Spinal Nerve Root

Question 1

Segmental Organization

Answer 1

• 8 cervical (C1-C8).
• 12 thoracic (T1-T12).
• 5 lumbar (L1-L5).
• 5 sacral (S1-S5).
• 1 coccygeal (Co).
• Growth of bones after cord stops = conus medullaris, ~ L1-L2.
• Cauda equina.
• Filum terminal.

Question 2

Spinal Cord

Answer 2

Question 3

Organization

Answer 3

• Motor & sensory roots (L & R) arise from each segment except C1.
• C1 has no sensory roots, ONLY motor.
• Cervical enlargement (C5-T1).
• Lumbar enlargement (L1-S3).
• Mixed spinal nerves from each segment (*except?)

Question 4

Vertebae

Answer 4

Question 5

Vertebrae

Answer 5

• Provide mechanical support.
• Anteriorly; vertebral body.
• Posteriorly; superior & inferior articular processes.
• Protection.
• Spinal cord through the vertebral canal surrounded by meninges.

Question 6

Vertebrae

Answer 6

Question 7

Vertebrae

Answer 7

Question 8

Vertebrae

Answer 8

Question 9

Spinal Canal

Answer 9

• As dura exits skull, outer layer becomes 1 with periosteum- indistinguishable.
• Layer of epidural fat between dura & periosteum in spinal canal (landmark.)
• Batson’s venous plexus; valveless.
• Network connecting deep pelvic veins draining bladder, prostate & rectum to internal vertebral venous plexus.
• *Mets.

Question 10

Spinal Canal

Answer 10

Question 11

Disc Herniations

Answer 11

• N.R. involved usually corresponds to lower of 2 adjacent vertebrae.
• C-spine PLL thick & N.R.s exit horizontally; herniates laterally.

Question 12

Disc Herniations

Answer 12

•L & S-spine N.R.s travel down & into lateral recesses of canal of canal; closest to disc for posterolateral herniation.

Question 14

Disc Herniations

Answer 14

•Far lateral disc herniation reach N.R. exiting at that level = impingement of next higher N.R.

Question 15

Dermatomes

Answer 15

• Sensory distribution on skin by a N.R.
• A map but references vary some.
• Face = trigeminal nerve.
• Rest of head mostly C2 (greater & lesser occipital nerves.)
• Torso; nipples T4, umbilicus T10.

Question 16

Dermatomes

Answer 16

Question 17

Dermatomes

Answer 17

Question 18

Dermatomes

Answer 18

Question 19

Myotomes

Answer 19

•Muscles innervated by a single nerve root.

Question 20

Myotomes

Answer 20

Question 21

Summary of Peripheral Nerves, muscles, Nerve Roos in the Upper and Lower Extremities

Answer 21

Question 22

Summary of Peripheral Nerves, muscles, Nerve Roos in the Upper and Lower Extremities

Answer 22

Question 23

Summary of Peripheral Nerves, muscles, Nerve Roos in the Upper and Lower Extremities

Answer 23

Question 24

Summary of Peripheral Nerves, muscles, Nerve Roos in the Upper and Lower Extremities

Answer 24

Question 25

Summary of Peripheral Nerves, muscles, Nerve Roos in the Upper and Lower Extremities

Answer 25

Question 26

Disorders of Nerve, NMJ, & Muscle

Answer 26

* Peripheral sensory or motor patterns/deficits. * LMN lesions. * Atrophy, fasciculations, decreased tone, & hyporeflexia.

Question 27

Disorders of Nerve, NMJ, & Muscle

Answer 27

* Causes: * Mechanical. * Toxic. * Metabolic. * Infectious. * Autoimmune. * Inflammatory. * Degenerative.

Question 28

Common Neuropathies

Answer 28

* A nerve disorder. * Axon, myelin or both involved. * Large diameter, small diameter, or both involved. * Usually both motor and sensory involved. * Reversible or permanent. * Radiculopathy involved spinal nerve root.

Question 29

Important Causes-Neuropathies

Answer 29

* Diabetes. * Mechanical disorders. * Infectious disease; HIV, CMV, Lyme disease, varicella-zoster virus, hep-B. * Toxins. * Malnutrition. * Immune disorders; Guillain-Barre, Charcot-Marie-Tooth disease...

Question 30

Diabetic Neuropathy

Answer 30

* Compromised microvascular blood supply to peripheral nerves. * Distal symmetrical polyneuropathy. * Stocking glove distribution of sensory loss. * Mononeuropathy. * Cranial or spinal nerves but CNIII, femoral & sciatic commonly. * Sudden onset, maybe painful paresthesia. Partial or complete recovery

Question 31

Mechanical Causes of Nerve Injury

Answer 31

* Extrinsic compression, traction, laceration or entrapment. * Intrinsic compression by bone, or CT. * Neuropraxia; temporary impairment of NCV. * Wallerian degeneration; severe injury & distal death. * Axonal regeneration; 1mm/day. * RSD; regional pain syndrome following injury without specific nerve damage. * Causalgia; damage to specific nerve.

Question 32

Long Term Complications

Answer 32

* Incomplete or aberrant reinnervation. * RSD (reflex sympathetic Dystropy Syndrome); regional pain syndrome following injury without specific nerve damage. * Causalgia; damage to specific nerve. Local, intense burning pain with edema, sweating, & changed skin blood supply

Question 33

Guillain-Barre Syndrome Acute Inflammatory Demyelinating Polyneuropathy (AIDP)

Answer 33

* Immune-mediated demyelination of PNS. * 1-2 weeks post viral infection. * Camphylobacteri jejuni enteritis, HIV... * Progressive weakness, areflexia, tingling paresthesias of hands, feet with more severe motor involvement. * Wort 1-3 weeks after onset; recovery = months. Dx: symptomatology & elevated CSF proteins wo increased WBC s & (+)EMG for demyelination

Question 34

Disorders of NMJ

Answer 34

* Motor weakness without sensory deficits. * Causes: * M.G. * NM blocking agents & other drugs. * Lambert-Eaton myasthenic syndrome. * Botulism.

Question 35

Myasthenia Gravis

Answer 35

* Immune-mediated disorder. * Postsynaptic nicotinic acetylcholine receptor antibodies. * Sometimes runs with other autoimmune dys(fx). * Hypothyroidism. * SLE. * R.A. * Vitiligo.

Question 36

Myasthenia Gravis

Answer 36

* Onset: * 20-30y.o.; females * 60-70y.o.;males. * Generalized symmetrical weakness, proximal limb, neck, diaphragm, eye muscles, & bulbar muscles (CN IX-XII): facial weakness, nasal voice & dysphagia. * \*\*WEAKNESS BECOMES MORE SEVERE WITH REPEATED USE. **_IF JUST EYES=_** **_OCULAR MYASTHENIA_** **_(15%)._**

Question 38

Myasthenia Gravis

Answer 38

* Diagnosis: * Clinical features. * Ice pack test (ptosis.) * Repetitive nerve stimulation. * Measurement of antibodies. * Tensilon test (old-2008 DQ) * Neostigmine. CMAP=characteristic decrement in amplitude

Question 39

Dermato- & Polymyositis

Answer 39

* Immune-mediated inflammatory myopathies. * Increased blood CPK. * (+) EMG for myopathy. * Dermatomyositis: characteristic violet-colored skin rash on extensor surface knuckles & other joints. * Duchenne M.D. most common form M.D\> * X-linked inheritance * Male children. * Progressive proximal weakness.

Question 40

Back Pain

Answer 40

* One of the most common causes to seek medical attention. * Diverse causes. * Importance of careful Hx & P.E. * NMS causes are most common. * \> 50... neoplasm? * Never neglect bowel, bladder, & sexual fx.

Question 41

Differential Diagnosis of Back Pain

Answer 41

Question 42

Clarifying Definitions for Degenerative Disorders of the Spine

Answer 42

Question 43

Disc Herniation

Answer 43

* Most common * C5-C6, C6-C7. * L4-5, L5-S1 * L/S are 2-3 x more common than cervical disc herniations. * Osteophyte formation. * Spinal stenosis. * \>\>\>chronic injury to cord.

Question 44

Orthopedics

Answer 44

* SLR * (+)=10-60 degrees with reproduction of radiculopathy. * Crossed SLR * 90% (+) for L/S N.R. compression. * Valsalva’s maneuver. * Percussion of spine. * (+)Metastatic disease, epidural abscess, osteomyelitis, & other bone disorders.

Question 45

Straight Leg Raise

Answer 45

Question 46

Radiculopathy

Answer 46

* Stenosis; narrowing of the spinal canal; congenital or degenerative. * Lumbar stenosis. * Neurogenic claudication. * Bilateral leg pain & weakness with ambulation. * Cervical stenosis. * Radicular signs. * Long tract signs. * Trauma; compression, traction, avulsion. * Diabetic neuropathy. * Epidural mets; usually to vertebral body but can extend laterally & compress N.R.

Question 47

Radiculopathy

Answer 47

* Many causes of neuropathies have preference for N.R. so can be a radiculopathy. * Guillain-Barre syndrome. * Varicella-zoster virus in DRG \> herpes zoster=shingles. * Post herpetic neuralgia or pain syndrome. * Lyme disease. * CMV polyradiculopathy in patients with HIV. * HIV (milder than CMV) * Tumors. * Schwannomas. * Neurofibromas.

Question 48

Three important Nerve Root in the Arm

Answer 48

Question 49

Dermatomes of the Arm

Answer 49

Question 50

Three important Nerve Roots in the Leg

Answer 50

Question 51

Dermatomes of the Leg

Answer 51

Question 52

Cauda Equina Syndrome

Answer 52

* Impaired fx of multiple N.R.s below L1 or L2. * If deficit at S2 or lower – maybe not see L.E. motor weakness. * S2-S5 sensory loss = saddle anesthesia. * S2, S3, S4 = distended atonic bladder, urinary retention, incontinence, constipation, decreased rectal tone, loss of erections. (S2,3,4 keeps the Ps off the floor.) * Central disc, epidural mets, schwannoma, meningioma, neoplastic meningitis, trauma, epidural abscess, arachnioditis, CMV polyradiculitis.

Question 53

Surgery

Answer 53

* Usually disc herniation resolves without surgery. * Surgical emergency: * Cauda equina syndrome. * Progressive or severe motor deficit. * Intolerable, medically intractable pain. * Conservative care first 1-3 months.

Question 54

Common Surgical Approaches

Answer 54

**_Posterior approach:_** * Laminectomy * Discectomy. * Foraminotomy. * Hardware if necessary. **_Anterior approach to C-spine:_** * Discectomy. * Fusion (bone graft.) * Also for T-spine discs (rare.)