Where is the intermediolateral column/lateral horn in the spinal cord and what does it hold?

Thoracic level only, in lamina 7

holds preganglionic synpathetic autonomic fibers

Decorticate posturing

- What you see

- Motor GSC score

- Cause

- Upper extremity flexion to noxious stimuli

- lesion to or above the rubrospinal tract (lesion above the midbrain)

- motor GSC score of 3

Decerebrate posturing

- What you see

- motor GSC

- cause

- Extension of upper extremities to noxious stimuli

- motor GCS 2

- A lesion below the red nucleus that impairs the corticospinal, corticobulbar, or reticulospinal tracts

Caused by extensor innervation of the pontine reticulospinal and vestibulospinal tracts

Pathway of the corticospinal tract (8)

Primary motor cortex in the precentral gyrus (Brodmann area 4) and premotor cortex (area 6) and supplementary motor area (area 6) and postcentral gyrus (parietal) (areas 3,1,2), and parietal association cortex (areas 5 and 7) – includes some sensory

Homunculus: face and arm laterally, leg is medial cortex

-> corona radiata -> posterior limb of internal capsule (leg is posterior lateral, arm is middle, face is anteruor medial) -> cerebral peduncle (crus cerebri in midbrain) -> Basis pontis ->85% decussate in the lower lateral medulla in the pyramidal decussation -> lateral CS in the posterior lateral column, anterior CS in the anterior

Corticospinal tract

- function

- origin

- decussation

- localization in cord

- termination

Rubrospinal tract

- function

- origin

- decussation

- localization in cord

- termination

Vestibulospinal tract

- function

- origin

- decussation

- localization in cord

- termination

Reticulospinal tract

- function

- origin

- decussation

- localization in cord

- termination

congenital myopathy with a mutation in the Ryanodine receptor which predisposes to malignant hyperthermia (which you treat with dantrolene)

Anterior horn motor neurons are in lamina ___ and contain ___ and ___ cells

- What do these cells do?

Lamina 9

o Contains alpha and gamma fibers

§ Alpha goes to extrafusal fibers (most muscle fibers)

§ Gamma motor neurons go to intrafusal fibers in the muscle spindle

T1-L2

S2-S4

Stiff Person Syndrome

- Cause

- Result

Cause: GAD65 antibodies (GAD 65 converts glutamate to GABA)

Result: Spasticity

GAD65 has a cofactor of ___

- What does a deficiency of this cause in neonates

Cofactor of Vit B6

Deficiency causes seizures in neonates

- Destruction of descending inhibitory alpha motor neurons

o A sudden stretch activates muscle spindles, resulting in the stretch reflex.

o Tension produced by the muscle contraction activates the golgi tendon organs, which in turn activate an inverse stretch reflex, relaxing the muscle

§ Golgi tendon reflex aka Inverse stretch reflex aka inverse myotactic reflex: skeletal muscle contraction causes the antagonist muscle to simultaneously lengthen and relax

o If the stretch is sustained, the muscle spindles activate again, causing a cycle of alternating contractions and relaxations.

Hereditary Spastic Paraparesis (HSP)

- Genetics

- Abnormal protein

- Result

- Multiple potential genes involved but most common is AD in SPG4 gene on chromosome 22

- Spastin protein, codes for microtubules

- Spasticity

Baclofen

Diazepam

Tizanidine

Botox

Dentrolene

Cyclobenzaprine

At what level does the spinal cord end?

L1

How many segments of the spinal cord?

31
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

What 2 things can be found in thoracic Lamina 7?

intermediolateral nucleus which contains preganglionic sympathetic
and
Dorsal nucleus of Clarke which contains the dorsal spinocerebellar tract

paravertebral ganglia: sympathetic chain

prevertebral: celiac ganglion, superior mesenteric ganglion, inferior mesenteric ganglion