The document summarizes key information about spinal nerves and the brachial plexus. It describes: - The anatomy of spinal nerves, including their dorsal and ventral roots and formation of rami. - The 31 pairs of spinal nerves and their names based on point of issue from the spinal cord. - How ventral rami branch and join to form the cervical, brachial, lumbar, and sacral plexuses. - The major nerves of the brachial plexus and their motor and sensory innervation, including the axillary, radial, musculocutaneous, ulnar, and median nerves. - Common injuries to spinal nerves and the brachial plexus

1. Dr. Zahoor Ahmad
PGR,
Paediatric surgery,
SZMC/H, RYK,
Pakistan

2.  Spinal nerves attach to
Spinal Nerves 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
12-2

3. Spinal Nerves
 31 pair
 each contains thousands of nerve fibers
 All 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)
12-3

4. 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 body
 Ventral ramus
○ Larger
○ Neurons innervate the
ventral regions of the
body
○ Braid together to form
plexuses (plexi)
12-4

5. Dermatomal Map
 Spinal nerves indicated by capital letter and number
 Dermatomal map: skin area supplied with sensory
innervation by spinal nerves
12-5

6. Introduction to Nerve Plexuses
 Nerve plexus
 A 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.
12-6

7.  Dorsal Ramus
Branches of  Neurons within muscles of trunk and back
 Ventral Ramus (VR)
Spinal  Braid together to form plexuses
○ Cervical plexus - VR of C1-C4
Nerves ○ 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
12-7

8. 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 nerves
 Axillary
 Radial
 Musculocutaneous
 Ulnar
 Median
12-8

9. Brachial Plexus: Axillary Nerve
 Motor neurons stimulate
 Deltoid, teres minor
○ Abducts arm- deltoid
○ Laterally rotate arm-teres
minor
 Sensory neurons
 Skin: inferior lateral
shoulder
12-9

10. 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
12-10

11. Brachial Plexus:
Musculocutaneous Nerve
 Motor components stimulate
 Flexors in anterior upper arm:
(biceps brachii, brachialis)
○ Cause flexion movements at
shoulder and elbow
 Sensory: Skin along lateral
surface of forearm
12-11

12. Brachial Plexus: Ulnar Nerve
 Motor components
stimulate
 Flexor muscles in anterior
forearm (FCU, FDP, most
intrinsic muscles of hand)
 Results in wrist and finger
flexion
 Sensory: Skin on medial
part of hand
12-12

13. 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
12-13

14. Dermatomes of the Posterior Arm

15. Dermatomes of the Anterior Arm

16. 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)

17. Principles of Localization
 Certain sites are prone to nerve
entrapments/injuries
 Nerve opposing bone
○ Ulnar nerve at the elbow
 Closed spaces
○ Carpal tunnel
 Adjacent structures
○ Median nerve at the elbow, adjacent to
the brachial artery

18. Principles of localization (cont.)
 Order in which branches arise
 Movements at specific joints
 Single nerve
○ Elbow extension
 Radial
 Multiple nerves
○ Elbow flexion
 Musculocutaneous
 Radial

19. 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.

20.  Thiscauses 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.

21. 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.

22.  Deformity:
 waiter tip postion
c. limb will hang by the side,
d. medially rotated by sternocostal part
of the pectoralis major;
e. pronated forearm (biceps paralysis)

23. Erb-Duchenne palsy (waiter's tip)

24. 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)

25. 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.

27. Axillary Nerve injury
Causes:
crutch pressing upward into the
armpit,
Downward shoulder dislocations
fractures of the surgical neck of the
humerus.

28. Motor effects:
 Deltoidparalysis
 teres minor paralysis.
Sensory effects:
 lossof sensation at lower ½ of
deltoid
Deformity:
 Wasting of deltoid

30. Radial Nerve injury
Injury in axilla :
crutch pressing up into armpit
drunkard falling asleep with
one arm over the back of a
chair.
fractures of proximal humerus.

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

32. Sensory effects :
 small area of sansation
loss at arm and forearm
 sensory loss over lateral
part of the dorsum of the
hand (lat. 3.5 fingers
without distal phalynges)

33. Injuries at Spiral Groove
 Caused by fracture shaft of humerus.
 Motor effects: paralysis of
 extensors of the wrist
 Extensors of fingers

34.  Deformity:
 Wrist and finger drop
 Sensory effects:
 anesthesia is present over the
dorsal surface of the hand (lat.
3.5 fingers)

37. Median Nerve
injury
 Motor effects: paralysis of
 pronator muscles
 long flexor muscles of the wrist
and fingers,
 Exception:
e. flexor carpi ulnaris
f. medial half flexor digitorum profundus.

38. Deformity:
apelike hand
3.thenar muscles wasted
4.thumb is laterally rotated and
adducted.
5.index and to a lesser extent
the middle fingers tend to
remain straight on making
6.Weakening of lat. 2 fingers

39. Sensory:
 Sensory loss on the lat. 3.5
fingers on palmar side
 Sensory loss over distal
phalynges of lat. 4 fingers on
dorsal surface

43. Ulnar nerve injury
 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

44. Deformity:
 partial
claw hand
Sensory effects :
 Sensory loss over 1.5 fingers on
both surfaces

48. 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 TUNNEL
CARPAL TUNNEL SYNDROME
- CAUSED DUE TO COMPRESSION OF THE NERVE IN THE
TUNNEL
- CAUSES-
- 1. SWELLING OF THE TEDONS( OVERUSE)
- 2. PREGNANCY( EDEMA)
- 3. ARTHRITIS
SYMPTOMS- TINGLING OR NUMBNESS-LATERAL PART OF HAND,
WEAKNESS IN THUMB MOVEMENT
TREATMENT- REST, SPLINTING,ANTI-INFLAMMATORY DRUGS,
SURGERY

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

50. Treatment
 Most injuries recover without any Rx
 Rx is done in very highly specialized
centers
 Surgical options
d. nerve transfers
e. nerve grafting
f. muscle transfers
g. free muscle transfers
h. neurolysis of scar around the brachial
plexus in incomplete lesions.

51. 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

52. 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

59. Thank
you