Topics: Corticospinal tract, Muscle, Spinal cord Pages: 5 (1117 words) Published: March 2, 2013
• Diagnosed HIV Stage 4 on treatment (LTE)

• CMV retinitis

• Central facial palsy (flattening of R nasolabial fold)

- paresis of the lower half of one side of the face

- damage to upper motor neurons of the facial nerve.

- The facial motor nucleus has dorsal and ventral divisions that contain lower motor neurons supplying the muscles of the upper and lower face, respectively. The dorsal division receives bilateral upper motor neuron input (i.e. from both sides of the brain) while the ventral division receives only contralateral input (i.e. from the opposite side of the brain).

- Thus, lesions of the corticobulbar tract between the cerebral cortex and pons and the facial motor nucleus destroy or reduce input to the ventral division, but ipsilateral input (i.e. from the same side) to the dorsal division is retained. As a result, central facial palsy is characterized by hemiparalysis or hemiparesis of the contralateral muscles of facial expression, but not the muscles of the forehead

• Weakness of the left upper and lower extremities for 3 days


• (+) low grade fever of more than 1 week duration prior to onset of neuro deficit

• Recurring headache

• (-) vomiting but nauseous

• CD4+ count of 24 2 months ago

• (-) diabetes, asthma, TB

• Used to smoke 1 pack of cigarettes per day; occasional alcoholic drinker

• Multiple flat, hyperpigmented lesions on his arms, legs and trunk

• (+) flattening of the right nasolabial fold

• Neuro examination revealed

▪ Slurring of speech

▪ Central facial palsy, pupils 2 mm OU, BRTL

▪ 2-3/5 motor power on the left side

▪ Hemihypesthesia on the left (approximately 20-30%)

▪ (+++) DTRs on the left, (+) Kernig’s, (+) Brudzinki’s sign

Upper motor neuron
• Corticospinal neuron
• Corticonuclear neuron
Cerebral cortex (pyramidal tract) –> Precentral gyrus (motor strip) → internal capsule (posterior limb) → brainstem → spinal cord • 85% cross to opposite side
Upper motor neuron lesions
• Interruption of the corticospinal and corticonuclear tract along its course Lower motor neuron
• Neurons from the brain stem & spinal cord
o efferent motor fibres
o terminal axons & motor end plates
o muscle fibres
Anterior horn cells in spinal cord→nerve roots→nerve plexus →peripheral nerves Lower motor neuron lesions
• Degeneration of the motor neuron & peripheral nerves

• 2. CNS influence the activity of skeletal muscle through two sets of neuron• Upper motor neuron• Lower motor neuron • 3. UPPER MOTOR NEURON• Upper motor neurons (UMN) are responsible for conveying impulses for voluntary motor activity through descending motor pathways that make up the upper motor neurons.• UMN send fibers to the LMN, and that exert direct or indirect supranuclear control over the LMN of the cranial and spinal nerves.. • 4. WHERE THEY COME FROM• .

• 5. • Axons from the cortical areas form the corticospinal and corticobulbar tracts.• 1/3 from primary motor cortex (Betz’s cell axons -3-5%, and other 95% from small neurons)• 1/3 from the somatic sensory cortex (areas 1, 2, and 3), and• adjacent temporal lobe region. • 6. HOW UPPER MOTOR NEURON FUNCTION Upper motor neuron control lower motor neuron through two different pathways• Pyramidal tract• Extra pyramidal tract • 7. PYRAMIDAL TRACTS•corticospinal tractEXTRAPYRAMIDAL TRACTS-•Reticulospinal Olivospinal•Vestibulospinal•Tectospinal•Rubrospinal tract•Corticobulbar tract•Corticorubral tract • 8. Nerve pathways Descending Tracts Tract Signal function Fine voluntary motor control of the limbs. TheCorticospinal (pyramidal) pathway also controls voluntary body posture adjustments. Involved in involuntary adjustment of arm position in Rubrospinal...
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