A 3-year-old girl is brought to the emergency department by her parents with sudden onset shortness of breath. They tell the emergency physician that their daughter was lying on the bed watching television when she suddenly began gasping for air. They observed a bowl of peanuts lying next to her when they grabbed her up and brought her to the emergency department. Her respirations are 25/min, the pulse is 100/min and the blood pressure is 90/65 mm Hg. The physical findings as of now are apparently normal. She is started on oxygen and is sent in for a chest X-ray. Based on her history and physical exam findings, the cause of her current symptoms would be seen on the X-ray at which of the following sites?
Q2
A 75-year-old man presents to the clinic for chronic fatigue of 3 months duration. Past medical history is significant for type 2 diabetes and hypertension, both of which are controlled with medications, as well as constipation. He denies any fever, weight loss, pain, or focal neurologic deficits. A complete blood count reveals microcytic anemia, and a stool guaiac test is positive for blood. He is subsequently evaluated with a colonoscopy. The physician notes some “small pouches” in the colon despite poor visualization due to inadequate bowel prep. What is the blood vessel that supplies the area with the above findings?
Q3
A 76-year-old woman with hypertension and coronary artery disease is brought to the emergency department after the sudden onset of right-sided weakness. Her pulse is 83/min and blood pressure is 156/90 mm Hg. Neurological examination shows right-sided facial drooping and complete paralysis of the right upper and lower extremities. Tongue position is normal and she is able to swallow liquids without difficulty. Knee and ankle deep tendon reflexes are exaggerated on the right. Sensation to vibration, position, and light touch is normal bilaterally. She is oriented to person, place, and time, and is able to speak normally. Occlusion of which of the following vessels is the most likely cause of this patient's current symptoms?
Q4
A 65-year-old man presents to the emergency department with vague, constant abdominal pain, and worsening shortness of breath for the past several hours. He has baseline shortness of breath and requires 2–3 pillows to sleep at night. He often wakes up because of shortness of breath. Past medical history includes congestive heart failure, diabetes, hypertension, and hyperlipidemia. He regularly takes lisinopril, metoprolol, atorvastatin, and metformin. His temperature is 37.0°C (98.6°F), respiratory rate 25/min, pulse 67/min, and blood pressure 98/82 mm Hg. On physical examination, he has bilateral crackles over both lung bases and a diffusely tender abdomen. His subjective complaint of abdominal pain is more severe than the observed tenderness on examination. Which of the following vessels is involved in the disease affecting this patient?
Q5
A 78-year-old left-handed woman with hypertension and hyperlipidemia is brought to the emergency room because of sudden-onset right leg weakness and urinary incontinence. Neurologic examination shows decreased sensation over the right thigh. Muscle strength is 2/5 in the right lower extremity and 4/5 in the right upper extremity. Strength and sensation in the face are normal but she has difficulty initiating sentences and she is unable to write her name. The most likely cause of this patient’s condition is an occlusion of which of the following vessels?
Q6
A 3175-g (7-lb) male newborn is delivered at 39 weeks' gestation to a 29-year-old primigravid woman following a spontaneous vaginal delivery. Apgar scores are 8 and 9 at 1 and 5 minutes, respectively. Cardiac examination in the delivery room shows a continuous machine-like murmur. An echocardiogram shows a structure with blood flow between the pulmonary artery and the aorta. This structure is most likely a derivate of which of the following?
Q7
A researcher is investigating the blood supply of the adrenal gland. While performing an autopsy on a patient who died from unrelated causes, he identifies a vessel that supplies oxygenated blood to the inferior aspect of the right adrenal gland. Which of the following vessels most likely gave rise to the vessel in question?
Q8
A 40-year-old woman is brought to the emergency department by a paramedic team from the scene of a motor vehicle accident where she was the driver. The patient was restrained by a seat belt and was unconscious at the scene. On physical examination, the patient appears to have multiple injuries involving the trunk and extremities. There are no penetrating injuries to the chest. As part of her trauma workup, a CT scan of the chest is ordered. At what vertebral level of the thorax is this image from?
Q9
A 68-year-old man is brought to the emergency department by ambulance after he was found to be altered at home. Specifically, his wife says that he fell and was unable to get back up while walking to bed. When she approached him, she found that he was unable to move his left leg. His past medical history is significant for hypertension, atrial fibrillation, and diabetes. In addition, he has a 20-pack-year smoking history. On presentation, he is found to still have difficulty moving his left leg though motor function in his left arm is completely intact. The cause of this patient's symptoms most likely occurred in an artery supplying which of the following brain regions?
Q10
A 25-year-old man presents with progressive weakness and urinary retention. MRI of the spine shows an intramedullary lesion from T10-T12 with expansion of the spinal cord and syrinx formation. The conus medullaris is identified at the L1-L2 level (normal: L1-L2). The filum terminale appears thickened at 3 mm. CSF flow study shows obstruction at the lesion site. Evaluate these radiologic landmarks and their relationships to determine the neurological level most likely affected.
Vascular radiologic landmarks US Medical PG Practice Questions and MCQs
Question 1: A 3-year-old girl is brought to the emergency department by her parents with sudden onset shortness of breath. They tell the emergency physician that their daughter was lying on the bed watching television when she suddenly began gasping for air. They observed a bowl of peanuts lying next to her when they grabbed her up and brought her to the emergency department. Her respirations are 25/min, the pulse is 100/min and the blood pressure is 90/65 mm Hg. The physical findings as of now are apparently normal. She is started on oxygen and is sent in for a chest X-ray. Based on her history and physical exam findings, the cause of her current symptoms would be seen on the X-ray at which of the following sites?
A. The superior segment of the right lower lobe
B. The posterior segment of the right lower lobe (Correct Answer)
C. The lingula of the left upper lobe
D. The apical segment of the right upper lobe
E. The apical segment of the left upper lobe
Explanation: ***The posterior segment of the right lower lobe***
- This is the **most common site for foreign body aspiration in a supine or lying down position** due to gravity and anatomical orientation.
- The history explicitly states the child was **"lying on the bed watching television"** when aspiration occurred, making the **posterior segment of the right lower lobe** the most gravity-dependent and therefore most likely location.
- The **right main bronchus** is wider, shorter, and more vertical than the left, making the right lung the predominant site for aspiration, and in supine position, the posterior segment is most dependent [1, 2].
*The superior segment of the right lower lobe*
- The **superior segment of the right lower lobe** is the most common site for aspiration in **upright, standing, or semi-upright positions**, not in a supine position.
- Since the child was lying down (supine), gravity would direct the aspirated peanut to the **posterior segment** rather than the superior segment.
- This would be correct if the child had aspirated while sitting upright.
*The lingula of the left upper lobe*
- The **lingula** is an uncommon site for aspiration because the **left main bronchus** has a sharper angle and smaller diameter compared to the right bronchus [2].
- The anatomical differences make aspiration into the right lung significantly more common than the left lung [2].
- The lingula is not a gravity-dependent area in the supine position.
*The apical segment of the right upper lobe*
- The **apical segment of the right upper lobe** is associated with aspiration when the patient is in **Trendelenburg position** (head lower than feet) or in extreme head-down positions.
- The described scenario of lying flat on the bed does not favor aspiration into apical segments, which are non-gravity-dependent in supine position.
- This location would be contra-gravity in the supine position.
*The apical segment of the left upper lobe*
- Aspiration into the **left upper lobe** is less frequent than the right lung due to the sharper angle of the left main bronchus [2].
- The **apical segment** would require head-down positioning (Trendelenburg) that is not described in this clinical scenario.
- This is the least likely location given both the supine position and left-sided anatomy.
Question 2: A 75-year-old man presents to the clinic for chronic fatigue of 3 months duration. Past medical history is significant for type 2 diabetes and hypertension, both of which are controlled with medications, as well as constipation. He denies any fever, weight loss, pain, or focal neurologic deficits. A complete blood count reveals microcytic anemia, and a stool guaiac test is positive for blood. He is subsequently evaluated with a colonoscopy. The physician notes some “small pouches” in the colon despite poor visualization due to inadequate bowel prep. What is the blood vessel that supplies the area with the above findings?
A. Ileocolic artery
B. Superior mesenteric artery
C. Inferior mesenteric artery (Correct Answer)
D. Middle colic artery
E. Right colic artery
Explanation: ***Inferior mesenteric artery***
- The patient's **microcytic anemia** and **positive stool guaiac test** indicate chronic gastrointestinal blood loss, highly suggestive of **diverticulosis** presenting as "small pouches" in the colon.
- Diverticulosis commonly affects the **descending colon** and **sigmoid colon**, which are primarily supplied by branches of the **inferior mesenteric artery**.
*Ileocolic artery*
- The ileocolic artery is a branch of the **superior mesenteric artery** and supplies the **ileum**, **cecum**, and **ascending colon**.
- Diverticula are less commonly found in these regions compared to the left colon.
*Superior mesenteric artery*
- The superior mesenteric artery supplies the **midgut derivatives**, including the **small intestine** and the **right half of the large intestine** (up to the distal transverse colon).
- While it supplies a large portion of the GI tract, the typical location of diverticulosis (descending and sigmoid colon) is outside its primary distribution.
*Middle colic artery*
- The middle colic artery is a branch of the **superior mesenteric artery** and supplies the **transverse colon**.
- While diverticula can occur in the transverse colon, it is not the most common location, and the inferior mesenteric artery supplies the areas most frequently affected.
*Right colic artery*
- The right colic artery is a branch of the **superior mesenteric artery** and supplies the **ascending colon**.
- Diverticula are less frequently found in the ascending colon compared to the descending and sigmoid colon.
Question 3: A 76-year-old woman with hypertension and coronary artery disease is brought to the emergency department after the sudden onset of right-sided weakness. Her pulse is 83/min and blood pressure is 156/90 mm Hg. Neurological examination shows right-sided facial drooping and complete paralysis of the right upper and lower extremities. Tongue position is normal and she is able to swallow liquids without difficulty. Knee and ankle deep tendon reflexes are exaggerated on the right. Sensation to vibration, position, and light touch is normal bilaterally. She is oriented to person, place, and time, and is able to speak normally. Occlusion of which of the following vessels is the most likely cause of this patient's current symptoms?
A. Ipsilateral anterior cerebral artery
B. Contralateral middle cerebral artery
C. Anterior spinal artery
D. Contralateral lenticulostriate artery (Correct Answer)
E. Ipsilateral posterior inferior cerebellar artery
Explanation: ***Contralateral lenticulostriate artery***
- The patient presents with **pure motor hemiparesis** affecting the face, arm, and leg equally on the right side, with **no sensory deficits, aphasia, or cognitive impairment**.
- This clinical pattern is classic for a **lacunar stroke** affecting the **internal capsule**, which is supplied by the **lenticulostriate arteries** (branches of the middle cerebral artery).
- The internal capsule contains tightly packed corticospinal and corticobulbar fibers; a small infarct here causes complete contralateral motor deficits without cortical signs.
- The **absence of cortical findings** (normal speech, cognition, and sensation) distinguishes this from cortical MCA stroke.
*Contralateral middle cerebral artery*
- A **cortical MCA stroke** would typically present with **cortical signs** such as aphasia (if left hemisphere), neglect (if right hemisphere), sensory loss, and visual field defects.
- MCA strokes usually show **arm and face > leg** weakness (the leg area is supplied by ACA).
- This patient's **pure motor syndrome** without cortical signs points to a subcortical lesion, not cortical MCA occlusion.
*Ipsilateral anterior cerebral artery*
- First, the lateralization is incorrect - symptoms are right-sided, indicating left hemisphere pathology, so it would be **contralateral** ACA.
- ACA occlusion causes weakness predominantly in the **contralateral leg > arm**, with relative sparing of the face.
- This patient has equal involvement of face, arm, and leg, which is inconsistent with ACA territory.
*Anterior spinal artery*
- The **anterior spinal artery** supplies the anterior two-thirds of the spinal cord, including the corticospinal tracts and anterior horn cells.
- Occlusion causes **bilateral** motor weakness below the lesion level and bilateral loss of pain/temperature sensation.
- It does not cause **unilateral facial weakness** or the distribution of deficits seen in this patient.
*Ipsilateral posterior inferior cerebellar artery*
- Again, lateralization is incorrect - symptoms would be from **contralateral** PICA for motor findings, but PICA supplies the lateral medulla and inferior cerebellum.
- PICA occlusion causes **lateral medullary syndrome (Wallenberg syndrome)**: ataxia, vertigo, dysphagia, dysarthria, Horner syndrome, and contralateral pain/temperature loss.
- The patient's **pure motor hemiparesis** without cerebellar or brainstem signs is incompatible with PICA occlusion.
Question 4: A 65-year-old man presents to the emergency department with vague, constant abdominal pain, and worsening shortness of breath for the past several hours. He has baseline shortness of breath and requires 2–3 pillows to sleep at night. He often wakes up because of shortness of breath. Past medical history includes congestive heart failure, diabetes, hypertension, and hyperlipidemia. He regularly takes lisinopril, metoprolol, atorvastatin, and metformin. His temperature is 37.0°C (98.6°F), respiratory rate 25/min, pulse 67/min, and blood pressure 98/82 mm Hg. On physical examination, he has bilateral crackles over both lung bases and a diffusely tender abdomen. His subjective complaint of abdominal pain is more severe than the observed tenderness on examination. Which of the following vessels is involved in the disease affecting this patient?
A. Left anterior descending
B. Celiac artery and superior mesenteric artery (Correct Answer)
C. Left colic artery
D. Right coronary artery
E. Meandering mesenteric artery
Explanation: **Celiac artery and superior mesenteric artery**
- The patient's presentation with **vague, constant abdominal pain** out of proportion to physical exam findings (**abdominal pain more severe than tenderness**) in the setting of **congestive heart failure** and **hypotension** is highly suggestive of **non-occlusive mesenteric ischemia (NOMI)**.
- NOMI results from **splanchnic vasoconstriction** leading to hypoperfusion of the bowel, primarily affecting the territories supplied by the **celiac artery** and **superior mesenteric artery**, which supply the foregut and midgut, respectively.
*Left anterior descending*
- The left anterior descending (LAD) artery primarily supplies the **left ventricle** and interventricular septum.
- Occlusion of the LAD typically causes a **myocardial infarction** with chest pain, EKG changes, and elevated cardiac enzymes, which is not the primary presentation here, although a degree of cardiac compromise exacerbates the NOMI.
*Left colic artery*
- The left colic artery is a branch of the **inferior mesenteric artery** and supplies portions of the **descending colon**.
- While bowel ischemia can affect this region, NOMI, a more widespread condition, is unlikely to be isolated to the left colic artery distribution, and the patient's symptoms are more consistent with multi-vessel involvement.
*Right coronary artery*
- The right coronary artery (RCA) supplies the **right ventricle**, inferior wall of the left ventricle, and often the **SA and AV nodes**.
- RCA occlusion typically leads to **inferior wall myocardial infarction** and can cause bradyarrhythmias, but it would not directly cause the described abdominal pain and out-of-proportion findings.
*Meandering mesenteric artery*
- The meandering mesenteric artery is an anatomical variant, an **anastomotic connection** between the superior and inferior mesenteric arteries.
- While it can be a source of collateral flow, it is not a primary vessel targeted in the pathogenesis of NOMI, which affects the main mesenteric arteries due to global hypoperfusion.
Question 5: A 78-year-old left-handed woman with hypertension and hyperlipidemia is brought to the emergency room because of sudden-onset right leg weakness and urinary incontinence. Neurologic examination shows decreased sensation over the right thigh. Muscle strength is 2/5 in the right lower extremity and 4/5 in the right upper extremity. Strength and sensation in the face are normal but she has difficulty initiating sentences and she is unable to write her name. The most likely cause of this patient’s condition is an occlusion of which of the following vessels?
A. Right vertebrobasilar artery
B. Right middle cerebral artery
C. Left posterior cerebral artery
D. Left anterior cerebral artery (Correct Answer)
E. Right anterior cerebral artery
Explanation: ***Left anterior cerebral artery***
- Stroke in the **left anterior cerebral artery (ACA)** territory typically causes **contralateral leg weakness** (right leg in this case) and **urinary incontinence** due to involvement of the paracentral lobule.
- The patient's difficulty writing her name (agraphia) and initiating sentences (transcortical motor aphasia, which can manifest as difficulty initiating speech) is consistent with damage to the supplemental motor area in the dominant (left) hemisphere, provided by the ACA.
*Right vertebrobasilar artery*
- Occlusion of the vertebrobasilar artery typically presents with a wide range of symptoms including **vertigo**, **ataxia**, **dysarthria**, and bilateral or alternating sensory/motor deficits.
- It would not selectively cause isolated right leg weakness, urinary incontinence, and dominant hemisphere language difficulties without other brainstem or cerebellar signs.
*Right middle cerebral artery*
- A stroke in the **right middle cerebral artery (MCA)** would cause **left-sided deficit**, not right-sided.
- Although it can cause motor and sensory deficits, it typically affects the arm and face more than the leg, and would not cause the specific language deficits of the dominant hemisphere seen here.
*Left posterior cerebral artery*
- Occlusion of the **left posterior cerebral artery (PCA)** typically leads to issues like **contralateral homonymous hemianopia**, visual field defects, and potentially memory impairment or alexia without agraphia if the splenium of the corpus callosum is involved.
- It directly affects posterior brain regions, so it would not cause the anterior cerebral artery specific symptoms such as prominent contralateral leg weakness, urinary incontinence, or the described language difficulties.
*Right anterior cerebral artery*
- Occlusion of the **right anterior cerebral artery (ACA)** would cause **left leg weakness** and **left-sided sensory deficits**, not the right-sided deficits observed in this patient.
- While it could cause urinary incontinence, the combination of right-sided weakness and dominant hemisphere language deficits points against a right ACA occlusion.
Question 6: A 3175-g (7-lb) male newborn is delivered at 39 weeks' gestation to a 29-year-old primigravid woman following a spontaneous vaginal delivery. Apgar scores are 8 and 9 at 1 and 5 minutes, respectively. Cardiac examination in the delivery room shows a continuous machine-like murmur. An echocardiogram shows a structure with blood flow between the pulmonary artery and the aorta. This structure is most likely a derivate of which of the following?
A. 4th aortic arch
B. 1st aortic arch
C. 6th aortic arch (Correct Answer)
D. 2nd aortic arch
E. 3rd aortic arch
Explanation: ***6th aortic arch***
- The description of a "continuous machine-like murmur" and a structure with blood flow between the pulmonary artery and the aorta is characteristic of a **patent ductus arteriosus (PDA)**.
- The **ductus arteriosus** is a remnant of the **6th aortic arch**, connecting the pulmonary artery to the aorta in fetal life.
*4th aortic arch*
- The **4th aortic arch** contributes to the formation of the **aortic arch** itself on the left side and the proximal **right subclavian artery** on the right.
- Abnormalities of the 4th arch can lead to conditions like **coarctation of the aorta** or **vascular rings**, which do not typically present as a PDA.
*1st aortic arch*
- The **1st aortic arch** largely disappears, but its remnants contribute to the formation of the **maxillary artery** and the **external carotid artery**.
- It is not involved in developmental anomalies of the major vessels between the pulmonary artery and aorta.
*2nd aortic arch*
- The **2nd aortic arch** also largely regresses, but its remnants contribute to the **stapedial artery** and part of the **hyoid artery**.
- It does not play a role in the formation of the ductus arteriosus or other major arteries of the heart.
*3rd aortic arch*
- The **3rd aortic arch** develops into the common carotid arteries and the proximal internal carotid arteries.
- Genetic disorders and malformations involving this arch typically affect the carotid system, not the connection between the pulmonary artery and aorta.
Question 7: A researcher is investigating the blood supply of the adrenal gland. While performing an autopsy on a patient who died from unrelated causes, he identifies a vessel that supplies oxygenated blood to the inferior aspect of the right adrenal gland. Which of the following vessels most likely gave rise to the vessel in question?
A. Inferior phrenic artery
B. Abdominal aorta
C. Renal artery (Correct Answer)
D. Superior mesenteric artery
E. Common iliac artery
Explanation: ***Renal artery***
- The **inferior suprarenal artery**, which supplies the inferior part of the adrenal gland, typically arises from the **renal artery**.
- The adrenal glands receive a rich blood supply from three main arterial sources: superior, middle, and inferior suprarenal arteries.
*Inferior phrenic artery*
- The **superior suprarenal arteries** typically arise from the **inferior phrenic arteries** and supply the superior aspect of the adrenal glands.
- While critical for adrenal blood supply, they do not typically contribute to the inferior aspect directly.
*Abdominal aorta*
- The **middle suprarenal artery** usually arises directly from the **abdominal aorta**.
- This vessel supplies the central part of the adrenal gland, but not primarily the inferior aspect.
*Superior mesenteric artery*
- The **superior mesenteric artery** primarily supplies structures of the midgut (e.g., small intestine, ascending colon) and does not typically give rise to vessels supplying the adrenal glands.
- It is located inferior to the origin of the renal arteries and the adrenal glands.
*Common iliac artery*
- The **common iliac arteries** supply the lower limbs and pelvic organs, originating from the abdominal aorta bifurcation.
- These arteries are located much too far inferior to supply the adrenal glands, which are retroperitoneal structures in the upper abdomen.
Question 8: A 40-year-old woman is brought to the emergency department by a paramedic team from the scene of a motor vehicle accident where she was the driver. The patient was restrained by a seat belt and was unconscious at the scene. On physical examination, the patient appears to have multiple injuries involving the trunk and extremities. There are no penetrating injuries to the chest. As part of her trauma workup, a CT scan of the chest is ordered. At what vertebral level of the thorax is this image from?
A. T1
B. T6
C. T4
D. T5
E. T8 (Correct Answer)
Explanation: ***T8***
- The CT image shows the **inferior vena cava (IVC)** located anterior and to the right of the aorta, and the **esophagus** located posterior to the aorta and slightly to the left. The **azygos vein** is seen to the right of the vertebral body and posterior to the esophagus.
- The **mainstem bronchi** are no longer visible, indicating a level below the carina. The presence of the IVC, aorta, esophagus, and azygos vein with the absence of mainstem bronchi is characteristic of the **T8 vertebral level**.
*T1*
- At the T1 level, the structures would primarily be the **trachea** anterior to the esophagus, with the main great vessels (e.g., brachiocephalic veins and arteries) visible, not the IVC.
- The mainstem bronchi would not yet be visualized at this higher level.
*T6*
- At the T6 level, the **trachea would have already bifurcated into the mainstem bronchi**, which would be prominent structures visible on the CT scan.
- While the aorta and esophagus would be present, the specific arrangement relative to the mainstem bronchi would differentiate it from T8.
*T4*
- The T4 level is typically associated with the **carina**, where the trachea bifurcates into the mainstem bronchi.
- The great vessels would be prominent, but the IVC in its more inferior course would not be as distinctly visualized in this configuration compared to T8.
*T5*
- At the T5 level, the **mainstem bronchi** would still be clearly visible, having just diverged from the trachea.
- While vessels like the aorta are present, the key differentiating factor from T8 is the presence of the mainstem bronchi.
Question 9: A 68-year-old man is brought to the emergency department by ambulance after he was found to be altered at home. Specifically, his wife says that he fell and was unable to get back up while walking to bed. When she approached him, she found that he was unable to move his left leg. His past medical history is significant for hypertension, atrial fibrillation, and diabetes. In addition, he has a 20-pack-year smoking history. On presentation, he is found to still have difficulty moving his left leg though motor function in his left arm is completely intact. The cause of this patient's symptoms most likely occurred in an artery supplying which of the following brain regions?
A. Motor cortex (ACA) (Correct Answer)
B. Cerebellum (PICA/SCA)
C. Occipital cortex (PCA)
D. Brainstem (Vertebrobasilar)
E. Motor cortex (MCA)
Explanation: ***Motor cortex (ACA)***
- The patient's inability to move his **left leg** while his **left arm** remains intact points to an injury in the **right cerebral hemisphere** affecting the leg area of the motor cortex.
- The leg area of the **primary motor cortex** is primarily supplied by the **anterior cerebral artery (ACA)**, making an ACA stroke the most likely cause.
*Motor cortex (MCA)*
- The **middle cerebral artery (MCA)** primarily supplies the motor cortex areas responsible for the **face and arm**, not typically isolated leg weakness.
- If the MCA were affected, you would expect to see involvement of the face and/or arm on the contralateral side in addition to leg weakness.
*Brainstem (Vertebrobasilar)*
- A **brainstem stroke** would likely present with more widespread neurological deficits, including **cranial nerve palsies**, ataxia, or altered consciousness.
- Isolated contralateral leg weakness without arm involvement is not characteristic of a brainstem lesion.
*Cerebellum (PICA/SCA)*
- The **cerebellum** is primarily involved in **coordination and balance**, not direct motor strength.
- A cerebellar stroke would present with symptoms like **ataxia**, dysarthria, or nystagmus, not isolated paralysis.
*Occipital cortex (PCA)*
- The **occipital cortex** is primarily responsible for **vision**.
- A posterior cerebral artery (PCA) stroke would typically cause **visual field defects** (e.g., contralateral homonymous hemianopia) rather than motor weakness.
Question 10: A 25-year-old man presents with progressive weakness and urinary retention. MRI of the spine shows an intramedullary lesion from T10-T12 with expansion of the spinal cord and syrinx formation. The conus medullaris is identified at the L1-L2 level (normal: L1-L2). The filum terminale appears thickened at 3 mm. CSF flow study shows obstruction at the lesion site. Evaluate these radiologic landmarks and their relationships to determine the neurological level most likely affected.
A. Cauda equina only, sparing upper motor neurons
B. Conus medullaris with mixed upper and lower motor neuron signs
C. Thoracic cord with pure upper motor neuron signs below T10
D. Epiconus (T12-L1) with distal lower extremity and sphincter dysfunction (Correct Answer)
E. Lower thoracic nerve roots with radicular pain pattern only
Explanation: ***Epiconus (T12-L1) with distal lower extremity and sphincter dysfunction***
- The **epiconus** encompasses spinal segments **L4-S2**, which anatomically correspond to the vertebral levels **T12-L1**; a lesion here characteristically causes **bladder/bowel dysfunction** and weakness.
- This location accounts for the **urinary retention** and progressive weakness while sparing the higher thoracic functions, fitting the intramedullary expansion seen at the lower thoracic-lumbar transition.
*Cauda equina only, sparing upper motor neurons*
- A **cauda equina** lesion involves the **nerve roots** below the level of the conus (L2) and presents with **purely lower motor neuron (LMN)** signs.
- The intramedullary nature of the lesion at **T10-T12** indicates involvement of the spinal cord itself, which would typically involve **upper motor neuron (UMN)** features or a mixed picture.
*Conus medullaris with mixed upper and lower motor neuron signs*
- The **conus medullaris** corresponds to segments **S3-Co1** and is located at the vertebral level of **L1-L2**, which is distal to the primary lesion core reported at T10.
- Conus lesions typically present with **early autonomic dysfunction** and symmetric saddle anesthesia, but the lesion described extends higher into the **epiconus** region.
*Thoracic cord with pure upper motor neuron signs below T10*
- A lesion at the **mid-thoracic cord** (T10-T12) would primarily produce **spasticity** and hyperreflexia typical of **UMN syndrome** in the lower extremities.
- However, because this specific region houses the lower lumbar and upper sacral segments (the **epiconus**), it frequently yields a complex focal clinical picture involving specific root-level deficits.
*Lower thoracic nerve roots with radicular pain pattern only*
- **Radicular pain** results from compression of exiting **nerve roots**, whereas an **intramedullary lesion** like the one described involves the central cord parenchyma.
- The presence of **urinary retention** and a **syrinx** indicates deep spinal cord involvement and syrinx-related neurological deficits, not mere peripheral root irritation.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
