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”. Cervical plexopathies: Rarely affected in traction injuries, and usually in conjunction with the upper trunk of the brachial plexus. Findings include sensory loss in the upper cervical Genetic testing NCV/EMG Laboratory Imaging Biopsy ++ Anatomy Cutaneous nerves Muscle branches Clinical picture 90 dermatomes and radiologic evidence of diaphragmatic paralysis (phrenic nerve). Cervicogenic headache (controversial): Although often cited, the evidence for this condition is unconvincing. Lesser occipital nerve: Damaged in the posterior triangle of the neck (e.g., lymph node biopsy). Causes numbness behind the ear. Neck tongue syndrome: Damage to the C2 ventral ramus causes occipital numbness and paraesthesias of the tongue when turning the head. Presumably there are connections be- tween the trigeminal and hypoglossal nerve. Nervus auricularis magnus (greater): Traverses the sternocleidomatoid and the angle of the jaw. Injury causes transient numbness and unpleasant paraesthesias in and around the ear. Injury can occur during face-lift surgery, carotid endarterectomy, and parotid gland surgery (injury to the terminal branches). Occipital neuralgia/neuropathy: Accidents, whiplash, fracture dislocation, subluxation in RA, spondylitic changes, neurofibroma at C2. Iatrogenic: 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 Lower trunk, 4 Lateral cord, 5 Posterior cord, 6 Medial cord, 7 Ulnar nerve, 8 Radial nerve, 9 Median nerve, 10 Me- dial brachial cutaneus nerve, 11 Medial antebrachial cutaneus nerve, 12 Cervical plexus 92 Fig. 2 . Various types of me- chanical pressure exerted on the brachial plexus: A Clavicu- 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 plexus. Note tumorous enlarge- ment of nerve roots and C bra- chial plexus. B Note the palpa- ble supraclavicular mass Fig. 5. Radiation injury of the brachial plexus: the upper pic- ture shows the damaged skin after radiation therapy. The right hand is atrophic and has trophic skin changes. The finger movements were spontaneous and due to continuous muscle fiber activity after radiation of the brachial plexus 94 The trunks of the brachial plexus are formed by the union of the ventral rami of spinal nerves C5 to C8. The three trunks bifurcate into anterior and posterior divisions. The ventral rami from C5 and C6 fuse to form the upper trunk, those from C8 and T1 the lower trunk and the continuation of the ventral C7 fibers form the middle trunk. The trunks branch and reassemble to form the anterior, medial, and posterior cords (see Fig. 1). The three major nerves of the brachial plexus: a) The radial nerve is a continuation of the posterior cord and receives contri- butions from C5–8. b) The ulnar nerve’s fibers stem from C8 and T1 via the lower trunk and the medial cord. c) The median nerve has two components: The lateral part, which is mainly sensory, is derived from C5/6 (via the upper trunk and lateral cord) and some C7 fibers. The medial part (all motor) is from C8 and T1 ventral rami, via the lower 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 structures 95 T 1: Lung apex and first part of the lower trunk. The lower trunk curves over the first rib. Subclavian vessels (artery, vein). Various classifications of brachial plexus divisions: a) Interscalene triangle b) Clavicle c) First rib Supraclavicular Infraclavicular Supraclavicular: Preganglionic and postganglionic Supraclavicular: Upper plexus: incomplete traction, obstetric palsy, brachial plexus neuropathy Lower plexus: metastatic tumors (e.g., pancoast), poststernotomy, thoracic outlet syndrome (TOS), surgery for TOS Fig. 6. Traumatic lesion of the left brachial plexus. Note the deltoid muscle and muscles fix- ing the scapula are intact. Atro- phy of the lower arm and hand muscles. Note the inward rota- tion of the left hand while standing Lesions of the brachial plexus 96 Infraclavicular: 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. Sensory: complete loss in affected areas, often with pain. Root avulsion: Clinically: Functional loss may affect the entire limb. Sweating is intact, with severe burning, paralysis of serratus anterior, rhomboid and paraspinal mus- cles. Associated with Horner’s syndrome (if appropriate root is damaged). Tinel’s sign can be elicited in the supraclavicular region. The neurologic examination may show signs of an associated myelopathy. Radiographs may show fracture of transverse process, elevated hemidia- phragm. CT: spinal cord displacement, altered root sleeves, contrast media enhance- ment. MRI: traumatic meningoceles, root sleeves are not filled. Symptoms Signs 97 Electrophysiology: NCV: Motor responses are unobtainable. Despite clinical sensory loss, sensory NCVs are obtainable (preserved dorsal rootganglion). F Waves are absent. EMG: fibrillations in cervical and high thoracic paraspinal muscles. Metabolic: Diabetic ketoacidosis Toxic: Alcohol, heroin, high dose cytosine arabinoside Vascular: Hematoma, transcutaneous transaxillary angiograms, puncture of axillary ar- tery, aneurysm. Pseudoaneurysms: May result from trauma or injuries. Slow onset and develop- ment. Infectious: 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. Pathogenesis 98 Differential diagnosis: Hereditary neuralgic amyotrophy, hereditary neuropathy with liability to pressure palsies (HNPP) – Multifocal motor neuropathy: Rare type of polyneuropathy, immune mediated with two or more lesions and with characteristic conduction block in motor NCV. Occasionally, the brachial plexus is affected. Clinically: progressive muscle weakness and wasting, sometimes with fascicu- lations and cramps. Pain and sensory complaints are absent. Electrophysiology: distantly intact NCVs. Motor NCV with supraclavicular stimulation is difficult. Sensory NCVs are unimpaired. MRI may show diffuse swelling of the plexus. – Monoclonal gammopathy and CIDP: MRI investigation of the brachial plexus in patients with these disorders have shown involvement of the plexus. Compressive: – Rucksack paralysis: Caused by carrying of backbags in recreational and military setting. Clinically: Lesion of the upper and middle trunks, occasionally individual nerves. Pain is uncommon, parasthesias may occur. Affected muscles include deltoid, supra/infraspinatus, serratus anterior, triceps, biceps and wrist extensors. Electrophysiology: conduction block, axonal loss in 25%. Prognosis: recovery in 2–3 months. Table 5. Lesions in neuralgic amyotrophy. A review by Cruz-Martinez, et al (2002) showed the following distribution in 40 patients Nerve Number of lesions Percentage Suprascapular 25 30.9 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. [...]... Epidemiology of cervical radiculopathy A population based study of Rochester, Minnesota, 1976 through 1990 Brain 117: 32 5 33 5 References 126 Thoracic radiculopathy Genetic testing NCV/EMG Laboratory Imaging + + +++ Fig 4 Abdominal muscle weakness: A demonstrates effect of abdominal muscle weakness in a patient with CSF certified borreliosis His first symptom was a feeling of distension of his abdomen... syndrome Muscle Nerve 18: 229– 233 Roos DB, Hachinski V (1990) The thoracic outlet syndrome is underrated/overdiagnosed Arch Neurol 47: 32 7 33 0 Swift DR, Nichols FT (1984) The droopy shoulder syndrome Neurology 34 : 212–215 References 106 Lumbosacral plexus Genetic testing NCV/EMG Laboratory Imaging Biopsy + + + DM (femoral) Fig 7 1 Branch to lumbar plexus, 2 Greater sciatic nerve, 3 Pudendal nerve 107 Fig... therapy 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:... 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... 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,... peripheral neuropathies Lippincott, Philadelphia, pp 35 5 37 4 Thomas JE, Cascino TL, Earle JD, et al (1985) Differential diagnosis between radiation and tumor plexopathy of the pelvis Neurology 35 : 1–7 Wohlgemuth WA, Stöhr M (2002) Percutaneous arterial interventional treatment of exercise induced neurogenic intermittent claudication due to ischemia of the lumbosacral plexus J Neurol 249: 988–992 References... M1 + M2: represent the mobile parts 119 Cervical radiculopathy Genetic testing NCV/EMG + Laboratory Imaging Biopsy ++ Fig 2 Left hand: C8 radiculopathy with atrophy in a patient with leukemic infiltration Fig 3 Meningeal carcinomatosis with neoplastic deposits in C6 and C7 Extensor deficits of fingers 3, 4, 5 mimicks partial radial paralysis 120 Anatomy With exception of the upper two, the cervical... 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... 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... iliohypogastric, ilioinguinal, and genitofemoral nerves, and motor branches for the psoas and iliacus muscles Lumbar 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 . plex- us, 2 Greater sciatic nerve, 3 Pudendal nerve 107 Fig. 8 . 1 Subcostal nerve, 2 Ilio- hypogastric nerve, 3 Ilioin- guinal nerve, 4 Genitofemoral nerve, 5 Lateral cutaneous fem- oris. 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 plexus. Note tumorous enlarge- ment of. Traumatic lesion of the left brachial plexus. Note the deltoid muscle and muscles fix- ing the scapula are intact. Atro- phy of the lower arm and hand muscles. Note the inward rota- tion of the left