Approach to patient with motor weakness Flashcards
2 cerebral hemispheres
• They are connected to each other
Corpus callosum
outer gray matter (cerebral cortex):
is composed of
nerve cells & contains area that control specific function
Inner white matter (depth of cerebral hemisphere): it
is composed
nerve fibers that conduct impulses to
and from cerebral cortex
Basal ganglia
Site
Structure
Function
At the base of each hemisphere deep in white
matter.
• Caudate, Putamen, Globus pallidus.
• Control extrapyramidal system
Brain Stem (from above downwards)
Midbrain: contains the motor nuclei of cranial
nerves 3, 4.
2- Pons: contains the motor nuclei of cranial
nerves 5, 6, 7.
3- Medulla: contains the motor nuclei of cranial
nerves 9, 10, 11, 12.
have no motor nuclei.
They are sensory nerves concerned with special sensations.
The 1st, 2nd, and 8th cranial nerv
Cerebellum site
It lies at the back and bottom of the cranium
behind the brain stem in the posterior cranial
fossa.
Spinal cord (Transverse section)
It contains gray matter (Cells) surrounded by
white matter (Fibers)
• The gray matter: H shaped
2 anterior horns: motor function
2 posterior horns: sensory function
• The white matter: nerve fibers arranged into
ascending and descending tracts
Spinal cord ascending tracts
Lateral & ventral spinothalamic: for superficial sensations
Posterior column: for deep sensations
Spinocerebellar: for cerebellar information
Spinal cord The important descending tracts
The pyramidal tract (corticospinal)
The extrapyramidal tracts
The cerebello-spinal tracts
50 years old
gentleman
presented with low
back pain.
He has history of
lifting heavy objects.
Intervertebral disc prolapse
The pyramidal system
Oridin
Terminal
Control
Function
Origin: in the cerebral cortex (motor area 4,
premotor area 6).
• Termination: at the AHCs of the different levels of
the spinal cord.
• Control: it controls the opposite side of the body.
• Function:
Initiation of the voluntary motor activity
Inhibition of the deep reflexes
Inhibition of the muscle tone
The extrapyramidal system
Origin ‘termination
Conytal
Function
Origin: from the basal ganglion
• Termination: at the AHCs of the different
levels of the spinal cord.
• Control: it controls the opposite side of the
body
• Functions:
Regulation of the voluntary motor activity
Regulation of the emotional & associated movements
Inhibition of the muscle tone
The cerebellar system
Origin
Terminal
Control
Functions
Origin: from the cerebellum.
• Termination: at the AHCs of the different
levels of the spinal cord.
• Control: it controls the same side of the body.
• Functions:
Coordination of the voluntary motor activity initiated by
pyramidal system
Maintenance of equilibrium
The voluntary motor impulses originates mainly
in the large pyramidal cells
Betz cells
In the brain stem, some of the descending fibers
separate to supply the motor nuclei of the
cranial nerves of BOTH sides except
lower ½
of the facial nucleus and all of the hypoglossal
nucleus which are supplied only from the
opposite pyramidal tract.
Does all cortico spinal tract decessuate at lower medilla
85% of fibers cross (decussate) to descend in the
white matter of the opposite side of the spinal cord.
- 15% of the fibers descend directly in the white
matter of the same side of the spinal cord.
The surest sign of pyramidal lesion.
Clonus
Signficance of fassiculation
Lmnl at ahc
Difference in wasting between umnl
Lmnl
Late dissue
Early marked
Difference between babinksin in umnl lmnl
Plantar extension
Plantar fekxion or absent
Site of lesion of hemiplegia
pyramidal tract lesion at any point
from its origin in the cerebral cortex down to the
5th cervical segment of the spinal cord.
Paraplegia
UMNL at any
level of pyramidal tract below level of C5 and
above level of L2) or flaccid paraplegia (LMNL at
any level from AHCs till muscles)
Bilat umnl
Paraplegia
Quadriplegia
