Nervous System Lesions: Segmental vs. vertical Flashcards
1
Q
Segmental organization: what are segments
A
- identified by the same designation as their corresponding spinal nerves
- a segmental lesions = problems with function at that level of spinal cord
2
Q
Dorsal rhizotomy
A
- cutting of selected roots is a treatment for muscle overativity in spastic CP
3
Q
Dermatomes and their relation to segmental lesions
A
- dermatome is an area of skin innervated by axons from cell bodies in a single dorsal root
- segmental lesions will follow a dermatome
4
Q
Describe how axons are entering the spinal cord based on what information they carry
A
- axons carrying information from touch and proprioception enters medially through 1A and A beta
- axons carrying information about tissue damage or threat to tissue damage and temperature enter the cord laterally
5
Q
Spinal organization and spinal nerves
how are the regions named
A
- cervical region spinal nerves are found above the corresponding vertebra
- exception is 8th spinal nerve emerges between C7 and T1
- remainder of the spinal cord = spinal nerves lie below the corresponding vertebrae
- spinal cord ends at L1-2 vertebrae spaces
- L2-5 nerve roots ravel downward below the end of the spinal cord before exiting as the cauda equina
6
Q
Segmental lesions
presentation
A
- produces loss of sensation from dermatome and myotome
- sensory and motor will be interrupted
7
Q
Sensory signs of segmental dysfunction
A
- imparied sensation = paresthesia
OR
- loss of sensation = anesthesa
- in a dermatomal pattern
8
Q
Motor signs of segmental dysfunction
A
- LMN signs
- atrophy
- flaccid weakness
- fasciculations = quick twitch seen below skin
- fibrillations = brief contraction of motor unit that cannot be seen nder skin
- reflexes are absent if either the motor OR sensory fibers in the circuit are damaged
9
Q
Segmental pain control/gait control theory
A
- feel the need to touch a painful area
- when you add pressure = mechanoreceptors are stimulated
- goes to an interneuron to release enkephalin
- enkephalin inhibits/dampens pain signals
10
Q
Segmental lesion exmaples/: radiculopathy
A
- lesion of dorsal or ventral nerve root
- produces pain in the innervated dermatome and weakness in the muscles innervated by the spinal cord segment
- herniated disc, tumor, dislocated fracture
11
Q
How can a dorsal or ventral root lesion occur
A
- infection
- avulsion severence
12
Q
Avulsion severence
A
- complete severenace of dorsal root that produces pain in the innervated deramtome
- Erbs palsy (C5-C6)
- Klumpke’s palsy (C8-T1
- if ventral root deprives muscle innervation and results in atrophy and fibrillation
13
Q
Erbs palsy
A
- C5-C6
- forceful seperation of head and shoulder
- lost Abduction, ER, elbow flexion
- bicep and brachioradilis reflex lost
14
Q
Klumpke’s paralysis
A
- C8-T1
- claw hand
- traction of Abducted arm
- hand intrinscics, long finger flexors and extensors
15
Q
Dorsal root ganglion lesion s
A
- more sensitive to mechanical change than proximal or distal axons of primary nociceptive afferents
- DRG develop action potentials in response to mechanical stimulation that are preceived as pain in the perheral axon +hyperalgesia
- EX: sciatica
- infection of DRG from herpes zoster/shingles = dermatome rash
