NERVES OF UPPER LIMB AND THEIR INJURIES

LEARNING OBJECTIVES

• Revise the course and branches of nerves of upper limbs• Understand Injuries associated with these nerves• Know causes and motor and sensory loss associated with

nerve injuries of upper limb• Know deformities associated with these nerves

BRACHIAL PLEXUS

• Present in neck and axilla• Formed by ventral primary rami of C5-T1 ROOTS• C5+C6=UPPERTRUNK• C7----( MIDDLE TRUNK• C8+T1 = LOWER TRUNK• All trunk divides into anterior and posterior

DIVISIONS• Anterior divisions of upper and middle trunk unite

to form LATERAL CORD• Anterior division of middle trunk continues as

MEDIAL CORD• Posterior divisions of all 3 trunk form POSTERIOR CORD

BRANCHES FROM ROOTS & TRUNKSROOTS: Dorsal scapular nerve C5, Long thoracic nerve C5,6,7

UPPER TRUNK C5 C6 Suprascapular nerve , Nerve to subclavius

BRANCHES FROM LATERAL CORD Lateral pectoral nerve Musculocutaneous nerve Lateral root of median

BRANCHES FROM MEDIAL CORD Medial pectoral nerve Medial cutaneous nerve of arm and

forearm Ulnar nerve Medial root of median

BRANCHES FROM POSTERIOR CORD Upper and lower subscapular nerves Thoracodorsal Axillary nerve Radial nerve

BRACHIAL PLEXUS INJURIES

1. Upper lesions of brachial plexus Erb duchenne palsy

2. Lower lesions of brachial plexus Klumpke palsy

UPPER LESION OF BRACHIAL PLEXUS• Traction or even tearing of C5 and C6 root• Cause: • Excessive displacement of head to opposite side

and depression of shoulder on same side• In infants during a difficult delivery • In adults following a fall on or a blow to the

shoulder

Nerves involved: Supra scapular nerve, Nerve to Subclavius Musculocutaneous nerve ,Axillary nerve

MUSCLES AND FUNCTIONS LOST

Lateral rotation of arm: • Teres minor• Infraspinatus

Abduction of shoulder• Supraspinatus• Deltoid

Flexion of shoulder: • corobrachialis• Biceps brachii

Flexion of elbow:• Brachialis• Biceps brachii

Supination of forearm• Biceps brachii

ERB’S PALSY (UPPER TRUNK INJURY)• Loss of muscle function innervated by C5 and C6• Also known as waiter’s tip or policeman’s tip• Arm medially rotated, adducted, hangs by side• Forearm extended and pronated

LOWER LESIONS OF BRACHIAL PLEXUS• Fibers of C8 and mostlyT1 root are torn

Cause:Excessive abduction of arma) Birth injury in breech deliveryb) Person falling from a height clutching an object to

save himselfCompression of lower trunka) Cervical ribb) Malignant mets in lower deep cervical lymph nodes

Nerves involved T1 fibers run in ulnar and median nerveMuscles involved All small muscles of the hand( interossei and lumbricals)Sensory loss along the medial side of forearm

KLUMPKE,S PALSY• Clawed hand

• Hyperextension of metacarpophalangeal joint----- by unopposed extensor digitorum

• Flexion at interphalangeal joint by unopposed flexor digitorum superficialis and profundus

LONG THORACIC NERVE

• Arise from roots c5 , c6 and c7Muscles involved

Serratus anteriorFunctions lost

Abduction above 90 degreesCauses:• Blows or pressure in posterior triangle of neck• In radical mastectomyDeformity Winging of scapula vertebral border and inferior angle of scapula unduly prominent

AXILLARY NERVE• From posterior cord• Important landmarks• Axilla quadrangular space scapular region• In quadrangular space----close relation with shoulder joint

and surgical neck of humerus• Terminates by dividing into anterior and posterior branches

AXILLARY NERVE INJURY• Arise from posterior cord of brachial plexus

Causesa. Fracture of surgical neck of humerusb. Inferior dislocation of shoulder jointc. Pressure of badly adjusted crutch upward into armpitd. Misplaced injection into deltoid

Muscles involved Deltoid Teres minor

Sensory loss Upper lateral cutaneous nerve of arm Loss of skin sensation over the lower half of deltoid muscle

RADIAL NERVE

• Largest branch of plexus• From posterior cord• Arise in axilla ---( spiral groove -( lateral

intermuscular septum -( front of lateral epicondyle -( divides into superficial and deep

• Superficial --( lateral side of radial artery posterior surface of wrist

• Deep branch supinator neck of radius posterior surface of wrist

RADIAL NERVEBranches in axilla• Posterior cutaneous nerve of ARM• Nerve to long head of triceps• Nerve to medial head of triceps

Branches in spiral groove• Lower lateral cutaneous nerve of arm• Posterior cutaneous nerve of forearm• Nerve to lateral head of triceps• Nerve to medial head of tricepsBranches in anterior compartment of arm:• Nerve to small part of brachialis• Nerve to brachioradialis• Nerve to extensor carpi radialis longus

Branches in cubital fossa:• Deep branch of radial nerve to extensor carpi radialis brevis, supinator

and all muscles in posterior compartment of forearm• Superficial branch provides sensation to dorsum of hand and dorsum ofBranches in distal fore arm• Palmar cutaneous branch----skin on lateral side of palmBranches in palm• Muscle of thenar eminence• First 2 lumbricals • Skin of palmar surface of lateral 3 ½ fingers• lateral 3 ½ fingers

RADIAL NERVE INJURIES IN AXILLACauses• Pressure of badly fitted crutch into armpit• Falling asleep with arm over the back of chair------

Saturday night palsyMotor loss:• Extension at elbow----- paralysis of triceps and

anconeus• Extension of wrist and fingers-----paralysis of

extensors of wrist and all muscles of posterior compartment

• Supination----can still be performed by

• Deformity known as WRIST DROP -----flexion of wrist as a result of action of unopposed flexors of wrist and fingers

Sensory loss• posterior surface of arm and fore arm• Dorsum of hand and dorsal surface of lateral 3 ½ fingers

RADIAL NERVE INJURY IN SPIRAL GROOVE• Most commonly in distal part of groove beyond the

origin of nerves to triceps and anconeus and cutaneous nerves

Causes:• Fracture of shaft of humerus• Prolonged pressure on the back of arm as in• Unconscious patient by edge of operating table• Prolonged application of tourniquet in thin lean

personMotor loss: Extension of wrist, fingers and thumb Elbow extension is sparedSensory loss:• Dorsum of hand and dorsum of lateral 3 ½ fingers• Sensations on posterior arm and forearm are spared

MEDIAN NERVE

Formed in axilla by lateral and medial roots from respective cords

Anterior compartment of arm ---- crosses brachial artery from lateral to medial

At elbow crossed by bicipital aponeurosis Passes between 2 heads of pronator teres to enter

forearm At wrist at lateral border of flexor digitorum

profundus Enter palm beneath flexor retinaculum

Branches in axilla and arm no branches

Branches in proximal forearm To all anterior compartment muscles except flexor carpi ulnaris and

medial half of flexor digitorum profundus

Branches in distal fore arm Palmar cutaneous branch----skin on lateral

side of palmBranches in palm

Muscle of thenar eminence First 2 lumbricals Skin of palmar surface of lateral 3 ½ fingers

INJURY TO MEDIAN NERVE AT ELBOWCause:• Supracondylar fracture of humerusMotor loss• Loss of pronator of forearm• Loss of long flexors of wrist and fingers except medial half of flexor

digitorum profundus and flexor carpi ulnaris• Loss of flexion of terminal phalanx of thumb• Loss of thenar muscles (wasted)

Deformity:Forearm ----supinatedWrist----flexion is weak accompanied by adductionFingers----no flexion of interphalangeal joint of index and middleThumb---flexion, abduction and opposition is lostAPE’S HAND----thumb laterally rotated adducted and thenar

eminence flattened

Sensory loss• Lateral side of palm• Palmar surface of lateral 3 ½ fingers• Distal part of dorsal surface of lateral 3 ½ fingers

INJURY TO MEDIAN NERVE AT WRIST• Most common injury of median nerveCauses• Due to penetrating injuries or stab wound at the wristMotor loss• Muscle of thenar eminence• First two lumbricalsDeformity APE’S HANDSensory loss• Same as in elbow lesion

INJURY TO MEDIAN NERVE IN CARPAL TUNNEL• Carpal tunnel---Osseo fibrous space formed by anterior concave

surface of carpus and flexor retinaculum• Passage of long flexor tendon and median nerve

Syndrome is caused by compression of median nerve due t o reduced size of canal

Causes• Inflammation of retinaculum• Arthritis of carpal bones• Inflammation of synovial sheaths of flexor tendons

Sensory and motor Loss:• Pain and paraesthesia of lateral one and half finger• Weakness of thenar muscle

ULNAR NERVE• Arise from medial cord in axilla• Descends between axillary artery and vein• In anterior compartment of arm on medial side of brachial

artery• Pierces medial intermuscular septum to enter in posterior

compartment• At elbow lies behind medial epicondyle• Enter forearm between 2 heads of flexor carpi ulnaris• At wrist between tendons of flexor carpi ulnaris and

digitorum profundus• Enter palm superficial to flexor retinaculum

Branches in axilla or arm• No branchesBranches in proximal forearm• Nerve to flexor carpii ulnaris• Medial half of flexor digitorum profundusBranches in distal forearm• Palmar cutaneous branch -----skin of

hypothenar eminence

• Posterior cutaneous branch----skin of medial third of dorsum of hand and dorsal side of medial one and half finger

Branches in palm• Superficial branch of ulnar---- skin of palmar surface of medial one and

half finger

• Deep branch of ulnar• All small muscles of hand except of thenar muscles and first 2 lumbricals

ULNAR NERVE INJURY AT THE ELBOW• Most commonly injured at this siteCause• Fracture of medial epicondyleMotor loss• Flexor carpi ulnaris and medial half of flexor digitorum

profundus• Small muscle of hand are paralyzed except thenar

muscles and first 2 lumbricalsDeformity• Wasting of ulnar border of forearm• Terminal phalanges of little and ring finger can not be flexed• Inability to abduct and adduct fingers• Loss of adduction of thumb• Forment’s sign flexion of terminal phalanx of thumb while attempting

adduct the thumb in ulnar nerve palsy• CLAW HANDa. Metacarpophalangeal joints of fourth and fifth finger are hyper

extendedb. Interphlangeal joint of fourth and fifth fingers are flexed

• Flattening of hypothenar eminence

• Hollowing between metacarpals on dorsum of hand due to paralysis of dorsal interossei

Sensory loss

• Anterior and posterior surfaces of medial half of hand and medial one and half fingers

ULNAR NERVE INJURY AT WRIST• Due to superficial positionCauses• Penetrating wounds

Motor loss• Small muscles of hand except those of thenar

eminence and first 2 lumbricals Deformity• Claw hand more prominent

Sensory loss• On the medial side of palm and palmar and dorsal surface of 1 ½ fingers• Sensation on posterior medial surface of hand is intact

summary

• Erb’s palsy------upper trunk

• Klumpke’s palsy---- lower trunk

• Winging of scapula---- long thoracic nerve

• Ape’ s hand---- median nerve---- supracondylar fracture

• Wrist drop------ Radial nerve---fracture of spiral groove

• Claw hand-----ulnar nerve----- fracture of medial epicondyle