Dr. Zahoor AhmadPGR,

Paediatric surgery, SZMC/H, RYK,

Pakistan

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Spinal Nerves Spinal nerves attach to

the spinal cord via roots Dorsal root

Has only sensory neurons Attached to cord via rootlets Dorsal root ganglion

○ Bulge formed by cell bodies of unipolar sensory neurons

Ventral root Has only motor neurons No ganglion - all cell bodies

of motor neurons found in gray matter of spinal cord

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Spinal Nerves 31 pair

each contains thousands of nerve fibersAll are mixed nerves have both sensory and motor

neurons) Connect to the spinal cord Named for point of issue from the spinal cord

8 pairs of cervical nerves (C1-C8)12 pairs of thoracic nerves (T1-T12)5 pairs of lumbar nerves (L1-L5)5 pairs of sacral nerves (S1-S5)1 pair of coccygeal nerves (Co1)

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Formation of Rami Rami are lateral branches of a

spinal nerve Rami contain both sensory

and motor neurons Two major groups

Dorsal ramus○ Neurons innervate the

dorsal regions of the bodyVentral ramus

○ Larger○ Neurons innervate the

ventral regions of the body

○ Braid together to form plexuses (plexi)

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Dermatomal Map Spinal nerves indicated by capital letter and number Dermatomal map: skin area supplied with sensory

innervation by spinal nerves

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Introduction to Nerve Plexuses

Nerve plexusA network of ventral rami

Ventral rami (except T2-T12)Branch and join with one another Form nerve plexuses

○ In cervical, brachial, lumbar, and sacral regions○ No plexus formed in thoracic region of s.c.

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Branches of Spinal Nerves

Dorsal Ramus Neurons within muscles of trunk and back

Ventral Ramus (VR)Braid together to form plexuses

○ Cervical plexus - VR of C1-C4○ Brachial plexus - VR of C5-T1○ Lumbar plexus - VR of of L1-L4○ Sacral plexus - VR of L4-S4○ Coccygeal plexus -VR of S4 and S5

Communicating Rami: communicate with sympathetic chain of ganglia Covered in ANS unit

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Brachial Plexus Formed by ventral rami of

spinal nerves C5-T1 Five ventral rami form

three trunks that separate into six divisions that then form cords that give rise to nerves

Major nervesAxillaryRadialMusculocutaneousUlnarMedian

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Brachial Plexus: Axillary Nerve

Motor neurons stimulateDeltoid, teres minor

○ Abducts arm- deltoid○ Laterally rotate arm-teres

minor

Sensory neuronsSkin: inferior lateral

shoulder

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Brachial Plexus: Radial Nerve Motor components stimulate

Posterior muscles of arm, forearm, and hand○ Triceps, supinator, brachioradialis,

extensors○ Cause extension movements at elbow

and wrist, thumb movements

Sensory components Skin on posterior surface of arm and

forearm, hand

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Brachial Plexus:Musculocutaneous Nerve

Motor components stimulateFlexors in anterior upper arm:

(biceps brachii, brachialis)○ Cause flexion movements at

shoulder and elbow

Sensory: Skin along lateral surface of forearm

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Brachial Plexus: Ulnar Nerve Motor components

stimulateFlexor muscles in anterior

forearm (FCU, FDP, most intrinsic muscles of hand)

Results in wrist and finger flexion

Sensory: Skin on medial part of hand

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Brachial Plexus: Median Nerve

Motor components stimulate All but one of the flexors of the

wrist and fingers, and thenar muscles at base of thumb (Palmaris longus, FCR, FDS, FPL, pronator)

Causes flexion of the wrist and fingers and thumb

Sensory components Stimulate skin on lateral part

of hand

Dermatomes of the Posterior Arm

Dermatomes of the Anterior Arm

Etiology traffic accidents birth injuries humerus luxations brachial plexus neuritis stab and bullet wounds tumors (especially lung cancer) cervical rib, fibrous band from C7

(neurogenic thoracic outlet syndrome)

Principles of Localization

Certain sites are prone to nerve entrapments/injuriesNerve opposing bone

○ Ulnar nerve at the elbowClosed spaces

○ Carpal tunnelAdjacent 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

RadialMultiple nerves

○ Elbow flexionMusculocutaneousRadial

Brachial Plexus Injuries Upper Lesions of the Brachial

Plexus (Erb’s Palsy): resulting from excessive displacement of the head to opposite side and depression of shoulder on the same side.

This causes excessive traction or even tearing of C5 and 6 roots of the plexus. It occurs in infants during a difficult delivery or in adults after a blow to or fall on shoulder.

Effects:Motor: paralysis of the supraspinatus, infraspinatus, subclavius, biceps brachii, part of brachialis, coracobrachialis; deltoid teres minor. Sensroy: sensory loss on the lateral side

of the arm.

Deformity: waiter tip postion

a. limb will hang by the side,

b. medially rotated by sternocostal part of the pectoralis major;

c. pronated forearm (biceps paralysis)

Erb-Duchenne palsy (waiter's tip)

Lower Lesions of the Brachial Plexus

(Klumpke Palsy) traction injuries by excessive abduction of

the arm i.e. occurs if person falling from a height

clutching at an object to save himself or herself.

Can be caused by cervical rib. T1 is usually torn (ulnar and median

nerves)

Motor Effects: paralysis of all the small muscles of the hand.

Sensory effects: loss of sensation along the medial side of the arm.

deformity: claw hand caused by hyperextension of the metacarpophalangeal joints and flexion of the interphalangeal joints.

Axillary Nerve injuryCauses: crutch pressing upward into the armpit, Downward shoulder dislocationsfractures of the surgical neck of the humerus.

Motor effects: Deltoid paralysis teres minor paralysis. Sensory effects: loss of sensation at lower ½ of

deltoid Deformity: Wasting of deltoid

Radial Nerve injuryInjury in axilla : crutch pressing up into armpit drunkard falling asleep with one arm over the back of a chair.

fractures of proximal humerus.

Motor effects:paralysis of triceps Anconeus extensors of the wrist Extensors of fingers. Brachioradialis supinator muscle Deformity: Wrist and finger

drop

Sensory effects : small area of sansation

loss at arm and forearmsensory loss over lateral

part of the dorsum of the hand (lat. 3.5 fingers without distal phalynges)

Injuries at Spiral Groove

Caused by fracture shaft of humerus. Motor effects: paralysis of extensors of the wrist Extensors of fingers

Deformity: Wrist and finger drop Sensory effects: anesthesia is present over the

dorsal surface of the hand (lat. 3.5 fingers)

Median Nerve Median Nerve injuryinjury Motor effects: paralysis of pronator muscles long flexor muscles of the wrist

and fingers, Exception:a. flexor carpi ulnarisb. medial half flexor digitorum profundus.

Deformity: apelike hand apelike hand 1.thenar muscles wasted 2.thumb is laterally rotated and

adducted. 3.index and to a lesser extent

the middle fingers tend to remain straight on making

4.Weakening of lat. 2 fingers

Sensory: Sensory loss on the lat. 3.5

fingers on palmar side Sensory loss over distal

phalynges of lat. 4 fingers on dorsal surface

Ulnar nerve Ulnar nerve injuryinjury

Motor effects: paralysis of flexor carpi ulnaris medial half of the flexor digitorum

profundus All interossei 3-4 lumbricals loss of abduction and adduction of

fingers Wasting of hypothenar

Deformity: partial claw hand Sensory effects : Sensory loss over 1.5 fingers on

both surfaces

CARPAL TUNNEL TUNNEL FORMED BETWEEN THE CONCAVITY OF THE

CARPAL BONES AND A LIGAMENT THAT COVERS THIS( FLEXOR RETINACULAM)

TENDONS OF THE FLEXORS PASS THROUGH MEDIAN NERVE ALSO PASSES THROUGH CROWDED TUNNELCARPAL TUNNEL SYNDROME- CAUSED DUE TO COMPRESSION OF THE NERVE IN THE

TUNNEL- CAUSES-- 1. SWELLING OF THE TEDONS( OVERUSE)- 2. PREGNANCY( EDEMA)- 3. ARTHRITISSYMPTOMS- TINGLING OR NUMBNESS-LATERAL PART OF HAND,

WEAKNESS IN THUMB MOVEMENTTREATMENT- REST, SPLINTING,ANTI-INFLAMMATORY DRUGS,

SURGERY

Diagnosis Relies mainly on clinical examination No specific lab. Studies CT myelography MRI Nerve conduction studies

Treatment Most injuries recover without any Rx Rx is done in very highly specialized centers Surgical options

a. nerve transfers

b. nerve grafting

c. muscle transfers

d. free muscle transfers

e. neurolysis of scar around the brachial plexus in incomplete lesions.

Advances in nerve injury Rx Carlstedt obtained promising initial

results with the repair of preganglionic lesions by replanting nerve rootlets directly into the spinal cord.

This is a dramatic advance because preganglionic lesions were previously thought to be irreparable

End-to-side radial sensory to median nerve transfer has been reported to improve sensation and to relieve pain in C5 and C6 nerve root avulsion

Thank you