Musculoskeletal Radiology Practice Questions

Q: Residual asymmetric deformity of the mandible is seen in which condition?

Caffey disease. **Explanation:** **Caffey Disease (Infantile Cortical Hyperostosis)** is the correct answer. It is a rare, self-limiting inflammatory disorder characterized by a clinical triad of fever, soft tissue swelling, and irritability, alongside the hallmark radiological finding of **subperiosteal new bone formation**. * **Mandibular Involvement:** The mandible is the most commonly affected site (75-80% of cases). While the condition usually resolves spontaneously within months, it can leave behind a **residual asymmetric deformity** of the mandible as the cortical thickening undergoes remodeling. **Why other options are incorrect:** * **Thalassemia:** Characterized by "Hair-on-end" appearance of the skull and "Chipmunk facies" due to maxillary marrow expansion. While it causes facial deformity, it is typically symmetric and involves marrow hyperplasia rather than primary cortical hyperostosis of the mandible. * **Achondroplasia:** A disorder of endochondral ossification leading to rhizomelic dwarfism, frontal bossing, and midface hypoplasia. It does not cause asymmetric mandibular cortical thickening. * **Paget Disease:** Involves abnormal bone remodeling (osteoclastic/osteoblastic activity). While it can affect the mandible (causing "Leontiasis Ossea"), it is a disease of adulthood, whereas Caffey disease is specifically infantile. **High-Yield Clinical Pearls for NEET-PG:** * **Age of Onset:** Almost always presents before **6 months** of age. * **Classic Triad:** Irritability, soft tissue swelling, and cortical thickening. * **Most Common Site:** Mandible > Clavicle > Ulna. * **Radiology:** "Onion-peel" appearance of periosteal reaction may be seen. * **Laboratory:** Elevated ESR and Alkaline Phosphatase are common during the acute phase.

Q: What radiological feature differentiates myositis ossificans from a bone tumor?

Discontinuity with the bone. **Explanation:** The hallmark radiological feature that differentiates **Myositis Ossificans (MO)** from a malignant bone tumor (like Osteosarcoma) is its **discontinuity with the underlying bone**. 1. **Why Option C is Correct:** Myositis ossificans is a benign, post-traumatic heterotopic ossification occurring within soft tissue. On imaging (X-ray or CT), a characteristic **radiolucent zone** (the "string sign") is often seen separating the calcified mass from the adjacent bone cortex. In contrast, primary bone tumors typically arise directly from the bone, showing cortical destruction or direct continuity with the medulla. 2. **Why Other Options are Incorrect:** * **Option A (Peripheral Ossification):** While this is a classic feature of MO (known as the **zonal phenomenon**, where the lesion matures from the outside in), it is a feature of the internal architecture rather than the relationship with the bone. * **Option B (Central Lucency):** MO does have a more radiolucent (immature) center compared to its periphery, but this is also part of the internal zonal pattern and is less definitive for differentiation than the lack of bony attachment. **NEET-PG High-Yield Pearls:** * **Zonal Phenomenon:** MO matures from the periphery (mature lamellar bone) to the center (immature osteoid). **Osteosarcoma is the opposite** (dense central ossification, immature periphery). * **Clinical History:** Often follows blunt trauma (e.g., "thigh blow"), appearing 2–6 weeks post-injury. * **Imaging Gold Standard:** **CT scan** is the best modality to demonstrate the peripheral mineralization and the separation from the bone. * **Biopsy Warning:** Early-stage MO can histologically mimic Osteosarcoma due to high osteoblastic activity; clinical and radiological correlation is vital to avoid unnecessary radical surgery.

Q: What pathology can be seen on X-ray?

Psoriasis. The correct answer is **Psoriasis (Psoriatic Arthritis)**. ### **Explanation** The hallmark radiographic feature of Psoriatic Arthritis (PsA) is the **"Pencil-in-cup" deformity**. This occurs due to the combination of aggressive periarticular erosions (tapering of the distal end of a phalanx) and exuberant new bone formation (widening of the base of the adjacent distal phalanx). Unlike Rheumatoid Arthritis, PsA typically involves the **Distal Interphalangeal (DIP) joints** and is characterized by a lack of periarticular osteopenia. Other classic signs include "telescoping" of digits (arthritis mutilans) and asymmetrical joint involvement. ### **Why the other options are incorrect:** * **Osteoarthritis (OA):** While OA involves the DIP joints (Heberden’s nodes), it is characterized by joint space narrowing, subchondral sclerosis, and **osteophytes**, rather than the erosive "pencil-in-cup" morphology. * **Gouty Arthritis:** Gout typically presents with **"punched-out" erosions** with overhanging edges (Martel’s sign). It usually spares the joint space until late stages and is associated with soft tissue tophi. * **Ankylosing Spondylitis:** While part of the same seronegative family, it primarily affects the **axial skeleton** (Sacroiliitis and "Bamboo spine"). Peripheral involvement is less common and rarely presents with the specific digital erosive patterns of PsA. ### **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** DIP joint involvement + Dactylitis ("Sausage digit") + Nail pitting/onycholysis. * **Radiology Buzzwords:** Pencil-in-cup deformity, Mouse-ear erosions, Ivory phalanx, and asymmetric sacroiliitis. * **Serology:** Patients are typically **Rheumatoid Factor (RF) negative** (Seronegative Spondyloarthropathy).

Q: Which disease is shown by the following X-ray of a foot?

Gout. ***Gout*** - Classic X-ray features include **punched-out erosions** with **overhanging edges** (Martel sign) and **soft tissue tophi**, typically affecting the first metatarsophalangeal joint. - **Preserved joint space** and absence of **periarticular osteoporosis** are characteristic findings that distinguish it from other arthropathies. *Rheumatoid arthritis* - Shows **symmetric joint erosions** with **periarticular osteoporosis** and **joint space narrowing**, unlike the preserved joint spaces in gout. - Typically affects **metacarpophalangeal** and **proximal interphalangeal joints** with **swan neck** or **boutonniere deformities**. *Osteoarthritis* - Characterized by **joint space narrowing**, **osteophyte formation**, and **subchondral sclerosis** rather than punched-out erosions. - Commonly affects **weight-bearing joints** like knees and hips, with **Heberden's** and **Bouchard's nodes** in hands. *Psoriatic arthritis* - Shows **pencil-in-cup deformity** and **ankylosis** with **asymmetric joint involvement**, different from gout's punched-out pattern. - Associated with **psoriatic skin lesions** and **nail pitting**, often affecting **distal interphalangeal joints**.

Q: What diagnosis is suggested by the findings on this anteroposterior radiograph of the right tibia?

Marrow hyperplasia. ***Marrow hyperplasia*** - Characterized by **widened medullary cavity** and **thinned cortex** on radiographs, commonly seen in **hemolytic anemias** like sickle cell disease or thalassemia. - Shows **coarsened trabecular pattern** due to increased **erythropoietic activity** expanding the bone marrow space. *Ewing's sarcoma* - Presents with **aggressive permeative bone destruction** and characteristic **onion-skin periosteal reaction** on radiographs. - Typically shows a **soft tissue mass** with bone destruction, not marrow expansion patterns. *Osteomalacia* - Characterized by **Looser zones** (pseudofractures) and **generalized osteopenia** due to **vitamin D deficiency** or phosphate disorders. - Shows **delayed mineralization** and **bowing deformities**, not medullary cavity widening. *Polyostotic fibrous dysplasia* - Demonstrates **ground-glass appearance** with **well-defined sclerotic margins** and **shepherd's crook deformity** in proximal femur. - Shows **fibrous tissue replacement** of normal bone, creating characteristic **cystic lesions** with expansion.

Q: On an X-ray, what is the appearance of dead bone?

More radiopaque. **Explanation:** The correct answer is **A. More radiopaque**. In musculoskeletal radiology, dead bone (known as a **sequestrum**) appears more radiopaque (whiter/denser) than the surrounding living bone. This occurs due to two primary mechanisms: 1. **Loss of Blood Supply:** Dead bone lacks a blood supply, meaning it cannot undergo the normal process of bone resorption. 2. **Disuse Osteoporosis:** The surrounding healthy bone, stimulated by inflammation and hyperemia, undergoes active resorption and becomes osteoporotic (more radiolucent). This contrast makes the dead bone appear relatively denser. Additionally, new bone formation (involucrum) around the dead bone further enhances this visual density. **Analysis of Incorrect Options:** * **B & C (Radiolucent/Less radiopaque):** These terms describe bone that has lost mineral content (e.g., osteoporosis, osteolysis, or infection). Dead bone cannot lose mineral content because the osteoclasts required for resorption cannot reach it without a blood supply. * **D (Is not seen at all):** Dead bone is highly visible on X-rays, specifically in chronic osteomyelitis, where it serves as a hallmark diagnostic feature. **High-Yield NEET-PG Pearls:** * **Sequestrum:** A piece of dead bone that has become separated during the process of necrosis. * **Involucrum:** A layer of new periosteal bone that grows around the sequestrum. * **Cloaca:** An opening in the involucrum through which pus and debris (and sometimes small sequestra) can escape. * **Imaging Choice:** While X-ray is the initial investigation, **MRI** is the most sensitive for early osteomyelitis, and **CT** is the best for identifying a sequestrum.

Q: What is the first-choice imaging modality for evaluating a shoulder joint?

Digital X-ray. **Explanation:** In musculoskeletal radiology, the **Digital X-ray** remains the **initial and first-choice imaging modality** for evaluating the shoulder joint. This is based on the fundamental clinical principle of "starting with the simplest and most cost-effective tool." X-rays provide an immediate overview of bony anatomy, joint alignment, and gross pathology such as fractures, dislocations, or degenerative changes (osteoarthritis). **Why other options are incorrect:** * **CT Scan:** While superior for evaluating complex intra-articular fractures or preoperative planning for glenoid bone loss, it involves high radiation and is considered a second-line investigation for bone detail. * **MRI:** This is the "Gold Standard" for soft tissue evaluation (rotator cuff tears, labral injuries, and marrow edema). However, it is expensive and time-consuming, making it a secondary investigation after X-rays have ruled out bony pathology. * **Ultrasound (USG):** Excellent for dynamic evaluation of the rotator cuff and biceps tendon, but it is operator-dependent and cannot visualize deep intra-articular structures or bony architecture effectively. **High-Yield Clinical Pearls for NEET-PG:** * **Standard Views:** The most common views for the shoulder are Anteroposterior (AP), Internal/External rotation, and the **Axillary view** (best for detecting subtle dislocations). * **Hill-Sachs & Bankart Lesions:** While X-rays may show a "Stryker Notch" or "West Point" view, **MRI/MR Arthrography** is the definitive investigation for these recurrent dislocation sequelae. * **Snowcap Sign:** A classic radiological sign seen on X-ray in **Avascular Necrosis (AVN)** of the humeral head.

Q: What is the earliest radiological change observed in rheumatoid arthritis?

Periarticular osteopenia. **Explanation:** In Rheumatoid Arthritis (RA), the primary pathology is **synovitis**. The inflamed synovium (pannus) releases inflammatory cytokines and increases local blood flow (hyperemia). This hyperemia leads to increased osteoclast activity and the leaching of calcium from the bone surrounding the joint, resulting in **Periarticular Osteopenia** (also known as juxta-articular osteoporosis). This is the **earliest** radiological sign of RA. **Analysis of Options:** * **Periarticular Osteopenia (Correct):** The earliest change caused by local inflammatory hyperemia before structural bone destruction occurs. * **Decreased Joint Space:** This occurs later as the pannus destroys the articular cartilage. In RA, joint space narrowing is typically **uniform/symmetrical**, unlike the asymmetrical narrowing seen in osteoarthritis. * **Articular Erosion:** These are "marginal erosions" that occur at the "bare areas" (where the bone is not covered by cartilage). While characteristic of RA, they appear after osteopenia. * **Subchondral Cyst:** These are more characteristic of degenerative conditions like Osteoarthritis (Geodes). While they can occur in late-stage RA, they are not an early or primary feature. **NEET-PG High-Yield Pearls:** 1. **Earliest Sign (Overall):** Soft tissue swelling (due to effusion/synovitis). 2. **Earliest Bony Sign:** Periarticular osteopenia. 3. **Characteristic Feature:** Symmetrical involvement of small joints (MCP, PIP) sparing the DIP joints. 4. **Late Radiological Signs:** Subluxations (e.g., Atlanto-axial), ulnar deviation of fingers, and ankylosis. 5. **MRI** is the most sensitive imaging modality to detect early synovitis and bone marrow edema before they appear on X-rays.

Q: Increased heel pad thickness is associated with which of the following conditions?

Acromegaly. **Explanation:** **Correct Answer: C. Acromegaly** The measurement of heel pad thickness is a classic radiological sign used in the evaluation of **Acromegaly**. Excess Growth Hormone (GH) and Insulin-like Growth Factor-1 (IGF-1) cause soft tissue hypertrophy and overgrowth of connective tissue throughout the body. In the foot, this manifests as thickening of the soft tissue between the calcaneus and the skin surface. * **Diagnostic Threshold:** On a lateral radiograph of the foot, a heel pad thickness **>25 mm in males** and **>23 mm in females** is highly suggestive of acromegaly. **Why other options are incorrect:** * **A. Rickets:** Characterized by defective mineralization of osteoid, leading to radiological signs like cupping, splaying, and fraying of the metaphyses, not soft tissue thickening. * **B. Paget’s Disease:** A disorder of bone remodeling resulting in thickened, disorganized trabeculae and cortical thickening (e.g., "picture frame" vertebra or "cotton wool" skull), but it does not typically cause heel pad hypertrophy. * **D. Fibrous Dysplasia:** A condition where normal bone is replaced by fibrous tissue, showing a characteristic "ground-glass" appearance on X-ray. **High-Yield Clinical Pearls for NEET-PG:** * **Other causes of increased heel pad thickness:** Obesity (most common cause), Myxedema (Hypothyroidism), Acromegaly, and certain drugs (e.g., Phenytoin). * **Radiological signs of Acromegaly:** 1. **Skull:** Enlarged sella turcica, frontal bossing, and prominent external occipital protuberance. 2. **Hands:** "Spade-like" appearance of phalanges and tufting of distal phalanges. 3. **Joints:** Widened joint spaces (due to cartilage hypertrophy) followed by premature osteoarthritis.

Question 1

Residual asymmetric deformity of the mandible is seen in which condition?

Accepted Answer

Caffey disease

Answer

Thalassemia

Answer

Achondroplasia

Answer

Paget disease

Question 2

What radiological feature differentiates myositis ossificans from a bone tumor?

Accepted Answer

Discontinuity with the bone

Answer

Peripheral ossification

Answer

Central lucency

Answer

None of the above

Question 3

What pathology can be seen on X-ray?

Accepted Answer

Psoriasis

Answer

Osteoarthritis

Answer

Gouty arthritis

Answer

Ankylosing spondylitis

Question 4

Which disease is shown by the following X-ray of a foot?

Accepted Answer

Gout

Answer

Rheumatoid arthritis

Answer

Osteoarthritis

Answer

Psoriatic arthritis

Question 5

Which of the following is NOT a radiological finding seen in rickets?

Accepted Answer

Looser's zones

Answer

Cupping and splaying of metaphyses

Answer

White line of Frankel

Answer

Triradiate pelvis

Question 6

What diagnosis is suggested by the findings on this anteroposterior radiograph of the right tibia?

Accepted Answer

Marrow hyperplasia

Answer

Ewing's sarcoma

Answer

Osteomalacia

Answer

Polyostotic fibrous dysplasia

Question 7

On an X-ray, what is the appearance of dead bone?

Accepted Answer

More radiopaque

Answer

Radio-lucent

Answer

Less radiopaque

Answer

Is not seen at all

Question 8

What is the first-choice imaging modality for evaluating a shoulder joint?

Accepted Answer

Digital X-ray

Answer

CT scan

Answer

MRI

Answer

Ultrasound (USG)

Question 9

What is the earliest radiological change observed in rheumatoid arthritis?

Accepted Answer

Periarticular osteopenia

Answer

Decreased joint space

Answer

Articular erosion

Answer

Subchondral cyst

Question 10

Increased heel pad thickness is associated with which of the following conditions?

Accepted Answer

Acromegaly

Answer

Rickets

Answer

Paget's disease

Answer

Fibrous dysplasia

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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