations, Radial head excision
- 54. Clinical features • Ulnar paresthesia on elbow flexion • Involvement of ulnar dorsal hand rules out Guyon canal involvement • Night symptoms due to elbow flexion • Atrophy of 1st webspace and interossei • Ulnar clawing • Weak grasp- loss of MCP flexion • Weak pinch- 70 % loss due to adductor pollicis
- 56. EARL AND VALSTOU SIGN X SIGN
- 57. • Tinel's sign over cubital tunnel • Elbow flexion X 60 s • Compression on cubital tunnel • EMG- adductor policis, FCU • Non operative management Night splint in extension and neutral rotation • Operative In-situ decompression Anterior transposition Medial epicondylectomy
- 58. Cubital tunnel decompression Medial incision 5-10 cm long Avoid too proximal release- causes ulnar subluxation Release all possible entrapping structures Best results in compression restricted to Osborne fascia Poor results Presence of muscle atrophy (chronic) Compression secondary to elbow deformity Compression by tumours and cyst
- 59. Ulnar nerve decompression and anterior transposition Indications • Failed in situ release • Intractable long standing neuritis • Throwing athlete • Metabolic/ Granulomatous neuropathy • ORIF of intra-articular fractures • Elbow reconstruction & arthroplasty Types of ulnar nerve transposition • Subcutaneous • Submuscular • Intramuscular
- 60. Medial epicondylectomy • May create valgus instabilty
- 62. BOUNDARIES • Floor- Transverse carpal ligament, hypothenar muscles • Roof- Volar carpal ligament • Ulnar border- Pisiform and pisohamate ligament, AbDM • Radial border- hook of hamate
- 63. ZONES OF GUYON’S CANAL
- 64. Etiology Anatomical • Ganglion cyst- Most common nontraumatic cause • Lipoma/ Neurilemmoma • Fibrous bands • Pisiform – hamate coalition • Accessory FDM, palmaris brevis or palmaris longus Traumatic • Nonunion or # hook of hamate • Handlebar palsy • Pisiform dislocation Systemic • Diabetes • Alcoholism • Hypothyroid Hypothenar hammer syndrome- ulnar artery thrombosis Calcinosis PVNS
- 65. Clinical features • Pure motor • Pure sensory • Mixed • Wrist pain and ulnar paresthesias/ numbness • Ulnar clawing • Intrinsic paralysis • Weak grasp and pinch • Froment sign • Bunnel O sign • Scratch collapse test
- 66. Diagnosis • Plain Xray • MRI Main DD- Cubital tunnel syndrome • Less clawing- long flexor involve • Positive elbow flexion test • Motor deficit in FDP, FCU • Sensory deficit in ulnar dorsum of hand • Tinels positive at elbow
- 67. Treatment Non operative Operative • For clawing • Loss of grasp and pinch • Local decompression incision in line radial aspect 4th digit • Done sequentially zone 123 • Tendon transfers- for claw • Lasso procedure- use FDS 4 or ECRB
- 68. RADIAL NERVE • ROOT VALVE (C5-C8,T1) • MUSCLE SUPPLY : BSG- LONG & MED. HEAD OF TRICEPS SG - LATERAL HEAD & ANCONEUS ASG- BRACHIALIS,BR,ECRL • PIN MUSCLE SUPPLY:ECRB,SUPINATOR,ED,EDM,ECU APL,EPB,EPL,EXTENSOR INDICIS
- 69. RADIAL TUNNEL SYNDROME/ SUPINATOR SYNDROME
- 70. • Combined sensory motor • Just after radial nerve splits into PIN and RSN • Not a true compressive neuropathy because Prominent focal tenderness Normal neurology No confirmatory EMG • Medial wall- Brachialis, biceps tendon • Lateral wall & roof- ECRL, ECRB, EDC • Floor- Capsule of radiocapitellar joint
- 72. Sites of compression 5 potential sites • Between brachialis and BCR • Leash of Henry • Origin of ECRB • Arcade of Frohse • Distal edge of supinator
- 73. Etiology of compression • Repetitive prono-supination • Monteggia/ radial head fractures • Space occupying lesions • Rheumatoid synovitis of radio-capitellar joint • Iatrogenic
- 74. Clinical features • Pain in forearm and wrist • Night pain • Pronation and wrist extension aggravates the pain • Motor weakness • Weakness of wrist extension in ulnar deviation- ECU • Painful resisted supination- arcade of Frohse • Painful resisted middle finger extension- ECRB and BR
- 75. Treatment • Non operative- wrist splinting in 15ᵒ extension ± elbow flexion • Avoid provocative activities • UST, Cryotherapy • Stretching ex • Local steroid injections • Operative- Resistant cases Compression by mass detected on MRI Anterior approach between brachioradialis and biceps tendon Posterior approach between ECRB and EDC or BR and ECRL All possible sites are decompressed
- 77. Cheiralgia paresthetica/ Handcuff neuropathy/ Wristwatch neuritis • Pure sensory – RSN involvement • During pronation, scissoring between BR and ECRL is main cause • Fascial bands • Trauma • Anatomic variations in BR • Lipoma • Diabetes
- 78. Clinical features • History of handcuff or tight wristwatch use • Ill defined pain over dorsoradial hand • Avoids wearing watch • Paresthesia in dorsal hand radially aggravates by wrist flexion and ulnar deviation • Tinel's sign over wrist radial styloid • Dellon’s provocative test- wrist flexion, ulnar deviation and pronation X 1 min • Finkelstein test +ve in 95 % due to traction on RSN
- 79. Treatment • Mostly nonoperative • Rarely decompression- volar to Tinels sign to protect lateral cutaneouous nerve of forearm
- 81. • Pure motor neuropathy • Thumb and finger drop • ECRL and Brachioradialis spared • Predominant medial- ECU, EDC, EDM • Predominant lateral- EPB, APL, EIP, EPL • Iatrogenic • Lipomas • Ganglion • Synovial chondromatosis • Rheumatoid arthritis
- 82. Treatment • Splint- wrist drop and finger drop splint- allows active flexion and passive extension • Surgical release in radial tunnel
- 84. • Mixed nerve, c5-c6 roots • Passes under omohyoid and anterior border of trapezius to reach suprascapular notch
- 85. Etiology • Trauma- direct injury to Erbs point, scapula #, malunion • Traction- volleyball players, scapular instability • Entrapment under scapular notch- ganglions, lipoma, synovial sarcoma, Ewings sarcoma or in spinoglenoid notch by ganglion cysts Clinical features • Vague pain in posterolateral aspect of shoulder radiates across scapula • Paresthesia and burning pain • Pain brought about by crossbody adduction and external rotation • Supraspinatus and infraspinatus atrophy in chronic
- 86. • Pure motor type seen in professional volleyball players , involvement at spinoglenoid notch and spares the sensory branch • Scapular dyskinesia Investigations • MRI • EMG Treatment Conservative: • Steroid injections • Scapular stabiliser strengthening exercises • Restrict overhead strenuous activities
- 87. Surgical management • Removal of underlying pathology • Posterior Swafford and Lichtman approach- oblique incision along spine of scapula • Trapezius elevated subperiosteally
- 89. superior - subscapularis and teres minor inferior - teres major medial - long head of triceps brachii lateral - surgical neck of the humerus QUADRILATERAL SPACE SYNDROME
- 90. Etiology of compression Compression and reduction of quadrangular space due to • Tight fibrous bands, muscular hypertrophy • Paralabral cysts (most commonly inferior labral tears) • Trauma (scapular fracture, shoulder dislocation) • Benign or malignant masses Pathomechanics • greatest amount of compression occurs when the arm is positioned in the late cocking phase of throwing (abduction and external rotation)
- 91. Clinical features • 20-40 year age • Dominant shoulder • Throwing atheletes- basketball, volleyball • Poorly localized pain of the posterior/lateral shoulder • Often worse at night • Worse with overhead activity or late cocking/acceleration phase of throwing • Non-dermatomal distribution of paraesthesia along the lateral shoulder and arm • Shoulder external rotation weakness
- 92. • Atrophy of the teres minor and deltoid (chronic) • Point tenderness over the quadrangular space • External rotation weakness with the arm abducted in throwing position • Pain exacerbated by active and resisted abduction and external rotation of the arm Neurological examination • usually normal • have mild sensory changes in the axillary nerve distribution
- 93. Investigations Xrays- shoulder series (AP, lateral, axillary views) • usually normal • used to rule out pathologic entities MRI • often used to rule out rotator cuff pathology • may show atrophy of teres minor (axillary innervation) • may show compression of the quadrilateral space • may show inferior paralabral cyst associated with labral tear Arteriogram • may shows lesion in posterior humeral circumflex artery EMG • used to confirm diagnosis • will show axillary nerve involvement
- 94. Treatment Non operative NSAIDS, activity restriction, physiotherapy • glenohumeral joint mobilization and strengthening • posterior capsule stretching • massage • most people improve with 3-6 months of nonoperative treatment Operative- open release of quadrilateral space +/- arthroscopic repair of labral tear • failure of nonoperative management • significant weakness and functional disability • decompression of space-occupying lesion
- 95. THANK YOU
Editor's Notes
- Accompanies brachial artery in the arm, crossing it during its course (lateral to medial) approximately 15 cm from the medial epicondyle Supplies some branches to the elbow joint but has no branches in the arm itself Medial to brachial artery and superficial to brachialis muscle as it passes In forearm, the median nerve splits the two heads of the pronator teres and then runs between the FDS and FDP. Supplies all the superficial flexor muscles of the forearm except the FCU. Anterior interosseous nerve branches 4 cm distal to elbow and runs between the FPL and FDP, supplies all the deep flexors except the ulnar half of the FDP. Terminates in the pronator quadratus (PQ). Palmar cutaneous branch arises approximately 6 cm proximal to radial styloid and passes superficial to the flexor retinaculum to innervate the thenar skin. Median nerve passes through the carpal tunnel between FDS and flexor carpi radialis (FCR) to supply the radial lumbricals, thenar musculature via a deep recurrent branch, and sensation to the volar aspect of thumb, index, long, and radial half of the ring fingers.
- Accompanies brachial artery in the arm, crossing it during its course (lateral to medial) approximately 15 cm from the medial epicondyle Supplies some branches to the elbow joint but has no branches in the arm itself Medial to brachial artery and superficial to brachialis muscle as it passes In forearm, the median nerve splits the two heads of the pronator teres and then runs between the FDS and FDP. Supplies all the superficial flexor muscles of the forearm except the FCU. Anterior interosseous nerve branches 4 cm distal to elbow and runs between the FPL and FDP, supplies all the deep flexors except the ulnar half of the FDP. Terminates in the pronator quadratus (PQ). Palmar cutaneous branch arises approximately 6 cm proximal to radial styloid and passes superficial to the flexor retinaculum to innervate the thenar skin. Median nerve passes through the carpal tunnel between FDS and flexor carpi radialis (FCR) to supply the radial lumbricals, thenar musculature via a deep recurrent branch, and sensation to the volar aspect of thumb, index, long, and radial half of the ring fingers.
- Accompanies brachial artery in the arm, crossing it during its course (lateral to medial) approximately 15 cm from the medial epicondyle Supplies some branches to the elbow joint but has no branches in the arm itself Medial to brachial artery and superficial to brachialis muscle as it passes In forearm, the median nerve splits the two heads of the pronator teres and then runs between the FDS and FDP. Supplies all the superficial flexor muscles of the forearm except the FCU. Anterior interosseous nerve branches 4 cm distal to elbow and runs between the FPL and FDP, supplies all the deep flexors except the ulnar half of the FDP. Terminates in the pronator quadratus (PQ). Palmar cutaneous branch arises approximately 6 cm proximal to radial styloid and passes superficial to the flexor retinaculum to innervate the thenar skin. Median nerve passes through the carpal tunnel between FDS and flexor carpi radialis (FCR) to supply the radial lumbricals, thenar musculature via a deep recurrent branch, and sensation to the volar aspect of thumb, index, long, and radial half of the ring fingers.
- Accompanies brachial artery in the arm, crossing it during its course (lateral to medial) approximately 15 cm from the medial epicondyle Supplies some branches to the elbow joint but has no branches in the arm itself Medial to brachial artery and superficial to brachialis muscle as it passes In forearm, the median nerve splits the two heads of the pronator teres and then runs between the FDS and FDP. Supplies all the superficial flexor muscles of the forearm except the FCU. Anterior interosseous nerve branches 4 cm distal to elbow and runs between the FPL and FDP, supplies all the deep flexors except the ulnar half of the FDP. Terminates in the pronator quadratus (PQ). Palmar cutaneous branch arises approximately 6 cm proximal to radial styloid and passes superficial to the flexor retinaculum to innervate the thenar skin. Median nerve passes through the carpal tunnel between FDS and flexor carpi radialis (FCR) to supply the radial lumbricals, thenar musculature via a deep recurrent branch, and sensation to the volar aspect of thumb, index, long, and radial half of the ring fingers.
- Accompanies brachial artery in the arm, crossing it during its course (lateral to medial) approximately 15 cm from the medial epicondyle Supplies some branches to the elbow joint but has no branches in the arm itself Medial to brachial artery and superficial to brachialis muscle as it passes In forearm, the median nerve splits the two heads of the pronator teres and then runs between the FDS and FDP. Supplies all the superficial flexor muscles of the forearm except the FCU. Anterior interosseous nerve branches 4 cm distal to elbow and runs between the FPL and FDP, supplies all the deep flexors except the ulnar half of the FDP. Terminates in the pronator quadratus (PQ). Palmar cutaneous branch arises approximately 6 cm proximal to radial styloid and passes superficial to the flexor retinaculum to innervate the thenar skin. Median nerve passes through the carpal tunnel between FDS and flexor carpi radialis (FCR) to supply the radial lumbricals, thenar musculature via a deep recurrent branch, and sensation to the volar aspect of thumb, index, long, and radial half of the ring fingers.