What is myelopathy?
• Myelopathy: Disorder resulting in spinal cord dysfunction.
What is a nerve root?
o Nerve Root: Combined sensory and motor rami of the spinal cord (e.g. L5)
What is a tract?
o Tracts: Axons that travel in the spinal cord to relay information. (e.g. corticospinal tract).
What is a hyperesthesia?
Hyperesthesia: Abnormal acuteness of sensitivity to touch, pain, or other sensory stimuli
What is a dysesthesia?
o Dysesthesia: Impairment of sensation short of anesthesia
What is a parasthesia?
o Paresthesia: An abnormal sensation, can include burning, pricking, tickling, or tingling. Sometimes characterized as “pins and needles”
What is an intervertebral foramen?
o Intervertebral foramen: Opening formed by 2 adjacent vertebral bodies through which the nerve roots travel.
What is a radiculopathy?
o Radiculopathy: Sensory and/or motor dysfunction due to injury to a nerve root.
What is a myotome?
o Myotome: Muscles innervated by an individual motor root.
What is a dermatome?
o Dermatome: Cutaneous area served by an individual sensory root.
How many pairs of nerve roots are there coming from what spinal levels?
31 pairs of nerve roots (8 Cervical, 12 Thoracic, 5 Lumbar, 5 Sacral, 1 Coccygeal).
There are 7 cervical vertebrae, but how many cervical nerves?
8 cervical nerves, to 7 cervical vertebrae.
What’s the general rule of thumb to use when keeping track of vertebral body level injuries correlating to spinal cord level injuries?
• Upper cervical
○ Vertebra # overlies same cord segment #
• Lower cervical
○ Vertebra # overlies cord segment +1 (C6 is over C7)
• Upper thoracic
○ Vertebra # overlies cord segment +2 (T4 is over T6)
• Lower thoracic/lumbar
○ Vertebra # overlies cord segment +2-3 (range)
§ T11 overlies L1-2 cord
§ The vertebral bodies are bigger at that point than the spinal cord segments
• Lower edge of the L1 vertebral body overlies the cord tip (conus medullaris)
○ Thus the lumbar puncture)
What spinal cord levels make up the conus medullaris?
What does the conus medullaris innervate?
What spinal cord levels make up the cauda equina?
• LS roots within the lumbosacral cistern
Because of the organization of the spinal cord tracts, what will an extramedullary tumor present as?
Because of the organization of the spinal cord tracts, what will an INTRAmedullary tumor present as?
The spinothalamic tract is organized how?
• With bundles moving from medial to lateral
○ Whole thing is anterolateral tract, pain and temperature from the contralateral side
• Cervical (medial), then thoracic, lumbar and sacral moving lateral
• Thus intrameddullary lesion has pain and temp loss in a descending pattern
What spinal cord structure is organized (from medial to lateral) in an ascending manner?
The lateral corticospinal tract is organized how?
Following the normal dermatome map is great, but you must remember one detail…?
• Variations are common, and a persons variation is +/- one full dermatome
What are the major dermatomal landmarks?
The observational part of the neuro exam is looking for what?