89
Cervical plexus and cervical spinal nerves
The ventral rami of the upper cervical nerves (C1–4) form the cervical plexus.
The plexus lies close to the upper four vertebrae. The dorsal rami of C1–4
innervate the paraspinal muscles and the skin at the back of neck.
Greater auricular
Greater occipital
Lesser occipital
Supraclavicular
Transversus colli
Transverse cutaneous nerve of the neck
Intertransversarii cervicis (C2–C7)
Rectus capitis anterior (C1–3)
Rectus capitis lateralis (C1)
Rectus capitis longus (C1–3)
M. longus colli (C2–6)
Major motor nerve: phrenic nerve
Fibers from C2–C4 also contribute to the innervation of the sternocleidomas-
toid and trapezius muscles
The ansa cervicalis connects with the hypoglossal nerve.
Other communicating branches exist with caudal cranial nerves and auto-
nomic fibers, cervical vertebrae and joints, and nerve roots/spinal nerves
(C1/C2 and C3–8).
Complete cervical plexus injury:
Sensory loss in the upper cervical dermatomes. Clinical or radiological evi-
dence of diaphragmatic paralysis.
High cervical radiculopathies:
Less common, affected by facet joint. C3/4 foramen most often involved.
C2/3: site for Herpes Zoster, with post-herpetic neuralgia possible.
C2 dorsal ramus spinal nerve (or greater occipital nerve) irritation is better
labeled “occipital neuropathy”.

Operations, ENT procedures, lymph node biopsy
Trauma:
Traction injuries
History of operation. Imaging of spinal vertebral column. There are few reliable
NCV studies, except for the phrenic nerve.
Cervical radiculopathies.
Pain management, anti-inflammatory drugs, physical therapy.
Mumenthaler M, Schliack H, Stöhr M (1998) Läsionen des Plexus cervico-brachialis. In:
Mumenthaler M, Schliack H, Stöhr M (eds) Läsionen peripherer Nerven und radikuläre
Syndrome. Thieme, Stuttgart, pp 203–260
Stewart J (2000) Upper cervical spinal nerves, cervical plexus and nerves of the trunk. In:
Stewart J (ed) Focal peripheral neuropathies. Lippincott, Williams & Wilkins, Philadelphia,
pp 71–96
Symptoms
Pathogenesis
Diagnosis
Differential diagnosis
Therapy
References
91
Genetic testing NCV/EMG Laboratory Imaging Biopsy
(+) + + +
Brachial plexus
Fig. 1
. 1
Upper trunk,
2
Middle
trunk,
3

lar fracture with a pseudoar-
throtic joint. In some positions
electric sensations were elicited
due to pressure on the brachial
plexus. B A patient with arm
pain and brachial plexus lesion.
Note the mass over her right
shoulder. The biopsy showed
lymphoma. C MRI scan of a bra-
chial plexus of a 70 year old
woman, who was treated for
breast carcinoma 10 years earli-
er. Infiltration and tumor mass
in the lower brachial plexus
Fig. 3
.
Features of a long stand-
ing complete brachial plexus
lesion: A Atrophy of the left
shoulder and deltoid. B The left
hand is atrophic and less volu-
minous than the right hand. C
Left sided Horner’s syndrome.
D Trophic changes of the left
hand, glossy skin and nail and
nailbed changes
93
Fig. 4. Neurofibromatosis and
the brachial plexus. A MRI of
the nerve roots and brachial

trunk and the medial cord (median nerve muscles can be divided into two
segmental categories: some are innervated by C5–7, but most are by C8/T1).
Posterior rami of the brachial plexus:
Leave the spinal nerves and innervate paraspinal muscles.
Some nerves stem directly from the plexus:
Phrenic nerve (see also cervical plexus and mononeuropathies)
Dorsal scapular nerve (rhomboid muscles)
Long thoracic nerve (serratus anterior muscle)
Suprascapular nerve (supra and infraspinatus muscles)
Lateral cord:
Lateral pectoral nerve: upper pectoral
Musculocutaneous nerve: elbow flexors
Median nerve (C5/6)
Posterior cord:
Thoracodorsal nerve: latissimus dorsi
Axillary nerve: deltoid
Radial nerve
Medial cord:
Medial pectoral nerve: lower part of the pectoral muscle
Medial cutaneous nerve: supplying arm and forearm
Ulnar nerve
Median nerve (C8/T1)
Neck:
The interscalene triangle consists of the anterior scalene, medial scalene, and
first rib. The plexus emerges from behind the lower part of the sternocleidomas-
toid muscles, passes under the clavicle, and under the tendon of the pectoral
muscle to reach the axilla.
Anatomy
Composition of cords
Anatomically related

Cords/branches: radiation, gunshot, humeral fracture, dislocation, orthopedic,
axillary angiography, axillary (anesthetic) plexus block, neurovascular trauma,
aneurysm
Panplexopathy:
Trauma, severe traction, postanesthetic paralysis, late metastastic disease, late
radiation-induced plexopathy
Different classification:
Upper brachial plexus lesion
Lower brachial plexus paralysis
Isolated C7 paralysis
Fascicular lesions (medial, lateral and dorsal)
Complete brachial plexus lesions
Plexus lesion with or without root avulsion
Symptoms depend on the site of the lesion (supraclavicular/infraclavicular), on
the cause (traumatic versus inflammatory or neoplastic) or association with
pain, sensory, or autonomic symptoms.
Lateral cord:
Weakness of elbow flexion, forearm pronation.
Sensory loss in the anterolateral forearm. Absent or diminished biceps brachii
reflex.
Medial cord:
Weakness of finger flexion, extension and abduction, and of ulnar wrist flexion.
Sensory loss: medial arm, forearm and hand.
Posterior cord:
Weakness of arm abduction, anterior elevation and extension.
Weakness with extension of the forearm, wrist and fingers.
The sensory loss varies over the deltoid to the base of the thumb.
Complete brachial plexus lesion (see Fig. 3 through 5):
Weakness of proximal and distal muscles, including levator scapulae and
serratus anterior.

Botulinus
CMV
EBV
Herpes zoster
HIV
Lyme disease
Parvovirus
Yersiniosis
Inflammatory-immune mediated:
Immunotherapy: interferons, IL-2 therapy
Immunization, serum sickness
– Neuralgic amyotrophy (Parsonage-Turner syndrome, acute brachial neuritis):
Clinically: sudden onset and pain located in the shoulder, persisting up to
2 weeks. Weakness appears often when pain is subsiding. The distribution is in
the proximal arm with involvement of the deltoid, serratus anterior, supra/in-
fraspinatus muscles. Other muscles that may be involved include those innervat-
ed by the anterior interosseus nerve, pronator teres muscle, muscles innervated
by the musculocutaneous nerve and diaphragm. Bilateral involvement occurs in
20%. Prominent atrophy develops, but sensory loss is minor. Antecedent illness in
30% of cases: upper respiratory infection, immunization, surgery, or childbirth.
Lab: CSF normal
EMG: Neurogenic lesion in affected muscles. Abnormal lateral antebrachial
cutaneous nerve in 50% of cases. Other nerves often unremarkable.
Other nerves that may be affected include the phrenic, spinal accessory, and
laryngeal nerve.
Prognosis: improvement begins after one or more months. Ninety percent
recovery is achieved in 2–4 years.
Treatment: pain control, physiotherapy.
Childhood variant: onset at 3 years, after respiratory infection, with full
recovery.

Axillary 21 25.9
Musculocutaneous 11 13.6
Long thoracic 7 8.6
Radial 5 6.2
CN XI 4 4.9
CN VII 4 4.9
Dorsal interosseus 1 1.2
Anterior interosseus 1 1.2
Phrenic 1 1.2
Lateral antebrachial 1 1.2
cutaneous nerve
Total nerves 81
Modified from: Cruz-Martinez A, Barrio M, Arpa J (2002) Neuralgic amyotrophy: variable
expression in 40 patients. J Peripheral Nervous System 7: 198–204.
99
Genetic conditions:
Ehlers Danlos Syndrome
HNPP
Neuralgic amyotrophy
– Hereditary neuropathy with liability to pressure palsies (HNPP)
Chromosome 17p11.2-p12; dominant.
Clinically: recurrent painless brachial neuropathy. May be the only involvement.
Electrodiagnostic: Demyelination
Prognosis: Recovery is common
– Neuralgic amyotrophy (HNA1)
Chromosome 17q24-q25; dominant, distinct from HNPP.
Onset: first (occasionally congenital) to third decade.
Neurological: recurrent episodes occur over periods of years. Several years
may pass between episodes. Precipitating factors include surgery, stress, preg-
nancy, puerperium.

brachial plexopathy have weakness involving mainly the muscles innervated
by the C8–T1 roots or lower trunk. Conversely, “diffuse” involvement of the
100
plexus in some studies was equally common among patients with metastases
and patients with radiation damage (see Fig. 5).
Contrary to prior classifications, acute plexopathies may occur during radia-
tion, as an early delayed plexopathy (4 months after radiotherapy), or late (“late
delayed plexopathy”) – see above.
Also an acute ischemic plexopathy due to thrombosis of the subclavian
artery has been described. Possibly concomitant chemotherapy may enhance
the radiation toxicity.
Primary tumors of the brachial plexus:
Rare: Neurofibromas associated with NF-1 or intraneural perineuroma (local-
ized hypertrophic neuropathy) (see Fig. 4).
Hemangiopericytoma
Neural sheath tumors
Neurofibromas about 30% NF 1, dumbbell tumors
Lipoma, ganglioneuroma, myeloblastoma, lymphangioma, dermoids
Malignant neurogenic sarcomas and fibrosarcoma
Schwannoma
Iatrogenic:
Radiotherapy: most common type. Usually painless, upper plexus preferred
(see Table 6).
Surgery: Neck dissection, carotid endarterectomy. Median sternotomy: e.g.,
coronary bypass surgery (2–7%). Unilateral lower trunk/medial cord damage
(C8), sometimes bilateral. Differential diagnosis: ulnar nerve compression at the
elbow.
Orthopedic and other surgeries: shoulder dislocations (axillary nerve), crutch
use, shoulder joint replacement, shoulder arthroscopy, radical mastectomy,
upper dorsal sympathectomy, humeral neck fractures.

countries.
Most commonly affects the upper plexus: C5/6, sometimes with C7.
Less frequent: C8/T1–lower plexus. Rarely affects the whole plexus.
The diaphragm can be involved in 5% of cases, and bilateral lesions occur in
10–20%.
Risks: high birth weight, prolonged labor, shoulder dystocia, difficult forceps
delivery.
Associated features: fractures of humerus or clavicle.
Half of the patients show complete or partial improvement within 6 months.
Surgery remains controversial.
Aberrant regeneration can occur in any traumatic plexus injury, leading to
innervation of other muscle groups either with or without motor function.
Others: “Burner” syndrome
Sudden forceful depression of the shoulder, occurs in US football. Transient
sudden dysesthesia occurs in the whole limb, but may remain longer in upper
trunk distribution.
Table 6. Brachial plexopathy: metastasis versus radiation therapy (RT)
Metastatic Post-radiation
Onset: Pain in shoulder and hand (C8/T1) Onset: Paresthesia, median nerve inner-
Palpable supraclavicular mass vated hand. Slowly progressive, with or
Less than three months after RT without pain
Lower supraclavicular lesion Infraclavicular lesion
Metastases elsewhere Duration: 2–4 years
Onset: 4–41 years
Horner’s syndrome RT: 44–50 Gy
“Pancoast” symptomatology
Imaging: mass
Electrodiagnosis: Electrodiagnosis: small sensory NCVs,
Denervation Conduction block across clavicle
Myokymia

Trunk Cord Peripheral nerve
Upper Lateral Lateral antebrachial cutaneous nerve
Upper Lateral Median to first and second digit
Upper Posterior Radial to base of the thumb
Middle Posterior Posterior antebrachial cutaneous nerve
Middle Lateral Median to second digit
Middle Lateral Median to third digit
Lower Medial Ulnar to fifth digit
Lower Medial Dorsal ulnar cutaneous
Lower Medial Medial antebrachial cutaneous nerve
Motor
Upper Lateral Musculocutaneous nerve
Upper Posterior Axillary nerve
Upper Suprascapular nerve
Middle Posterior Radial nerve
Lower Medial Ulnar nerve
Other studies: F waves, spinal nerve root stimulation (electrical or magnetic), needle EMG
of distal and paraspinal muscles.
103
Brachialgias
Cervical radiculopathies
Cervical radiculopathies with root avulsion
Effort thrombosis
Myopathies
Proximal mononeuropathies: Axillary, suprascapular, long thoracic, musculo-
cutaneous
Shoulder injury:
Fracture and dislocation (axillary, suprascapular nerve)
Rotator cuff injury
Shoulder joint contractures

Muscle Nerve 24: 1451–1462
Wilbourn AJ (1992) Brachial plexus disorders. In: Dyck PJ, Thomas PK, Griffin JP, et al (eds)
Peripheral neuropathy. Saunders, Philadelphia, pp 911–950
Differential diagnosis
Therapy
Prognosis
References
104
True neurogenic TOS
Arterial TOS
Venous TOS
Nonspecific (disputed) neurologic TOS
Combinations
Droopy shoulder (see below)
Involvement of the lower trunk of the brachial plexus; young and middle aged
females, often unilateral.
Symptoms:
Paresthesias in the ulnar border of the forearm, palm, and fifth digit. Pain is
unusual, but aching of the arm may occur.
Signs:
Insidious wasting and weakness of the hand, with slow onset. Thenar muscles
(abductor pollicis brevis) are more involved than other muscles. Only mild
weakness of ulnar hand muscles. Sensory abnormalities are in lower brachial
plexus trunk distribution (ulnar nerve, medial cutaneous nerve of the forearm
and arm). Contrary to ulnar sensory loss, the fourth finger is usually not split.
Only in severe cases are intrinsic hand muscles wasted. Weakness may also
involve muscles of the flexor compartment of forearm.
Causes:
Compression by the anterior scalene muscle
Elongated transverse process (C7)

Clinically may present with weakness and pain: resulting in unilateral hand and
finger ischemia and pain.
Minor vascular
involvement results in reduced arterial pulse during hyper-
abduction of the arm.
Occurs in young athletes and swimmers, from throwing, occlusion, stenosis,
aneurysm, or pseudoaneurysm. Humeral head may compress axillary artery.
With (or without) cervical rib.
No rib changes. Symptoms, but no objective changes of TOS.
Symptoms are variable: pain and paresthesias in the lower trunk distribution,
supraclavicular tenderness.
Stable and non-progressive.
Treatment: disputed, potentially the removal of the anterior scalene muscle.
Females with low set shoulders and long necks.
Symptoms: pain and paresthesias in upper neck, shoulder, head, sometimes
bilateral.
Reduced by passive shoulder elevation, increased by downward arm traction.
Electrodiagnosis: normal.
Bonney G (1965) The scalenus medius band: a contribution to the study of the thoracic
outlet syndrome. J Bone Joint Surg Br 47: 268–272
Katirji B, Hardy RW Jr (1995) Classic neurogenic thoracic outlet syndrome in a competitive
swimmer: a true scalenus anticus syndrome. Muscle Nerve 18: 229–233
Roos DB, Hachinski V (1990) The thoracic outlet syndrome is underrated/overdiagnosed.
Arch Neurol 47: 327–330
Swift DR, Nichols FT (1984) The droopy shoulder syndrome. Neurology 34: 212–215
Thoracic outlet
syndromes: Arterial
Disputed neurogenic
TOS
Droopy shoulder

6
Femoral nerve,
7
Obturator nerve
108
Fig. 9
. 1
Lumbar plexus,
2
Sac-
ral plexus
109
Three nerve plexus are commonly termed the “lumbosacral” plexus: lumbar,
sacral and coccygeal plexus (see Fig. 7 through 10).
Formed by the ventral rami of the first to fourth lumbar spinal nerves. Rami pass
downward and laterally from the vertebral column within the psoas muscle,
where dorsal and ventral branches are formed.
The dorsal branches of L2–4 rami give rise to the femoral nerve, which
emerges from the lateral border of the psoas muscle. The femoral nerve passes
through the iliacus compartment and the inguinal ligament.
The obturator nerve arises from the ventral branches of L2–4 and emerges
from the medial border of the psoas, within the pelvis.
The lumbar plexus also gives rise to the lateral cutaneous nerve of the thigh,
the iliohypogastric, ilioinguinal, and genitofemoral nerves, and motor branches
for the psoas and iliacus muscles.
Communication with the sacral plexus occurs via the lumbosacral trunk (fibers
of L4 and all L5 rami).
The trunk passes over the ala of the sacrum adjacent to the sacroiliac joint.
The sacral plexus is formed by the union of the lumbosacral trunk and the
ventral rami of S1–S4. The plexus lies on the posterior and posterolateral walls

Lumbar plexus lesions may have pain radiating into the hip and thigh. The
motor deficit causes either loss of hip flexion, knee extension, or both. Adduc-
tors can be clinically spared, but usually show spontaneous activity in EMG.
Sensory loss is concentrated at the ventral thigh, but the saphenous nerve can
be involved. In acute lesions, patients have the hip and knee flexed.
The sacral plexus pain resembles sciatic nerve injury. Depending on the
lesion of the sacral plexus, motor symptoms are concentrated in L5, S1,
resulting in weakness of the sciatic nerve muscles. Proximal muscles that
exhibit weakness include the gluteus maximus muscle, but the gluteus medius
muscle is usually spared. Sensory symptoms may also involve proximal areas,
such as the distributions for the pudendal nerve and the posterior cutaneous
nerve of the thigh. Sphincter involvement can occur.
Metabolic:
Diabetic amyotrophy (“Bruns Garland syndrome”):
This entity has several names, including diabetic femoral neuropathy, although
usually more than the femoral nerve is affected.
Diabetic amyotrophy is usually a unilateral (but can be bilateral) proximal
plexopathy affecting the hip flexors, femoral nerve, and some adjacent struc-
tures. Vasculopathies, metabolic causes, or vasculitic changes have been de-
scribed.
A paper by Dyck (1999) summarizes the characteristic features: it typically
strikes elderly diabetic individuals between 36 and 76 years (median 65 years).
The duration of diabetes has a median of 4.1 years (range 0–36 years), HbA1c
has a median value of 7.5 (range 5–12). The CSF protein can be moderately
elevated and a mild pleocytosis may occur. All except one patient of this series
had type II diabetes.
A clinical feature is severe weight loss before the neurologic disease.
Pain is the dominant symptom, radiating into the hip or anterior thigh, and
weakness and atrophy occur. Hip flexors, gluteal muscles, and quadriceps
showed weakness, and adductors can be involved, demonstrating clearly that

the iliac arteries or distal abdominal aorta, common or internal iliac arteries.
Treatment: Percutaneous transluminal angioplasty and application of stents.
Hemorrhagic compartment syndromes:
May be caused by anticoagulants or bleeding disorders.
Most frequently the femoral nerve is affected. The proximal iliacus muscle may
also be affected by hemorrhage.
Psoas bleeding may cause lumbar plexopathy.
Treatment is not clear: operative versus non operative treatment.
Infectious:
Abscess, Lyme disease, immunizations, EBV, HIV, CMV
Bilateral lumbar and sacral plexopathy can occur in HIV.
Inflammatory-immune mediated:
Injury caused by immune vasculopathy is characterized by advanced age,
asymmetric proximal weakness, and variable sensory loss. The course is pro-
gressive over weeks and months, sometimes associated with diabetes.
Lab investigations show elevated sedimentation rate. Nerve biopsy demon-
strates inflammatory cells around small epineurial blood vessels.
Treatment with corticosteroids induces recovery.
A similar condition can be induced by vaccination and resembles serum
sickness.
112
Hypersensitivity in drug addicts using intravenous heroin can cause limb
dysfunction, bladder dysfunction, and rhabdomyolysis.
Compressive:
Lesions by compression are rare, except for tumors (especially retroperitoneal
tumors and lymphomas).
Genetic:
Neuralgic amyotrophy, HNPP
Neoplastic (predominantly sacral plexus):
Malignancy: colorectal, breast, cervical carcinomas, sarcomas, lymphomas.

Few descriptions, involving renal transplant, iliac artery used for revasculariza-
tion of the kidney, and after hip surgery.
Trauma:
Uncommon.
Exceptionally violent trauma, road accidents, falls, rarely gunshot wounds.
113
Lesions of the plexus are often associated with bony fractures of the pelvic ring
or acetabulum, or rupture of the sacroiliac joint.
Gunshot: greater chance of involving the lumbar plexus.
Most commonly, injury is secondary to double vertical fracture dislocations of
the pelvis. Resulting symptoms are in the L5 and S1 distribution with poor
recovery.
Pelvic fractures:
Classification of pelvic fractures: stable, partially stable and unstable.
Classification of sacral fractures: lateral, foraminal, transforaminal, medial
foraminal.
Fig. 11. The malignant psoas
syndrome: A Shows a CT recon-
struction; note the mass infil-
trating the psoas (normal on the
other side). B Also shows the
mass infiltrating and destroying
the psoas muscle. Clinically, the
patient had a gastrointestinal
stromal tumor and intractable
pain. She was only able to lie in
supine position with the hip and
knee flexed
Fig. 12. Autopsy site showing
large haematoma in the psoas