1.
A 73-year aid woman experienced worsening diplopia. MRI examinations showed bilateral roundish parasellar and intracavernous masses, with homogeneous contrast-enhancement. CerebraI angiography revealed bilateral aneurysms of the intracavernous carotid artery. The aneurism was compressing the nerve directly next to the mass. The diplopia was due to progressive bilateral paresis of which muscles?
Correct Answer
C. Lateral rectus
Explanation
The diplopia experienced by the 73-year-old woman was due to progressive bilateral paresis of the lateral rectus muscles. The MRI examinations showed masses in the parasellar and intracavernous regions, which were compressing the intracavernous carotid artery. This compression was directly affecting the nerve next to the mass, leading to the weakness of the lateral rectus muscles.
2.
A 26-year old woman presented with diplopia. The abduction of both eyes were normal. The adduction of both eyes were quite limited in each eye. MRI revealed a multifocal lesion in the pons bilaterally next to the midline. Which structure is most probably affected?
Correct Answer
E. Medial longitudinal fascicle
Explanation
The patient's presentation of limited adduction of both eyes suggests a dysfunction in the medial longitudinal fascicle (MLF). The MLF is responsible for coordinating eye movements, specifically the conjugate movement of the eyes during horizontal gaze. Lesions in the MLF can result in internuclear ophthalmoplegia, which is characterized by impaired adduction of the affected eye and nystagmus in the contralateral abducting eye. Therefore, the most probable structure affected in this patient is the medial longitudinal fascicle.
3.
A 56-year old male had a sexually transmitted disease 20 years ago after an unprotected sexual encounter. He now presents with neurological problems including cognitive and visual problems. On physical examination you would expect his pupils to:
Correct Answer
D. Not react to light and accommodate
Explanation
The patient's history of a sexually transmitted disease 20 years ago suggests the possibility of neurosyphilis, which can cause neurological problems including cognitive and visual problems. One of the characteristic signs of neurosyphilis is the Argyll Robertson pupil, which is a pupil that does not react to light but still accommodates (constricts) when focusing on near objects. Therefore, in this case, we would expect the patient's pupils to not react to light but still accommodate.
4.
A young boy is brought to the clinic. He appears quite small for his age and complains of not being able to see as well as he used to. Visual field examination reveals a bi-temporal hemianopsia . You suspect a tumor located near which of the following?
Correct Answer
A. Pituitary gland and stalk
Explanation
The young boy's symptoms of being small for his age and experiencing visual field loss, specifically a bi-temporal hemianopsia, suggest a tumor located near the pituitary gland and stalk. The pituitary gland is responsible for producing hormones that control growth and development, so a tumor in this area could affect the boy's growth and also compress the optic chiasm, resulting in visual field loss. The other options listed are not associated with the symptoms described.
5.
A 52-year-old woman has difficulty reading small print in newspapers and magazines. Her ophthalmologist explains to her that she is suffering from a condition due to a loss of her ability to accommodate and focus on near objects. She most likely has which of the following?
Correct Answer
E. Presbyopia
Explanation
Presbyopia is the loss of ability to focus on near objects that typically occurs with age. This condition is characterized by difficulty reading small print and is commonly seen in individuals over the age of 40. Astigmatism refers to an irregularly shaped cornea, cataracts involve clouding of the lens, optic atrophy is the degeneration of the optic nerve, and macular degeneration affects the central vision. None of these conditions specifically explain the difficulty in focusing on near objects, making presbyopia the most likely diagnosis.
6.
A 50-year old taxi driver is currently hospitalized after suffering from a stroke. During the history, he denied impairment of his vision. The significant findings on physical examination were decreased vision and decreased movement of the vertical movements of his left eye. He also had left homonymous hemianopsia. Based on the findings, his stroke was most likely due to lesion affecting the area supplied which artery?
Correct Answer
B. Posterior cerebral arteries
Explanation
The patient's symptoms of decreased vision, decreased movement of the vertical movements of his left eye, and left homonymous hemianopsia suggest that the stroke is affecting the posterior cerebral arteries. The posterior cerebral arteries supply the occipital lobe, which is responsible for vision processing. Lesions in this area can lead to visual impairments and eye movement abnormalities.
7.
Imaging studies were ordered. If the deficits seen were due to the stroke, the lesion would most likely to be located in shaded area in:
Correct Answer
E. E
Explanation
The question mentions that imaging studies were ordered to determine the location of the lesion causing the deficits. The correct answer, E, suggests that the lesion is most likely located in that area. The information provided does not give any specific details about the deficits or the imaging findings, so it is not possible to provide a more detailed explanation.
8.
During a routine neurological examination you perform a corneal reflex text. When you touch the right eye of your patient there is no direct reflex but an intact consensual reflex. This suggests damage to which region of the nervous system?
Correct Answer
A. Damage to the facial nerve fibers that innervate the ipsilateral orbicularis oculi muscles
Explanation
The corneal reflex is mediated by the trigeminal nerve (cranial nerve V) and the facial nerve (cranial nerve VII). When the cornea is touched, sensory fibers from the ophthalmic branch of the trigeminal nerve send signals to the brainstem, which then activates the facial nerve to produce a blink response. In this case, there is no direct reflex when the right eye is touched, but there is an intact consensual reflex, suggesting that the sensory fibers of the trigeminal nerve are intact and the damage is localized to the facial nerve fibers that innervate the ipsilateral orbicularis oculi muscles.
9.
A 21-year old professional female basketball player was advised by her coach to go to see her physician. She could not perform so well lately, she often did not notice the ball coming from the back and she had constant headaches. She said it was probably due to her emotional state, because she broke up with her boyfriend a few months ago. Even her period became very irregular the last few months. The coach wanted the doctor to prescribe some calming pills for her, but the doctor became suspicious that there were some other problems, since he found visual field loss on both temporal sides. His suspicion was confirmed later by MRI. Which of the following is most possible based on the symptoms?
Correct Answer
B. Pituitary adenoma, causing compression of the optic chiasma and leading to hormonal deficiencies.
Explanation
The symptoms described in the question, such as visual field loss on both temporal sides, irregular periods, and hormonal deficiencies, suggest a problem with the pituitary gland. The pituitary gland is responsible for producing hormones that regulate various bodily functions, including the menstrual cycle. A pituitary adenoma, a benign tumor of the pituitary gland, can cause compression of the optic chiasma, leading to visual field loss, as well as hormonal imbalances. This explanation is supported by the fact that the doctor confirmed the suspicion later with an MRI.
10.
The electron micrograph below was taken of a section of the eye. The positions of the landmarks "Photoreceptor outer segments" and "Cap" (designating a capillary) are shown. Of the choices below, the arrow is pointing to the nucleus of which cell type?
Correct Answer
D. Melanocyte
Explanation
The electron micrograph of the eye section shows the positions of the landmarks "Photoreceptor outer segments" and "Cap" (capillary). The arrow is pointing to the nucleus of a cell type, and the correct answer is Melanocyte.
11.
Shown above is a drawing of a portion of the iris of the eye. What is the function of the structure located at the tip of the arrow?
Correct Answer
B. Pupil constriction
Explanation
The structure located at the tip of the arrow is responsible for pupil constriction. Pupil constriction is an important function of the iris, as it helps regulate the amount of light entering the eye. When the pupil constricts, it becomes smaller, allowing less light to enter the eye. This is particularly important in bright environments, as it helps protect the retina from excessive light exposure and maintains optimal vision.
12.
Which of the following statements about the choroid of the eye is INCORRECT?
Correct Answer
D. The choroid touches the neural retina
Explanation
The choroid does not directly touch the neural retina. There is a layer called the Bruch's membrane that separates the choroid from the neural retina. The choroid is responsible for supplying blood and nutrients to the retina, but it does not make direct contact with it.
13.
Oescemet's membrane is found in which structure of the eye?
Correct Answer
E. Cornea
Explanation
Descemet's membrane is a thin, transparent layer located in the cornea of the eye. It is a part of the posterior layer of the cornea and is composed of collagen fibers. It helps maintain the shape and integrity of the cornea, providing structural support and protection to the eye.
14.
An astigmatism is caused by a region of unequal curvature in
Correct Answer
C. A or B.
Explanation
An astigmatism is caused by a region of unequal curvature in either the lens or the cornea. This means that the surface of either the lens or the cornea is not perfectly spherical, leading to distorted vision. The unequal curvature causes light to be focused at different points on the retina, resulting in blurred or distorted images. Therefore, the correct answer is A or B.