Dorsal scapula (C5 frequent contribution C4) - rhomboids
Long thoracic (C5,6,7) - serratus anterior
Nerve to subclavius(C5 occasional fibres from C4 & C6) -
Supprascapular (C5,6 often also C4) - supraspinatus and
Lateral cord (3 branches)
Lateral pectoral (C5,6,7) - pectoralis major and via branch to
medial pectoral supplies minor (note: called lateral pectoral because from
lateral cord, lies more medial than medial pectoral)
Musculocutaneous (C5,6,7) - coracobrachialis, biceps brachii,
brachialis, ends lateral antebrachial cutaneous nerve
Lateral root of median nerve - joins medial root of median nerve
to form median nerve
Medial cord (5 branches)
Medial pectoral nerve (C8, T1) - pectoralis minor and part of
Medial brachial cutaneous nerve (C8, T1)
Medial antebrachial cutaneous nerve (C8, T1)
Ulnar nerve (C8, T1 sometimes C7) - Flexor carpi ulnaris, FDP to
ring and little fingers, intrinsic muscles of the hand
Medial root of Median nerve - joins lateral root of median nerve
to form median nerve (see
Posterior cord (5 branches)
Upper subscapular nerve (C5,6) - subscapularis
Thoracodorasal nerve (C6,7,8) - latissimus dorsi
Lower subscapular nerve (C5,6) - also subscapularis and teres
Axillary nerve (C5,6) - deltoid and teres minor
Radial nerve (C5,6,7, T1) - triceps, anconeus, brachioradialis,
wrist and finger extensors
Mostly follow high energy injuries, classically associated with motorcycle
Most injuries are closed traction
injuries, but direct compression and penetrating injuries also occur.
Male: Female : 8:1
Mechanisms of Injury
- Crush - Caused by direct blunt trauma to the neck and upper
extremity, with or without associated injuries. The plexus is crushed between
the clavicle and the first rib.
- Traction - This is usually combined with flexion of the neck toward
the contralateral side and/or hyperextension of the arm. Caudal traction of the
arm will usually affect the upper roots and trunks. Cephalad traction will most
likely involve the lower plexus.
- Compression - From hematomas or adjacent tissue elements that have
been injured. Delayed compression from Callous in clavicular fractures or
subclavian pseudoaneuerysms has been reported.
- Penetrating injury
- Iatrogenic - directly during surgery in the region or compression/
traction in poor patient positioning
In closed injuries the position of the arm in relation to the neck and the
trunk, the velocity and magnitude of force applied to the roots and trunks are
of great importance. In most cases, these factors determine the severity of
the injury and affect the overall prognosis.
Note carefully mechanism of injury
and amount of energy transfer, ask/ look for associated high energy injuries.
Ask about recovery of function. If Horner syndrome
noted ask about
prior abnormalities of the pupils or eyelids.
Treatment thus far and patients
Expose from waist up.
At way patient undresses, observe adaption to
loss of extremity function.
Overall symmetry and obvious scars related to either the initial trauma or subsequent
Palpate supraclavicular and infraclavicular
fossae feeling for bony spurs, callus from clavicular fracture.
Palpation should also include the ipsilateral chest for
diagnosis of fractured ribs. This is important when one contemplates harvesting
of intercostal nerves as motor donors for brachial plexus reconstruction.
Document motor power using MRC
Docuument sensory loss - light touch
, two point and moving two point discrimination
Tinel sign, tap supraclavicular fossa,
a positive sign suggests root rupture as opposed to avulsion. Repeat at
subsequent examinations looking for advancement, ie nerve recovery.
pulses / perfusion, look for subclavian pseudoaneurysm (palpate, listen for
Consider angiogram if planning
brachial plexus reconstruction.
syndrome (meiosis, ptosis and anhydrosis)
C-spine - Fractures of the transverse processes might indicate avulsions of the
corresponding roots, due to the attachments of the deep cervical fascia between
the cervical roots and the transverse processes.
Shoulder - Look closely at
clavicle and scapula. Fractures of the clavicle and scapula or dissociation of
these bony structures from the thorax could indicate a worse supraclavicular injury to
CXR - Look for fractures of the ribs, because they could indicate injury to the
intercostal nerves, a potential source of motor fibres for subsequent
neurotization. Inspiration and expiration films or fluoroscopy give information
on phrenic nerve function. this is important when considering the ipsilateral
phrenic nerve as a motor donor, similarly if going to use the intercostal nerves
you want to be sure the phrenic nerve is working.
Essentially looking for root
avulsions as opposed to ruptures. (pre ganglionic vs post ganglionic)
The main advantage of the CT/myelography is the
visualization of pseudomeningoceles, which are usually the result of meningeal
tears and subsequent scarring following root avulsion. It is better to perform
the myelography at least 1 month after the injury to allow for the
pseudomeningocele to be sealed and to prevent the dye from flowing freely to the
surrounding spaces. The decision to subject a patient to an invasive procedure
such as the myelogram should be made in conjunction with the decision to
operate. The cervical CT scan might reveal the absence of
rootlets from the corresponding spinal level; this indicates root avulsion. To
better use the results of such a study, one should consider that the presence of pseudomeningoceles is strongly indicative of avulsion; however, avulsed roots
can exist despite a normal myelogram. Moreover, intact roots can exist in a
formed pseudomeningocele if the traction force is strong enough to create a
tear in the dura mater but not strong enough to avulse the root from the spinal
cord. Because neuroradiology is not pathognomonic, many authors no longer use
Magnetic Resonance Imaging
MRI has the advantage of good visualization of the brachial plexus beyond the
On the other hand, good visualization
and delineation of the intradural portion of the rootlets are difficult, mainly
because of technical deficiencies. Technically, a conventional MRI cannot
provide good anatomic depiction of root sleeves and nerves because of the
insufficient contrast between the subarachnoid space and the neural structures,
a problem caused mainly by cerebrospinal fluid pulsatility. Moreover,
correlation of the intradural surgical findings with conventional MRI studies is
not reliable in the preoperative diagnosis of root avulsions in 48-52%
of patients. This is mainly because of partial root avulsions and intradural fibrosis.
Sensitivity - 81% (up to 89%)
Specificity - 95%
Diagnostic accuracy - 92%
contrast CT/myelography provides a reliable preoperative diagnosis that
correlates with the intraoperative diagnosis in more than 95% of
Axonal discontinuity results not
only in predictable pathologic features but also in time-related electrical
changes that parallel the pathophysiology of denervation. Wallerian degeneration
results in the emergence of spontaneous electrical discharges or fibrillations
that will appear at least 3 weeks after the injury. Therefore, a needle
electromyogram should be postponed for at least that long. In addition to
denervation potentials (fibrillations), a needle electromyogram can also elicit
larger potentials (sharp positive waves). These are valuable when there is a
question whether muscle denervation is complete or if there is some attempt at
reinnervation. Needle electromyogram of the paraspinal muscles, which are
innervated by the dorsal rami of the spinal roots, should also be routinely
performed; denervation of these muscles provides strong evidence of avulsion of
the corresponding roots. On the contrary, if these muscles are electrically
intact, then the injury is most likely infraganglionic and the root is most
likely ruptured. Of course, voluntary potentials in different limb muscles
indicate some neuromuscular continuity. As Bonney and Gilliat demonstrated in
1958, in addition to motor conduction studies, sensory conduction velocities
should also be recorded to differentiate between ruptured and avulsed spinal
roots. If, in a flail anesthetic arm, normal sensory conduction velocities are
elicited, this is a bad prognostic sign that implies root avulsion, which makes
spontaneous nerve regeneration impossible.
Many surgeons find the use of intraoperative somatosensory-evoked potentials
useful to verify a suspected avulsion of a root or to determine whether
resection of a neuroma and interposition nerve grafting should be performed.
The advocates of this intraoperative electrophysiologic technique believe
that root avulsion is definitely excluded only if direct stimulation of the
individual surgically exposed cervical nerve root elicits reproducible
cortical somatosensory-evoked potentials. Others believe that intraoperative
transcranial electrical motor-evoked potentials can be of use in assessing the
connectivity of the roots to the spinal cord.
However, the false positive and false negative recordings are quite high; in
addition, this type of study is time consuming and susceptible to electrical
interferences in the operating theatre.
Treatment depends on the nature of
Treatment includes, neurolysis and/or
resection of damaged nerve with interposition nerve grafting
Root avulsions carry the worst prognosis and make the reconstruction of
the plexus more challenging. A variety of extraplexus donors should be recruited
in these cases to reconstruct the distal plexus elements. When the upper plexus
roots (C5 and C6) are avulsed from the spinal cord, reconstruction of the
shoulder and elbow function can be achieved by means of the C7 root, which can
be sacrificed. In that case, the distal targets innervated by the C7 root can be
neurotized with extraplexus motor donors. When the three upper roots (C5, C6,
and C7) are avulsed, more extraplexus motor donors are needed for
reconstruction. Intercostal nerves, if harvested properly, yield acceptable
results, especially for reconstruction of the axillary, triceps, or
Pain Management in Brachial Plexus Injuries
Injury to the brachial plexus can cause severe pain
in about 10- 20% of patients. More common in root avulsions.
Pain usually starts a few days after the pain
from the initial trauma subsides and can be intractable. It is commonly
described as continuous, burning, and compressing and is frequently located in
Limb amputation for control of pain
is controversial, because pain associated with pre ganglionic injury is not
improved by amputation. Early exploration and reconstruction of the brachial plexus, in the majority of
the cases, not only improves the function of the arm but also relieves the postavulsion pain and the pain related to the instability of the shoulder.
Terzis, Julia K. M.D., Ph.D.. Papakonstantinou, Konstantinos C. M.D., Ph.D..
The Surgical Treatment of Brachial Plexus Injuries in Adults. Plastic &
Reconstructive Surgery. 106(5):1097-1124, October 2000.