The patient may have impaired voluntary movements.
The cerebellum is a part of the brain concerned with motor coordination of voluntary movements, equilibrium, and muscle tone. Any damage to the cerebellum may lead to the impairment of voluntary movements or motor functions in the patient. The function of the hypothalamus is the maintenance of temperature, appetite, sex drive, heart rate, and blood pressure; therefore, the patient may have loss of libido and impaired thermoregulation when there is damage in the hypothalamus. The function of the cerebral cortex is to govern thought processes, memory, reasoning, and sensation; therefore, the patient with cerebral cortex injury or damage may have complete or partial loss of memory.
The back is hyperextended, and the palms are pronated.
In decerebrate rigidity, the upper extremities of the patient are stiffly extended and adducted. The palms are pronated, the teeth are clenched, and the back is hyperextended. It indicates a lesion in the brainstem at the midbrain or upper pons. In decorticate rigidity, the arms are flexed and adducted (i.e., tight against the thorax), and the legs are extended with plantar flexion. This indicates a hemispheric lesion of the cerebral cortex. In flaccid quadriplegia, complete loss of muscle tone and paralysis of all four extremities occur. It indicates a completely nonfunctional brainstem. Prolonged arching of the back, with the head and heels bent backward, is a symptom of opisthotonos. This indicates meningeal irritation.
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Degeneration of the dopamine-containing neurons
Resting tremors, slow movement, or bradykinesia, flat expression, reduced eye blinking, and slouched posture indicate parkinsonism in the patient. It is a neurodegenerative disease of the central nervous system. It occurs due to the degeneration of the dopaminergic neurons in the substantia nigra of the brain. Damage to the cerebral cortex may cause cerebral palsy, but not parkinsonism. The patient with cerebral palsy may have seizures, but not resting tremors. Damage to the corticospinal tract and degeneration of the upper motor neurons may result in hemiplegia, which refers to the contralateral paralysis of the upper and lower limbs. The patient with hemiplegia will not necessarily have slouched posture. The patient with hemiplegia may have a posture characterized by an adducted shoulder, flexed elbow, pronated wrist, and extended leg.
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Cranial nerve II
Cranial nerve III
Multiple sclerosis is an immune-mediated disease in which axons undergo inflammation, demyelination, degeneration, and finally sclerosis. Cranial nerve II (the optic nerve) and cranial nerve III (the oculomotor nerve) frequently undergo demyelination in patients with multiple sclerosis, resulting in nystagmus and diplopia. Damage to cranial nerve I (the olfactory nerve) may occur due to fracture of the cribriform plate, a lesion in the frontal lobe, or due to the presence of a tumor in the olfactory bulb. A tumor in the brainstem may cause damage to the abducens, or cranial nerve VI. Damage to cranial nerve VII, the facial nerve, is associated with Bell's palsy, but not multiple sclerosis.
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The patient bites the tongue.
The patient opens the mouth and the eyes.
Excessive and abnormal neuronal activity in the brain may cause seizures in the patient. The different phases of a generalized seizure include loss of consciousness followed by the tonic phase, clonic phase, and postictal phase. The patient will have muscle rigidity during the tonic phase, and may bite the tongue, open the mouth, and cry in a high-pitched voice during the tonic phase. Increased heart rate, facial grimace, and violent muscular contractions characterize the clonic phase. The postictal phase is the last phase of a generalized seizure, and is characterized by deep sleep, disorientation, and confusion.
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The patient has bilateral lesions on cranial nerve X.
Cranial nerve X is also known as the vagus nerve, and it innervates the heart and the digestive tract. The patient with bilateral lesions on the vagus nerve may have difficulty swallowing, and the fluids may be regurgitated through the nose. Cranial nerve XII, which is also known as the hypolossal nerve, innervates the tongue and controls the movement of the tongue. Therefore, the patient with a cranial nerve XII lesion may have a slow rate of movement of the tongue. Cranial nerve V, which is also referred to as the trigeminal nerve, innervates the muscles of the jaw. Therefore, the patient with a unilateral cranial nerve V lesion may have weakness of the jaw muscles. Cranial nerve III, which is also referred to as the oculomotor nerve, innervates the muscles of the eyeball. Therefore, the patient with cranial nerve III paralysis may have dilated pupils and ptosis, or drooping eyelids.