The document discusses the anatomy and lesions of the brachial plexus. It begins by describing the formation and branches of the brachial plexus from the cervical spinal nerves. It then discusses various types of lesions that can occur including total plexus palsy, upper plexus paralysis (Erb's palsy), middle plexus paralysis, and lower plexus paralysis. Electrodiagnostic studies and radiological imaging that can help evaluate brachial plexus lesions are also summarized. Specific lesions involving the trunks, cords, and individual nerves are outlined. Causes of brachial plexus injuries include trauma, tumors, radiation exposure, and idiopathic neuropathies.

1. BRACHIAL PLEXUS
Anatomy &
localisation of
lesion

2. anatomy
• Formed by anterior primary rami of
c5,c6, c7,c8 and t1
• 15 cms long ,spinal column to axilla
• Divided into 5 major components-
Roots, Trunks, Divisions,Cords,and
Branches(robert taylor drinks cold beer) from
proximal to distal
• Pre fixed-c4 ,one level up
• Post fixd-T2 ,one level down

3. Anatomy of brachial plexus

6. trunks
• C5,c6 roots pass down wards between scalenus
medius and scalenus anterior muscles and unite
to form upper trunk
• C7 root pass between scalenus muscles and at
laeral border of scalenus anterior emeges as
middle trunk
• C8, T1 roots unite behind a fascial sheet (sibson”s
fascia) and beneath the subclavian artery form
lower trunk
• The three trunks traverse supraclavicular fossa
protected by cervical and scalene musculature

7. Divisions,cords
• Lateral to the 1st rib , where three trunks are
located behind the axillary artery ,they separate
into 3 anterior and 3 posterior divisions
• 3 posterior divisions unite to form posterior
cord
• Anterior divisions of upper and ,middle trunks
(C5-C7) unite to form lateral cord
• Anterior division of lower trunk forms medial
cord(C8-T1)
• Cords passes through the thoracic outlet and give
off major branches

8. Branches from roots
• Dorsal scapular nerve-(c4-c5)- levator
scapulae, rhomboids
• Subclavian nerve(c5-c6)- subclavian muscle
• Long thoracic nerve(c5-c7)- serratus anterior
muscle– isolated palsy may be a manifestation
of neuralgic amyotrophy or familial nerve
palsy

9. Branch from trunk
• Supra scapular nerve(c5-c6)- branch from
upper trunk.
• Gives branches to supraspinatus ,capsule of
shoulder joint and supplies infraspinatus

10. Pectoral nerves
• Lateral anterior thoracic nerve(c5-c7) arises
from anterior divisions of upper, middle trunks
• Medial anterior thoracic nerve(c8-T1) branch
of medial cord
• Anterior thoracic nerves(c5-T1) supplies
pectoralis major, pectoralis minor

11. BRANCHES FROM CORDS
• Lateral cord-1)musculocutaneous nerve(c5-c7)
2)lateral head of median nerve(c5-c7)
• Medial cord-1)med.ant.thoracic nerve(c8-T1)
2)med. Cut. Nerve of arm(c8-T1)
3)med.cut. Nerve of forearm(c8-T1)
4)ulnar nerve(c7-T1)
5)med. Head of median nerve(c8-T1)
• Posterior cord-
1)subscapular nerve(upper,lower)(c5-c7)
2)thoraco dorsal nerve(c5-c7)
3)axillary nerve(c5-c6)
4)radial nerve(c5-c8)

12. Lesions of brachial plexus
• Usually incomplete
• Muscle paralysis
• Muscle atrophy
• Loss of tendon reflexes
• Sensory changes
• Clinical deficit involving >one
spinal/peripheral nerve

13. Total plexus palsy
• Usually due to severe trauma
• Entire arm is paralysed
• All arm”s musculature may undergo rapid
atrophy
• Complete anesthesia of arm distal to a line
extending obliquely from tip of shoulder to
medial arm half way to elbow
• Entire upper limb is areflexic

14. Upper plexus paralysis
• Erb –duchenne palsy results from the damage to c5,c6 roots/upper trunk
• Causes- forceful separation of head and shoulder,pressure on
shoulder, fire arm recoil, birth injury, and idiopathic plexitis
• Paralysis of deltoid, biceps, brachioradialis, brachialis, and occasionally
supra spinatus,infraspinatus and sub scapularis
• Iimb is internally rotated, adducted, fore arm is extended and
pronated,palm facing out and back ward-police man”s tip position
• shoulder abduction(deltoid, supraspinatus);elbow
flexion(biceps, brachioradialis, brachialis);ext.rotation of
arm(infraspinatus);fore arm supination (biceps) are impaired
• Very proximal lesions can cause weakness of rhomboids,levator
scapulae, serratus anterior,and scalene muscles
• Sensation is usually intact, some sensory loss may occur over the outer
surface of upper arm
• Biceps, brachioradialis reflexes are depressed or absent

15. Middle plexus paralysis
• C7 root of radial nerve is involved
• Rare occurrence but occasionally with trauma
• Extensors of fore arm, hand, and finger are
paretic(triceps, anconeus, ext. carpi radialis and
ulnaris,ext. digitorum, ext. digiti
minimi,ext.pollices longus and brevis,abductor
pollicis longus,and ext.indices)
• Triceps reflex is absent
• Sensory deficit is inconsistent and patchy, may
occur over the ext. surface of fore arm and radial
aspect of dorsum of hand

16. Lower plexus paralysis
• Dejerine-klumpke -follows injury to c8,T1 roots
• Results from trauma; arm traction in abducted
position,surgical procedures for lung tumour , mass
lesion like aneurysm of aortic arch
• Weakness of wrist flexion, finger flexion, and intrinsic
muscles of hand resulting in claw hand deformity
• Sensation may be lost in medial arm ,medial fore arm
,ulnar aspect of hand
• Finger flexor reflex is lost/depressed(c8-T1)
• When T1 root is involved, sympathetic fibers destined
for superior cevical ganglion are inturrupted;ipsilatral
horner syndrome develops(ptosis, miosis,anhydrosis)

17. Lesions of lateral cord
• Surgical/local trauma
• Musculocutaneous nerve, lateral head of median
nerve are involved
• Paralysis of biceps, brachialis and coraco
brachialis,which control elbow flexion and fore arm
supination-musculocutaneous nerve
• Paresis of muscles supplied by median nerve except
intrinsic hand muscles-pronator teres, flexo carpi
radialis,flexor digitorum superficialis;(flexor nerve of
wrist)
• Biceps reflex is absent
• Sensory loss may occur lateral fore arm

18. Lesions of medial cord
• Weakness of muscles supplied by ulnar nerve and
medial head of median nerve
• ulnar muscles involved are flexor carpi ulnaris, flexor
digitorum lll and lV and ulnar intrinsic hand muscles
• Median muscles involved are abductor pollicis
brevis, superficial head of flexor pollicis
brevis, opponens pollicis, 1st and 2nd lumbricals
• With proximal lesions med. Ant. Tho. Nerve may be
injured ,paresis of pectoralis
• Finger flexor reflex is depressed
• Sensory loss over medial arm and fore arm

19. Lesions of posterior cord
• Subscapular, thoraco dorsal, axillary, and radial nerves are
involved
• Sub scapular nerve- paresis of teres
major,subscapularis(internal rotators of humerus)
• Thoraco dorsal nerve- lattismus dorsi paresis
• Axillary injury manifest as deltoid(arm abduction) and teres
minor(lateral rotation of shoulder)paresis and sensory loss
over lateral arm
• Radial injury results in paresis of elbow extension ,wrist
extension ,fore arm supination and finger extension,
sensory loss over entire extensor surface of arm and fore
arm and on the back of the hand and dorsum of first four
fingers

20. Electro diagnostic studies
• NCS,EMG
Confirming clinical diagnosis
Character of lesion
Prognosis for recovery
• Axonal loss brachial plexopathy-SNAPs, CMAPs are attenuated /lost
• Demyelinating lesions-CVs are slowed, motor evoked responses dispersed , distal latencies
prolonged
• EMG is very sensitive for detecting even mild motor fiber loss, because fibrillations potentials
develop in affected muscles by 3 wks after onset of disease
• Axonal loss plexopathy-
1)minimal lesion-SNAPs, CMAPs are unaffected, but needle ex. Shows fibrillation potentials
2)increase in severity in lesion –SNAPs become attenuated, while CMAPs are still spared
3)most severe lesions – compromise both sensory and motor responses
• In post ganglionic plexopathy numbness, sensory loss are associated with reduced/absent SNAPs
because lesion is locatd distal to DRG
• In pure radiculopathy sensory loss is found in presence of normal SNAPs

21. Radiological studies
• Plain films of neck & chest- cervical rib, long
transverse process of C7, in thoracic out let
syndrome ; lesion in pulmonary apex , erosion of
head of 1st 2nd rib , or transverse process of c7
andT1 as in pancoast”s tumor
• High resolution CT and MRI scanning useful in
detecting mass lesions of plexus and allow early
diagnosis and specific therapy
• CT guided biopsy can be used to obtain
cytological and histological material for precise
diagnosis

22. Traumatic plexopathy
1)direct trauma
2)secondary injury from damage to structures around the
shoulder and neck, such as fractures of clavicle and
first rib
3)iatrogenic injury as in nerve blocks
Early management-weakness and sensory loss depending
on part involved
if portions of plexus have been sharply transected
early repair can be done
in open injuries ,disrupted nerve elements can be
tagged for later repair , damage to vessels and lung
require immediate intervention

23. Long term management
• Sensory and motor function assessment made after the
general condition stabilization
• Neuraprxia and minimal axontmesis- return to normal
strength and sensation is expected
• Intra operative motor evoked potentials are helpful in
assessing functional state of anterior motor roots and
motor fibers
• Depending on the findings ,neurolysis, nerve grafting or
reneurotization is performed
• Joint and tendon surgeries are best performed as
secondary operations after a period of physiotherapy
• The chances of recovery are reduced if repair was delayed
for more than 6 months

24. Thoracic out let syndrome
• Compression of brachial plexus or subclavian
vessels In the space between 1st rib and the
clavicle
 Compressive factors
1) cervical rib
2)enlarged c7 transverse process
3)hypertrophied anterior scalene muscle
4)clavicular abnormalities
5)fibrous band from c7 transverse process to 1st
rib or anterior scalene muscle

25. • Vascular signs-
• recurrent coldness, cyanosis, pallor of hand;
• frank gangrene or raynaud”s phenomenon is rare;
• a bruit may be heard over supra clavicular or infra
clavicular areas, especially when arm is fully abducted
• radial pulse obliteration with arm abduction to 90
degrees, and ext. rotation ;
• vein compression results in arm edema , cyanosis, and
prominence of veins of arm and chest

26. • Neuropathic signs-
• lower trunk of plexus is involved;
• intermittent pain referred to ulnar border of hand and
medial fore arm and arm;
• paresthesias and sensory loss in same distribution;
• motor and reflex findings are those of lower plexus
palsy;
• when only c8 is involved thenar wasting and paresis
may be prominent sparing ulnar supplied muscles
• Treatment is surgical division of compression factor

27. Metastatic plexopathy
• Lung and breast carcinoma most common
• Lymphoma ,sarcoma, melanoma less common
• Tumor metastasis spread through lymphatics , most
commonly involved is adjacent to lateral group of
axillary lymph nodes,which are close to lower plexus
• Severe pain is hallmark of disease
• Signs referable to lower plexus and its divisions
• > ½ patients have horner”s syndrome
• Few may have lymphedema of hands
• Pancoast syndrome in non small cell bronchogenic
carcinoma

28. Pancoast syndrome
• Superior pulmonary sulcus tumor
• Arises from the pleural surface of apex of lung
• Grows into para vertebral space and posterior chest wall
• Invades C8 ,T1 spinal nerves , sympathetic chain, stellate
ganglion, necks of 1st 3 ribs, transverse processes and
borders of the vertebral bodies of C7 through T3
• Eventually invade spinal canal and compress the spinal cord
• Severe shoulder pain radiating to head and neck
,axilla, chest, and arm
• Pain and paresthesias of the medial aspect of arm and 4th
5th digits,
• Weakness with atrophy of intrinsic hand muscles

29. Metastatic plexopathy
• DD radiation plexopathy
Treatment-
1)Radiotherapy
2)chemotherapy
3)opioids , NSAIDs , AEDs , transcutaneous
stimulation, para sympathetic blockade, and
dorsal rhijotomy
4) Surgical resection if possible

30. Radiation –induced plexopathy
• > 6000 c GY
• Interval 3 months – 26 years , mean -6 yrs
• Limb paresthesias, and swelling.
• Pain is less severe
• Usually affects upper trunk or entire plexus
• Lower trunk relatively protected by clavicle, shorter
course
• Pathogenesis-
1)endo neural and peri neural fibrosis with obliteration
of blood vessels.
2) direct damage to myelin sheaths and axons

31. Metastatic plexopathy Radiation plexopahy
Trunks involved Lower trunk Upper trunk or entire
plexus
Duration of symptoms Short long
Onset symptoms Pain Paresthesia, weakness
EMG Myokemic discharges
Horner syndrome Common Less common
Lymphedema Less common Common

32. Idiopathic brachial plexopathy
• Arm pain , weakness
• All age groups ,3rd- 7th decades
• Men involved in vigorous activities
• Precipitating event in > ½ URI ,flu like illness
, immunisation , surgery, stress or post partum
• Familial form-AD, chr. 17q 25, episodes of
pain, paresthesias, paralysis with good
prognosis for recovery with each attack
children

33. Clinical features
• Abrupt onset of pain in shoulder, scapular area, trepezius
ridge, upper arm, fore arm ,hand;pain lasts for hours to wks and
abates gradually
• Weakness develops simultaneously progress for 2-3 wks
• O/E weakness of shoulder girdle muscles both upper &lower
plexus involved
• Arm kept in position of adduction at shoulder and flexion at elbow
• Discrete lesions of individual nerves can occur
• Can also involve cranial nerves VII and X , phrenic nerves
• Sensory loss is less common ,outer surface of upper arm , fore arm
• 1/3 rd are bilateral
• In small no. of patients diaphragm paralysis can occur

34. diagnosis
• DD – cervical radiculopathy- persistent pain
, neck stiffness, pain persists as weakness
develops, EMG increased insertional activity
and fibrillation potentials
neoplastic plexopathy- unremittingly
painful, lower plexus mostly involved
motor neuron disease- sensation is usually
spared

35. Diagnostic tests
• Confirm diagnosis and r/o other conditions
• Reduced amplitudes of SNAPs , CMAPs
• EMG absence of fibrillations because distal to DRG
• MRI of plexus – to exclude structural lesions , high T2
signal intensity , fatty atrophy of involved muscles
• Elevated liver enjymes in patients with b/l disease and
phrenic nerve involvement
• Anti ganglioside anti bodies in some
• CSF priein elevation, and oligoclonal bands in few
• Pathogenesis- ischemic /auto immune mechanism
suggested

36. Treatment
• Opioid analgesics for pain
• 2 wks course of oral prednisone is tried
• Immobilisation of arm in sling
• With onset of paralysis , exercises can prevent
contractures
• Natural course of disease is benign
• 36% recovered by one year
• 76% by the end of 2 yrs
• 89% b y the end of 3 yrs