Musculoskeletal Radiology Practice Questions

Q: A 16-year-old male presents with a 6-week history of progressively worsening pain and swelling around the right knee. The pain is worse at night and does not respond to analgesics. There is no history of trauma. Serum alkaline phosphatase is markedly elevated. A plain radiograph of the distal femur is shown in Image 3. Which investigation should be performed next to best assess local extent of disease and guide surgical planning?

A. MRI of the right femur with contrast. ***A. MRI of the right femur with contrast*** - **MRI with contrast** is the gold standard for **local staging** of primary bone tumors like **osteosarcoma**, as it provides superior visualization of **intramedullary extent** and **soft tissue involvement**. - It is essential for surgical planning to identify **skip lesions**, joint involvement, and the relationship of the tumor to the **neurovascular bundle**. *B. Tc-99m bone scintigraphy of the whole skeleton* - This modality is highly sensitive for detecting **distant skeletal metastases** or **polyostotic disease** throughout the body. - It lacks the anatomical resolution required to assess the **local extent** of the primary tumor or guide precise **surgical margin** planning. *C. CT of the distal femur with 3D reconstruction* - While CT provides excellent detail of **cortical bone destruction** and **matrix mineralization**, it is inferior to MRI for evaluating **bone marrow** and soft tissue infiltration. - It is generally reserved for cases where MRI is contraindicated or to visualize complex **ossification patterns** (e.g., in osteoid osteoma). *D. PET-CT with F-18 FDG* - PET-CT is primarily utilized for **systemic staging** to identify occult distant metastases and to monitor **metabolic response** to chemotherapy. - It does not offer the anatomical precision and **soft tissue contrast** needed by surgeons to determine the specific landmarks for **limb-salvage surgery**.

Q: Superior rib notching is caused by which of the following?

All of the above. **Explanation:** Rib notching is a classic radiological sign characterized by cortical erosion along the rib margins. While **inferior rib notching** is most commonly associated with Coarctation of the Aorta (due to dilated intercostal arteries), **superior rib notching** is typically caused by conditions that affect bone resorption, connective tissue integrity, or chronic pressure from muscle atrophy. **Why "All of the Above" is Correct:** 1. **Hyperparathyroidism (Option A):** This is the most common cause of superior rib notching. Increased parathyroid hormone leads to subperiosteal bone resorption, which frequently occurs along the superior borders of the ribs. 2. **Poliomyelitis (Option B):** Chronic paralysis and muscle atrophy lead to a loss of the normal mechanical stress on the bone and decreased vascular supply. The resulting localized pressure and trophic changes cause thinning and notching of the superior rib margins. 3. **Marfan Syndrome (Option C):** This connective tissue disorder results in weakened periosteal attachments and abnormal bone remodeling, leading to superior rib erosions. **High-Yield Clinical Pearls for NEET-PG:** * **Inferior Rib Notching (Roesler’s Sign):** Classically involves the 3rd to 9th ribs. It is a hallmark of **Coarctation of the Aorta** (post-ductal). It is *not* seen in the 1st and 2nd ribs because they are supplied by the costocervical trunk, not the intercostal arteries. * **Other causes of Superior Notching:** Osteogenesis Imperfecta, Rheumatoid Arthritis, and Systemic Lupus Erythematosus (SLE). * **Unilateral Rib Notching:** Suggests a Blalock-Taussig shunt or subclavian artery stenosis.

Q: What is the most common source of error leading to a false positive finding of dental caries?

Cervical burnout. **Explanation:** **Cervical burnout** is the most common radiographic artifact mimicking dental caries. It appears as a radiolucent (dark) area at the neck of the tooth, between the enamel cap and the alveolar bone crest. **Why it occurs:** This phenomenon is due to the **anatomical configuration** of the tooth. At the cervical region, there is a relative lack of tooth mass compared to the crown (protected by thick enamel) and the root (surrounded by bone). Because fewer X-rays are absorbed in this narrow neck area, more radiation reaches the film, creating a radiolucency that clinicians often mistake for proximal or root caries. **Analysis of Incorrect Options:** * **Fluorosis (B):** This is a developmental disturbance caused by excess fluoride. While it causes physical changes like mottling or pitting of the enamel, it does not typically create localized radiolucencies on a radiograph that mimic the specific appearance of caries. * **Dental Pigmentation (C):** Surface staining or pigmentation is a clinical visual finding. Since these pigments do not significantly alter the density of the tooth structure, they do not produce false-positive radiolucencies on an X-ray. **High-Yield Clinical Pearls for NEET-PG:** * **Differential Diagnosis:** To distinguish cervical burnout from true caries, look for the **intactness of the tooth outline**. Burnout disappears when the X-ray angle is changed, whereas true caries remains visible. * **Mach Band Effect:** Another common optical illusion in radiology where the high contrast between enamel and dentin creates a perceived dark line, often leading to a false diagnosis of "occlusal caries." * **Adumbration:** This is the technical term for the shadowing effect seen in cervical burnout.

Q: Spoke wheel calcification in an osteolytic lesion is seen in which of the following conditions?

Hemangioma. **Explanation:** **Vertebral Hemangiomas** are the most common benign primary tumors of the spine. The characteristic **"Spoke-wheel"** appearance (also known as the **"Polka-dot"** or **"Salt and pepper"** sign on axial imaging) occurs due to the resorption of horizontal trabeculae and the compensatory thickening of vertical trabeculae. On a lateral X-ray, this presents as vertical striations called the **"Corduroy cloth"** or **"Jail-bar"** appearance. **Analysis of Options:** * **Hemangioma (Correct):** The "Spoke-wheel" pattern refers specifically to the radiating trabecular pattern seen in flat bones (like the skull) or the axial cross-section of a vertebral body affected by hemangioma. * **Secondaries (Incorrect):** Skeletal metastases typically present as purely lytic (e.g., RCC, Thyroid), blastic (e.g., Prostate), or mixed lesions. They usually cause irregular bone destruction without the organized trabecular thickening seen in hemangiomas. * **Plasmacytoma (Incorrect):** While it presents as a "punched-out" osteolytic lesion or a "soap-bubble" appearance (in the expansile form), it does not show the classic spoke-wheel calcification. * **Hydatid Disease (Incorrect):** In the bone, *Echinococcus* causes multiloculated, "bunch of grapes" osteolytic lesions. Calcification, if present, is usually in the cyst wall (pericyst), not in a spoke-wheel trabecular pattern. **High-Yield Pearls for NEET-PG:** * **Corduroy Cloth Sign:** Vertical trabeculations in the spine (Hemangioma). * **Sunburst Appearance:** Malignant periosteal reaction (Osteosarcoma). * **Soap Bubble Appearance:** Giant Cell Tumor (GCT). * **Onion Skin Appearance:** Ewing’s Sarcoma. * **Most common site for Hemangioma:** Thoracic and Lumbar spine.

Q: A radiolucency in bone without periosteal bone reaction is seen in which of the following conditions?

Squamous cell carcinoma. **Explanation:** The presence or absence of a **periosteal reaction** is a critical diagnostic marker in bone radiology. It occurs when the periosteum is irritated by trauma, infection, or tumors, leading to new bone formation. **Why Squamous Cell Carcinoma (SCC) is correct:** When SCC (typically from the oral cavity or skin) invades underlying bone, it does so by **direct extension and pressure necrosis**. Because the tumor destroys the bone from the "outside-in" and often progresses rapidly without stimulating the osteoblastic activity of the periosteum, it typically presents as a **"punched-out" radiolucency** or an infiltrative lucent lesion **without periosteal reaction**. This is a classic radiological feature of secondary bone invasion by epithelial malignancies. **Why the other options are incorrect:** * **Garre’s Osteomyelitis:** Also known as proliferative periostitis, it is characterized by a prominent, "onion-skin" laminated periosteal reaction. It is a hallmark of chronic irritation in children/young adults. * **Osteosarcoma:** As a highly aggressive primary bone malignancy, it almost always presents with complex periosteal reactions, such as the **Codman’s triangle** or **Sunburst appearance**. * **Chronic Osteomyelitis:** This condition is defined by periosteal activity. The formation of an **Involucrum** (new bone sheath around the dead bone) is a classic example of a thick, exuberant periosteal reaction. **High-Yield Clinical Pearls for NEET-PG:** 1. **No Periosteal Reaction:** Seen in SCC invasion, Multiple Myeloma (punched-out lesions), and some slow-growing benign tumors. 2. **Onion-skin Reaction:** Ewing’s Sarcoma and Garre’s Osteomyelitis. 3. **Sunburst/Spiculated Reaction:** Osteosarcoma. 4. **Codman’s Triangle:** Indicates an aggressive process (Malignancy or Acute Osteomyelitis) lifting the periosteum.

Q: Which of the following is NOT a radiological feature of rheumatoid arthritis?

Osteophytes. ### Explanation The core distinction in musculoskeletal radiology for NEET-PG is differentiating between **Inflammatory Arthritis** (e.g., Rheumatoid Arthritis) and **Degenerative Arthritis** (e.g., Osteoarthritis). **Why Osteophytes is the correct answer:** Osteophytes (bony spurs) are the hallmark of **Osteoarthritis (OA)**. They represent a reparative response of the bone to mechanical stress and cartilage loss. In contrast, Rheumatoid Arthritis (RA) is a chronic inflammatory process characterized by synovial hypertrophy (pannus) that leads to bone **destruction** rather than bone formation. **Analysis of incorrect options:** * **Subchondral Osteopenia:** This is one of the earliest radiological signs of RA. Inflammatory cytokines and increased vascularity in the synovium lead to localized bone loss near the joint (juxta-articular osteopenia). * **Subchondral Cysts (Geodes):** In RA, synovial fluid is forced into the bone through marginal erosions under pressure, creating "pseudocysts" or geodes in the subchondral bone. * **Subchondral Swelling:** Early RA presents with soft tissue swelling around the joints (fusiform appearance) due to synovial inflammation and effusion. **Clinical Pearls for NEET-PG:** * **Classic RA Triad on X-ray:** Juxta-articular osteopenia, symmetrical joint space narrowing, and marginal erosions. * **Joints involved:** RA typically involves the MCP, PIP, and MTP joints, characteristically **sparing the DIP joints** (which are involved in OA and Psoriatic Arthritis). * **Deformities:** Look for "Rat-bite" erosions, ulnar deviation at MCP joints, and Swan-neck or Boutonniere deformities. * **Key Differentiator:** If you see **subchondral sclerosis** or **osteophytes**, think Osteoarthritis. If you see **osteopenia** and **erosions**, think Rheumatoid Arthritis.

Q: What is the best radiographic view for a fracture of the C1-C2 vertebrae?

Odontoid view. ### Explanation The **Odontoid view** (also known as the **Open-mouth view**) is the gold standard radiographic projection for evaluating the C1 (Atlas) and C2 (Axis) vertebrae. **Why it is correct:** In a standard AP view, the mandible and the base of the skull superimpose over the upper cervical spine, obscuring the anatomy. By opening the mouth wide, these structures are moved out of the way, allowing a clear view of the **dens (odontoid process)**, the **lateral masses of C1**, and the **atlanto-axial joints**. This view is essential for diagnosing: * **Jefferson fractures** (burst fracture of C1): Look for lateral displacement of the C1 lateral masses relative to C2. * **Odontoid fractures** (C2): Specifically Type II and III fractures. **Why other options are incorrect:** * **AP View:** Useful for the lower cervical spine (C3-C7) but, as mentioned, the upper segments are hidden by the jaw. * **Lateral View:** While excellent for seeing the "Pre-vertebral soft tissue space" and the "Atlantodental interval (ADI)," it can miss non-displaced odontoid fractures or subtle lateral mass displacements. * **Oblique View:** Primarily used to visualize the **intervertebral foramina** and the facet joints, not the C1-C2 complex. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of Spence:** On an odontoid view, if the combined lateral displacement of C1 lateral masses over C2 is **>6.9 mm**, it indicates a rupture of the **Transverse Ligament**. * **Harris Lines:** Always check the four parallel lines on a lateral view to ensure spinal alignment. * **Pre-vertebral Space:** At C2, the soft tissue shadow should be **<7 mm**. Widening suggests a hidden fracture or hematoma. * **Gold Standard:** While the odontoid view is the best *radiographic* view, **Non-contrast CT** is the overall gold standard for diagnosing cervical spine fractures in trauma.

Q: What is the best radiographic view for the temporomandibular joint (TMJ)?

Orthopantomogram (OPG). ### Explanation **Correct Answer: D. Orthopantomogram (OPG)** **Why OPG is the best view:** The Orthopantomogram (OPG) is the primary screening modality and the most commonly used radiographic view for the Temporomandibular Joint (TMJ). Its superiority lies in its ability to provide a **panoramic, bilateral, and comparative view** of both TMJs, the mandibular condyles, and the ascending rami on a single film. It is particularly effective for detecting gross bony changes, fractures of the condylar neck, and developmental anomalies. While MRI is the gold standard for soft tissue (disc) evaluation, OPG remains the best initial radiographic choice for osseous assessment. **Analysis of Incorrect Options:** * **A. Lateral Oblique View:** While it can visualize the condyle, it often suffers from superimposition of the contralateral side and base of the skull, making it less diagnostic than a panoramic view. * **B. PA View:** This view is primarily used to assess mediolateral displacement of fractures or gross asymmetry but provides poor visualization of the joint space and condylar morphology due to the density of the petrous temporal bone. * **C. Waters View (Occipitomental):** This is the gold standard for **Paranasal Sinuses (specifically the Maxillary sinus)**. It does not provide a clear view of the TMJ anatomy. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard for TMJ Disc/Soft Tissue:** MRI (T1 for anatomy, T2 for effusion). * **Best for Bony Erosion/Ankylosis:** Non-contrast CT (NCCT). * **Trans-cranial View (Schuller’s):** Historically used to see the lateral aspect of the joint, but largely replaced by OPG/CT. * **Reverse Towne’s View:** Excellent for visualizing high condylar fractures and the condylar neck.

Q: Champagne glass pelvis is seen in which of the following conditions?

Achondroplasia. **Explanation:** **Achondroplasia** is the most common cause of disproportionate short-limbed dwarfism. It is an autosomal dominant condition caused by a mutation in the **FGFR3 gene**, which leads to abnormal endochondral ossification. The characteristic **"Champagne Glass Pelvis"** occurs due to specific bony deformities: * **Short, squat iliac wings:** The ilia are reduced in vertical height. * **Horizontal acetabular roofs:** This creates a flat appearance. * **Narrow sacrosciatic notch:** This combination results in a pelvic inlet that is wide and shallow, resembling the bowl of a champagne glass. **Analysis of Incorrect Options:** * **Congenital Dislocation of Hip (CDH/DDH):** Characterized by Putti’s Triad (superolateral displacement of the femoral head, increased acetabular angle, and delayed ossification of the femoral epiphysis), not a champagne glass shape. * **Down’s Syndrome:** Associated with an **"Elephant Ear Pelvis"** (large, flared iliac wings) and a decreased acetabular and iliac angle. * **Cretinism (Hypothyroidism):** Radiologically presents with delayed skeletal maturation, epiphyseal dysgenesis (fragmented "stippled" epiphysis), and increased bone density, but not the specific champagne glass morphology. **High-Yield Clinical Pearls for NEET-PG:** * **Spine:** Posterior scalloping of vertebrae and narrowing of the interpedicular distance (caudally). * **Hands:** **Trident Hand** (persistent space between the 3rd and 4th digits). * **Long Bones:** Rhizomelic shortening (proximal segments like femur/humerus are shortest) and "Chevrons" (V-shaped) physeal growth plates. * **Skull:** Frontal bossing with midface hypoplasia and a narrowed foramen magnum.

Q: Which condition is associated with Martel's sign?

Gout. **Explanation:** **Martel’s sign** (also known as the **Gouty Overhanging Edge** sign) is a classic radiographic feature of chronic tophaceous **Gout**. It refers to a thin, bony shelf-like protrusion that overhangs a "punched-out" erosive lesion. This occurs because the urate crystal deposition (tophus) causes eccentric bone erosion while simultaneously stimulating the periosteum to form new bone at the margins, creating the characteristic overhanging edge. **Analysis of Options:** * **Gout (Correct):** Martel’s sign is pathognomonic. The erosions are typically "punched-out," periarticular, and have sclerotic borders, distinguishing them from the marginal erosions seen in Rheumatoid Arthritis. * **SLE:** Radiographic findings in SLE are usually non-erosive. While Jaccoud’s arthropathy (reducible deformities) can occur, bone destruction and overhanging edges are not features. * **Takayasu Arteritis:** This is a large-vessel vasculitis (Pulseless disease) affecting the aorta and its branches. It presents with vascular symptoms (claudication, absent pulses) rather than erosive joint disease. * **Kawasaki Disease:** A medium-vessel vasculitis primarily affecting children. Its most critical complication is coronary artery aneurysms; it does not cause chronic erosive arthritis or Martel’s sign. **High-Yield Pearls for NEET-PG:** * **Joint involved:** Most common site is the 1st Metatarsophalangeal (MTP) joint (**Podagra**). * **Synovial Fluid:** Negatively birefringent, needle-shaped crystals. * **Radiology:** Joint space is usually preserved until late stages (unlike RA). * **Associated Sign:** "Rat-bite" erosions.

Question 1

A 16-year-old male presents with a 6-week history of progressively worsening pain and swelling around the right knee. The pain is worse at night and does not respond to analgesics. There is no history of trauma. Serum alkaline phosphatase is markedly elevated. A plain radiograph of the distal femur is shown in Image 3. Which investigation should be performed next to best assess local extent of disease and guide surgical planning?

Accepted Answer

A. MRI of the right femur with contrast

Answer

B. Tc-99m bone scintigraphy of the whole skeleton

Answer

C. CT of the distal femur with 3D reconstruction

Answer

D. PET-CT with F-18 FDG

Question 2

Superior rib notching is caused by which of the following?

Accepted Answer

All of the above

Answer

Hyperparathyroidism

Answer

Poliomyelitis

Answer

Marfan syndrome

Question 3

What is the most common source of error leading to a false positive finding of dental caries?

Accepted Answer

Cervical burnout

Answer

Fluorosis

Answer

Dental pigmentation

Answer

All of the above

Question 4

Spoke wheel calcification in an osteolytic lesion is seen in which of the following conditions?

Accepted Answer

Hemangioma

Answer

Secondaries

Answer

Plasmacytosis

Answer

Hydatid disease

Question 5

A radiolucency in bone without periosteal bone reaction is seen in which of the following conditions?

Accepted Answer

Squamous cell carcinoma

Answer

Garre's osteomyelitis

Answer

Osteosarcoma

Answer

Chronic osteomyelitis

Question 6

Which of the following is NOT a radiological feature of rheumatoid arthritis?

Accepted Answer

Osteophytes

Answer

Subchondral cysts

Answer

Subchondral osteopenia

Answer

Subchondral swelling

Question 7

What is the best radiographic view for a fracture of the C1-C2 vertebrae?

Accepted Answer

Odontoid view

Answer

AP view

Answer

Lateral view

Answer

Oblique view

Question 8

What is the best radiographic view for the temporomandibular joint (TMJ)?

Accepted Answer

Orthopantomogram (OPG)

Answer

Lateral oblique view

Answer

PA view

Answer

Waters view

Question 9

Champagne glass pelvis is seen in which of the following conditions?

Accepted Answer

Achondroplasia

Answer

Congenital Dislocation of Hip (CDH)

Answer

Down's syndrome

Answer

Cretinism

Question 10

Which condition is associated with Martel's sign?

Accepted Answer

Gout

Answer

Systemic Lupus Erythematosus (SLE)

Answer

Takayasu arteritis

Answer

Kawasaki disease

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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