SC 2 Flashcards
(35 cards)
Conus medullaris syndrome
1(S2 – S5):
- Late pain in thighs & buttocks
- Pelvic floor muscle weakness
- Symmetric saddle anesthesia numb
- Early bladder dysfunction
- Early loss of bowel and sexual functioning
Cauda equina syndrome
(L1 – S5):
- Early root pain radiating to legs
- Leg weakness and DTRs (LMNs)
- Patchy, asymmetric “saddle”
- Late bladder dysfunction
- Late loss of bowel & sexual dysfunction
mictrition neural pathways
is coordinated activity of the bladder detrusor and the sphincter muscles.
voiding bladder
under the control of higher cortical centers that develops as continence and is achieved early in childhood.
incontinence
- occurs when neuroanatomic pathways that innervate the bladder are interrupted or when there are physical problems with the pelvic floor and sphincter muscles.
- Important symptom occurs in association with other neurological deficits that localize to the spinal cord.
bladder control is controlled by
areas of the brain and brainstem that send axons down the spinal cord, traveling just medial to the LCST.
bilateral projections of bladder control terminate on
preganglionic parasympathetic neurons at S2, S3 and S4
- The preganglionic parasympathetic neurons send their axons out the ventral roots of the S2, S3, and S4 to synapse on postganglionic parasympathetic cells in ganglia near the bladder
- These postganglionic parasympathetic cells in turn innervate the detrusor (smooth) muscle of the bladder for voiding.
There are muscle spindles, nociceptors, and other sensory receptors in the detrusor muscle & bladder wall whose cell bodies lie in the
dorsal root ganglia at S2, S3 and S4.
These fibers participate in local reflex arcs and ascend the nervous system via the AL pathway and dorsal columns.
bladder filling steps
- bladder fills and muscle spindles of detrusor and bladder wall are stretched
- firing is increased.
- initially enhances (through reflex pathway) neuronal firing of sympathetic preganglionic neurons in the intermediolateral cell column from T11-L1
- this causes increased constriction of the internal urethral sphincter
- this info also travels in a reflex pathway that results in decreased neuronal firing or pregang symp at s2-s4 and inhibits contraction of detrusor
- filling increases and afferent info activates higher center in BS and cortex
- descending pathway along medial LCST, coordinated inhibition of sympathetic done and activation of parasymp contraction of detrusor
- results in contraction of voluntary sphincter prevents voiding
PNS LMN lesion controlling micturition
weakness atrophy, hyporeflexia
—>bladder does not contract
PNS LMN lesion controlling micturition
sensory afferents affected
no sensation of full bladder will be recieved
PNS LMN lesion controlling micturition
Intact sensory afferents with affected motor efferents
urge to void but good detrusor
PNS LMN lesion controlling micturition
lesion location
- anywhere from pregang parasymp neurons at S2, S3, S4
- sacral roots of cauda equina
- pelvis plexus
- 2 postganglionic parasymp neuron that innervates the detrusor
UMN lesion controlling micturition
To affect bladder function, lesions must be bilateral.
Detrusor becomes flaccid –>
urinary retention –>
flaccid bladder
With time, spasticity develops and the bladder contracts with small degrees of stretch
1. Urinary frequency and urgency
2. Whenever the bladder fills a little: increased stretch carried by afferents activate
the parasympathetic motor neurons that control the detrusor and thus intermittent voiding –> Spastic bladder
C5 sensory territory
- shoulders
2. upper lateral arm
c5 motor territory
- deltoid
- infrapinatus
- biceps
c5 reflex component
biceps
c6 sensory territory
1st and 2nd digits of hand
c6 motor territory
- wrist extension
2. biceps
c6 reflex components
- biceps
2. brachioradialis
C7 sensory territory
3rd digit
C7 motor territory
triceps
C7 reflex component
triceps
L4 sensory territory
- knee
2. medial leg
