brachial plexus

BRACHIAL BRACHIAL PLEXUS PLEXUS

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

The plexus is formed by the ventral The plexus is formed by the ventral rami of spinal nerves C5–8 and T1. rami of spinal nerves C5–8 and T1.

These are the roots of the brachial These are the roots of the brachial plexus that supplies the upper limb.plexus that supplies the upper limb.

C5–8 emerge into the neck between C5–8 emerge into the neck between scalenus anterior and medius. scalenus anterior and medius.

T1 emerges inferior to the neck of the T1 emerges inferior to the neck of the first rib, but joins the plexus above first rib, but joins the plexus above the apex of the lung. the apex of the lung.

C5 and C6 form the upper trunk, C7 C5 and C6 form the upper trunk, C7 continues as the middle trunk, while continues as the middle trunk, while C8 and T1 form the lower trunkC8 and T1 form the lower trunk

The trunks pass laterally and lie The trunks pass laterally and lie around the subclavian artery while around the subclavian artery while passing over the first rib to enter the passing over the first rib to enter the axilla, between the clavicle and the axilla, between the clavicle and the scapula.scapula.

Behind the clavicle, each trunk splits Behind the clavicle, each trunk splits into anterior and posterior divisions.into anterior and posterior divisions.

These recombine to form the These recombine to form the posterior , lateral and medial cords posterior , lateral and medial cords around the axillary arteryaround the axillary artery

The upper roots (C5–7) tend to stay The upper roots (C5–7) tend to stay lateral, the lower roots (C8,T1) tend lateral, the lower roots (C8,T1) tend to stay medial.to stay medial.

All roots contribute to the posterior All roots contribute to the posterior cord, and therefore also to the radial cord, and therefore also to the radial nerve.nerve.

The median nerve is formed from The median nerve is formed from both lateral and medial cords, both lateral and medial cords, therefore also contains all roots.therefore also contains all roots.

Proximal muscles tend to be Proximal muscles tend to be supplied by nerve roots that emerge supplied by nerve roots that emerge from higher segments of the spinal from higher segments of the spinal cord.cord.

Distal muscles are supplied by Distal muscles are supplied by nerves arising from the lower nerves arising from the lower segmentssegments

The five main branches of the brachial The five main branches of the brachial plexus are median , ulnar , radial , plexus are median , ulnar , radial , axillary and musculocutaneous nervesaxillary and musculocutaneous nerves

Branches from both lateral and medial Branches from both lateral and medial cords supply the pectoral muscles. After cords supply the pectoral muscles. After supplying the pectorals and contributing supplying the pectorals and contributing to the median nerve, the lateral cord to the median nerve, the lateral cord becomes the musculocutaneous nerve. becomes the musculocutaneous nerve.

subscapularis, teres major and subscapularis, teres major and latissimus dorsi are supplied by the latissimus dorsi are supplied by the posterior cord, which also gives the posterior cord, which also gives the axillary nerve to deltoid and teres minor axillary nerve to deltoid and teres minor before continuing as the radial nerve.before continuing as the radial nerve.

The medial cord contributes to the The medial cord contributes to the median nerve, and also gives cutaneous median nerve, and also gives cutaneous nerves to the medial arm and forearm nerves to the medial arm and forearm before continuing as the ulnar nerve.before continuing as the ulnar nerve.

Brachial plexus Brachial plexus

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

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

Brachial plexus Brachial 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, Brachial plexus lesion, superior trunksuperior trunk

EtiologyEtiology traffic accidents, birth injuries; these traffic accidents, birth injuries; these

injuries are normally combined with lesions injuries are normally combined with lesions of otherproximal structures (other trunks, of otherproximal structures (other trunks, root avulsions)root avulsions)

humerus luxations (unusual, may engage humerus luxations (unusual, may engage distal parts of plexus)distal parts of plexus)

brachial plexus neuritisbrachial plexus neuritis stab and bullet woundsstab and bullet wounds tumors (especially lung cancer and tumors (especially lung cancer and

metastasis of the lymph nodes in the axilla)metastasis of the lymph nodes in the axilla)

Brachial plexus lesion, Brachial plexus lesion, superior trunksuperior trunk

Clinical featuresClinical features

weakness and/or atrophy of weakness and/or atrophy of shoulder abduction, elbow flexion, shoulder abduction, elbow flexion, upper arm outward rotationupper arm outward rotation

loss of sensation over the lateral side loss of sensation over the lateral side of the upper arm and the thumbof the upper arm and the thumb

Brachial plexus lesion, Brachial plexus lesion, medial trunkmedial trunk


injuries are normally combined with lesions injuries are normally combined with lesions of otherproximal structures (other trunks, of otherproximal structures (other trunks, root avulsions)root avulsions)


acute idiopathic mononeuropathy (brachial acute idiopathic mononeuropathy (brachial plexus neuritis, neuralgic amyotrophy)plexus neuritis, neuralgic amyotrophy)

stab and bullet woundsstab and bullet wounds tumors (especially lung cancer and tumors (especially lung cancer and

metastasis of the lymf nodes in the axilla)metastasis of the lymf nodes in the axilla)

Brachial plexus lesion, Brachial plexus lesion, medial trunkmedial trunk


weakness of elbow extension, wrist weakness of elbow extension, wrist flexion and extensionflexion and extension

numbness and/or loss of sensation in numbness and/or loss of sensation in fingers 2-3fingers 2-3

Brachial plexus lesion, Brachial plexus lesion, inferior trunkinferior trunk

EtiologyEtiology cervical rib, fibrous band from C7 (neurogenic cervical rib, fibrous band from C7 (neurogenic

thoracic outlet syndrome)thoracic outlet syndrome) traffic accidents, birth injuries. these injuries are traffic accidents, birth injuries. these injuries are

normally combined with lesions of other normally combined with lesions of other proximalstructures (other trunks, root avulsions)proximalstructures (other trunks, root avulsions)

humerus luxations (unusual, may engage distal humerus luxations (unusual, may engage distal parts of plexus)parts of plexus)


stab and bullet woundsstab and bullet wounds tumors (especially lung cancer and metastasis of tumors (especially lung cancer and metastasis of

the lymf nodes in the axilla)the lymf nodes in the axilla)

Brachial plexus lesion, Brachial plexus lesion, inferior trunkinferior trunk


weakness and/or atrophy of intrinsic weakness and/or atrophy of intrinsic hand muscles hand muscles

numbness and/or loss of sensation in numbness and/or loss of sensation in fingers 4-5 fingers 4-5

Brachial plexus lesion, Brachial plexus lesion, lateral fasciclelateral fascicle


injuries are normally combined with lesions injuries are normally combined with lesions of other proximal structures (other trunks, of other proximal structures (other trunks, root avulsions)root avulsions)





Brachial plexus lesion, Brachial plexus lesion, lateral fasciclelateral fascicle Clinical featuresClinical features

weakness and atrophy of muscles weakness and atrophy of muscles innervated by n.medianus and innervated by n.medianus and n.musculocutaneusn.musculocutaneus

numbness and/or loss of sensation of numbness and/or loss of sensation of fingers 1-3fingers 1-3

Brachial plexus lesion, posterior Brachial plexus lesion, posterior fasciclefascicle







Brachial plexus lesion, posterior Brachial plexus lesion, posterior fasciclefascicle


weakness and atrophy of muscles weakness and atrophy of muscles innervated by n.axillaris and n.radialisinnervated by n.axillaris and n.radialis

Brachial plexus lesion, medial Brachial plexus lesion, medial fasciclefascicle







Brachial plexus lesion, medial Brachial plexus lesion, medial fasciclefascicle


weakness of muscles innervated by weakness of muscles innervated by n.ulnaris and n.medianusn.ulnaris and n.medianus

numbness and/or loss of sensation in numbness and/or loss of sensation in fingers 4-5fingers 4-5

Erb's Palsy (Brachial Erb's Palsy (Brachial Plexus Birth Palsy)Plexus Birth Palsy)

Erb's palsy is a form of brachial plexus Erb's palsy is a form of brachial plexus palsy. It is named for one of the doctors who palsy. It is named for one of the doctors who first described this condition, Wilhelm Erb.first described this condition, Wilhelm Erb.

The brachial plexus is a network of nerves The brachial plexus is a network of nerves near the neck that give rise to all the nerves near the neck that give rise to all the nerves of the arm. These nerves provide movement of the arm. These nerves provide movement and feeling to the arm, hand, and fingers. and feeling to the arm, hand, and fingers. Palsy means weakness, and brachial plexus Palsy means weakness, and brachial plexus birth palsy causes arm weakness and loss of birth palsy causes arm weakness and loss of motion.motion.

One or two of every 1,000 babies have this One or two of every 1,000 babies have this condition. It is often caused when an infant's condition. It is often caused when an infant's neck is stretched to the side during a neck is stretched to the side during a difficult delivery.difficult delivery.

Most infants with brachial plexus birth palsy Most infants with brachial plexus birth palsy will recover both movement and feeling in will recover both movement and feeling in the affected arm. Parents must be watchful the affected arm. Parents must be watchful and active participants in the treatment and active participants in the treatment process to make sure their child recovers process to make sure their child recovers maximum function in the affected arm.maximum function in the affected arm.

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

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

NeurapraxiaNeurapraxia A stretch injury that "shocks," but does A stretch injury that "shocks," but does

not tear the nerve is the most common not tear the nerve is the most common type. This is called a neurapraxia. type. This is called a neurapraxia. Normally, these injuries heal on their own, Normally, these injuries heal on their own, usually within 3 months.usually within 3 months.

Neurapraxia can happen in adults, as well Neurapraxia can happen in adults, as well as infants. For example, when it happens as infants. For example, when it happens to football players who are injured during to football players who are injured during play, it is called "burners and stingers."play, it is called "burners and stingers."

NeuromaNeuroma A stretch injury that damages some A stretch injury that damages some

of the nerve fibers may result in scar of the nerve fibers may result in scar tissue. This scar tissue may press on tissue. This scar tissue may press on the remaining healthy nerve. This the remaining healthy nerve. This condition is called a "neuroma." condition is called a "neuroma." Some, but not total, recovery usually Some, but not total, recovery usually occursoccurs

RuptureRupture A stretch injury that causes the A stretch injury that causes the

nerve to be torn apart (ruptured) nerve to be torn apart (ruptured) will not heal on its own. A rupture will not heal on its own. A rupture happens when the nerve itself is happens when the nerve itself is torn.torn.

AvulsionAvulsion An avulsion happens when the nerve is torn An avulsion happens when the nerve is torn

from the spinal cord. Nerve ruptures and from the spinal cord. Nerve ruptures and avulsions are the most serious types of nerve avulsions are the most serious types of nerve injury. It may be possible to repair a rupture injury. It may be possible to repair a rupture by "splicing" a donor nerve graft from by "splicing" a donor nerve graft from another nerve of the child. It is not possible another nerve of the child. It is not possible to repair an avulsion from the spinal cord. In to repair an avulsion from the spinal cord. In some cases, it may be possible to restore some cases, it may be possible to restore some function in the arm by using a nerve some function in the arm by using a nerve from another muscle as a donor.from another muscle as a donor.

CauseCause

Brachial plexus stretch injuries in newborns Brachial plexus stretch injuries in newborns usually occur during a difficult delivery, usually occur during a difficult delivery, such as with a large baby, a breech such as with a large baby, a breech presentation, or a prolonged labor. It may presentation, or a prolonged labor. It may also happen when a birth becomes also happen when a birth becomes complicated and the person assisting the complicated and the person assisting the delivery must deliver the baby quickly and delivery must deliver the baby quickly and exert some force to pull the baby from the exert some force to pull the baby from the birth canal. If one side of the baby's neck is birth canal. If one side of the baby's neck is stretched, the nerves may also be 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 the A pediatrician is usually the one to make the

diagnosis of a brachial plexus palsy injury, based diagnosis of a brachial plexus palsy injury, based on weakness of the arm and physical on weakness of the arm and physical examination.examination.

Your doctor may order an x-ray or other imaging Your doctor may order an x-ray or other imaging study to learn whether there is any damage to study to learn whether there is any damage to the bones and joints of the neck and shoulder. the bones and joints of the neck and shoulder. He or she may also do some tests to learn He or she may also do some tests to learn whether any nerve signals are present in the whether any nerve signals are present in the muscle of the upper arm. These tests may muscle of the upper arm. These tests may include an electromyogram (EMG) or a nerve include an electromyogram (EMG) or a nerve conduction study (NCS).conduction study (NCS).

TreatmentTreatment Because most newborns with brachial Because most newborns with brachial

plexus birth palsy recover on their own, plexus birth palsy recover on their own, the doctor will re-examine the child the doctor will re-examine the child frequently to see if the nerves are frequently to see if the nerves are recovering. It may take up to 2 years for recovering. It may take up to 2 years for complete recovery.complete recovery.

Nonsurgical Treatment Nonsurgical Treatment Daily physical Daily physical therapy is the main treatment method for therapy is the main treatment method for Erb's palsy. Because a baby cannot move Erb's palsy. Because a baby cannot move the affected arm all alone, parents must the affected arm all alone, parents must take an active role in keeping the joints take an active role in keeping the joints limber and the functioning muscles fit.limber and the functioning muscles fit.

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

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

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brachial plexus

Health & Medicine

nerve roots

posterior cord

axillary nerve

radial nerve

ulnar nerve

medianthe medial cord

lower roots c8

lateralthe median nerve