Brachial plexus

 plexus is a latin word meaning "braid"; axonsplexus is a latin word meaning "braid"; axons
from spinal cord levels C5-T1 are mixedfrom spinal cord levels C5-T1 are mixed
(braided) in the brachial plexus and repackaged(braided) in the brachial plexus and repackaged
into terminal branches so that each branchinto terminal branches so that each branch
contains axons from several spinal cordcontains axons from several spinal cord
segmental levelssegmental levels

 The plexus is formed by the ventral rami ofThe plexus is formed by the ventral rami of
spinal nerves C5–8 and T1.spinal nerves C5–8 and T1.
 These are the roots of the brachial plexus thatThese are the roots of the brachial plexus that
supplies the upper limb.supplies the upper limb.
 C5–8 emerge into the neck between scalenusC5–8 emerge into the neck between scalenus
anterior and medius.anterior and medius.
 T1 emerges inferior to the neck of the first rib,T1 emerges inferior to the neck of the first rib,
but joins the plexus above the apex of the lung.but joins the plexus above the apex of the lung.

 C5 and C6 form the upper trunk, C7 continuesC5 and C6 form the upper trunk, C7 continues
as the middle trunk, while C8 and T1 form theas the middle trunk, while C8 and T1 form the
lower trunklower trunk
 The trunks pass laterally and lie around theThe trunks pass laterally and lie around the
subclavian artery while passing over the first ribsubclavian artery while passing over the first rib
to enter the axilla, between the clavicle and theto enter the axilla, between the clavicle and the
scapula.scapula.

 Behind the clavicle, each trunk splits intoBehind the clavicle, each trunk splits into
anterior and posterior divisions.anterior and posterior divisions.
 These recombine to form the posterior , lateralThese recombine to form the posterior , lateral
and medial cords around the axillary arteryand medial cords around the axillary artery
 The upper roots (C5–7) tend to stay lateral, theThe upper roots (C5–7) tend to stay lateral, the
lower roots (C8,T1) tend to stay medial.lower roots (C8,T1) tend to stay medial.

 All roots contribute to the posterior cord, andAll roots contribute to the posterior cord, and
therefore also to the radial nerve.therefore also to the radial nerve.
 The median nerve is formed from both lateralThe median nerve is formed from both lateral
and medial cords, therefore also contains alland medial cords, therefore also contains all
roots.roots.

 Proximal muscles tend to be supplied by nerveProximal muscles tend to be supplied by nerve
roots that emerge from higher segments of theroots that emerge from higher segments of the
spinal cord.spinal cord.
 Distal muscles are supplied by nerves arisingDistal muscles are supplied by nerves arising
from the lower segmentsfrom the lower segments

 The five main branches of the brachial plexusThe five main branches of the brachial plexus
are median , ulnar , radial , axillary andare median , ulnar , radial , axillary and
musculocutaneous nervesmusculocutaneous nerves
 Branches from both lateral and medial cordsBranches from both lateral and medial cords
supply the pectoral muscles. After supplying thesupply the pectoral muscles. After supplying the
pectorals and contributing to the median nerve,pectorals and contributing to the median nerve,
the lateral cord becomes the musculocutaneousthe lateral cord becomes the musculocutaneous
nerve.nerve.

 subscapularis, teres major and latissimus dorsisubscapularis, teres major and latissimus dorsi
are supplied by the posterior cord, which alsoare supplied by the posterior cord, which also
gives the axillary nerve to deltoid and teresgives the axillary nerve to deltoid and teres
minor before continuing as the radial nerve.minor before continuing as the radial nerve.
 The medial cord contributes to the medianThe medial cord contributes to the median
nerve, and also gives cutaneous nerves to thenerve, and also gives cutaneous nerves to the
medial arm and forearm before continuing asmedial arm and forearm before continuing as
the ulnar nerve.the ulnar nerve.

Brachial plexusBrachial plexus

 Upper trunk injuryUpper trunk injury removes C5 and C6, whichremoves C5 and C6, which
supply the shoulder abductors and externalsupply the shoulder abductors and external
rotators, and the elbow flexors and supinators.rotators, and the elbow flexors and supinators.
Consequently, the upper limb lies at the sideConsequently, the upper limb lies at the side
adducted and internally rotated. . The elbow isadducted and internally rotated. . The elbow is
extended and pronated. The fingers may flexextended and pronated. The fingers may flex
slightly and the condition , Erb’s palsy, is oftenslightly and the condition , Erb’s palsy, is often
called ‘waiter’s tip’ palsycalled ‘waiter’s tip’ palsy

 Lower trunk injuryLower trunk injury (Klumpke’s paralysis)(Klumpke’s paralysis)
removes C8 and T1, therefore all the thenar andremoves C8 and T1, therefore all the thenar and
hypothenar muscles are affected, along with thehypothenar muscles are affected, along with the
lumbricals and interossei. The hand is flattenedlumbricals and interossei. The hand is flattened
and the fingers clawed.and the fingers clawed.

Brachial plexusBrachial plexus
 dorsal scapular,dorsal scapular,
 long thoracic,long thoracic,
 n. to subclavius,n. to subclavius,
 suprascapular,suprascapular,
 lateral and medial pectoral,lateral and medial pectoral,
 medial brachial and antebrachial cutaneous,medial brachial and antebrachial cutaneous,
 upper, middle and lower subscapular,upper, middle and lower subscapular,
 musculocutaneous,musculocutaneous,
 ulnar,ulnar,
 median,median,
 axillary,axillary,
 radialradial

Brachial plexus lesion, superior trunkBrachial plexus lesion, superior trunk
EtiologyEtiology
 traffic accidents, birth injuries; these injuries aretraffic accidents, birth injuries; these injuries are
normally combined with lesions of otherproximalnormally combined with lesions of otherproximal
structures (other trunks, root avulsions)structures (other trunks, root avulsions)
 humerus luxations (unusual, may engage distal parts ofhumerus luxations (unusual, may engage distal parts of
plexus)plexus)
 brachial plexus neuritisbrachial plexus neuritis
 stab and bullet woundsstab and bullet wounds
 tumors (especially lung cancer and metastasis of thetumors (especially lung cancer and metastasis of the
lymph nodes in the axilla)lymph nodes in the axilla)

Brachial plexus lesion, superior trunkBrachial plexus lesion, superior trunk
Clinical featuresClinical features
 weakness and/or atrophy of shoulderweakness and/or atrophy of shoulder
abduction, elbow flexion, upper arm outwardabduction, elbow flexion, upper arm outward
rotationrotation
 loss of sensation over the lateral side of theloss of sensation over the lateral side of the
upper arm and the thumbupper arm and the thumb

Brachial plexus lesion, medial trunkBrachial plexus lesion, medial trunk
EtiologyEtiology
normally combined with lesions of otherproximalnormally combined with lesions of otherproximal
plexus)plexus)
 acute idiopathic mononeuropathy (brachial plexusacute idiopathic mononeuropathy (brachial plexus
neuritis, neuralgic amyotrophy)neuritis, neuralgic amyotrophy)
lymf nodes in the axilla)lymf nodes in the axilla)

Brachial plexus lesion, medial trunkBrachial plexus lesion, medial trunk
 weakness of elbow extension, wrist flexion andweakness of elbow extension, wrist flexion and
extensionextension
 numbness and/or loss of sensation in fingers 2-numbness and/or loss of sensation in fingers 2-
33

Brachial plexus lesion, inferior trunkBrachial plexus lesion, inferior trunk
EtiologyEtiology
 cervical rib, fibrous band from C7 (neurogenic thoracic outletcervical rib, fibrous band from C7 (neurogenic thoracic outlet
syndrome)syndrome)
 traffic accidents, birth injuries. these injuries are normallytraffic accidents, birth injuries. these injuries are normally
combined with lesions of other proximalstructures (other trunks,combined with lesions of other proximalstructures (other trunks,
root avulsions)root avulsions)
 humerus luxations (unusual, may engage distal parts of plexus)humerus luxations (unusual, may engage distal parts of plexus)
 acute idiopathic mononeuropathy (brachial plexus neuritis,acute idiopathic mononeuropathy (brachial plexus neuritis,
neuralgic amyotrophy)neuralgic amyotrophy)
 tumors (especially lung cancer and metastasis of the lymf nodestumors (especially lung cancer and metastasis of the lymf nodes
in the axilla)in the axilla)

Brachial plexus lesion, inferior trunkBrachial plexus lesion, inferior trunk
 weakness and/or atrophy of intrinsic handweakness and/or atrophy of intrinsic hand
musclesmuscles
55

Brachial plexus lesion, lateral fascicleBrachial plexus lesion, lateral fascicle
EtiologyEtiology traffic accidents, birth injuries; these injuries aretraffic accidents, birth injuries; these injuries are
normally combined with lesions of other proximalnormally combined with lesions of other proximal
plexus)plexus)

Brachial plexus lesion, lateral fascicleBrachial plexus lesion, lateral fascicle
 weakness and atrophy of muscles innervated byweakness and atrophy of muscles innervated by
n.medianus and n.musculocutaneusn.medianus and n.musculocutaneus
 numbness and/or loss of sensation of fingers 1-numbness and/or loss of sensation of fingers 1-
33

Brachial plexus lesion, posterior fascicleBrachial plexus lesion, posterior fascicle
EtiologyEtiology
plexus)plexus)

Brachial plexus lesion, posterior fascicleBrachial plexus lesion, posterior fascicle
 weakness and atrophy of muscles innervated byweakness and atrophy of muscles innervated by
n.axillaris and n.radialisn.axillaris and n.radialis

Brachial plexus lesion, medial fascicleBrachial plexus lesion, medial fascicle
EtiologyEtiology
plexus)plexus)

Brachial plexus lesion, medial fascicleBrachial plexus lesion, medial fascicle
 weakness of muscles innervated by n.ulnaris andweakness of muscles innervated by n.ulnaris and
n.medianusn.medianus
55

Erb's Palsy (Brachial PlexusErb's Palsy (Brachial Plexus
Birth Palsy)Birth Palsy)
 Erb's palsy is a form of brachial plexus palsy. ItErb's palsy is a form of brachial plexus palsy. It
is named for one of the doctors who firstis named for one of the doctors who first
described this condition, Wilhelm Erb.described this condition, Wilhelm Erb.
 The brachial plexus is a network of nerves nearThe brachial plexus is a network of nerves near
the neck that give rise to all the nerves of thethe neck that give rise to all the nerves of the
arm. These nerves provide movement andarm. These nerves provide movement and
feeling to the arm, hand, and fingers. Palsyfeeling to the arm, hand, and fingers. Palsy
means weakness, and brachial plexus birth palsymeans weakness, and brachial plexus birth palsy
causes arm weakness and loss of motion.causes arm weakness and loss of motion.

 One or two of every 1,000 babies have thisOne or two of every 1,000 babies have this
condition. It is often caused when an infant'scondition. It is often caused when an infant's
neck is stretched to the side during a difficultneck is stretched to the side during a difficult
delivery.delivery.
 Most infants with brachial plexus birth palsy willMost infants with brachial plexus birth palsy will
recover both movement and feeling in therecover both movement and feeling in the
affected arm. Parents must be watchful andaffected arm. Parents must be watchful and
active participants in the treatment process toactive participants in the treatment process to
make sure their child recovers maximummake sure their child recovers maximum
function in the affected arm.function in the affected arm.

In most cases of brachial plexus birth palsy, it isIn most cases of brachial plexus birth palsy, it is
the upper nerves that are affected. This is knownthe upper nerves that are affected. This is known
as Erb's palsy. The infant may not be able toas Erb's palsy. The infant may not be able to
move the shoulder, but may be able to move themove the shoulder, but may be able to move the
fingers. If both the upper and lower nerves arefingers. If both the upper and lower nerves are
stretched, the condition is usually more severestretched, the condition is usually more severe
than just Erb's palsy. This is called a "global," orthan just Erb's palsy. This is called a "global," or
total, brachial plexus birth palsy.total, brachial plexus birth palsy.

 In general, there are four types of nerve injuries.In general, there are four types of nerve injuries.
All can occur at the same time in the sameAll can occur at the same time in the same
infant. The symptoms of a nerve injury are theinfant. The symptoms of a nerve injury are the
same (loss of feeling and partial or completesame (loss of feeling and partial or complete
paralysis), regardless of the type of injury. It isparalysis), regardless of the type of injury. It is
the severity of the injury that affects boththe severity of the injury that affects both
treatment decisions and the extent of recoverytreatment decisions and the extent of recovery
possible.possible.

NeurapraxiaNeurapraxia
 A stretch injury that "shocks," but does not tearA stretch injury that "shocks," but does not tear
the nerve is the most common type. This isthe nerve is the most common type. This is
called a neurapraxia. Normally, these injuriescalled a neurapraxia. Normally, these injuries
heal on their own, usually within 3 months.heal on their own, usually within 3 months.
 Neurapraxia can happen in adults, as well asNeurapraxia can happen in adults, as well as
infants. For example, when it happens toinfants. For example, when it happens to
football players who are injured during play, it isfootball players who are injured during play, it is
called "burners and stingers."called "burners and stingers."

NeuromaNeuroma
 A stretch injury that damages some of the nerveA stretch injury that damages some of the nerve
fibers may result in scar tissue. This scar tissuefibers may result in scar tissue. This scar tissue
may press on the remaining healthy nerve. Thismay press on the remaining healthy nerve. This
condition is called a "neuroma." Some, but notcondition is called a "neuroma." Some, but not
total, recovery usually occurstotal, recovery usually occurs

RuptureRupture
 A stretch injury that causes the nerve to be tornA stretch injury that causes the nerve to be torn
apart (ruptured) will not heal on its own. Aapart (ruptured) will not heal on its own. A
rupture happens when the nerve itself is torn.rupture happens when the nerve itself is torn.

AvulsionAvulsion
 An avulsion happens when the nerve is tornAn avulsion happens when the nerve is torn
from the spinal cord. Nerve ruptures andfrom the spinal cord. Nerve ruptures and
avulsions are the most serious types of nerveavulsions are the most serious types of nerve
injury. It may be possible to repair a rupture byinjury. It may be possible to repair a rupture by
"splicing" a donor nerve graft from another"splicing" a donor nerve graft from another
nerve of the child. It is not possible to repair annerve of the child. It is not possible to repair an
avulsion from the spinal cord. In some cases, itavulsion from the spinal cord. In some cases, it
may be possible to restore some function in themay be possible to restore some function in the
arm by using a nerve from another muscle as aarm by using a nerve from another muscle as a
donor.donor.

CauseCause
 Brachial plexus stretch injuries in newbornsBrachial plexus stretch injuries in newborns
usually occur during a difficult delivery, such asusually occur during a difficult delivery, such as
with a large baby, a breech presentation, or awith a large baby, a breech presentation, or a
prolonged labor. It may also happen when aprolonged labor. It may also happen when a
birth becomes complicated and the personbirth becomes complicated and the person
assisting the delivery must deliver the babyassisting the delivery must deliver the baby
quickly and exert some force to pull the babyquickly and exert some force to pull the baby
from the birth canal. If one side of the baby'sfrom the birth canal. If one side of the baby's
neck is stretched, the nerves may also beneck is stretched, the nerves may also be
stretched, and injury may result.stretched, and injury may result.

SymptomsSymptoms
 Weakness in one armWeakness in one arm
 Loss of feeling in the armLoss of feeling in the arm
 Partial or total paralysis of the armPartial or total paralysis of the arm

DIAGNOSISDIAGNOSIS
 A pediatrician is usually the one to make theA pediatrician is usually the one to make the
diagnosis of a brachial plexus palsy injury, baseddiagnosis of a brachial plexus palsy injury, based
on weakness of the arm and physicalon weakness of the arm and physical
examination.examination.
 Your doctor may order an x-ray or otherYour doctor may order an x-ray or other
imaging study to learn whether there is anyimaging study to learn whether there is any
damage to the bones and joints of the neck anddamage to the bones and joints of the neck and
shoulder. He or she may also do some tests toshoulder. He or she may also do some tests to
learn whether any nerve signals are present inlearn whether any nerve signals are present in
the muscle of the upper arm. These tests maythe muscle of the upper arm. These tests may
include an electromyogram (EMG) or a nerveinclude an electromyogram (EMG) or a nerve
conduction study (NCS).

TreatmentTreatment
 Because most newborns with brachial plexusBecause most newborns with brachial plexus
birth palsy recover on their own, the doctor willbirth palsy recover on their own, the doctor will
re-examine the child frequently to see if there-examine the child frequently to see if the
nerves are recovering. It may take up to 2 yearsnerves are recovering. It may take up to 2 years
for complete recovery.for complete recovery.
 Nonsurgical TreatmentNonsurgical Treatment Daily physical therapy isDaily physical therapy is
the main treatment method for Erb's palsy.the main treatment method for Erb's palsy.
Because a baby cannot move the affected arm allBecause a baby cannot move the affected arm all
alone, parents must take an active role inalone, parents must take an active role in
keeping the joints limber and the functioningkeeping the joints limber and the functioning
muscles fit.muscles fit.

 Daily physical therapy and range of motionDaily physical therapy and range of motion
exercises, done as often as possible during theexercises, done as often as possible during the
day, begin when a baby is about 3 weeks old.day, begin when a baby is about 3 weeks old.
The exercises will maintain the range of motionThe exercises will maintain the range of motion
in the shoulder, elbow, wrist, and hand. This willin the shoulder, elbow, wrist, and hand. This will
prevent the joint from becoming permanentlyprevent the joint from becoming permanently
stiff, a condition called joint contracture.stiff, a condition called joint contracture.

 Surgical TreatmentSurgical Treatment If there is no change overIf there is no change over
the first 3 to 6 months, doctors may suggestthe first 3 to 6 months, doctors may suggest
exploratory surgery on the nerves to improveexploratory surgery on the nerves to improve
the potential outcome. Nerve surgery will notthe potential outcome. Nerve surgery will not
restore normal function, and is usually notrestore normal function, and is usually not
helpful for older infants. Because nerves recoverhelpful for older infants. Because nerves recover
very slowly, it may take several months, or evenvery slowly, it may take several months, or even
years, for nerves repaired at the neck to reachyears, for nerves repaired at the neck to reach
the muscles of the lower arm and hand. Manythe muscles of the lower arm and hand. Many
children with brachial plexus injuries willchildren with brachial plexus injuries will
continue to have some weakness in the shoulder,continue to have some weakness in the shoulder,
arm, or hand. There may be surgical proceduresarm, or hand. There may be surgical procedures
that can be performed at a later date that mightthat can be performed at a later date that might

Brachial plexus

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