5. Clinical manifestations of lesions in the
vary depending on the area
affected. If the medulla oblongata is affected the clinical presentations are ipsilateral myasthenia, hyperactive limb reflexes and proprioceptive deficits. If the pons is affected the manifestations are hemiparesis or quadripariesis, hyperactive limb reflexes, depression, and trigeminal nerve defects. If the lesion is located in the midbrain there may be occulomotor nerve deficits visible with mild injury and coma or stupor in cases of severe lesions.
6. Lesions affecting the vestibular system affect and spatial orientation. Clinically lesions of the vestibular system are seen as loss of balance, frequent falling, rolling, head tilt, nystagmus, strabismus, and asymmetric ataxia.
Peripheral nervous system lesions may affect the autonomic, or involuntary, branch of the nervous system or they may affect the somatic, or voluntary, branch of the nervous system. Lesions of the peripheral nervous system are detected through the testing of the function of the effector organs. In the case of the autonomic nervous system the function of smooth muscle, glands and reflexes allows us to explore the integrity of the autonomic nerves, and in the case of the somatic nervous system the function of skeletal muscle reveals the condition of the somatic nerves. nervous system may be seen as exaggeration of either the sympathetic innervation or of the parasympathetic innervation. These two parts of the autonomic nervous system are antagonistic. Most of the body has innervation by both these systems, and neural input from both keep the body functioning within normal parameters. If one part of the autonomic nervous system is damaged there is a loss of balance which is seen as the exaggerated expression of the undamaged part. 7. Lesions affecting the Sympathetic outflow is thoracolumbar while parasympathetic outflow is craniosacral. Absence of sympathetic control and exaggeration of parasympathetic control is indicative of damage to the thoracolumbar spinal nerves from T1 to L4. Clinically sympathetic lesions are seen as ptosis, miosis, enophthalmos, and bradycardia if the cervical ganglia are affected, and as impotence and increased gastrointestinal tract motility if the celiac and mesenteric ganglia are affected. If the entire sympathetic trunk is affected the above symptoms will be present as well as hypotension, and fainting. Absence of parasympathetic control and exaggeration of the sympathetic control is indicative of damage to the cranial nerves or the sacral spinal nerves. Loss of sacral parasympathetic innervation is usually seen as urinary incontinence, and sometimes constipation, while loss of cranial parasympathetic innervation is seen as inability to constrict pupils in response to light, strabismus, decreased saliva production, increased sweating, dysphasia, tachycardia, and death.
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