BRACHIAL PLEXUS

PRESENTED BY,

• PUVANESWARI• THENMOLI• ROHINIE• THARSHINI

BRACHIAL PLEXUS•Formed by anterior(ventral) rami of C5 to C8, and most of the anterior ramus of T1.

•Originates from neck, passes laterally and inferiorly over rib I, and enters axilla.

•The part of brachial plexus from medial to laterally are roots, trunks, divisions, and cords.

•Proximal part is posterior to subclavian artery

•Distal part is surrounds by axilliary artery.

ROOTS

• Originates froms C5-C8 and most of T1• Receives grays rami communicates from the

symphatetic trunk.• Carry postganglionic symphatetic fibers onto

root for distribution of periphery.• Root and trunk enter posterior triangle of neck

by passing between anterior scalene and middle scalene muscles and lies between superior and posterior to subclavian artery.

TRUNKS

• C5,c6 roots pass down wards between scalenus medius and scalenus anterior muscles and unite to form SUPERIOR 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

DIVISION

• Lateral to the 1st rib , where three trunks are located behind the axillary artery ,they separate into 3 anterior and 3 posterior divisions

• The 3 anterior division form parts of brachial plexus that ultimately give rise to peripheral nerves associated with the anterior compartment of arm or forearm.

• The 3 posterior division combine to form parts of the brachial plexus that give rise to nerves associated with the posterior compartments.

CORDS

• 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

BRANCHES OF ROOTS

•Dorsal scapular nerve-(c4-c5)- levator scapulae, rhomboids (MAJOR-MINOR)•Subclavian nerve(c5-c6)- subclavian muscle•Long thoracic nerve(c5-c7)- serratus anterior muscle

PECTORAL NERVE

• 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

BRANCHES FROM CORD• Lateral cord-1)musculocutaneous nerve(c5-c7) FUNCTION:sensory for skin on lateral side of

forearm 2)lateral head of median nerve(c5-c7) FUNCTION: motor nerve for ,Pectoralis major

MEDIAL CORD.• Medial cord-1)med.ant.thoracic nerve(c8-T1) FUNCTION: Pectoralos major and minor 2)med. Cut. Nerve of arm(c8-T1) FUNCTION: Skin on medial side of distal one-third of arm 3)med.cut. Nerve of forearm(c8-T1) FUNCTION: Skin of medial side of forearm 4)ulnar nerve(c7-T1) FUNCTION: supply all intrinsic muscle of hand(except thenar muscles and 2 lateral lembricals),also carpi ulnaris and median half of flexor digitorum profundus in forearm. 5)med. Head of median nerve(c8-T1)

POSTERIOR CORD

• 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)

Lesions of brachial plexus

• Usually incomplete• Muscle paralysis• Muscle atrophy• Loss of tendon reflexes• Sensory changes• Clinical deficit involving >one spinal/peripheral

nerve

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

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

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)

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

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

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

Traumatic plexopathy

1)direct trauma2)secondary injury from damage to structures around the

shoulder and neck, such as fractures of clavicle and first rib3)iatrogenic injury as in nerve blocksEarly 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

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

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

Metastatic plexopathy

Treatment-1)Radiotherapy 2)chemotherapy 3)opioids , NSAIDs , AEDs , transcutaneous

stimulation, para sympathetic blockade, and dorsal rhijotomy

4) Surgical resection if possible

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

Erb’sparalysis•C5 -C6 •Birth injury•Arm hangs by the side+Rotatemedially •Forearm pronated+ extended•Flexed wrist + fingers•deltoid –supraspinatus–infraspinatus–biceps -

brachialis

Klumpke’sparalysis•C8 –T1•Intrinsic muscles of the hand + long flexors of

the hand ------paralysis•Claw hand = extension at MPJ + flexion at IPJ•Cervical rib can cause paralysis similar to

Klumpke’sparalysis with post-fixed T2 contribution

Winging of the scapula•Injury to the long thoracic nerve•Paralysis of serratusanterior muscle

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

DIAGONOSTIC

• 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

Diagnostic tests

• Confirm diagnosis and r/o other conditions• Reduced amplitudes of SNAPs , CMAPs• 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

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

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