1.
The 105 YO female patient from Portsmouth, Dominica seems completely unaware of an ugly ulceration on the tip of her tongue. As you record this observation, you review the pathway of the pain fibers from the region, remembering that the cell bodies for pain, pressure and temperature from the anterior part of the tongue are located in the ...
Correct Answer
A. Semilunar (trigeminal) ganglion
Explanation
The semilunar (trigeminal) ganglion is the correct answer because it contains the cell bodies for pain, pressure, and temperature from the anterior part of the tongue. These sensory fibers travel from the tongue to the ganglion, where they synapse with second-order neurons before continuing to the brain. This ganglion is part of the trigeminal nerve, which is responsible for transmitting sensory information from the face and mouth. Therefore, any sensory deficits or unawareness of the ulceration on the tip of the tongue could be attributed to dysfunction or damage to the semilunar (trigeminal) ganglion.
2.
The 70 YO hypertensive patient had suffered numerous problems from her elevated blood pressure and vascular fragility. The most recent problem was a severe nosebleed from the anteroinferior portion of her nasal septum. Which of the following arteries would be LEAST LIKELY to be involved directly in such bleeding?
Correct Answer
C. Posterior ethmoidal
Explanation
The posterior ethmoidal artery is least likely to be involved directly in the severe nosebleed. The posterior ethmoidal artery is a branch of the ophthalmic artery and supplies blood to the posterior ethmoidal sinus and the nasal cavity. In this case, the bleeding is described as originating from the anteroinferior portion of the nasal septum, which is more likely to be supplied by other arteries such as the greater palatine artery, anterior ethmoidal artery, sphenopalatine artery, or superior labial artery.
3.
While on a fox hunt near Raleigh, North Carolina (where you are doing a 6 week rotation), a 21‑year‑old woman is thrown from her horse, which accidentally tramples her. She is kicked in the right side of the head at the pterion, and is dazed but not unconscious when her companions reach her. On the way back to the stable, however, she collapses and loses consciousness. When she is presented to you for examination, her right pupil is dilated in comparison with the left pupil. Her injury is MOST LIKELY
Correct Answer
E. Epidural hematoma
Explanation
The woman's injury is most likely an epidural hematoma because she experienced a head injury and subsequently collapsed and lost consciousness. The dilation of her right pupil suggests an increase in intracranial pressure, which is a characteristic of an epidural hematoma. This type of hematoma occurs when there is bleeding between the skull and the dura mater, typically caused by a tear in the middle meningeal artery. The delayed onset of symptoms after the initial injury is also consistent with an epidural hematoma.
4.
A 5O‑year‑old man is involved in an automobile accident and is brought into the Emergency Department with multiple injuries including trauma to the right side of the face and head. After his condition is stabilized a neurologic examination is performed. The patient complains of double vision. When you ask him to look downward and medially, you observe that the patient simply cannot turn the right pupil from an adducted position to a depressed position; that is, cannot look down and medially with that eye. What nerve(s) has (have) been injured?
Correct Answer
C. Right trochlear nerve
Explanation
The patient's inability to turn the right pupil from an adducted position to a depressed position suggests an injury to the right trochlear nerve. The trochlear nerve is responsible for innervating the superior oblique muscle, which controls downward and medial movement of the eye. In this case, the trauma to the right side of the face and head likely caused damage to the trochlear nerve, resulting in double vision and the specific eye movement deficit described.
5.
Which of the following structures would be MOST LIKELY subject to congenital malformation of structures derived from the first branchial (pharyngeal) arch?
Correct Answer
D. Mandible
Explanation
The mandible is the correct answer because it is derived from the first branchial (pharyngeal) arch during embryonic development. The first branchial arch gives rise to several structures in the head and neck region, including the mandible. Therefore, any congenital malformation affecting the first branchial arch would most likely affect the development of the mandible.
6.
An inexperienced emergency aid worker approaches the scene of an accident and finds a man unconscious and not breathing. He attempts a tracheostomy in order to place an oxygen tube in the patient's windpipe. However, blood begins to spurt briskly out of the deep midline incision that the technician has made in the patient's neck below the cricoid cartilage. What mistake has the technician made?
Correct Answer
B. Forgotten that 10% of people have a thyroid ima artery
Explanation
The technician has made the mistake of forgetting that 10% of people have a thyroid ima artery. This artery is located in the midline of the neck and can be inadvertently cut during a tracheostomy. This would result in brisk bleeding from the incision made by the technician.
7.
The artery which might MOST reasonably cause the nerve compression described in the previous question would be the ...
Correct Answer
B. Right posterior cerebral artery.
Explanation
The right posterior cerebral artery is the most likely artery to cause nerve compression in the previous question. This is because the right posterior cerebral artery supplies blood to the occipital lobe of the brain, which is responsible for vision. Compression of this artery could lead to impaired vision and potentially affect the nerve described in the previous question.
8.
The 25 YO laborer is your subject for a physical examination in the ICM course, an examination which will determine your academic fate in the next semester. The presenting complaint is cranial nerve dysfunction. As the physical exam proceeds, you gently stroke his left limbus with a cotton swab and note, with some surprise, that there is an ipsilateral response, but no contralateral response. You confirm your initial diagnosis by stroking his right limbus and observing a blink response only of the left upper eyelid. With this information you can rightly conclude that he has paralysis of his
Correct Answer
A. Right facial nerve
Explanation
Based on the information provided, when the left limbus is stroked, there is an ipsilateral response (response on the same side) and no contralateral response (response on the opposite side). This indicates that there is a dysfunction in the right facial nerve, as the right facial nerve controls the muscles responsible for blinking the left upper eyelid. The other options can be ruled out as the symptoms and findings mentioned in the question are specific to the right facial nerve.
9.
The patient was a 22 YO female, a visitor to the Ross campus, who complains that she is having problems with her right eye. To examine the eye, you find it necessary to elevate her superior palpebra with your finger, because of her inability to raise it normally. Her right pupil is deviated to the right and slightly downward. Her complaint about your bright examination light seems due to the dilation of her right pupil. Cerebral imaging studies reveal that one of her cranial nerves is being compressed by an aneurysm of an adjacent artery, just above the tentorium cerebelli, adjacent to the tentorial notch. The neural structure which is being affected by the aneurysm is the ...
Correct Answer
C. Right oculomotor nerve
Explanation
The patient's symptoms, such as the inability to raise her superior palpebra, deviation of the right pupil, and sensitivity to light, suggest dysfunction of the oculomotor nerve. The oculomotor nerve is responsible for controlling the movement of the eyelid and the constriction of the pupil. The compression of one of the cranial nerves by an adjacent artery, as revealed by cerebral imaging studies, further supports the involvement of the oculomotor nerve. Therefore, the correct answer is the right oculomotor nerve.
10.
The elderly fisherman was brought by his daughter to the clinic at Roseau. She states that he seems very confused lately; that his memory is not as sharp as she knows it usually to be, and that he doesn't move with his usual quickness and athleticism. She does not initially remember any injuries that he might have suffered. Your examination confirms the patient's lack of equilibrium and memory deficits. However, after you observe, and ask about a partially healed scalp laceration over the area of the lambda, she remembers that he complained about 10 days previously of having slipped and hitting his head on the mast of his boat. He said that he did not lose consciousness. Lumbar puncture reveals nothing; that is, there is no trace of blood in the CSF. You can, therefore, CORRECTLY conclude that ...
Correct Answer
B. A cerebral vein was torn, resulting in slow accumulation of blood in the subdural space.
Explanation
Based on the information provided, the patient's symptoms of confusion, memory deficits, lack of equilibrium, and a partially healed scalp laceration over the area of the lambda suggest a possible head injury. The absence of blood in the CSF indicates that there is no active bleeding, ruling out an epidural hematoma or subarachnoid hemorrhage. The tear in a cerebral vein would result in slow accumulation of blood in the subdural space, which can explain the patient's symptoms. Therefore, the correct conclusion is that a cerebral vein was torn, resulting in slow accumulation of blood in the subdural space.
11.
Following a road accident, a skull x‑ray reveals a fracture through the base of the skull involving the jugular foramen. Which of the following would NOT be seen with this type of injury?
Correct Answer
A. Lacrimal gland dysfunction
Explanation
A fracture through the base of the skull involving the jugular foramen would not cause lacrimal gland dysfunction. Lacrimal gland dysfunction is associated with damage to the facial nerve, which is not directly affected by this type of injury. The jugular foramen is located in the skull base and is responsible for transmitting the jugular vein and cranial nerves IX, X, and XI. Damage to these cranial nerves can result in hoarseness, dysphagia, parotid gland dysfunction, and dropped shoulder on the same side, but it would not affect the lacrimal gland.
12.
A patient presents with an arrow embedded in the carotid triangle. Which of the following is NOT LIKELY to be involved?
Correct Answer
A. Brachial plexus
Explanation
The brachial plexus is a network of nerves that innervates the upper limb, while the carotid triangle is located in the neck. Therefore, it is unlikely for the brachial plexus to be involved in this scenario.
13.
Which of the following statements is INCORRECT?
Correct Answer
C. Rupture of the middle meningeal artery causes a subdural hematoma
14.
A 35‑year‑old man comes to your office following a neck injury, which involves the cervical portion of the sympathetic trunk. Physical examination leads to a diagnosis of Horner's syndrome. Which of the following are NOT clinical signs of Horner's syndrome?
Correct Answer
A. Absence of the blink reflex
Explanation
Horner's syndrome is characterized by a triad of symptoms including pupillary miosis (constriction of the pupil), ptosis (drooping of the upper eyelid), and anhidrosis (absence of facial sweating). Additionally, flushing of the facial skin can also be observed in Horner's syndrome due to vasodilation. However, the absence of the blink reflex is not a clinical sign of Horner's syndrome. The blink reflex is mediated by the trigeminal nerve (cranial nerve V) and is not directly affected by sympathetic dysfunction in the cervical portion of the sympathetic trunk.
15.
A blink reflex occurs in your patient when you lightly touch the cornea. Which nerve carries the sensory (afferent) fibers involved in this reflex?
Correct Answer
B. OpHthalamic division of trigeminal nerve
Explanation
The ophthalmic division of the trigeminal nerve carries the sensory (afferent) fibers involved in the blink reflex. This division of the trigeminal nerve is responsible for providing sensation to the cornea, which is why when the cornea is lightly touched, the blink reflex is triggered. The other options listed in the question are not involved in carrying sensory fibers from the cornea.
16.
A 5‑year‑old female gradually developed difficulty walking and lack of coordination using her hands. Her doctor suspected that she might have a cerebellar tumor. From among the following, which test should be requested next in the evaluation of this patient?
Correct Answer
E. Magnetic resonance imaging (MRI) of the brain
Explanation
The correct answer is Magnetic resonance imaging (MRI) of the brain. This is the most appropriate test to evaluate a suspected cerebellar tumor in a 5-year-old female with difficulty walking and lack of coordination using her hands. MRI provides detailed images of the brain and can help identify the presence and location of a tumor. Skull radiographs, arteriogram of the arteries supplying the spinal cord, carotid Doppler ultrasound, and sonography of the brain through the anterior fontanelle are not the most appropriate tests for evaluating a cerebellar tumor.
17.
The median sacral artery
Correct Answer
B. Supplies part of the lower sigmoid colon and rectum
Explanation
The correct answer is "supplies part of the lower sigmoid colon and rectum." The median sacral artery is a branch of the abdominal aorta that supplies blood to the lower part of the sigmoid colon and the rectum. It does not supply blood past the "critical point of Sudeck," which is the point at which the blood supply to the sigmoid colon changes. It is not the main blood supply to the anorectal canal, and it is not a major site of thrombus formation affecting the sigmoid colon.
18.
In infants, chronic subdural hematoma can cause an enlarged head circumference. A subdural hematoma is MOST LIKELY to result from a ruptured
Correct Answer
D. Cerebral vein
Explanation
A chronic subdural hematoma is a collection of blood between the outermost layer of the brain (dura mater) and the middle layer (arachnoid mater). It is most commonly caused by a rupture of the cerebral vein, which drains blood from the brain back to the heart. When the cerebral vein ruptures, blood accumulates in the subdural space, leading to the formation of a hematoma. This can cause an increase in pressure within the skull, leading to an enlarged head circumference in infants.
19.
A 32‑year‑old woman sustained a head injury during a traffic accident, which resulted in palsy of her fourth cranial nerve. Injury to the 4th cranial nerve is MOST LIKELY to cause weakness of the:
Correct Answer
A. Superior oblique muscle
Explanation
Injury to the fourth cranial nerve, also known as the trochlear nerve, is most likely to cause weakness of the superior oblique muscle. The trochlear nerve innervates the superior oblique muscle, which is responsible for downward and outward movement of the eye. Damage to this nerve can result in difficulty in moving the eye in these directions, leading to weakness of the superior oblique muscle.
20.
During an annual medical examination the physician gently passed a feather over the patient's forehead, nose (dorsum) and upper eyelid. The patient, however, was unable to feel a touch sensation. Which nerve carries the sensory fibers involved in the innervation of the skin of the forehead, dorsum of nose and upper eyelid?
Correct Answer
E. OpHthalmic division of trigeminal
Explanation
The ophthalmic division of the trigeminal nerve carries the sensory fibers involved in the innervation of the skin of the forehead, dorsum of the nose, and upper eyelid. This division of the trigeminal nerve is responsible for providing sensation to these areas of the face.
21.
Following a traffic accident, a patient had difficulty chewing. She developed sensory loss from the mandibular teeth, anterior two thirds of tongue, lateral scalp and chin. The fracture site MOST LIKELY involved is the:
Correct Answer
E. Foramen ovale
Explanation
The foramen ovale is a small opening in the sphenoid bone located in the middle cranial fossa. It is responsible for transmitting the mandibular nerve, which provides sensory innervation to the mandibular teeth, anterior two-thirds of the tongue, lateral scalp, and chin. In this case, the patient's difficulty chewing and sensory loss in these specific areas suggest that the fracture site involved the foramen ovale, leading to damage or compression of the mandibular nerve.