Central Nervous System
Not true for myelopathy (AIIMS NOV.2011)
|A||Sensory loss of facial area|
|B||Brisk Jaw jerk|
|C||Brisk pectoral jerk|
|D||Bladder and bowel involvement|
Spinal cord compression by degenerative spine disease is one of the more common causes of myelopathy, however tumors or other masses can also cause myleopathies. Intraspinal tumors may originate in the substance of the spinal cord (intramedullary tumors) or compress it from the outside (extramedullary tumors).
II. Clinical Findings:
a. upper motor neuron findings such as hyper-reflexia, clonus, or Babinski's sign may be present;
b. funicular pain, characterized by central burning and stinging with or w/o (Lhermitte's phenomenon - radiatineg lightening like sensations down back with neck flexion) may also be present with myelopathy;
c. upper extremity: - mixed upper and lower motor neuron findings;
d. myelopathy can initially present w/ hand dysfunction w/ loss of fine motor function such as writing;
e. lower extremity - upper motor neuron signs;
f. lateral cord involvement: causes spasticity, hyper-reflexia, and frank clonus in lower extremities;
g. posterior cord involvement: causes decline in ability to walk, apparent ataxia;
h. loss of lower extremity proprioception;
III. Babinski's sign:
a. may not be present until myelopathy becomes severe;
b. upper motor neuron findings such as hyper-reflexia, clonus, or Babinski's sign may be present;
IV. Remember, lesions of the spinal cord rostral to the sacral cord result first in a flaccid (atonic; acute) bladder, followed by a spastic (chronic) bladder. Lesions from S1 down, and involving all of the various nerves, result in ONLY a flaccid bladder.
a. The trigeminal nucleus extends throughout the entire brainstem, from the midbrain to the medulla, and continues into the cervical cord, where it merges with the dorsal horn cells of the spinal cord.
b. The nucleus is divided anatomically into three parts, visible in microscopic sections of the brainstem. From caudal to rostral (i.e., going up from the medulla to the midbrain) they are the spinal trigeminal nucleus, the main trigeminal nucleus, and the mesencephalic trigeminal nucleus.
c. The three parts of the trigeminal nucleus receive different types of sensory information. The spinal trigeminal nucleus receives pain/temperature fibers. The main trigeminal nucleus receives touch/position fibers. The mesencephalic nucleus receives proprioceptor and mechanoreceptor fibers from the jaws and teeth.
d. Therefore pain and temp can be lost over face in cervical myelopathy due to spinal trigeminal nucleus, but Jaw jerk would not be involved.