Nervous system terms I had to look up or get further clarification on. Flashcards
UMN Lesion
tone: spasticity present
Atrophy: not significant
Fasciculations and fibrillations: not present
clonus: present
reflexes: hyperreflexia
clonus
is an abnormal reflex response that involves involuntary and rhythmic muscle contractions. It happens due to an upper motor neuron lesion.
LMN lesion
tone: flaccid
Atrophy: significant
fasciculations: present
Reflexes: hyporeflexia
Clonus: not present
Node of ranvier
Each interruption of myelin where a new depolarization has to occur is called this.
tract
myelinated fibers fibers organized into columns in the spinal cord. Ascending sensory tracts and descending motor tracts.
locations of motor neurons
anterior horn of spinal cord and frontal lobe of brain.
Posterior tracts that are sensory are
proprioceptive, pressure and vibration.
Lateral corticospinal tract
descend from motor cortex to the spinal cord. Cross at lower brain stem. synapse with motor nuclei in the anterior horn.
Neural arch (couldn’t remember this one from A&P)
The neural arch (often also called the “vertebral arch”) is the portion of the vertebra posterior to the body, formed by the pedicles and laminae, and it does give rise to the transverse and spinous processes. It encloses the vertebral foramen, through which the spinal cord passes.
intervertebral foramina
small openings formed by the inferior vertebral notch of one vertebra and the superior vertebral notch of the vertebra below, where spinal nerves exit the CNS.
Layers of the meniges
Dura mater - thick outer layer
Arachnoid mater - middle thinner layer
Pia mater - tender inner layer
occipital lobe
sensory input for vision, including recognition of shape size and color
Parietal lobe
receives sensory information
temporal lobe
regulates behavior, hearing and language.
Thalamus
relay for sensation - perception of pain
hypothalamus
hormone regulation and behavior
basal ganglia
coordination of movement
midbrain
controls visual reflexes
pons
relay connecting various nuclei to cerebellum
medulla oblongata
Ventilation and respiration, blood pressure and HR
Cerebellum
muscle tone, coordination and posture.
cauda equina
spinal nerves L2 and below
conus medullaris
cone shape end of spinal cord. approx L2
PNS
unlike CNS is capable of regeneration after injury. - regeneration is slow and may not be complete.
Seddon - neuropraxia - sunderland - first degree
localized myelin damage
Seddon - axonotmesis - Sunderland - second degree
axon severed but endoneurium intact.
Seddon - axonotmesis - Sunderland -third degree
axon and endoneurium severed
Seddon - axonotmesis - Sunderland - fourth degree
Loss of continuity of all layers of peripheral nerve, except epineurium
Seddon - Neurotmesis - Sunderland Fifth degree
Complete disruption of entire nerve
Cervical nerves exit
above the cervical vertebrae to C8 which exits above T1. T1 exits below T1 and continues down through the sacrum
Dorsal ramus
posterior ramus- muscles and skin of the posterior trunk
ventral ramus
anterolateral trunk (the muscles and skin of the front and sides of the trunk) as well as the limbs (via the major nerve plexuses: cervical, brachial, lumbar, sacral).
White Ramus Communicans
Carries preganglionic sympathetic fibers from the spinal nerve to the sympathetic chain ganglion.
Gray Ramus Communicans (unmyelinated)
Carries postganglionic sympathetic fibers from the sympathetic chain ganglion back to the spinal nerve.
Ventral rami becomes
intercostal nerves which innervate the muscles of the skin and anterior lateral trunk.
Dermatomes
areas of the skin with muscle fibers
myotomes
are all of the muscles that receive motor innervation from a specific spinal cord leval.
Cervical plexus
C1-C4 - neck
Brachial plexus
C5-T1 - kneck and upper extremities
Lumbosacral plexus
L1-S3
Sternocleidomastoid
C2-C3
C3-C4
Trapezius.
Levator scapula
C3-C5
Phrenic nerve
C3-C5
Superior trunk of Brachial plexus
C5-C6 - Anterior and posterior cords
Middle trunk of brachial plexus
C7- Anterior and posterior cords
Inferior trunk of brachial plexus
C8, T1- Anterior and posterior cords
Lateral cord of the brachial plexus
combination of anterior divisions of superior and middle trunk.
Posterior cord of the brachial plexus
combination of posterior division of all three trunks
Medial cord
a continuation of the inferior trunk anterior division.
Five major nerves of the brachial plexes
Axillary,
musculocutaneous nerve,
radial nerve,
median nerve,
ulnar nerve.
Axillary nerve
branch of the posterior cord
Musculocutaneous nerve
branch of lateral cord
radial nerve
branch of posterior cord.
median nerve
combination of lateral and medial cords
ulnar nerve
continuation of medial cord.
Lumbar Plexus
L1-L4
Sacral plexus
L5-S3
Femoral Nerve
Posterior div of L2-L4
Obturator nerve
anterior of L2-L4
Superior Gluteal nerve
Posterior of L4-S1
Sciatic nerve
Formed from division of L4-S3 - forms tibial and fibular nerves.
Tibial nerve
Anterior divisions of L4-s3
Common fibular nerve
posterior divisions of L4-S2
muscle spindle
sensory receptors that respond to stretch.
Golgi tendon organs
stretch receptors in tendons
Deep tendon reflex
stretching a muscle to elicit a contraction. example - tapping the quadriceps tendon between the patella and int’s insertion on the tibial tuberosity elicits knee extension.
ALS
Amyotrophic lateral sclerosis - degenerative motor disease of both upper and lower motor neurons.
Duchenne Muscular dystrophy
weakness of proximal muscles followed by distal muscles. (often have oversized calve muscles that are weak.)
Bell palsy
Injury to facial nerve (VII) typically affects one side of face
scapular winging
sign of injury to the long thoracic nerve. serratus anterior muscle. rising of the medial border of the scapula away from the rib cage.
Thoracic outlet syndrome
nerves of brachial plexus, subclavian artery, or subclavian vein or a combo are compressed in the thoracic outlet.
pain, sensory and motor loss and interference with blood flow.
thoracic outlet
space between the clavicle, first rib and scalene muscles.
Burners or Stingers
overstretch or compression of brachial plexus. \
Blow to head or shoulder.
weakness and muscle tenderness of kneck may continue for a few days.
Erb Palsy
a traction injury to the upper portions of the brachial plexus. birth injury. affected arm has weakness
Saturday night palsy
radial nerve. compressed as it spirals around the mid humerus
weakness or paralysis of wrist and finger extensors.
Sciatica
L4-S3 irritation of nerve roots. (herniated lumbar disc)
Foot drop
injury to common fibular (peroneal) nerve. Pressure on the nerve by the head of the fibula. Weakness of dorsiflexion.
Neuroma
mass of neurovascular tissue.
Morton neuroma
compression of a neuroma in a confined space. Most often between third and fouth toes.
Pain and paresthesia.
