Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology Indian Medical PG Practice Questions and MCQs

Question 121: A 48-year-old man with a long history of low back pain presents with similar symptoms. His previous X-ray 6 years ago showed degenerative disc changes. What should be done next?

A. Repeat X-ray
B. X-ray should not be repeated (Correct Answer)
C. If any systemic disease is suspected, MRI should be done
D. If neurological deficit is suspected, CT should be done

Explanation: ### Explanation **1. Why Option B is Correct:** The management of chronic low back pain (LBP) is guided by the principle of avoiding unnecessary radiation and costs when clinical findings remain stable. In this patient, the symptoms are "similar" to his previous presentation, and a prior X-ray already confirmed degenerative disc changes. According to the **ACR (American College of Radiology) Appropriateness Criteria**, repeat imaging is not indicated for patients with stable, non-specific chronic LBP unless there is a significant change in clinical status or the development of "red flags." Degenerative changes are common age-related findings and often do not correlate directly with the severity of pain. **2. Why Other Options are Incorrect:** * **Option A:** Repeating an X-ray is unlikely to change the management plan for stable symptoms. It exposes the patient to unnecessary ionizing radiation. * **Option C:** While systemic disease (like malignancy or infection) warrants advanced imaging, **MRI** (not CT) is the gold standard. However, the question implies a routine follow-up of known degenerative pain, making "no repeat imaging" the primary answer. * **Option D:** If a neurological deficit (e.g., radiculopathy or cauda equina syndrome) is suspected, **MRI** is the investigation of choice to visualize soft tissues and nerve roots. CT is generally reserved for bone-related pathology or when MRI is contraindicated. **3. Clinical Pearls for NEET-PG:** * **Red Flags for LBP:** Weight loss, night pain, fever, history of malignancy, trauma, or saddle anesthesia. If these are present, immediate imaging (MRI) is required. * **Imaging Choice:** MRI is the most sensitive modality for disc herniation, spinal stenosis, and infections (discititis/osteomyelitis). * **High-Yield Fact:** Over 90% of LBP cases are mechanical and resolve within 4–6 weeks with conservative management; imaging in the first 6 weeks is generally discouraged unless red flags exist.

Question 122: Which of the following conditions is NOT associated with the 'bone within a bone' appearance?

A. Osteopetrosis
B. Acromegaly
C. Hyperthyroidism (Correct Answer)
D. Hypercalcemia

Explanation: The **'bone within a bone'** appearance (also known as endobone) refers to a radiologic finding where a distinct, smaller bone-shaped density is seen within the medullary space of a larger bone. This occurs due to an interruption in normal bone growth or a sudden change in bone density. ### **Explanation of the Correct Answer** **C. Hyperthyroidism:** This is the correct answer because hyperthyroidism is associated with **increased bone resorption** and high-turnover osteoporosis. It typically presents with subperiosteal bone resorption or generalized osteopenia, rather than the dense, layered deposition required for the 'bone within a bone' appearance. ### **Analysis of Incorrect Options** * **A. Osteopetrosis:** This is the classic cause. Defective osteoclast function leads to failure of bone remodeling, resulting in dense, sclerotic bands that mimic the shape of the bone within the marrow cavity. * **B. Acromegaly:** Excess growth hormone can cause periosteal new bone formation and cortical thickening, which may occasionally manifest as this appearance. * **D. Hypercalcemia:** While less common than osteopetrosis, chronic hypercalcemia (often associated with Vitamin D toxicity or heavy metal poisoning like lead) can cause dense metaphyseal bands that create a 'bone within a bone' effect during periods of growth arrest and recovery. ### **High-Yield Clinical Pearls for NEET-PG** * **Differential Diagnosis for 'Bone within a Bone':** 1. **Osteopetrosis** (Albers-Schönberg disease) - Most common. 2. **Heavy metal poisoning** (Lead, Bismuth). 3. **Sickle Cell Anemia** (due to infarction and subsequent repair). 4. **Thorotrast** administration. 5. **Healing Rickets** or Scurvy. 6. **Normal variant** in the vertebrae of infants. * **Key Radiologic Sign:** In the spine, this appearance is often specifically referred to as a **"Sandwich Vertebra"** (dense endplates) or a **"Rugger Jersey Spine"** (though the latter is more specific to Renal Osteodystrophy).

Question 123: In ankylosing spondylitis, what are the first radiological changes seen?

A. Sacro-iliac joints (Correct Answer)
B. Intervertebral ligament
C. Vertebral bodies
D. Intervertebral discs

Explanation: **Explanation:** **Ankylosing Spondylitis (AS)** is a chronic inflammatory seronegative spondyloarthropathy that primarily affects the axial skeleton. **1. Why Sacro-iliac (SI) joints are the correct answer:** The hallmark of AS is **bilateral, symmetrical sacroiliitis**. Radiologically, the SI joints are the **earliest** site of involvement. The changes typically begin in the lower two-thirds of the joint (the synovial portion) and progress from subchondral erosions and sclerosis ("pseudowidening") to eventual bony ankylosis (fusion). According to the Modified New York Criteria, radiological evidence of sacroiliitis is essential for a definitive diagnosis. **2. Why the other options are incorrect:** * **Vertebral bodies:** While "squaring" of vertebral bodies (due to enthesitis at the corners) is a classic sign, it occurs after the initial SI joint involvement. * **Intervertebral ligaments:** Ossification of the outer fibers of the annulus fibrosus (forming **syndesmophytes**) leads to the "Bamboo Spine" appearance, but this is a late-stage feature. * **Intervertebral discs:** AS primarily affects the entheses and synovial joints; the discs are involved secondarily through calcification or the Andersson lesion (inflammatory spondylodiscitis), not as a primary early event. **Clinical Pearls for NEET-PG:** * **Earliest Sign on MRI:** Bone marrow edema (STIR sequence) around the SI joints (detectable before X-ray changes). * **Earliest Sign on X-ray:** Blurring of the joint margins (Grade 1 sacroiliitis). * **HLA-B27:** Strongly associated (>90% of cases). * **Dagger Sign:** A single central radiodense line on X-ray due to ossification of supraspinous and interspinous ligaments. * **Trolley Track Sign:** Three vertical linear densities due to ossification of the central ligaments and lateral facet joint capsules.

Question 124: Raindrop skull is a characteristic finding in which of the following conditions?

A. Multiple myeloma (Correct Answer)
B. Eosinophilic granuloma
C. Thalassemia
D. Sickle cell anemia

Explanation: **Explanation:** The **Raindrop Skull** is a classic radiological sign of **Multiple Myeloma**. It refers to multiple, well-defined, small, "punched-out" lytic lesions of varying sizes scattered throughout the calvarium. These lesions occur due to the proliferation of malignant plasma cells in the bone marrow, which secrete osteoclast-activating factors (like RANKL), leading to focal bone destruction without any surrounding osteoblastic reaction (sclerosis). **Analysis of Incorrect Options:** * **Eosinophilic Granuloma (Langerhans Cell Histiocytosis):** Typically presents as a large, solitary, "punched-out" lesion with beveled edges (the "hole-within-a-hole" appearance) rather than multiple small "raindrop" lesions. * **Thalassemia & Sickle Cell Anemia:** These are hemolytic anemias that cause compensatory extramedullary hematopoiesis. This leads to widening of the diploic space and thinning of the outer table, resulting in a **"Hair-on-end"** or **"Crew-cut"** appearance on a lateral skull X-ray, not lytic drops. **Clinical Pearls for NEET-PG:** * **Multiple Myeloma:** The most common primary bone malignancy in adults. Key features include CRAB criteria (Calcium elevation, Renal insufficiency, Anemia, Bone lesions). * **Skull X-ray vs. Bone Scan:** In Multiple Myeloma, a **Technetium-99m bone scan is often false-negative** because there is no osteoblastic activity. A skeletal survey (X-rays) or MRI is preferred. * **Bence-Jones Proteins:** Light chains found in urine; they do not show up on a standard dipstick (which detects albumin). * **Pepperpot Skull:** Do not confuse "Raindrop Skull" with "Pepperpot Skull" (salt-and-pepper appearance), which is characteristic of **Hyperparathyroidism**.

Question 125: What is the earliest radiological sign indicative of sacroiliitis on X-ray?

A. Osteophytes
B. Erosion
C. Blurring of the sacroiliac joint (Correct Answer)
D. Sclerosis

Explanation: ### Explanation **1. Why "Blurring of the sacroiliac joint" is correct:** In the early stages of sacroiliitis (typically seen in Spondyloarthropathies like Ankylosing Spondylitis), the inflammatory process begins at the synovial-cartilaginous interface. The earliest detectable change on a conventional radiograph is the **loss of definition or "blurring" of the subchondral bone margins**. This occurs due to focal demineralization and microscopic erosions that make the sharp cortical line of the joint appear fuzzy or hazy. This corresponds to **Grade 1** in the New York Criteria for sacroiliitis. **2. Why the other options are incorrect:** * **Erosion (Option B):** These are small "punched-out" defects in the subchondral bone. While a hallmark of sacroiliitis, they appear *after* the initial blurring. Extensive erosions can lead to a "pseudo-widening" of the joint space (Grade 2). * **Sclerosis (Option C):** This refers to increased bone density (whiteness) adjacent to the joint as a reactive response to inflammation. It typically follows the erosive phase (Grade 3). * **Osteophytes (Option A):** These are bony outgrowths associated with degenerative joint disease (Osteoarthritis), not inflammatory sacroiliitis. In inflammatory conditions, we see **syndesmophytes** (vertical bridges) or **ankylosis** (fusion), which represent the end-stage of the disease. **3. Clinical Pearls for NEET-PG:** * **Gold Standard:** While X-ray is the initial investigation, **MRI (STIR sequence)** is the most sensitive modality to detect "Bone Marrow Edema," which predates any X-ray changes. * **Symmetry:** Ankylosing Spondylitis usually presents with **symmetrical** sacroiliitis, whereas Psoriatic Arthritis and Reiter’s Syndrome often present **asymmetrically**. * **Grading (New York Criteria):** * Grade 0: Normal * Grade 1: Suspicious (Blurring) * Grade 2: Minimal (Small erosions/sclerosis) * Grade 3: Unequivocal (Gross erosions, sclerosis, and widening/narrowing) * Grade 4: Complete Ankylosis.

Question 126: Shenton's line is a radiological line used to determine the pathology of:

A. Hip (Correct Answer)
B. Ankle
C. Elbow
D. Shoulder

Explanation: **Explanation:** **Shenton’s Line** is a fundamental radiological landmark used in the evaluation of the **hip joint** on an Anteroposterior (AP) radiograph. It is an imaginary curved line formed by the continuous arc of the **inferior border of the superior pubic ramus** and the **medial margin of the femoral neck**. In a normal, healthy hip, this line is smooth and unbroken. A disruption or "step-off" in Shenton’s line indicates pathology, most commonly **Developmental Dysplasia of the Hip (DDH)**, femoral neck fractures, or slipped capital femoral epiphysis (SCFE). **Why other options are incorrect:** * **Ankle:** Key radiological lines include the *Tibiofibular clear space* and *Talar tilt*, used to assess syndesmotic injuries or fractures. * **Elbow:** The primary lines are the *Anterior Humeral Line* and the *Radiocapitellar Line*, crucial for diagnosing supracondylar fractures and radial head dislocations in pediatrics. * **Shoulder:** Evaluation focuses on the *Glenohumeral joint space* and the *Scapular 'Y' view* to detect dislocations. **High-Yield Clinical Pearls for NEET-PG:** * **DDH Triad:** Disruption of Shenton’s line is often seen alongside a shallow acetabulum and a lateralized femoral head. * **Hilgenreiner’s and Perkins’ Lines:** These are also used in hip radiography to calculate the acetabular index and determine femoral head position. * **Ward’s Triangle:** A radiolucent area in the neck of the femur (area of least resistance) important in osteoporosis assessment. * **Klein’s Line:** Specifically used to diagnose Slipped Capital Femoral Epiphysis (SCFE).

Question 127: All of the following are seen in rickets except?

A. Frenkels line (Correct Answer)
B. Widening of epiphysis-diaphysis distance
C. Cupping and splaying of metaphysis
D. Rarefaction

Explanation: In musculoskeletal radiology, distinguishing between the features of **Rickets** (childhood vitamin D deficiency) and **Scurvy** (Vitamin C deficiency) is a high-yield topic for NEET-PG. ### **Why Option A is the Correct Answer** **Fraenkel’s line** (also known as the "White line of Fraenkel") is a classic radiological sign of **Scurvy**, not rickets. It represents a dense, radiopaque band at the metaphysis due to the accumulation of calcified cartilage matrix that cannot be converted into bone because of defective collagen synthesis. ### **Explanation of Incorrect Options (Features of Rickets)** * **Widening of epiphysis-diaphysis distance (Option B):** In rickets, there is a failure of mineralization of the osteoid. This leads to an accumulation of non-mineralized cartilage at the growth plate, which appears radiolucent, effectively increasing the distance between the epiphysis and the shaft. * **Cupping and splaying of metaphysis (Option C):** Due to the weight-bearing load on soft, unmineralized osteoid, the metaphysis becomes widened (**splaying**) and develops a concave, saucer-like appearance (**cupping**). Fraying (shaggy margins) is also typically seen. * **Rarefaction (Option D):** This refers to a generalized decrease in bone density (osteopenia) due to poor mineralization, making the bones appear more "transparent" on X-ray. ### **NEET-PG High-Yield Pearls** * **Rickets:** Look for "Cupping, Splaying, and Fraying." The earliest sign is the loss of the **Zone of Provisional Calcification**. * **Scurvy:** Look for **Fraenkel’s line**, **Wimberger’s ring** (dense circular epiphysis), **Pelkan spurs** (metaphyseal spurs), and the **Trummerfeld zone** (scurvy zone/lucent band). * **Key Distinction:** Rickets affects the **growth plate** (widening), while Scurvy primarily affects the **metaphysis** (fragility and hemorrhage).

Question 128: What is the finding seen on X-ray of the right shoulder?

A. Fracture of the scapula
B. Fracture of the clavicle (Correct Answer)
C. Fracture-dislocation of the acromioclavicular joint
D. Fracture of the 1st rib

Explanation: ***Fracture of the clavicle*** - **Clavicle fractures** are the most common shoulder injuries, typically showing a clear **discontinuity** of the cortical bone with possible **displacement** or **angulation**. - On X-ray, look for **cortical disruption**, **bone fragment overlap**, or **step-off deformity** along the clavicular shaft, most commonly in the **middle third**. *Fracture of the scapula* - Scapular fractures are **uncommon** and require significant **high-energy trauma**, typically from motor vehicle accidents or falls from height. - X-ray would show **cortical breaks** in the scapular body, neck, or glenoid, often requiring **CT scan** for detailed evaluation due to overlapping structures. *Fracture-dislocation of the acromioclavicular joint* - AC joint injuries present with **widening** of the **acromioclavicular space** and possible **superior displacement** of the clavicle relative to the acromion. - Associated with **coracoclavicular ligament disruption**, showing increased **coracoclavicular distance** on X-ray, not a discrete bone fracture. *Fracture of the 1st rib* - First rib fractures are **extremely rare** and typically associated with **severe thoracic trauma** or **neurogenic thoracic outlet syndrome**. - Would appear as a **cortical break** in the **curved first rib** near the thoracic apex, often requiring **dedicated rib views** or **CT** for visualization.

Question 129: Which of the following is the most common cause of sclerotic skeletal metastasis in a female patient?

A. Carcinoma breast (Correct Answer)
B. Carcinoma ovary
C. Endometrial carcinoma
D. Melanoma

Explanation: **Explanation:** Bone metastases are broadly categorized into **osteolytic** (bone-destroying), **osteoblastic/sclerotic** (bone-forming), or **mixed**. 1. **Why Carcinoma Breast is correct:** Breast cancer is the most common malignancy in females and the most frequent cause of skeletal metastases in this demographic. While breast cancer typically presents with **mixed** (lytic and sclerotic) lesions, it is the **most common cause of sclerotic/osteoblastic metastases in females**. The sclerotic appearance occurs when tumor cells secrete factors (like TGF-β) that stimulate osteoblasts to lay down new bone. 2. **Why the other options are incorrect:** * **Carcinoma Ovary & Endometrial Carcinoma:** These gynecological malignancies rarely metastasize to the bone. When they do, the lesions are predominantly **osteolytic**. * **Melanoma:** This is notorious for causing highly aggressive, purely **osteolytic** (expansile) metastases. **High-Yield Clinical Pearls for NEET-PG:** * **Most common sclerotic metastasis (Overall/Males):** Prostate Carcinoma (classically purely blastic). * **Most common sclerotic metastasis (Females):** Breast Carcinoma. * **Most common lytic metastasis (Adults):** Lung Cancer (specifically Small Cell and NSCLC) and Renal Cell Carcinoma (RCC). * **Purely Lytic "Blow-out" Metastases:** Classically seen in RCC and Thyroid carcinoma. * **Imaging Gold Standard:** **MRI** is the most sensitive for early detection; **Bone Scan (Technetium-99m MDP)** detects osteoblastic activity but may show a "cold spot" in purely lytic lesions (like Multiple Myeloma).

Question 130: A hair on end appearance of the skull is seen in all of the following conditions EXCEPT:

A. Thalassemia
B. Sickle cell anemia
C. Cooley's anemia
D. Paget's disease (Correct Answer)

Explanation: ### Explanation The **"hair-on-end" appearance** (also known as the crew-cut sign) is a classic radiological finding characterized by vertical striations perpendicular to the skull vault. This occurs due to **extramedullary hematopoiesis** (EMH) in response to chronic hemolytic anemia. As the bone marrow expands to compensate for the loss of red blood cells, it thins the outer table of the skull and pushes the trabeculae outward, creating the appearance of hair standing on end. **Why Paget’s Disease is the correct answer:** In **Paget’s disease**, the skull typically shows a **"Cotton Wool" appearance**. This is characterized by thickened bone with disorganized areas of sclerosis (increased density) and lucency. While Paget’s involves bone remodeling, it does not involve the marrow expansion seen in chronic anemias, making it the exception in this list. **Analysis of Incorrect Options:** * **Thalassemia (A):** This is the most common cause of the hair-on-end sign. Severe marrow hyperplasia leads to significant widening of the diploic space. * **Sickle cell anemia (B):** Chronic hemolysis in sickle cell disease triggers the same compensatory marrow expansion, though often less severe than in Thalassemia. * **Cooley's anemia (C):** This is another name for **Thalassemia Major**. It is the classic condition associated with this radiological sign. **High-Yield Clinical Pearls for NEET-PG:** * **Hair-on-end appearance:** Seen in Thalassemia, Sickle Cell Anemia, Hereditary Spherocytosis, and Iron Deficiency Anemia (rarely). * **Cotton wool spots:** Pathognomonic for Paget’s disease of the skull. * **Salt and pepper skull:** Seen in Hyperparathyroidism. * **Raindrop skull (Punched-out lesions):** Classic for Multiple Myeloma. * **Note:** In Thalassemia, the **paranasal sinuses** (especially the maxillary sinus) are often obliterated due to marrow expansion, leading to "rodent facies." In contrast, Sickle Cell Anemia usually spares the sinuses.

Practice by Chapter

Radiographic Anatomy of Bones and Joints

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Imaging of Fractures and Dislocations

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Arthritides: Inflammatory and Degenerative

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Metabolic Bone Diseases

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Bone and Soft Tissue Tumors

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Congenital Skeletal Anomalies

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Spine Imaging

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Skeletal Infections

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Sports Medicine Imaging

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Imaging of Prostheses and Implants

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Musculoskeletal Ultrasound

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MSK Interventional Procedures

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