Musculoskeletal Radiology Practice Questions

Q: What is the normal metacarpal index?

5.4 to 7.9. The **Metacarpal Index (MCI)** is a radiographic measurement used to assess for arachnodactyly (abnormally long and slender fingers), a hallmark feature of connective tissue disorders like Marfan Syndrome. ### **Explanation of the Correct Answer** The MCI is calculated using a PA view of the hand. It is the average of the ratios of the length to the mid-shaft width of the **2nd, 3rd, 4th, and 5th metacarpals**. * **Normal Range:** In healthy individuals, the average index typically falls between **5.4 and 7.9**. * Values within this range indicate normal bone proportions relative to body habitus. ### **Analysis of Incorrect Options** * **Option A ( 8.0) is a highly suggestive radiological sign of Marfan Syndrome. * **Option D (> 10.4):** This represents extreme elongation, seen in severe cases of Marfan Syndrome or Homocystinuria. ### **NEET-PG High-Yield Pearls** * **Clinical Association:** A high Metacarpal Index is most commonly associated with **Marfan Syndrome**. It can also be seen in **Homocystinuria** and **Ehlers-Danlos Syndrome**. * **Other Signs of Arachnodactyly:** 1. **Steinberg Sign (Thumb Sign):** The thumb tip extends beyond the ulnar border of the clenched fist. 2. **Walker-Murdoch Sign (Wrist Sign):** The thumb and fifth finger overlap when encircling the opposite wrist. * **Radiology Tip:** While MCI is a classic exam question, it is less commonly used in modern clinical practice compared to genetic testing and echocardiography for Marfan diagnosis.

Q: Subperiosteal erosion is seen in which of the following conditions?

Hyperparathyroidism. ### Explanation **Correct Answer: B. Hyperparathyroidism** **Mechanism:** Subperiosteal bone resorption is the **pathognomonic** radiographic feature of hyperparathyroidism (HPT). Excess Parathyroid Hormone (PTH) stimulates osteoclastic activity, primarily at the subperiosteal surface where bone turnover is high. This typically manifests first along the **radial aspect of the middle phalanges** of the 2nd and 3rd fingers. As it progresses, it can lead to the "acro-osteolysis" (tuft resorption) and the characteristic "Salt and Pepper" appearance of the skull. **Why other options are incorrect:** * **Scurvy (Vitamin C deficiency):** Characterized by defective collagen synthesis. Key radiological signs include the **White line of Frankel** (dense zone of provisional calcification), **Wimberger’s ring** (sclerotic margin around epiphysis), and **Pelkan spurs**. * **Hypoparathyroidism:** Usually presents with increased bone density (osteosclerosis) or soft tissue/basal ganglia calcification, rather than erosions. * **Rickets (Vitamin D deficiency):** Primarily affects the growth plate (metaphysis) in children. Classic signs are **cupping, splaying, and fraying** of the metaphyses, and widening of the growth plate. **High-Yield Clinical Pearls for NEET-PG:** * **Rugger-Jersey Spine:** Sclerotic bands at vertebral endplates, seen in secondary hyperparathyroidism (Renal Osteodystrophy). * **Brown Tumors:** Osteoclastomas (lytic lesions) seen in advanced HPT; they are not true neoplasms but reactive lesions. * **Looser’s Zones (Pseudofractures):** Narrow radiolucent lines oriented perpendicular to the cortex, pathognomonic for **Osteomalacia/Rickets**. * **Sequence of Resorption in HPT:** Subperiosteal (most specific) → Intracortical (tunneling) → Endosteal → Subchondral (at SI joints/AC joints).

Q: All of the following are X-ray findings of Rheumatoid Arthritis except?

Periarticular new bone formation. **Explanation:** Rheumatoid Arthritis (RA) is a chronic, systemic inflammatory disease characterized by **erosive synovitis**. The hallmark of RA is the destruction of bone and cartilage, rather than the formation of new bone. **Why Option C is the Correct Answer:** **Periarticular new bone formation** (osteophytes) is a characteristic feature of **Osteoarthritis (OA)**, not Rheumatoid Arthritis. In RA, the inflammatory process leads to bone resorption and destruction. The presence of new bone formation or sclerosis actually helps differentiate OA or Seronegative Spondyloarthropathies (like Psoriatic Arthritis) from RA. **Analysis of Incorrect Options:** * **A. Reduced joint space:** This occurs due to the destruction of articular cartilage by the inflammatory "pannus." In RA, this is typically **uniform** (symmetric) joint space narrowing. * **B. Soft tissue swelling:** This is often the **earliest radiographic sign** of RA, representing fusiform swelling around the joints (e.g., PIP and MCP joints) due to synovial inflammation and effusion. * **D. Subchondral cyst:** Also known as "geodes," these occur when synovial fluid is forced into the bone through surface erosions. **NEET-PG High-Yield Pearls:** 1. **Earliest Sign:** Soft tissue swelling. 2. **Earliest Bone Sign:** Periarticular osteopenia (juxta-articular demineralization). 3. **Pathognomonic Sign:** Marginal erosions (occurring at the "bare areas" where bone is not covered by cartilage). 4. **Key Exclusion:** RA characteristically **spares the DIP joints** (unlike OA and Psoriatic Arthritis). 5. **Deformities:** Look for Ulnar deviation at MCP, Boutonniere, and Swan-neck deformities in late stages.

Q: Subperiosteal resorption, most apparent on the radial aspect of the middle phalanx of the second and third fingers, is characteristic of which condition?

Hyperparathyroidism. **Explanation:** **Hyperparathyroidism (HPT)** is the correct answer because **subperiosteal bone resorption** is considered the most specific radiographic hallmark of this condition. It occurs due to excessive Parathyroid Hormone (PTH) stimulating osteoclastic activity. While it can occur at various sites (like the phalanges, distal clavicles, and lamina dura of teeth), it is most classically and earliest seen on the **radial aspect of the middle phalanges of the 2nd and 3rd fingers**. **Analysis of Incorrect Options:** * **Hyperthyroidism:** While it can cause increased bone turnover and osteoporosis, it does not typically present with the focal subperiosteal resorption patterns seen in HPT. * **Osteoporosis:** This involves a generalized decrease in bone mass (quantitative loss) rather than the localized cortical erosions characteristic of HPT. * **Osteogenesis Imperfecta:** This is a genetic collagen disorder characterized by "brittle bones," blue sclera, and multiple fractures, but not specific subperiosteal resorption. **High-Yield NEET-PG Pearls for Hyperparathyroidism:** 1. **Rugger-Jersey Spine:** Sclerotic bands at the superior and inferior endplates of vertebrae (classic in Secondary HPT/Renal Osteodystrophy). 2. **Salt and Pepper Skull:** Multiple tiny lucencies in the calvarium. 3. **Brown Tumors (Osteoclastomas):** Well-defined lytic lesions (not true neoplasms) caused by rapid bone resorption. 4. **Acro-osteolysis:** Resorption of the terminal tufts of the phalanges. 5. **Soft Tissue Calcification:** Often seen in secondary HPT due to high calcium-phosphate product.

Q: The most likely pathology associated with the following radiograph is:

Garre's osteomyelitis. ***Garre's osteomyelitis*** - Characterized by **dense sclerosis**, **cortical thickening**, and prominent **periosteal reaction** without evidence of **sequestrum formation** or pus collection. - Also known as **sclerosing non-suppurative osteomyelitis**, it presents with characteristic **onion-peel** periosteal layering and absence of bone destruction. *Chronic suppurative (or rarefying) osteomyelitis* - Shows **bone destruction** with **sequestrum formation** and **involucrum** development, which are absent in this case. - Typically demonstrates **lytic lesions** with areas of bone necrosis and pus formation. *Acute osteomyelitis* - Presents with **bone marrow edema**, **soft tissue swelling**, and early **osteolytic changes** without significant sclerosis. - Lacks the characteristic **dense sclerotic reaction** and organized periosteal response seen here. *Sclerosing osteomyelitis* - This is a **broader category** that encompasses various sclerotic bone infections including Garre's osteomyelitis. - **Garre's osteomyelitis** is a specific subtype within sclerosing osteomyelitis, making it the more precise diagnosis in the Indian PG context.

Q: A 40-year-old female patient on long-term steroid therapy presents with recent onset of severe pain in the right hip. What is the imaging modality of choice for this problem?

MRI. **Explanation:** The clinical presentation of a patient on long-term steroid therapy with sudden onset hip pain is highly suspicious for **Avascular Necrosis (AVN) of the femoral head**. Steroids are a well-known risk factor for non-traumatic osteonecrosis. **Why MRI is the Correct Answer:** MRI is the **most sensitive (99%) and specific** imaging modality for the early diagnosis of AVN. It can detect changes in the bone marrow (edema and signal changes) even before any structural changes occur in the bone. It is the gold standard for diagnosing **Stage I AVN** (Ficat and Arlet classification), where X-rays appear completely normal. **Why other options are incorrect:** * **Plain X-ray:** While usually the first investigation performed, it is insensitive in early stages. It only shows changes (like the "Crescent sign" or sclerosis) in advanced stages (Stage II and beyond). * **CT Scan:** CT is excellent for evaluating the extent of subchondral collapse or cortical involvement, but it is less sensitive than MRI for early marrow changes. * **Bone Scan:** Technetium-99m bone scans can show a "cold spot" (early) or "hot spot" (late), but they lack the specificity and anatomical detail provided by MRI. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site for AVN:** Femoral head. * **Earliest sign on MRI:** Low-intensity T1 signal (Band-like pattern). * **Double Line Sign:** A pathognomonic MRI finding in AVN (high-intensity inner line and low-intensity outer line on T2-weighted images). * **Crescent Sign:** Seen on X-ray; indicates subchondral fracture (Stage III). * **Treatment:** Core decompression is the treatment of choice for early stages (pre-collapse). Total Hip Arthroplasty (THA) is indicated for late stages (post-collapse).

Q: A bone bruise or contusion is best identified using:

MRI scan. **Explanation:** A **bone bruise (bone marrow contusion)** represents a microscopic injury to the bone architecture, characterized by hemorrhage, edema, and hyperemia within the marrow space, without a macroscopic cortical fracture. **1. Why MRI is the Correct Answer:** MRI is the gold standard and the only imaging modality capable of detecting bone bruises. This is because MRI is highly sensitive to changes in **water content** within the bone marrow. On **T2-weighted images** (specifically fat-suppressed sequences like **STIR**), bone marrow edema appears as an area of high signal intensity (bright), contrasting against the dark background of normal fatty marrow. **2. Why Other Options are Incorrect:** * **Conventional X-ray:** X-rays only detect changes in bone mineral density or cortical continuity. Since bone bruises involve internal marrow changes without cortical disruption, they are invisible on X-rays. * **CT Scan:** While excellent for detecting cortical fractures and complex bony anatomy, CT lacks the soft-tissue contrast necessary to visualize marrow edema. * **PET Scan:** This is primarily used for metabolic activity (oncology/inflammation) and is neither specific nor practical for diagnosing acute traumatic bone bruises. **3. Clinical Pearls for NEET-PG:** * **STIR (Short Tau Inversion Recovery):** This is the most sensitive MRI sequence for identifying bone marrow edema/bruises. * **Mechanism of Injury:** The pattern of a bone bruise often acts as a "geographic footprint," indicating the mechanism of injury (e.g., a bruise on the lateral femoral condyle and posterior tibial plateau is classic for an **ACL tear**). * **Clinical Significance:** Bone bruises are often the cause of persistent pain after trauma when X-rays are negative. They typically resolve within 4–12 weeks.

Q: Osteoporosis circumscripta is seen with which of the following conditions?

Paget's disease. **Explanation:** **Osteoporosis circumscripta** is a classic radiological hallmark of the **early active (lytic) phase of Paget’s disease** (Osteitis deformans). It typically involves the skull, appearing as well-defined, large, geographic radiolucent areas (usually starting in the frontal or occipital bones) that represent intense osteoclastic activity. As the disease progresses to the mixed phase, these lucencies are replaced by "cotton wool" opacities. **Analysis of Options:** * **Paget’s Disease (Correct):** It is a disorder of bone remodeling. Osteoporosis circumscripta represents the lytic stage in the calvarium. * **Fibrous Dysplasia:** Characteristically shows a **"Ground-glass appearance"** or "shepherd’s crook deformity" of the femur, but not osteoporosis circumscripta. * **Chronic Phenytoin Therapy:** This is associated with **Osteomalacia** (due to Vitamin D metabolism interference), which presents with generalized osteopenia and Looser’s zones (pseudofractures). * **Cushing’s Syndrome:** Leads to generalized **Osteoporosis** due to excess glucocorticoids, often resulting in vertebral compression fractures and "codfish vertebrae," but not localized circumscribed lysis. **High-Yield Clinical Pearls for NEET-PG:** * **Skull Findings in Paget’s:** Osteoporosis circumscripta (Lytic phase) $\rightarrow$ Cotton wool spots (Sclerotic phase) $\rightarrow$ Diploic thickening. * **Biochemical Marker:** Isolated elevation of **Serum Alkaline Phosphatase (ALP)** with normal Calcium and Phosphate levels. * **Complications:** The most dreaded complication is **Osteosarcoma** (seen in <1% of cases). * **Treatment of Choice:** Bisphosphonates (e.g., Zoledronic acid).

Question 1

A dense metaphyseal band is typically seen on which of the following conditions?

Accepted Answer

Hypervitaminosis D

Answer

Hypervitaminosis A

Answer

Hypervitaminosis B

Answer

Scurvy

Question 2

What is the normal metacarpal index?

Accepted Answer

5.4 to 7.9

Answer

Less than 5.4

Answer

8.4 to 10.4

Answer

More than 10.4

Question 3

Subperiosteal erosion is seen in which of the following conditions?

Accepted Answer

Hyperparathyroidism

Answer

Scurvy

Answer

Hypoparathyroidism

Answer

Rickets

Question 4

All of the following are X-ray findings of Rheumatoid Arthritis except?

Accepted Answer

Periarticular new bone formation

Answer

Reduced joint space

Answer

Soft tissue swelling

Answer

Subchondral cyst

Question 5

Subperiosteal resorption, most apparent on the radial aspect of the middle phalanx of the second and third fingers, is characteristic of which condition?

Accepted Answer

Hyperparathyroidism

Answer

Hyperthyroidism

Answer

Osteoporosis

Answer

Osteogenesis imperfecta

Question 6

The most likely pathology associated with the following radiograph is:

Accepted Answer

Garre's osteomyelitis

Answer

Chronic suppurative (or rarefying) osteomyelitis

Answer

Acute osteomyelitis

Answer

Sclerosing osteomyelitis

Question 7

Anterior scalloping of vertebrae is seen in which of the following conditions?

Accepted Answer

Renal cell carcinoma

Answer

Osteogenesis imperfecta

Answer

Aortic aneurysm

Answer

Metastasis

Question 8

A 40-year-old female patient on long-term steroid therapy presents with recent onset of severe pain in the right hip. What is the imaging modality of choice for this problem?

Accepted Answer

MRI

Answer

CT scan

Answer

Bone scan

Answer

Plain X-ray

Question 9

A bone bruise or contusion is best identified using:

Accepted Answer

MRI scan

Answer

Conventional X-ray

Answer

CT scan

Answer

PET scan

Question 10

Osteoporosis circumscripta is seen with which of the following conditions?

Accepted Answer

Paget's disease

Answer

Fibrous dysplasia

Answer

Chronic Phenytoin Therapy

Answer

Cushing's syndrome

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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