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