Musculoskeletal Radiology Practice Questions

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).

Q: Which of the following conditions can manifest with the shown X-ray findings in the skull?

Thalassemia. ***Thalassemia*** - Causes **"hair-on-end"** or **"crew-cut"** appearance on skull X-ray due to **diploic widening** from compensatory **extramedullary hematopoiesis**. - The chronic hemolytic anemia leads to **bone marrow expansion** and characteristic **perpendicular trabeculae** extending outward from the skull. *Acute Myeloid Leukemia* - Primarily causes **lytic bone lesions** and **osteopenia** rather than the specific hair-on-end pattern. - X-ray findings typically show **punched-out lesions** and **pathological fractures**, not diploic expansion. *Iron deficiency anemia* - Does not cause significant **bone marrow expansion** as it's primarily a **microcytic hypochromic** anemia. - X-ray findings are typically **normal** or may show **osteopenia** but never the hair-on-end appearance. *Megaloblastic Anemia* - Results from **vitamin B12** or **folate deficiency** causing **ineffective erythropoiesis**. - Does not produce the **compensatory extramedullary hematopoiesis** necessary for diploic widening and hair-on-end pattern.

Q: Osteoblastic metastases commonly arise from which primary tumor?

Prostate. **Explanation:** Bone metastases are broadly classified into **osteoblastic** (bone-forming), **osteolytic** (bone-destroying), or mixed lesions. **Correct Answer: B. Prostate** Prostate cancer is the classic and most common cause of purely **osteoblastic** metastases in males. The tumor cells secrete factors like Bone Morphogenetic Proteins (BMPs) and endothelin-1, which stimulate osteoblast activity, leading to increased bone density (sclerotic lesions) on X-ray or CT. **Analysis of Incorrect Options:** * **A. Breast:** Breast cancer typically presents with **mixed** lesions (both lytic and blastic). While it is the most common cause of blastic metastases in females, it is not as exclusively blastic as prostate cancer. * **C. Lung:** Most lung cancers (especially Non-Small Cell Lung Cancer) produce **osteolytic** lesions. An exception is carcinoid tumors, which can be blastic. * **D. Renal Cell Carcinoma (RCC):** RCC is notorious for causing highly vascular, **purely osteolytic**, and "expansile" (blow-out) lesions. **High-Yield Clinical Pearls for NEET-PG:** * **Most common source of bone mets (Overall):** Breast (due to high prevalence). * **Purely Lytic Metastases:** RCC, Thyroid, Lung, and Multiple Myeloma (Note: Myeloma is "cold" on bone scans). * **Purely Blastic Metastases:** Prostate, Carcinoid, Medulloblastoma, and Hodgkin’s Lymphoma (Ivory vertebra). * **Investigation of Choice:** **MRI** is the most sensitive for detecting early marrow involvement; **Bone Scan (Technetium-99m MDP)** is used for screening the whole body for osteoblastic activity.

Q: What is the characteristic radiological finding of Ewing's sarcoma?

Onion peel appearance. **Explanation:** **Ewing’s Sarcoma** is a highly malignant small round cell tumor typically occurring in the first and second decades of life. The characteristic radiological finding is the **Onion peel appearance** (Option C). This occurs due to a rapid, aggressive periosteal reaction where the bone deposits multiple concentric layers of new bone in an attempt to contain the fast-growing tumor. It is most commonly seen in the diaphysis of long bones (e.g., femur). **Analysis of Incorrect Options:** * **Option A (Soap bubble appearance):** Characteristic of **Giant Cell Tumor (Osteoclastoma)**, typically seen in the epiphysis of long bones in young adults. It can also be seen in Adamantinoma. * **Option B (Sunray/Sunburst appearance):** Classic for **Osteosarcoma**. It represents spicules of bone forming perpendicular to the cortex along Sharpey’s fibers due to rapid malignant growth. * **Option D (Codman’s triangle):** While seen in Ewing’s sarcoma, it is **not pathognomonic**. It occurs when the periosteum is lifted by the tumor, forming a triangular elevation. It is more classically associated with Osteosarcoma but can occur in any aggressive lesion. **High-Yield NEET-PG Pearls:** * **Translocation:** t(11;22) involving the EWS-FLI1 gene. * **Histology:** Small, round, blue cells with **Homer-Wright rosettes** (though more common in neuroblastoma) and PAS-positive (due to glycogen). * **Location:** Diaphysis (Mid-shaft) of long bones. * **Clinical:** Often mimics osteomyelitis (presents with fever, raised ESR, and local swelling).

Q: Intraosseous skeletal tumors are best diagnosed by which imaging modality?

NMR (Nuclear Magnetic Resonance). **Explanation:** The diagnosis of intraosseous skeletal tumors relies on evaluating both cortical destruction and marrow involvement. **NMR (MRI)** is the gold standard for diagnosing and staging these tumors because of its superior **soft-tissue contrast resolution**. **Why NMR is the correct answer:** MRI is the most sensitive modality for detecting changes within the **bone marrow**. Since most primary bone tumors (like Osteosarcoma or Ewing’s sarcoma) and metastatic deposits originate or spread within the marrow cavity, MRI can precisely delineate the intramedullary extent of the tumor, "skip lesions," and involvement of adjacent neurovascular bundles and soft tissues. **Analysis of incorrect options:** * **Plain X-ray:** While often the *initial* investigation of choice to observe the pattern of bone destruction (e.g., geographic vs. permeative) and periosteal reactions, it lacks the sensitivity to detect early marrow changes or soft tissue extension. * **CT Scan:** CT is superior for evaluating **cortical integrity**, matrix calcification (e.g., osteoid vs. chondroid), and complex anatomy (like the spine or pelvis). However, it is less effective than MRI for intraosseous marrow assessment. * **CT with Scintiscan:** Bone scans (Scintigraphy) are highly sensitive for detecting "hot spots" (increased bone turnover) and are used for screening skeletal metastases, but they have poor specificity and spatial resolution for a definitive diagnosis of a primary tumor. **High-Yield Clinical Pearls for NEET-PG:** * **Investigation of Choice (IOC) for Marrow Edema/Infiltration:** MRI. * **IOC for Staging Bone Tumors:** MRI (to assess local extent) + CT Chest (to look for lung metastases). * **IOC for Cortical Bone/Matrix details:** CT Scan. * **First-line investigation for any bone lesion:** Plain Radiograph (X-ray).

Q: Maclean's sign is seen in which of the following conditions?

Gouty arthritis. **Explanation:** **Maclean's sign** is a classic radiological feature of **Gouty arthritis**. It refers to the presence of **overhanging margins** or edges of bone that displace outward, covering the characteristic "punched-out" erosions. These erosions are typically peri-articular, well-demarcated, and associated with soft tissue tophi. The overhanging edge is created by the remodeling of bone around a slow-growing tophus, distinguishing gout from other inflammatory arthritides where bone is simply destroyed. **Analysis of Options:** * **Rheumatoid Arthritis (RA):** Characterized by marginal erosions (at the "bare area"), symmetrical joint space narrowing, and periarticular osteopenia. It lacks the sclerotic borders and overhanging edges seen in gout. * **Osteoarthritis (OA):** Features include asymmetric joint space narrowing, subchondral sclerosis, subchondral cysts (Geodes), and osteophyte formation, rather than punched-out erosions with overhanging edges. * **Ochronosis (Alkaptonuria):** Classically presents with dense calcification of intervertebral discs ("vacuum phenomenon") and multi-level disc space narrowing, but not the specific erosive pattern of Maclean's sign. **High-Yield Pearls for NEET-PG:** * **Martel’s Sign:** Another name for the overhanging margin/Maclean's sign in Gout. * **Tophi:** Radiographically appear as eccentric soft tissue swelling; may show faint calcification if calcium urate crystals are present. * **Joint Space:** In Gout, the joint space is characteristically **preserved** until very late stages of the disease, unlike RA or OA. * **Dual-Energy CT (DECT):** The gold standard imaging for identifying urate crystal deposits (color-coded green).

Q: Multiple periapical radiolucencies are seen in which of the following conditions?

Jaw cyst basal cell nevus syndrome. **Explanation:** The correct answer is **Jaw cyst basal cell nevus syndrome** (also known as **Gorlin-Goltz Syndrome**). **1. Why the correct answer is right:** Gorlin-Goltz Syndrome is an autosomal dominant disorder characterized by the development of **multiple Odontogenic Keratocysts (OKCs)** in the jaws. On a radiograph, these appear as multiple, well-defined periapical or pericoronal radiolucencies. The syndrome is defined by a triad of: * Multiple OKCs (often the first sign). * Multiple Basal Cell Carcinomas (BCCs). * Skeletal anomalies (e.g., bifid ribs, ectopic calcification of the falx cerebri). **2. Why the incorrect options are wrong:** * **Odontogenic Keratocyst (OKC):** While OKCs are the lesions seen in Gorlin-Goltz, a solitary OKC is usually a sporadic finding. The question specifically asks for *multiple* radiolucencies, which points toward the syndromic association rather than the isolated lesion. * **Cherubism:** This is a genetic condition characterized by **bilateral, multilocular** radiolucencies typically located in the **posterior mandible/ramus**, leading to a "chubby" facial appearance. It does not typically present as simple periapical radiolucencies. * **Thyroid disorders:** These do not typically cause multiple periapical radiolucencies. Hyperparathyroidism (not thyroid) can cause "brown tumors" or a "ground-glass" appearance, but not multiple discrete periapical cysts. **3. High-Yield Clinical Pearls for NEET-PG:** * **Gorlin-Goltz Triad:** Multiple OKCs + Bifid Ribs + Calcified Falx Cerebri. * **OKC Pathology:** High recurrence rate; lined by parakeratinized stratified squamous epithelium with a "picket fence" basal layer. * **Radiographic Tip:** If you see "multiple OKCs" in a question stem, always look for Gorlin-Goltz Syndrome in the options.

Q: A lateral view X-ray of the lumbosacral spine shows which of the following findings?

Spondylolisthesis. ***Spondylolisthesis*** - **Lateral X-ray** is the gold standard for diagnosing spondylolisthesis, showing **anterior slippage** of one vertebra over another with a characteristic **step-off deformity**. - The **Meyerding classification** can be applied on lateral views to grade the degree of vertebral displacement. *Pott's spine* - Shows **vertebral body destruction** and **collapse** with **kyphotic angulation** rather than forward slippage. - Associated with **paravertebral soft tissue shadows** and **cold abscesses** due to **tuberculosis**. *Spondylosis* - Demonstrates **degenerative changes** like **osteophyte formation** and **disc space narrowing** without vertebral displacement. - Shows **facet joint arthritis** and **sclerosis** but lacks the **step-off deformity** seen in spondylolisthesis. *Ankylosing spondylitis* - Presents with **bamboo spine** appearance due to **syndesmophyte formation** and **vertebral fusion**. - Shows **sacroiliac joint erosion** and **squaring of vertebral bodies**, not vertebral slippage.

Q: A Judet view on an X-ray is primarily used for visualizing injuries to which anatomical structure?

Pelvis. **Explanation:** The **Judet view** is a specialized radiographic projection used specifically for evaluating the **acetabulum** and the **pelvic ring**. It consists of two 45-degree oblique views (Iliac oblique and Obturator oblique) taken to visualize the columns and walls of the acetabulum, which are often obscured on a standard AP pelvis view. * **Iliac Oblique View:** Best visualizes the **posterior column** and the **anterior wall** of the acetabulum. * **Obturator Oblique View:** Best visualizes the **anterior column** and the **posterior wall** of the acetabulum. **Why other options are incorrect:** * **Calcaneum:** The standard views are Lateral and Axial (Harris) views. * **Scaphoid:** Requires specific "Scaphoid views" (PA with ulnar deviation and oblique views) to visualize occult fractures. * **Spine:** Common views include AP, Lateral, and occasionally Oblique views (for pars interarticularis), but never Judet views. **High-Yield Clinical Pearls for NEET-PG:** 1. **Letournel Classification:** This is the gold standard classification for acetabular fractures, which relies heavily on the interpretation of Judet views. 2. **The "Teardrop" sign:** Seen on a pelvic X-ray, its displacement is a key indicator of acetabular floor fractures. 3. **Inlet and Outlet views:** These are other specialized pelvic views used to assess the displacement of the pelvic ring (superior/inferior or anterior/posterior).

Question 1

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

Question 2

Wide diploic space of the skull with a brush border (hair on end) appearance is characteristic of which condition?

Accepted Answer

Congenital hemolytic anemia

Answer

Multiple myeloma

Answer

Raised intracranial tension

Answer

Meningioma

Question 3

Which of the following conditions can manifest with the shown X-ray findings in the skull?

Accepted Answer

Thalassemia

Answer

Acute Myeloid Leukemia

Answer

Iron deficiency anemia

Answer

Megaloblastic Anemia

Question 4

Osteoblastic metastases commonly arise from which primary tumor?

Accepted Answer

Prostate

Answer

Breast

Answer

Lung

Answer

Renal Cell Carcinoma (RCC)

Question 5

What is the characteristic radiological finding of Ewing's sarcoma?

Accepted Answer

Onion peel appearance

Answer

Soap bubble appearance

Answer

Sunray appearance

Answer

Codman's triangle

Question 6

Intraosseous skeletal tumors are best diagnosed by which imaging modality?

Accepted Answer

NMR (Nuclear Magnetic Resonance)

Answer

Plain X-ray

Answer

CT scan (Computed Tomography scan)

Answer

CT with scintiscan

Question 7

Maclean's sign is seen in which of the following conditions?

Accepted Answer

Gouty arthritis

Answer

Rheumatoid arthritis

Answer

Osteoarthritis

Answer

Ochronosis

Question 8

Multiple periapical radiolucencies are seen in which of the following conditions?

Accepted Answer

Jaw cyst basal cell nevus syndrome

Answer

Odontogenic keratocyst

Answer

Cherubism

Answer

Thyroid disorders

Question 9

A lateral view X-ray of the lumbosacral spine shows which of the following findings?

Accepted Answer

Spondylolisthesis

Answer

Pott's spine

Answer

Spondylosis

Answer

Ankylosing spondylitis

Question 10

A Judet view on an X-ray is primarily used for visualizing injuries to which anatomical structure?

Accepted Answer

Pelvis

Answer

Calcaneum

Answer

Scaphoid

Answer

Spine

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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