Peripheral Nerves Of The Upper Limb
Dr. Garima Gupta (P.T)
Lecturer SCMAT Kanpur
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Topics
Introduction Brachial plexus Anatomy Branches Lesions Individual study of upper limb nerves Long thoracic nerve Dorsal scapular nerve Suprascapular nerve Median and lateral pectoral nerves Musculocutaneous nerve Median nerve Ulnar nerve Radial nerve Cutaneous nerves of the upper limb Summary References
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Introduction
The bundle of nerve fibers found in peripheral nervous system is called peripheral nerves.
Peripheral nerves include those that supplies the skin, muscles, joints and limbs and that those supply visceral structures e.g.: heart, lung stomach etc.
The peripheral nerves comprises of 12 pairs of cranial and 31 pair of spinal nerves. The anterior primary rami of all spinal nerves join together and/or branch to form network of nerves known as plexus.
The branches arising from plexus are also termed as peripheral nerves.
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The Brachial Plexus
It’s a large network of nerve fibers (plexus). Extending from spine(C5-T1), through the neck, the
axilla and into the arm. These nerves provide movement and feeling to the arm
and hand. Through these nerves brain sends electrical signal to the
individual muscles of arm and hand.
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Anatomy
Plexus consist of Roots
Trunks
Divisions
Cords
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Roots: Constituted by anterior primary rami of spinal nerves C5, 6, 7, 8 and T1.
Prefixed Plexus Postfixed Plexus Trunks: These roots merges to form 3 trunks
Upper C5-C6
Middle C7
Lower C8-T1
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Divisions: Each trunk splits to form an anterior and posterior division.
Cords: Posterior cord by 3 posterior divisions of the trunks.
Lateral cord by anterior division of upper and middle trunks.
Medial cord by anterior division of lower trunk.
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Branches of the plexus for the upper limb
Branches of the roots Long thoracic nerve.(serratus ant.)(C5,6,7) Dorsal scapular nerve.(rhomboids)(C5)
Branches of the trunks No branches from middle and lower trunks. Suprascapular nerve. (supraspinatus and infraspinatus
muscle)(C5,6). Nerve to subclavius.(C5,6)
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Branches of the cords
Branches of the lateral cord
1. Lateral pectoral (C5,6,7)2. Musculocutaneous (C5,6,7)3. Lateral root of median (C5,6,7)
Branches of medial cord
1. Medial pectoral (C8,T1)2. Medial cutaneous nerve of arm (C8,T1)3. Medial cutaneous nerve of forearm (C8,T1)4. Ulnar (C7,8,T1)5. Medial root of median. (C8,T1)
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Branches of posterior cord
1. Upper subscapular (upper part of subscapularis) (C5,6)
2. Thoracodorasl (latissismus dorsi)(C6,7,8)
3. Lower subscapularis (lower part of subscapularis+ teres major)(C5,6)
4. Axillary (deltoid+ teres minor)(C5,6)
5. Radial (triceps+ anconeus+ extensor muscles of forearm)
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Brachial Plexus Injury
Uncommon
Serious effects
Usually closed
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Tassin – Gilbert classification :
1. C 5/6 = full recovery in 90%
2. C 5/6 + partial C 7 = full recovery in 50 – 75%
3. C 5/6/7 + partial C 8/ T 1 = full recovery in 33%
4. C 5/6/7/8 + T 1 = no chance of full recovery.
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Upper root lesion of brachial plexus
Rusksack palsy
Erb’s palsy.
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Lesion Motor deficits Sensory deficits Nerves
Erb’s Palsy
(C5,6)
Loss of abduction, flexion and rotation at shoulder ; Weak shoulder extension - deltoid, rotator cuff
Posterior and lateral aspect of arm - axillary n
Axillary, Suprascapular, Upper and Lower subscapular
Very weak elbow flexion and supination of radioulnar joint - biceps brachii &
brachialis
Radial side of Forearm- musculocutaneous n. Thumb and 1st finger - superficial br. of radial; digital
brs. - Median n.
Musculocutaneous ; Radial N. brs. to supinator & brachioradialis muscles
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Lesion Motor deficits Sensory deficits
Nerves
Erb’s palsy
Susceptible to shoulder dislocation - loss of rotator cuff muscles
Suprascapular, Upper and Lower subscapular
“Waiters Tip" position
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Lesion Motor deficits Sensory deficits Nerves
Klumke’s Palsy
(C8, T1 )
Loss of opposition of thumb -Thenar muscles
Ulnar side of forearm , hand & & ulnar 1 1/2 & digits - ulnar and medial
Thenar branch of Median nerve
Loss of adduction of thumb - Adductor pollices
Ulnar nerve
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Lesion Motor deficits Sensory deficits
Nerves
Klumpke’s Palsy
(C8, T1 )
Loss of following finger movements: abduction and adduction of MCP joints; flexion at MCP & extension of IP joints. Lumbricals & interossei
Deep branch of Ulnar & Median
Very weak flexion of PIP& DIP joints FDS and FDP
Ulnar and Median
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Long thoracic nerve (Nerve of Bell)
C 5-C7 1st the nerve lies behind the brachial plexus, and the after
perforating scalenus muscle it reaches the upper most division of the serratus anterior muscle.
It then descend and gives off fine branches to the each division of the serratus muscle.
Serratus muscle fixes the medial edge of scapula to the chest.
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Clinical picture
1. Its paralysis causes – the scapula to lift up medially from the chest.
2. Winged scapula.
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Nerve Innervation Winging Position of scapula
abduction
Long thoracic
Serr. Ant Medial Closer to midline
Decrease winging
Spinal accessory
Trapezius Lateral Away from midline
Increase winging
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Dorsal scapular nerve (nerve to rhomboids)
C5 Innervates- levator scapulae
and rhomboids.
Clinical picture
1. Mild malposition of scapula is visible.
2. Scapula slightly externally rotated and inferior angle is slightly protruded.
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Suprascapular nerve
C5-6 Innervates supraspinous,
infraspinous and ligaments and parts of the capsule of the shoulder joint.
Clinical picture
1. Atrophy2. Weakness of arm evelation(1st
15 degrees).3. Tricks movements4. Weakness of external rotation
of shd.5. Pt will not be able to scratch
themselves behind the head.
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Median and Lateral pectoral nerves
Purely motor. C5-T1 Leave the plexus anteriorly and crosses subclavian
artery and vein, pass under the clavicle and reach the anterior wall of axilla.
Innervates the pectoral muscles.
Clinical picture
1. Weakness of adduction of the arm.
2. Atrophy of the muscles.
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Musculocutaneous nerve
Mixed nerve. Main nerve of the front of the arm. It leaves the axilla, and enters the front of the arm by
piercing the coracobrachialis. In the arm it runs downwards and laterally b/w biceps
and brachialis to reach the lateral side of the tendon of biceps.
It ends by piercing the deep fascia 2 cm above the bend of forearm.
Continues below the elbow as the lateral cutaneous nerve of the forearm.
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Clinical picture
1. Weakness of all 3 muscles.
2. Sensory deficits are less than expected bz it anastomoses with superficial branch of radial nerve.
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Median (labourer’s) nerve
Front of the forearm Enters the forearm by
passing b/w the 2 heads of pronator teres.
Along with the ulnar artery it runs deep to FDS and above to FDP.
5 cm above the wrist it becomes superficial and lies b/w the tendon of FCR and FDS.
Enters the palm by passing deep to flexor retinaculum.
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Branches in the forearm1. All superficial flexors of the
forearm, except the FCU.2. Anterior interosseus branch is
given off in the upper part of the forearm. It supplies the FPL and lateral half of the FDP and pronator quadratus.
3. Palmar cutaneous branches supplies the skin over thenar eminence and the central part of the palm.
4. Articular brs are given to elbow jt and to the proximal radioulnar jt.
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Immediately below the retinaculum it divides into medial and lateral divisions.
In the carpal tunnel it lies in front of the ulnar bursa enclosing the flexor tendons.
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Lateral division gives off muscular branches to the thenar muscles and 3 digital branches for the lateral 1 ½ digits including thumb.
Out of 3 digital branches 2 supplies the thumb and 1 the lateral side of the index finger and also supplies 1st lumbricals.
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Medial division divides into 2 digital branches for 2nd and 3rd interdigital clefts supplying index, middle and ring fingers and also 2nd lumbricals.
In the hand median nerve supplies 4 ½ muscles namely abductor pollicis brevis, superficial head of FPB, opponence pollicis and 1st and 2nd lumbricals.
Palmar skin over the middle and distal phalanges of the lateral 3 ½ digits.
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Clinical picture
When lesion is at the level of elbow
1. Pronator teres syndrome
2. Paralysis of FPL, inability to flex terminal phalanx of the thumb.
3. Paralysis of pronators, forearm is kept in supinated position.
4. Loss of flexion of IP joints of index and middle fingers. (Middle finger remain straight while making fist.) (Oath hand)
5. Ape thumb deformity (thenar muscles)
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When lesion is at the level of wrist
1. Loss of opposition of the thumb.2. Ape thumb. (Simian hand)3. Paralysis of the 1st and 2nd lumbricals makes the index and middle fingers
lag behind in slowly making fist4. Index finger remain extended while clasping both hands by interlocking
fingers and thumb. Due to paralysis of both long flexors of the index finger. (Oschner’s pointing index test)
5. Positive “bottle sign”. (weakness of thumb abduction)6. Anterior interosseous nerve lesion (purely motor branch of median nerve)
supplies FPL and FDP to index and middle finger as well as pronator quadratous. lesion makes it impossible to form an even ring with those fingers ”O”. Called as ok sign. weakness of pinch grasp. There is no sensory loss present.
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Sensory disturbance The median nerve is especially
rich in autonomic fibers. therefore lesion of autonomic fibers cause autonomic disturbance like edematous changes of hands , fingers, hyperpathia, causalgia.
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Carpal tunnel syndrome
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Martin- Gruber connection- multiple communicating branches b/w median nerve (some times anterior interosseus nerve) arises and join ulnar nerve. this motor fiber communication commonly referred as martin gruber connection, estimated to be present in 17% of individuals.
It presumably explains why isolated ulnar and median nerve lesions can sometimes be unpredictable in terms of pattern of intrinsic muscle paralysis.
Riche- Cannieu connection- communication b/w cutaneous branches of median and ulnar nerve.
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Ulnar (Musician’s) nerve
At the elbow, the nerve lies behind the medial epicondyle of the humerus, enters the forearm by passing b/w the 2 heads of FCU.
In the forearm the nerve runs b/w FDP and FDS.
Enters the palm superficial to the flexor retinaculum.
At wrist ,the ulnar neurovascular bundle lies b/w FCU and FDS.
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Branches in the forearm
Muscular, to FCU and medial half of the FDP.
Cutaneous
Palmar cutaneous branch = hypothenar eminence. Dorsal cutaneous branch = proximal parts of the ulnar 2 ½
fingers and the adjoining area of the dorsum of the hand.
Articular, to elbow joint.
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In the hand In the hand, nerve enters the palm by passing superficial to
retinaculum .here it divides into its superficial and deep terminal branches.
Superficial terminal branch:
1. Muscular – palmaris brevis.2. Cutaneous -2 palmar digital nerves supply the medial 1 ½
fingers. medial branch supplies the medial side of the little
finger. lateral branch is the common palmar digital nerve. It communicates with the median nerve.
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Deep terminal branch
1. Muscular – 3 hypothenar muscles, medial two lumbricals and 8 interossei.it terminates by supplying adductor pollicis,1st palmar interossei and the deep head of FPB.
2. Articular – wrist joint.
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Clinical picture
Lesion at elbow level:
1. FCU and FDP (medial half) are paralyzed. Due to that medial border border of he hand become flattened and attempt to produce flexion results in abduction of the hand.
2. Ulnar Claw hand.3. Tardy ulnar palsy4. Cubital tunnel syndrome
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Lesion at the level of wrist
1. Ulnar tunnel palsy
2. Sensory loss of medial 1/3 of palm and medial 1/3 of fingers.
3. Unable to spread out fingers = paralysis of dorsal interossei
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Radial nerve
Largest branch of posterior cord of brachial plexus.
C 5, 6, 7, 8, T 1.
In the lower part of axilla it runs downwards .
In the upper part of humerus it passes obliquely across the back of the humerus 1st b/w the lateral and medial head of triceps and then in the shallow groove (radial/ spiral groove).
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At the lower end of the groove , 5cm below the deltoid tuberosity , the nerve pierces the lateral inter muscular septum and passes into the anterior compartment of the arm.
In the cubital fossa the nerve run in a gap b/w brachialis (medially) and brachioradialis and ECRL (laterally).
At the level of lateral epicondyle it gives off the superficial branch (sensory) and deep branch of radial nerve (posterior interosseous) (motor), which leaves the fossa by piercing the supinator muscle.
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Superficial branch:
It runs downwards and in the distal 1/3 of the forearm it crosses under the tendon of the brachioradialis muscle to go to the extensor surface, where it branches out on the dorsal surface of the wrist and the dorsum of the hand.
It gives off 4 or 5 dorsal digital nerves, supplies thumb, index finger and the medial half of the 3rd finger.
An anastomosis connects it with the dorsal branch of the ulnar nerve.
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Deep branch: It emerges from the supinator on the back of the forearm, lies b/w the superficial and deep muscles.
It supplies the extensor muscles of the forearmSuperficial muscles ECRB ED EDM ECUDeep muscles Supinator AbPL EPB EPL EI
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Clinical picture
At the level of axilla
Crutch palsy: it also involves median, axillary, and
suprascapular nerve.
In the arm
Wrist drop+ Finger drop + Thumb drop
Spiral groove: Saturday night palsy or honeymooner’s palsy.
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At the elbow
Radial tunnel syndrome: entrapment neuropathy.
In the forearm
Posterior interosseous nerve syndrome (Supinator syndrome). It’s a
pure motor syndrome. All the radial nerve innervated distal muscles
get involved. Pseudo claw hand deformity due to finger extensor
muscles weakness. Radial deviation and wrist extension is noted. Due
to ECU weakness.
Superficial radial nerve neuropathy (Cheiralgia parathesia OR
wristwatch syndrome)
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Brachial Plexus Injuries
Nerve (Segment) Motor Deficit(s) Sensory Deficits
Long Thoracic(C 5,6,7)
Winged Scapula- Serratus Anterior None
Suprascapular(C 5,6 )
Hard to start shoulder abduction - Supraspinatus
None
Axillary (C 5,6 ) Difficult abducting arm to horizontal,
Lateral side of arm below point of shoulder Loss of shoulder roundness -
Deltoid
MusculocutaneousC 5,6,(7)
Very weak flexion of elbow joint- Biceps & Brachialis
Lateral forearm
Weak supination of radioulnar joint -Biceps
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Radial
(C 5 - T1)
Drop Wrist – ECRL,ECRB,ECU Posterior lateral &arm; dorsum of hand
Difficulty making a fist - synergy between wrist extensors and finger flexors
Median
( C 5 - T1) at Elbow
Pronation of radioulnar joints- Pronator teres & quadratus
Radial portion of palm; palmar surface & tips of radial 31/2 digits
Weak wrist flexion -FCR
Weakened opposition of thumb - thenar
Ape Hand- thumb hyper extended and adducted - thenar
Papal Hand Loss of flexion of I.P. joints of thumb & fingers 1 & 2 -FPL; FDS,FDP
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Median (C 5 - T1) at Wrist
Weakened opposition of thumb - Thenar muscles
Palmar surface & tips of radial 31/2 digits “Ape Hand”- thumb hyper extended
and adducted - Thenar muscles
Ulnar (C 8, T1) at Elbow
“Clawing” of fingers 3 & 4 - MCP hyper extended; PIP Flexed - Interossei & Lumbricals
Ulnar and dorsal aspect of palm and of ulnar 1 1/2 digits Loss of abduction & adduction of M.P
joints of fingers –Interossei
Thumb - abducted and extended -AP
Loss of flexion of D.I.P. joints of fingers 4 & 5 -FDP
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Ulnar (C 8, T1) at Wrist
“Clawing” of fingers 3 & 4- M.P. joints hyper extended; P.I.P. Flexed - Interossei & Lumbricals
Ulnar and dorsal aspect of palm and of ulnar 1 1/2 digits
Loss of abduction & adduction of M.P joints of fingers – Interossei
Thumb - abducted and extended - adductor pollices
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Cutaneous nerves of the upper limb
The skin of the upper limb is supplied by 15 sets of the cutaneous nerves.
Out of these only one set (supra clavicular) is derived from the cervical plexus, and another nerve (intercostobrachial) is derived from 2nd intercostal nerve.
The remaining 13 sets are derived from the brachial plexus through the musculocutaneous, median, ulnar, axillary, and radial nerves.
Some branches arises directly from the medial cord of the plexus
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References
Gray’s anatomy Human anatomy by B. D. Chaurasia Inderbir singh Peripheral nerve lesions by Mark Mumenthaler add Hans
Schliack Physical medicine and Rehablitation by Sara. J .
Cuccrullo Oxford text book of orthopaedics and trauma Vol-3 by
Chisrtopher Bulstrode , Joseph Buckalter Text book of orthopaedics by Natarajan and Kotwal www.google.co.in
Thank you