CSF production and circulation US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for CSF production and circulation. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
CSF production and circulation US Medical PG Question 1: A 61-year-old male is given acetazolamide to treat open-angle glaucoma. Upon diuresis, his urine is found to be highly alkaline. Which of the following accounts for the alkaline nature of this patient’s urine?
- A. Inhibition of bicarbonate reabsorption in the proximal tubule (Correct Answer)
- B. Inhibition of bicarbonate reabsorption in beta-intercalated cells
- C. Inhibition of acid secretion in alpha-intercalated cells
- D. Inhibition of chloride reabsorption in the distal convoluted tubule
- E. Inhibition of chloride reabsorption in the thick ascending loop of Henle
CSF production and circulation Explanation: ***Inhibition of bicarbonate reabsorption in the proximal tubule***
- **Acetazolamide** is a **carbonic anhydrase inhibitor** that primarily acts on the **proximal tubule** of the kidney.
- Its action here prevents the reabsorption of **bicarbonate (HCO3-)**, leading to its increased excretion in the urine and thus making the urine alkaline.
*Inhibition of chloride reabsorption in the distal convoluted tubule*
- This effect is typically associated with **thiazide diuretics**, which inhibit the **Na-Cl cotransporter** in the distal convoluted tubule.
- While it affects electrolyte balance, it does not directly lead to the observed **alkaline urine** in the manner described.
*Inhibition of bicarbonate reabsorption in beta-intercalated cells*
- **Beta-intercalated cells** in the collecting duct secrete bicarbonate, and their inhibition would lead to **acidic urine**, not alkaline.
- They play a role in **bicarbonate secretion**, not reabsorption as seen with acetazolamide's primary action.
*Inhibition of acid secretion in alpha-intercalated cells*
- **Alpha-intercalated cells** secrete acid (H+) into the urine. Inhibiting their function would reduce acid excretion, making the urine less acidic or even alkaline.
- However, the primary mechanism of acetazolamide's effect on urine pH is through **bicarbonate wasting** in the proximal tubule, not direct inhibition of acid secretion in the collecting duct.
*Inhibition of chloride reabsorption in the thick ascending loop of Henle*
- This is the mechanism of action for **loop diuretics** like furosemide, which inhibit the **Na-K-2Cl cotransporter**.
- While loop diuretics cause significant diuresis, they do not directly lead to the pronounced **urinary alkalinization** seen with acetazolamide.
CSF production and circulation US Medical PG Question 2: A 65-year-old patient presents with rapidly progressive dementia, myoclonus, and ataxia over 3 months. Laboratory studies, including serum vitamin B12 (cyanocobalamin), thyroxine (T4), and thyroid-stimulating hormone concentrations, are within normal limits. A lumbar puncture is performed. Cerebrospinal fluid (CSF) analysis is most likely to show which of the following?
- A. Increased 14-3-3 protein concentration (Correct Answer)
- B. Antiganglioside GM1 antibodies
- C. Anti-glutamic acid decarboxylase antibodies
- D. Increased α-synuclein protein concentration
- E. Oligoclonal bands
CSF production and circulation Explanation: ***Increased 14-3-3 protein concentration***
- The constellation of **rapidly progressive dementia**, **myoclonus**, and **ataxia** over 3 months with normal routine labs is highly suggestive of **Creutzfeldt-Jakob disease (CJD)**.
- An **elevated 14-3-3 protein concentration** in the CSF is a **classic diagnostic marker** for CJD, reflecting rapid neuronal destruction and included in the **WHO diagnostic criteria**.
- This is the most characteristic CSF finding in CJD, with high sensitivity and specificity.
*Oligoclonal bands*
- **Oligoclonal bands** are indicative of intrathecal antibody production and are characteristic of **inflammatory or demyelinating conditions** such as **multiple sclerosis** and **CNS infections**.
- They are **NOT typically found in prion diseases** like CJD, which involve protein misfolding rather than immune-mediated inflammation.
*Increased α-synuclein protein concentration*
- **Alpha-synuclein accumulation** is characteristic of **synucleinopathies** such as Parkinson's disease, Lewy body dementia, and multiple system atrophy.
- While these can involve dementia and motor symptoms, they typically have a **slower progression** and different symptom profile than the rapid course seen in CJD.
*Antiganglioside GM1 antibodies*
- **Anti-ganglioside GM1 antibodies** are primarily associated with autoimmune **motor neuropathies**, particularly **multifocal motor neuropathy** and some forms of Guillain-Barré syndrome.
- They are not typically associated with rapidly progressive dementia or CJD.
*Anti-glutamic acid decarboxylase antibodies*
- **Anti-glutamic acid decarboxylase (GAD) antibodies** are primarily associated with **stiff-person syndrome** and certain types of **autoimmune encephalitis**.
- While these conditions can present with neurological symptoms, the clinical picture of rapidly progressive dementia with myoclonus and ataxia is not typical for GAD antibody-mediated disorders.
CSF production and circulation US Medical PG Question 3: A 25-year-old man with no significant past medical history is brought in by ambulance after a witnessed seizure at home. On physical exam, temperature is 102.3 deg F (39.1 deg C), blood pressure is 90/62 mmHg, pulse is 118/min, and respirations are 25/min. He is unable to touch his chin to his chest and spontaneously flexes his hips with passive neck flexion. Appropriate empiric treatment is begun. CT head is unremarkable, and a lumbar puncture sample is obtained. Gram stain of the cerebrospinal fluid (CSF) reveals gram-positive diplococci. Which of the following would you expect to see on CSF studies?
- A. Elevated opening pressure, elevated protein, normal glucose
- B. Normal opening pressure, normal protein, normal glucose
- C. Elevated opening pressure, elevated protein, elevated glucose
- D. Normal opening pressure, elevated protein, normal glucose
- E. Elevated opening pressure, elevated protein, low glucose (Correct Answer)
CSF production and circulation Explanation: ***Elevated opening pressure, elevated protein, low glucose***
- **Bacterial meningitis** typically presents with an **elevated opening pressure** due to inflammation and increased intracranial pressure.
- The inflammatory response leads to increased vascular permeability, causing **elevated protein** in the CSF and **low glucose** due to bacterial consumption.
*Elevated opening pressure, elevated protein, normal glucose*
- While **elevated opening pressure** and **elevated protein** can be seen in inflammatory conditions, **normal CSF glucose** is more characteristic of viral meningitis or non-infectious inflammatory conditions, not bacterial.
- In bacterial meningitis, bacteria metabolize glucose, leading to a **decreased CSF glucose level**.
*Normal opening pressure, normal protein, normal glucose*
- This profile is typical for a **normal CSF study** or certain chronic neurological conditions, not acute bacterial meningitis.
- The patient's severe symptoms, including fever, seizure, and meningismus, contradict a normal CSF profile.
*Elevated opening pressure, elevated protein, elevated glucose*
- While **elevated opening pressure** and **elevated protein** can occur, **elevated CSF glucose** is inconsistent with any common form of meningitis.
- An elevated CSF glucose is rare and would suggest systemic hyperglycemia without impaired glucose transport into the CSF.
*Normal opening pressure, elevated protein, normal glucose*
- A **normal opening pressure** would be unusual in a patient with bacterial meningitis, given the inflammation and potential for increased intracranial pressure.
- While **elevated protein** and **normal glucose** can occur in certain conditions (e.g., Guillain-Barré syndrome), it does not fit the clinical picture of acute bacterial meningitis with fever and meningismus.
CSF production and circulation US Medical PG Question 4: A 23-year-old female presents to the emergency department with monocular blindness. She states that early this morning she lost her vision seemingly "out of nowhere." She denies trauma or any precipitating factors. She does state though that over the past year she has had occasional episodes of weakness and even an episode of urinary incontinence, which always resolve on their own. On exam, pain is elicited with eye movement and nystagmus is appreciated. The emergency physician performs a lumbar puncture. What is most likely to be observed in the CSF of this patient?
- A. Increased lymphocyte count
- B. Normal findings
- C. Albuminocytologic dissociation
- D. Oligoclonal bands (Correct Answer)
- E. Increased opening pressure
CSF production and circulation Explanation: ***Oligoclonal bands***
- The patient's presentation with **monocular blindness**, **pain with eye movement**, **nystagmus**, and a history of resolving neurological symptoms like weakness and urinary incontinence is highly suggestive of **multiple sclerosis (MS)**.
- **Oligoclonal bands** in the CSF, representing intrathecal immunoglobulin production, are a hallmark finding supportive of an MS diagnosis, found in over 90% of patients.
*Increased lymphocyte count*
- While there can be a mild increase in **lymphocytes** in the CSF of MS patients during acute exacerbations, a significant increase is more characteristic of infectious meningoencephalitis.
- A definitive diagnostic marker like oligoclonal bands is more specific for MS than a general increase in lymphocytes alone.
*Normal findings*
- Given the patient's symptoms and the strong clinical suspicion for **multiple sclerosis**, a completely normal CSF analysis is unlikely.
- MS is characterized by distinct immunological changes in the CSF, making a normal result improbable for diagnosis.
*Albuminocytologic dissociation*
- **Albuminocytologic dissociation**, characterized by a high protein count with a normal cell count, is a classic finding in **Guillain-Barré Syndrome (GBS)**.
- The patient's symptoms (monocular blindness, nystagmus, resolving neurological deficits) are not typical of GBS, which usually presents with ascending paralysis.
*Increased opening pressure*
- **Increased opening pressure** in the CSF is primarily associated with conditions like **idiopathic intracranial hypertension (pseudotumor cerebri)** or space-occupying lesions.
- While some MS patients might have mild elevations, it is not a hallmark diagnostic feature and the clinical picture does not point to conditions primarily causing increased intracranial pressure.
CSF production and circulation US Medical PG Question 5: An 18-month-old boy is brought to the physician for a well-child examination. His mother is concerned because he is unable to walk on his own. He has been increasingly irritable over the past month, has been feeding poorly, and has had multiple episodes of vomiting. His immunizations are up-to-date. He is at the 50th percentile for height, 40th percentile for weight, and 98th percentile for head circumference. He appears lethargic. His vital signs are within normal limits. Examination shows a bulging anterior fontanelle. The child is unable to stand without support and falls if he attempts to walk. Muscle tone is increased and deep tendon reflexes are 4+ in the lower extremities. Examination of the back is unremarkable. An MRI of the brain shows symmetrical enlargement of all four ventricles. Which of the following is the most appropriate treatment in this patient?
- A. Cerebral aqueductoplasty
- B. Acetazolamide therapy
- C. Ventriculoperitoneal shunt (Correct Answer)
- D. Furosemide therapy
- E. Serial lumbar punctures
CSF production and circulation Explanation: ***Ventriculoperitoneal shunt***
- The patient presents with symptoms and signs of **hydrocephalus** (e.g., rapidly increasing head circumference, bulging fontanelle, vomiting, irritability, gait disturbance, hypertonia, hyperreflexia). An MRI showing **symmetrical enlargement of all four ventricles** confirms communicating hydrocephalus.
- A **ventriculoperitoneal (VP) shunt** is the most appropriate long-term treatment for symptomatic hydrocephalus, diverting CSF from the ventricles to the peritoneal cavity.
*Cerebral aqueductoplasty*
- This procedure is indicated for **aqueductal stenosis**, which causes **obstructive (non-communicating) hydrocephalus**, where only the ventricles proximal to the obstruction are dilated (e.g., third and lateral ventricles).
- The MRI in this case shows **symmetrical enlargement of all four ventricles**, indicating **communicating hydrocephalus**, making aqueductoplasty unsuitable.
*Acetazolamide therapy*
- **Acetazolamide** is a carbonic anhydrase inhibitor that can reduce CSF production, typically used in cases of **idiopathic intracranial hypertension** or as a temporary measure in some forms of hydrocephalus.
- However, in a symptomatic infant with significant hydrocephalus and rapid head growth, medical therapy alone is usually insufficient for long-term management and does not address the underlying CSF drainage issue.
*Furosemide therapy*
- **Furosemide**, a loop diuretic, can also reduce CSF production but is generally not considered a primary treatment for hydrocephalus, especially in symptomatic infants.
- Its effects on CSF reduction are often transient and not as robust as surgical intervention for established hydrocephalus with neurological deficits.
*Serial lumbar punctures*
- **Serial lumbar punctures** can temporarily relieve pressure in **communicating hydrocephalus**, especially in neonates or patients awaiting shunt placement.
- However, they are not a long-term solution for symptomatic hydrocephalus in an older infant with ongoing symptoms and a need for definitive management and are associated with risks of infection and discomfort.
CSF production and circulation US Medical PG Question 6: A 26-year-old man presents to his primary doctor with one week of increasing weakness. He reports that he first noticed difficulty walking while attending his sister's graduation last week, and yesterday he had difficulty taking his coffee cup out of the microwave. He remembers having nausea and vomiting a few weeks prior, but other than that has no significant medical history. On exam, he has decreased reflexes in his bilateral upper and lower extremities, with intact sensation. If a lumbar puncture is performed, which of the following results are most likely?
- A. High lymphocytes, high protein, low glucose, high opening pressure
- B. Normal cell count, high protein, normal glucose, normal opening pressure (Correct Answer)
- C. High neutrophils, high protein, low glucose, high opening pressure
- D. Normal cell count, normal protein, normal glucose, normal opening pressure
- E. High lymphocytes, normal protein, normal glucose, normal opening pressure
CSF production and circulation Explanation: ***Normal cell count, high protein, normal glucose, normal opening pressure***
- This patient's presentation with **ascending paralysis** following a viral illness (nausea and vomiting a few weeks prior) is highly suggestive of **Guillain-Barré Syndrome (GBS)**.
- The classic cerebrospinal fluid (CSF) finding in GBS is **albuminocytologic dissociation**, characterized by a **normal white blood cell count** but **elevated protein levels** due to inflammation of nerve roots and increased permeability of the blood-nerve barrier.
*High lymphocytes, high protein, low glucose, high opening pressure*
- This CSF profile, particularly **low glucose** and **high lymphocytes**, is more characteristic of **bacterial meningitis** or certain **viral encephalitides**, which do not fit the clinical picture of ascending paralysis and intact sensation.
- While GBS can have high protein, the presence of low glucose points away from GBS.
*High neutrophils, high protein, low glucose, high opening pressure*
- This CSF profile strongly suggests **acute bacterial meningitis**, characterized by a prominent **neutrophilic pleocytosis**, low glucose, and high protein, which is not consistent with the patient's symptoms of progressive weakness.
- The patient's presentation is a subacute progressive weakness, not an acute infectious process affecting the CNS.
*Normal cell count, normal protein, normal glucose, normal opening pressure*
- A completely normal CSF profile would make the diagnosis of GBS less likely, as **elevated CSF protein** is a hallmark of the condition due to nerve root inflammation.
- While GBS can sometimes have normal CSF early in the disease, in the context of progressing weakness, elevated protein is expected.
*High lymphocytes, normal protein, normal glucose, normal opening pressure*
- This CSF profile with **high lymphocytes** and otherwise normal parameters might indicate a **viral meningioencephalitis** or other lymphocytic inflammatory conditions, but it does not align with the characteristic **elevated protein** seen in GBS.
- The absence of elevated protein despite significant neurological symptoms makes this less likely for GBS.
CSF production and circulation US Medical PG Question 7: A 62-year-old man is brought to the physician by his wife for increased forgetfulness and unsteady gait over the past 3 months. He is a journalist and has had difficulty concentrating on his writing. He also complains of urinary urgency recently. His temperature is 36.8°C (98.2°F) and blood pressure is 139/83 mm Hg. He is oriented only to person and place. He is able to recall 2 out of 3 words immediately and 1 out of 3 after five minutes. He has a slow, broad-based gait and takes short steps. Neurological examination is otherwise normal. Urinalysis is normal. Which of the following is the most likely diagnosis?
- A. Frontotemporal dementia
- B. Normal pressure hydrocephalus (Correct Answer)
- C. Vascular dementia
- D. Lewy body dementia
- E. Alzheimer disease
CSF production and circulation Explanation: ***Normal pressure hydrocephalus***
- This patient presents with the classic triad of **normal pressure hydrocephalus (NPH)**: **gait disturbance** (unsteady, broad-based, short-stepped), **urinary urgency** (often incontinence), and **cognitive impairment** (forgetfulness, difficulty concentrating).
- The symptoms are progressive over three months and the neurological examination (apart from gait) is otherwise normal, fitting the profile of NPH.
*Frontotemporal dementia*
- This dementia subtype typically presents with prominent **behavioral changes** (disinhibition, apathy) or **language disturbance** (aphasia), which are not highlighted in this case.
- While cognitive decline occurs, the classic triad of gait disturbance and urinary symptoms is not characteristic.
*Vascular dementia*
- Vascular dementia usually presents with a **step-wise decline** in cognitive function, often associated with a history of stroke or vascular risk factors like hypertension, hyperlipidemia, or diabetes.
- The presented symptoms do not describe a step-wise decline, and the gait disturbance in NPH is distinct from focal neurological deficits seen in multi-infarct dementia.
*Lewy body dementia*
- Key features of Lewy body dementia include **fluctuating cognition**, **recurrent visual hallucinations**, and **spontaneous parkinsonism**, none of which are explicitly mentioned here.
- While gait disturbance can occur, it's typically more **parkinsonian** (shuffling gait) rather than broad-based and unsteady, and urinary urgency is not a primary diagnostic criterion.
*Alzheimer disease*
- Alzheimer disease predominantly features prominent and progressive **memory impairment**, particularly for new information, along with other cognitive deficits. While forgetfulness is present, the pronounced gait disturbance and urinary urgency are not typical early or prominent features.
- Gait disturbance in Alzheimer's is usually a later symptom, and urinary issues are often due to a later stage of cognitive decline or other causes.
CSF production and circulation US Medical PG Question 8: A 25-year-old woman presents to the physician with a complaint of several episodes of headaches in the past 4 weeks that are affecting her school performance. These episodes are getting progressively worse, and over-the-counter medications do not seem to help. She also mentions having to raise her head each time to look at the board while taking notes; she cannot simply glance up with just her eyes. She has no significant past medical or family history and was otherwise well prior to this visit. Physical examination shows an upward gaze palsy and convergence-retraction nystagmus. What structure is most likely to be affected in this patient?
- A. Aqueduct of Sylvius
- B. Inferior colliculi
- C. 3rd ventricle
- D. Tegmentum
- E. Corpora quadrigemina (Correct Answer)
CSF production and circulation Explanation: ***Corpora quadrigemina***
- The patient presents with classic **Parinaud syndrome** (dorsal midbrain syndrome), characterized by **upward gaze palsy** and **convergence-retraction nystagmus**.
- These specific oculomotor signs result from direct damage to the **superior colliculi** and **pretectal area**, which are anatomical components of the **corpora quadrigemina** in the tectal region of the midbrain.
- The superior colliculi control vertical gaze, and the pretectal area coordinates pupillary reflexes and convergence movements. Compression or infiltration of this region (commonly by pineal tumors) produces the characteristic eye movement abnormalities.
- Progressive headaches indicate increased intracranial pressure, often from associated **aqueduct obstruction** causing hydrocephalus, which in turn compresses the tectal structures.
*Aqueduct of Sylvius*
- While obstruction of the aqueduct of Sylvius commonly **causes** Parinaud syndrome by leading to hydrocephalus and mass effect, the aqueduct itself is a CSF pathway and does not directly produce the eye movement abnormalities.
- The question asks which structure is "**affected**" - the affected structure producing these specific symptoms is the tectal region (corpora quadrigemina), not the obstructed aqueduct.
- This is an important distinction: the aqueduct is obstructed, but the corpora quadrigemina is compressed/affected.
*Inferior colliculi*
- The inferior colliculi are part of the corpora quadrigemina but serve the **auditory pathway**, not visual or oculomotor functions.
- Isolated lesions here would cause hearing deficits, not upward gaze palsy or convergence-retraction nystagmus.
*3rd ventricle*
- Lesions obstructing the third ventricle can cause hydrocephalus and headaches but do not directly affect the midbrain tectum unless they extend posteriorly.
- Third ventricular masses more commonly produce **endocrine disturbances** (hypothalamic-pituitary axis dysfunction) rather than the specific dorsal midbrain syndrome seen here.
*Tegmentum*
- The tegmentum is the ventral portion of the midbrain containing the **red nucleus**, **substantia nigra**, and **cranial nerve nuclei (III, IV)**.
- Tegmental lesions produce different oculomotor deficits (e.g., internuclear ophthalmoplegia, third nerve palsy) and movement disorders, not the dorsal midbrain syndrome pattern of Parinaud.
CSF production and circulation US Medical PG Question 9: An 8-year-old boy is brought to the physician by his mother because of a 3-week history of irritability and frequent bed wetting. She also reports that he has been unable to look upward without tilting his head back for the past 2 months. He is at the 50th percentile for height and weight. His vital signs are within normal limits. Ophthalmological examination shows dilated pupils that are not reactive to light and bilateral optic disc swelling. Pubic hair development is Tanner stage 2. The most likely cause of this patient's condition is a tumor in which of the following locations?
- A. Fourth ventricle
- B. Sella turcica
- C. Cerebellar vermis
- D. Cerebral falx
- E. Dorsal midbrain (Correct Answer)
CSF production and circulation Explanation: ***Dorsal midbrain***
- The inability to look upward (**Parinaud's syndrome**), dilated pupils with poor light reflex, and **optic disc swelling** (indicating increased intracranial pressure) are classic signs of a mass lesion compressing the **dorsal midbrain**, specifically the **tectal plate**.
- **Irritability and bedwetting** are nonspecific symptoms, but in this context, they could be related to **hydrocephalus** due to **aqueductal compression** by the tumor.
*Fourth ventricle*
- Tumors of the fourth ventricle typically present with symptoms related to **hydrocephalus** (headache, nausea, vomiting, papilledema) and **ataxia** due to cerebellar involvement, but not specifically with **Parinaud's syndrome**.
- **Truncal ataxia** and **gait instability** are common with posterior fossa tumors affecting the cerebellum.
*Sella turcica*
- Tumors in the sella turcica primarily affect the **pituitary gland** and **optic chiasm**, leading to **endocrine dysfunction** (e.g., growth retardation, precocious puberty, hypogonadism) and **bitemporal hemianopsia**.
- **Parinaud's syndrome** and **dilated, unreactive pupils** are not typical presentations for sellar tumors.
*Cerebral falx*
- Tumors associated with the cerebral falx (e.g., meningiomas) are often located **supratentorially** and can cause focal neurological deficits like **seizures** or **hemiparesis**, depending on their location and size.
- They do not typically cause the specific eye movement disorders or pupillary abnormalities seen in this patient.
*Cerebellar vermis*
- Cerebellar vermis tumors often lead to **truncal ataxia**, **gait disturbance**, and **hydrocephalus** due to compression of the aqueduct or fourth ventricle outflow.
- While they can cause increased intracranial pressure, they do not directly cause **Parinaud's syndrome** or isolated deficits of upward gaze.
CSF production and circulation US Medical PG Question 10: A 19-year-old man is brought to the emergency department following a high-speed motor vehicle collision in which he was a restrained passenger. He complains of pelvic pain and urinary retention with overflow incontinence, along with associated lower extremity weakness. Examination shows perineal bruising and there is pain with manual compression of the pelvis. Injury to which of the following structures is most likely responsible for this patient's urinary incontinence?
- A. Ilioinguinal nerve
- B. Obturator nerve
- C. Genitofemoral nerve
- D. Pelvic splanchnic nerves (Correct Answer)
- E. Superior gluteal nerve
CSF production and circulation Explanation: ***Pelvic splanchnic nerves***
- Urinary retention with overflow incontinence and lower extremity weakness following a pelvic trauma suggests damage to the **sacral spinal segments** or the **pelvic splanchnic nerves**.
- These nerves carry **parasympathetic fibers** that stimulate bladder contraction (detrusor muscle) and relaxation of the internal urethral sphincter, which are crucial for normal micturition.
*Ilioinguinal nerve*
- This nerve supplies sensory innervation to the **genitalia** and part of the inner thigh, and motor innervation to the internal oblique and transversus abdominis muscles.
- Damage to this nerve would primarily cause sensory deficits or abdominal muscle weakness, not urinary retention or lower extremity weakness.
*Obturator nerve*
- The obturator nerve primarily innervates the **adductor muscles of the thigh** and provides sensory innervation to the medial thigh.
- Injury would result in difficulty with hip adduction and sensory loss in the medial thigh, not bladder dysfunction or diffuse lower extremity weakness.
*Genitofemoral nerve*
- This nerve provides sensory innervation to the **anterior compartment of the thigh** and the external genitalia, and motor innervation to the cremaster muscle.
- Damage would typically manifest as altered sensation in these areas or an absent cremasteric reflex, without directly affecting bladder function.
*Superior gluteal nerve*
- The superior gluteal nerve innervates the **gluteus medius, gluteus minimus, and tensor fasciae latae muscles**, which are crucial for hip abduction and stabilization during walking.
- Injury would lead to a characteristic **Trendelenburg gait**, but would not directly cause urinary incontinence or retention.
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