Musculoskeletal radiologic landmarks US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Musculoskeletal radiologic landmarks. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Musculoskeletal radiologic landmarks US Medical PG Question 1: Following a motor vehicle accident, a 63-year-old man is scheduled for surgery. The emergency physician notes a posture abnormality in the distal left lower limb and a fracture-dislocation of the right hip and acetabulum based on the radiology report. The senior orthopedic resident mistakenly notes a fracture dislocation of the left hip. The surgeon's examination of the patient in the operating room shows an externally rotated and shortened left lower limb. The surgeon reduces the left hip and inserts a pin in the left tibia. A review of postoperative imaging leads to a second surgery on the fracture-dislocation of the right hip. Which of the following strategies is most likely to prevent the recurrence of this type of error?
- A. Marking the surgical site
- B. Implementing a checklist
- C. Conducting a preoperative time-out (Correct Answer)
- D. Verifying the patient’s identity
- E. Performing screening X-rays
Musculoskeletal radiologic landmarks Explanation: ***Conducting a preoperative time-out***
- A **preoperative time-out** is a crucial step in the Universal Protocol, ensuring that the entire surgical team confirms the correct patient, correct site, and correct procedure immediately before incision. This would have caught the discrepancy between the planned surgery and the surgeon's actions.
- The surgical time-out provides a final opportunity for all team members to voice concerns or identify errors, preventing wrong-site surgery as occurred here.
*Marking the surgical site*
- While **surgical site marking** is part of the Universal Protocol, it primarily prevents wrong-side or wrong-level surgery when multiple potential sites exist or when laterality is critical.
- In this scenario, the issue was a misidentification of the *injured* hip at the point of action, not necessarily an ambiguity on which limb *to mark*. The surgeon operated on the palpably injured hip, but it was the wrong one according to the actual diagnosis.
*Implementing a checklist*
- Implementing a comprehensive **surgical safety checklist** can reduce errors across many domains, but its effectiveness depends on strict adherence and a culture of safety.
- While valuable, a checklist alone might not have prevented this specific error if the initial misinterpretation of the radiology report by the resident wasn't explicitly cross-checked at a critical "stop" point.
*Verifying the patient’s identity*
- **Verifying patient identity** is a fundamental safety measure at multiple points, including admission, consent, and before surgery, but it prevents operating on the wrong patient.
- In this case, the correct patient was identified; the error was related to the specific surgical site on that patient.
*Performing screening X-rays*
- **Screening X-rays** are typically performed to assess the extent of injury and confirm the diagnosis before surgery. This was done, and the radiology report correctly identified the right hip injury.
- The error arose from the *interpretation* and *communication* of these findings, not the absence of imaging itself. The existing radiology report, if properly reviewed and confirmed, would have prevented the error.
Musculoskeletal radiologic landmarks US Medical PG Question 2: A 54-year-old man presents to his primary care physician for back pain. His back pain worsens with standing for a prolonged period of time or climbing down the stairs and improves with sitting. Medical history is significant for hypertension, type II diabetes mellitus, and hypercholesterolemia. Neurologic exam demonstrates normal tone, 5/5 strength, and a normal sensory exam throughout the bilateral lower extremity. Skin exam is unremarkable and dorsalis pedis and posterior tibialis pulses are 3+. Which of the following is the best next step in management?
- A. Surgical spinal decompression
- B. MRI of the lumbosacral spine (Correct Answer)
- C. Ankle-brachial index
- D. Radiography of the lumbosacral spine
- E. Naproxen
Musculoskeletal radiologic landmarks Explanation: ***MRI of the lumbosacral spine***
- The patient's symptoms of back pain worsening with standing/climbing downstairs and improving with sitting are classic for **neurogenic claudication** due to **lumbar spinal stenosis**.
- An **MRI** is the gold standard for visualizing the spinal canal, nerve roots, and any potential compression, providing the most detailed imaging to confirm the diagnosis and guide further management.
*Surgical spinal decompression*
- This is a definitive treatment option for severe **spinal stenosis** but should only be considered after a confirmed diagnosis and failed conservative management.
- Jumping straight to surgery without proper imaging and assessment of the severity would be premature and potentially unnecessary.
*Ankle-brachial index*
- This test is primarily used to diagnose **peripheral artery disease (PAD)**, which causes **vascular claudication**.
- While it's important to differentiate vascular from neurogenic claudication, the patient's symptoms (pain relief with sitting, no mention of exertional leg pain specifically) and normal pulses make vascular claudication less likely, and an MRI is more directly indicated for the suspected neurogenic cause.
*Radiography of the lumbosacral spine*
- While X-rays can show bone anomalies and degenerative changes like **osteophytes** and decreased disc space, they do not visualize soft tissues (spinal cord, nerve roots) or the extent of spinal canal narrowing.
- Therefore, X-rays are insufficient for diagnosing **spinal stenosis** and its impact on neural structures.
*Naproxen*
- **Naproxen**, an NSAID, can provide symptomatic relief for musculoskeletal pain but does not address the underlying structural issue of **spinal stenosis**.
- It would be a component of conservative management but not the definitive "next step" for diagnosing the cause of neurogenic claudication as described.
Musculoskeletal radiologic landmarks US Medical PG Question 3: A 25-year-old woman is brought to the emergency department after being involved in a rear-end collision, in which she was the restrained driver of the back car. On arrival, she is alert and active. She reports pain in both knees and severe pain over the right groin. Temperature is 37°C (98.6°F), pulse is 116/min, respirations are 19/min, and blood pressure is 132/79 mm Hg. Physical examination shows tenderness over both knee caps. The right groin is tender to palpation. The right leg is slightly shortened, flexed, adducted, and internally rotated. The remainder of the examination shows no abnormalities. Which of the following is the most likely diagnosis?
- A. Anterior hip dislocation
- B. Posterior hip dislocation (Correct Answer)
- C. Femoral neck fracture
- D. Pelvic fracture
- E. Femoral shaft fracture
Musculoskeletal radiologic landmarks Explanation: ***Posterior hip dislocation***
- The classic presentation of **posterior hip dislocation** involves the affected leg being **shortened, flexed, adducted, and internally rotated**, as described in the patient.
- This type of injury commonly occurs in **motor vehicle collisions** where the knee strikes the dashboard (dashboard injury), transmitting force up the femur to the hip joint, often causing the femoral head to dislocate posteriorly.
*Anterior hip dislocation*
- This typically presents with the affected leg in a position of **hip flexion, abduction, and external rotation**, which is contrary to the findings in this patient.
- Anterior dislocations are less common than posterior dislocations and usually result from a traumatic force applied to the hip while it is in **abduction and external rotation**.
*Femoral neck fracture*
- While a **femoral neck fracture** can cause pain and shortening of the leg, the typical presentation is usually one of **external rotation**, not internal rotation.
- The distinct **flexion, adduction, and internal rotation** triad is highly suggestive of hip dislocation, not a fracture of the femoral neck.
*Pelvic fracture*
- A **pelvic fracture** would likely present with more diffuse pelvic pain, potentially instability upon palpation of the pelvis, and possibly lower extremity neurological deficits or genitourinary symptoms depending on the fracture type.
- The specific limb positioning observed (shortened, flexed, adducted, internally rotated) is not a hallmark of an isolated pelvic fracture.
*Femoral shaft fracture*
- A **femoral shaft fracture** would cause severe pain along the shaft of the femur, significant swelling, and obvious deformity of the thigh.
- While the leg might be shortened, the specific combination of **flexion, adduction, and internal rotation** primarily points towards a hip joint issue rather than a mid-shaft fracture.
Musculoskeletal radiologic landmarks US Medical PG Question 4: A 69-year-old woman presents with pain in her hip and groin. She states that the pain is present in the morning, and by the end of the day it is nearly unbearable. Her past medical history is notable for a treated episode of acute renal failure, diabetes mellitus, obesity, and hypertension. Her current medications include losartan, metformin, insulin, and ibuprofen. The patient recently started taking high doses of vitamin D as she believes that it could help her symptoms. She also states that she recently fell off the treadmill while exercising at the gym. On physical exam you note an obese woman. There is pain, decreased range of motion, and crepitus on physical exam of her right hip. The patient points to the areas that cause her pain stating that it is mostly over the groin. The patient's skin turgor reveals tenting. Radiography is ordered.
Which of the following is most likely to be found on radiography?
- A. Loss of joint space and osteophytes (Correct Answer)
- B. Posterior displacement of the femoral head
- C. Hyperdense foci in the ureters
- D. Femoral neck fracture
- E. Normal radiography
Musculoskeletal radiologic landmarks Explanation: ***Loss of joint space and osteophytes***
- The patient's presentation with **hip and groin pain worsened by activity**, improved with rest, and associated with **crepitus** and **decreased range of motion**, is highly suggestive of **osteoarthritis**.
- **Osteoarthritis** is characterized radiographically by **loss of joint space**, **osteophytes** (bone spurs), subchondral sclerosis, and subchondral cysts.
*Posterior displacement of the femoral head*
- This finding is characteristic of a **posterior hip dislocation**, which usually presents with severe pain and an inability to bear weight after a significant traumatic event.
- While the patient fell, her symptoms are chronic and progressive, and she has signs of arthritis rather than acute dislocation.
*Hyperdense foci in the ureters*
- These would indicate **kidney stones**, which typically present with acute, severe flank pain radiating to the groin, and hematuria.
- The patient's symptoms are chronic and localized to the hip joint, making kidney stones an unlikely cause of her primary complaint.
*Femoral neck fracture*
- A **femoral neck fracture** would cause acute, severe hip pain, inability to bear weight, and often external rotation and shortening of the leg, usually following a fall.
- Although she fell, her chronic, activity-related pain and crepitus are more indicative of a degenerative process.
*Normal radiography*
- Given the patient's age, chronic and worsening hip pain, physical exam findings of crepitus and decreased range of motion, and risk factors like obesity, it is highly improbable that her hip X-rays would be normal.
- These symptoms are classic for **osteoarthritis**, which shows distinct radiographic changes.
Musculoskeletal radiologic landmarks US Medical PG Question 5: A 6-month-old boy is brought to the emergency department by his mother, who informs the doctor that her alcoholic husband hit the boy hard on his back. The blow was followed by excessive crying for several minutes and the development of redness in the area. On physical examination, the boy is dehydrated, dirty, and irritable and when the vital signs are checked, they reveal tachycardia. He cries immediately upon the physician touching the area around his left scapula. The doctor strongly suspects a fracture of the 6th, 7th, or 8th retroscapular posterior ribs. Evaluation of his skeletal survey is normal. The clinician is concerned about child abuse in this case. Which of the following is the most preferred imaging technique as the next step in the diagnostic evaluation of the infant?
- A. Bedside ultrasonography
- B. Magnetic resonance imaging
- C. Babygram
- D. Chest computed tomography scan
- E. Skeletal survey in 2 weeks (Correct Answer)
Musculoskeletal radiologic landmarks Explanation: ***Skeletal survey in 2 weeks***
- A repeat **skeletal survey in 2 weeks** is the most appropriate next step in suspected child abuse cases with an initial normal survey, as it allows for the detection of **healing fractures** that may not be apparent immediately after injury.
- New bone formation and callus development around a fracture site become radiographically visible after approximately 7 to 14 days, improving the detection rate of subtle or undisplaced fractures.
*Bedside ultrasonography*
- While **ultrasonography** can detect acute fractures, especially in cartilage and non-ossified bones, its utility in a comprehensive assessment for multiple non-displaced rib fractures as part of a child abuse workup is limited.
- It is highly **operator-dependent** and may not provide the full skeletal overview required in suspected child abuse.
*Magnetic resonance imaging*
- **MRI** is excellent for evaluating soft tissue injuries, bone marrow edema, and non-ossified cartilaginous structures. However, it is not the primary imaging modality for detecting acute or subacute fractures of ossified bone and requires **sedation** in infants, making it less practical for routine skeletal screening.
- The **high cost** and limited availability of MRI also make it less suitable as a first-line diagnostic tool for rib fractures in this context.
*Babygram*
- A **babygram** is a single large radiograph of an infant's entire body, often used to rapidly assess for gross developmental anomalies or immediate concerns.
- It provides **less detailed imaging** of individual bones compared to a standard skeletal survey and is insufficient for reliably detecting subtle or non-displaced rib fractures.
*Chest computed tomography scan*
- A **chest CT scan** is highly sensitive for detecting acute rib fractures, even subtle ones. However, it exposes the infant to **significant radiation** and is usually reserved for specific clinical indications, such as suspected internal organ injury, rather than as a primary screening tool for rib fractures in child abuse in an otherwise stable patient.
- It does not provide a comprehensive view of the entire skeleton, which is crucial for identifying other potential abuse-related injuries elsewhere.
Musculoskeletal radiologic landmarks US Medical PG Question 6: A previously healthy 2-year-old boy is brought to the emergency room by his mother because of persistent crying and refusal to move his right arm. The episode began 30 minutes ago after the mother lifted him up by the arms. He appears distressed and is inconsolable. On examination, his right arm is held close to his body in a flexed and pronated position. Which of the following is the most likely diagnosis?
- A. Proximal ulnar fracture
- B. Radial head subluxation (Correct Answer)
- C. Anterior shoulder dislocation
- D. Supracondylar fracture of the humerus
- E. Olecranon fracture
Musculoskeletal radiologic landmarks Explanation: ***Radial head subluxation***
- This presentation is classic for **radial head subluxation** (nursemaid's elbow), which typically occurs when a child is pulled or lifted by the hand or wrist, causing the **annular ligament** to slip over the radial head.
- The child usually presents with immediate pain, refusal to use the affected arm, and the arm held in a characteristic **flexed and pronated position**.
*Proximal ulnar fracture*
- A proximal ulnar fracture would typically present with more generalized pain, swelling, and **point tenderness** over the ulna, which are not described.
- The mechanism of injury (lifting by arms) is less consistent with an isolated proximal ulnar fracture and more suggestive of a traction injury at the elbow.
*Anterior shoulder dislocation*
- An anterior shoulder dislocation typically results from a fall or direct blow, not a traction injury to the arm, and the arm would be held in **abduction and external rotation**.
- This injury is also much less common in toddlers compared to radial head subluxation.
*Supracondylar fracture of the humerus*
- A supracondylar fracture usually results from a fall onto an outstretched hand and is associated with significant pain, swelling, and often a **visible deformity** or **neurovascular compromise**.
- The specific injury mechanism described does not fit the typical cause of a supracondylar fracture.
*Olecranon fracture*
- An olecranon fracture usually results from direct trauma or a fall onto the elbow, presenting with localized pain, swelling, and inability to extend the elbow against resistance.
- The "lifting by the arms" mechanism is unlikely to cause an olecranon fracture, and the classic presentation of a pronated arm is not characteristic of this injury.
Musculoskeletal radiologic landmarks US Medical PG Question 7: A 25-year-old male presents to his primary care physician for pain in his knee. The patient was in a wrestling match when his legs were grabbed from behind and he was taken to the floor. The patient states that the moment this impact happened, he felt a snapping and sudden pain in his knee. When the match ended and he stood back up, his knee felt unstable. Minutes later, his knee was swollen and painful. Since then, the patient claims that he has felt unstable bearing weight on the leg. The patient has no significant past medical history, and is currently taking a multivitamin and protein supplements. On physical exam you note a tender right knee, with erythema and an effusion. Which of the following is the most likely physical exam finding in this patient?
- A. Laxity to valgus stress
- B. Anterior translation of the tibia relative to the femur (Correct Answer)
- C. Clicking and locking of the joint with motion
- D. Laxity to varus stress
- E. Posterior translation of the tibia relative to the femur
Musculoskeletal radiologic landmarks Explanation: ***Anterior translation of the tibia relative to the femur***
- The rapid onset of a "snapping" sensation, immediate swelling, and instability after a traumatic event involving twisting or hyperextension of the knee is highly suggestive of an **anterior cruciate ligament (ACL) tear**.
- A torn ACL allows for excessive **anterior translation** of the tibia relative to the femur, which is assessed clinically with tests like the **Lachman test** or **anterior drawer test**.
*Laxity to valgus stress*
- **Laxity to valgus stress** indicates injury to the **medial collateral ligament (MCL)**. While MCL tears can occur with ACL tears, the mechanism described (legs grabbed from behind, taken to the floor, resulting in instability) more directly points to an ACL injury rather than primarily an MCL tear, which often results from a direct blow to the lateral knee.
- The patient's primary complaint of a single "snapping" event followed by instability is more characteristic of an ACL tear than an isolated MCL injury.
*Clicking and locking of the joint with motion*
- **Clicking and locking** of the joint are classic signs of a **meniscal tear**, which can accompany ACL injuries but are not the primary or most likely *initial* physical exam finding for an acute ACL tear.
- While instability is also present in meniscal tears, the immediate swelling and "snapping" described are more characteristic of ligamentous damage.
*Laxity to varus stress*
- **Laxity to varus stress** indicates injury to the **lateral collateral ligament (LCL)**, which is much less common than ACL or MCL tears and typically results from a varus force applied to the knee.
- The mechanism described (being taken to the floor from behind) does not strongly suggest an LCL injury as the primary lesion.
*Posterior translation of the tibia relative to the femur*
- **Posterior translation of the tibia relative to the femur** is indicative of a **posterior cruciate ligament (PCL) tear**, which usually results from a direct blow to the anterior tibia when the knee is flexed (dashboard injury) or a fall onto a flexed knee.
- The mechanism of injury in this patient (legs grabbed from behind, twisting/hyperextension) is not typical for a PCL injury.
Musculoskeletal radiologic landmarks US Medical PG 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)
Musculoskeletal radiologic landmarks 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.
Musculoskeletal radiologic landmarks US Medical PG Question 9: A 21-year-old man comes to the physician for a follow-up examination. Four days ago, he injured his right knee while playing soccer. Increased laxity of the right knee joint is noted when the knee is flexed to 30° and an abducting force is applied to the lower leg. The examination finding in this patient is most likely caused by damage to which of the following structures?
- A. Medial collateral ligament (Correct Answer)
- B. Anterior cruciate ligament
- C. Posterior cruciate ligament
- D. Lateral collateral ligament
- E. Lateral meniscus
Musculoskeletal radiologic landmarks Explanation: ***Medial collateral ligament***
- An abducting force applied to the lower leg (a **valgus stress**) when the knee is flexed to 30° tests the integrity of the MCL. Increased laxity indicates damage to this ligament.
- The MCL resists **valgus stress** and is commonly injured in contact sports, especially when a force is applied to the outside of the knee.
*Anterior cruciate ligament*
- The **anterior drawer test** and **Lachman test** (anterior translation of the tibia with the knee flexed) are used to assess ACL integrity.
- ACL injuries usually result from hyperextension, sudden stopping, or pivoting movements, leading to **anterior instability**.
*Posterior cruciate ligament*
- The **posterior drawer test** (posterior translation of the tibia with the knee flexed) is used to assess PCL integrity.
- PCL injuries typically occur from a direct blow to the tibia or an anterior force on the tibia, indicating **posterior instability**.
*Lateral collateral ligament*
- The LCL is assessed by applying an **adducting force** to the lower leg (a **varus stress**).
- Increased laxity during **varus stress** would indicate damage to the LCL.
*Lateral meniscus*
- Meniscal injuries are usually associated with clicking, locking, or catching sensations within the joint, and pain during twisting motions.
- Meniscal tears are primarily diagnosed using specific provocative tests like **McMurray's test** or **Apley's grind test**, not by assessing ligamentous laxity with abducting forces.
Musculoskeletal radiologic landmarks US Medical PG Question 10: A 27-year-old female ultramarathon runner presents to the physician with complaints of persistent knee pain. She describes the pain to be located in the anterior area of her knee and is most aggravated when she performs steep descents down mountains, though the pain is present with running on flat roads, walking up and down stairs, and squatting. Which of the following would most likely be an additional finding in this patient’s physical examination?
- A. Pain upon pressure placed on the lateral aspect of the knee
- B. Pain upon pressure placed on the medial aspect of the knee
- C. Pain upon compression of the patella while the patient performs flexion and extension of the leg (Correct Answer)
- D. Excessive posterior displacement of the tibia
- E. Excessive anterior displacement of the tibia
Musculoskeletal radiologic landmarks Explanation: ***Pain upon compression of the patella while the patient performs flexion and extension of the leg***
- The patient's symptoms (anterior knee pain aggravated by activity, especially descents, stairs, and squatting) are classic for **patellofemoral pain syndrome (runner's knee)**.
- The **patellofemoral grind test** (compressing the patella during knee flexion and extension) is a specific diagnostic maneuver that reproduces this pain in affected individuals.
*Pain upon pressure placed on the lateral aspect of the knee*
- This finding is more characteristic of conditions like **iliotibial band syndrome** or **lateral meniscus injury**, which typically present with lateral knee pain.
- The patient describes general anterior knee pain, not specifically lateral pain.
*Pain upon pressure placed on the medial aspect of the knee*
- This suggests conditions such as **medial collateral ligament (MCL) injury**, **pes anserine bursitis**, or **medial meniscus injury**.
- These conditions typically present with medial knee pain, which does not match the patient's anterior knee pain.
*Excessive posterior displacement of the tibia*
- This indicates **posterior cruciate ligament (PCL) insufficiency**, which is assessed by the posterior drawer test or sag sign.
- PCL injuries typically result from direct trauma to the anterior tibia or hyperflexion, and pain is often localized posteriorly or deep within the knee, not specifically anteriorly aggravated by the described activities.
*Excessive anterior displacement of the tibia*
- This finding is indicative of an **anterior cruciate ligament (ACL) rupture**, assessed by the Lachman test or anterior drawer test.
- ACL injuries usually result from a twisting injury or hyperextension and often present with acute swelling, instability, and giving way, which are not the primary complaints of this patient with chronic, activity-related anterior knee pain.
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