Musculoskeletal Radiology Practice Questions

Q: The following X-ray is diagnostic of:

Rickets. ***Rickets*** - Classic X-ray findings include **metaphyseal cupping**, **fraying**, and **widening of the growth plate** due to defective mineralization of the growth plate cartilage. - **Coxa vara**, **bowing deformities** of long bones, and **delayed ossification** are characteristic features that make this diagnosis evident on radiographs. *Scurvy* - X-ray shows **Frankel's line** (dense metaphyseal line), **Pelkan spurs** (corner fractures), and **Trümmerfeld zone** (rarefied metaphyseal area). - Caused by **vitamin C deficiency** affecting collagen synthesis, not calcium metabolism like rickets. *Hairline fracture of radius and ulna* - Would appear as **thin lucent lines** through the cortical bone without affecting the growth plates or causing metaphyseal changes. - **Acute trauma history** would be present, and there would be no generalized bone deformities or growth plate abnormalities. *Osteopetrosis* - X-ray shows **increased bone density** with a **marble bone appearance** and **sclerotic changes** throughout the skeleton. - **Erlenmeyer flask deformity** and **bone-in-bone appearance** are characteristic, opposite to the osteopenic changes seen in rickets.

Q: Salt-pepper skull is a characteristic radiographic finding in which of the following conditions?

Primary hyperparathyroidism. **Explanation:** **1. Why Primary Hyperparathyroidism is Correct:** The "Salt-and-Pepper" skull (also known as the granular skull) is a classic radiographic hallmark of **Hyperparathyroidism** (Primary, Secondary, or Tertiary). The underlying pathophysiology involves increased Parathyroid Hormone (PTH) levels, which stimulate osteoclastic activity. This leads to multiple tiny, well-defined areas of **trabecular bone resorption** (the "pepper") interspersed with areas of normal or sclerotic bone (the "salt"), resulting in a diffuse, mottled appearance of the calvarium. **2. Analysis of Incorrect Options:** * **Paget’s Disease:** Characterized by **"Cotton Wool Spots"** on the skull, which are thick, disorganized patches of sclerotic bone. It also features thickening of the diploic space and "Osteoporosis Circumscripta." * **Eosinophilic Granuloma (Langerhans Cell Histiocytosis):** Typically presents with **"Punched-out" lytic lesions** or a "Beveled edge" appearance due to uneven involvement of the inner and outer tables of the skull. * **Multiple Myeloma:** Characterized by multiple, discrete, small, circular **"Raindrop" lytic lesions**. Unlike the granular appearance of hyperparathyroidism, these lesions are sharply demarcated and uniform in size. **3. NEET-PG High-Yield Pearls:** * **Subperiosteal bone resorption** is the *most specific* radiographic sign of hyperparathyroidism, most commonly seen on the radial aspect of the middle phalanges of the 2nd and 3rd fingers. * **Brown Tumors** (Osteoclastomas) are non-neoplastic lytic lesions also associated with this condition. * **Rugger-Jersey Spine** is a classic finding in Secondary Hyperparathyroidism (Renal Osteodystrophy).

Q: Which imaging modality is NOT typically used for the detection of bone metastasis?

Ultrasound. **Explanation:** The detection of bone metastasis relies on identifying changes in bone mineral density, cortical integrity, or marrow signal. **Ultrasound (Option D)** is the correct answer because sound waves cannot penetrate the intact bony cortex, making it ineffective for evaluating intraosseous pathology. While ultrasound may occasionally show a soft tissue mass associated with cortical destruction, it is not a standard or reliable modality for screening or diagnosing bone metastases. **Analysis of other options:** * **Radionuclide Scan (Bone Scan):** This is the most common **screening** modality. It uses Technetium-99m MDP to detect osteoblastic activity. It is highly sensitive but has low specificity. * **MRI:** This is the **most sensitive** modality for detecting early bone marrow infiltration, often identifying lesions before they cause significant bone destruction visible on other scans. * **CT Scan:** Excellent for evaluating cortical bone destruction and assessing the risk of pathological fractures. It is often used to characterize lesions found on bone scans. **Clinical Pearls for NEET-PG:** * **Most sensitive screening tool:** MRI (specifically for marrow changes). * **Most common screening tool:** Radionuclide Bone Scan (Tc-99m MDP). * **Osteoblastic Metastases:** Classically seen in Prostate Cancer and Small Cell Lung Cancer. * **Osteolytic Metastases:** Classically seen in Renal Cell Carcinoma, Thyroid Cancer, and Multiple Myeloma (Note: Multiple Myeloma is often **cold** on a bone scan). * **PET-CT:** Increasingly used for detecting both lytic and blastic lesions with high sensitivity.

Q: Which X-ray view is best for evaluating a patellar fracture?

Skyline view. **Explanation:** The **Skyline view** (also known as the Sunrise or Merchant view) is the gold standard for evaluating the patella and the patellofemoral joint. In this tangential projection, the knee is flexed, and the X-ray beam passes superior-to-inferior (or vice versa) through the space between the patella and the femoral condyles. This view is superior for detecting **vertical (longitudinal) fractures**, marginal osteochondral fractures, and assessing patellar subluxation or tilt, which may be missed on standard AP or Lateral views. **Analysis of Incorrect Options:** * **Judet view:** These are specialized 45-degree oblique views of the pelvis used specifically to evaluate **acetabular fractures** (iliopubic and iliotschial columns). * **Water’s view:** This is a radiographic projection used to visualize the **paranasal sinuses** and midface fractures (e.g., Le Fort or tripod fractures). * **Oblique view:** While sometimes used in knee trauma to see the tibial plateaus, it is less specific and less effective than the Skyline view for visualizing the articular surface of the patella. **High-Yield Clinical Pearls for NEET-PG:** * **Standard Knee Series:** Includes AP and Lateral views. The **Lateral view** is best for identifying transverse patellar fractures and assessing patellar height (Patella Alta/Baja). * **Bipartite Patella:** A common mimic of a fracture, usually located in the **superolateral** quadrant with smooth, sclerotic margins (unlike the sharp, irregular edges of an acute fracture). * **Mechanism of Injury:** Patellar fractures usually occur via direct trauma (dashboard injury) or indirect force (sudden forceful contraction of the quadriceps). * **Surgical Indication:** Surgery (usually Tension Band Wiring) is indicated if there is >2mm of articular displacement or >3mm of fragment separation.

Q: Clover leaf skull is seen in which condition?

Thanatophoric Dysplasia. **Explanation:** **Cloverleaf skull (Kleeblattschädel deformity)** is a severe craniosynostosis where there is premature closure of all cranial sutures except the metopic and sagittal sutures. This causes the brain to expand through the open sutures, resulting in a trilobed appearance of the skull. 1. **Why Thanatophoric Dysplasia (TD) is correct:** TD is the most common lethal skeletal dysplasia. **Type II Thanatophoric Dysplasia** is specifically characterized by the presence of a cloverleaf skull and straight femurs. In contrast, Type I features curved femurs ("telephone receiver" appearance) but usually lacks the cloverleaf skull. 2. **Analysis of Incorrect Options:** * **Chiari Malformation:** Associated with a "Luckenschadel" (lacunar) skull, characterized by inner table thinning and "beaten silver" appearance, not a trilobed shape. * **Eosinophilic Granuloma:** Typically presents with "punched-out" lytic lesions or a "hole-within-a-hole" appearance (bevelled edges) in the skull. * **Multiple Myeloma:** Characterized by multiple, small, well-circumscribed "rain-drop" lytic lesions of uniform size. **High-Yield Clinical Pearls for NEET-PG:** * **Thanatophoric Dysplasia:** Look for "H-shaped" vertebrae (platyspondyly) and a narrow thorax (champagne cork appearance). * **Cloverleaf skull** can also be seen in severe cases of **Apert syndrome**, **Crouzon syndrome**, and **Pfeiffer syndrome**. * **Lemon sign:** Frontal bone scalloping (Spina bifida/Chiari II). * **Strawberry skull:** Flattening of the occiput and narrowing of the frontal bones (Trisomy 18).

Q: An oblique view is required for the diagnosis of which of the following carpal bones?

Scaphoid. **Explanation:** The **Scaphoid** is the most commonly fractured carpal bone. Due to its unique anatomy and oblique orientation within the wrist, it often appears foreshortened on standard Posteroanterior (PA) views. To visualize the scaphoid in its full longitudinal profile and rule out occult fractures, a specific **Scaphoid View** is required. This involves a **PA view with ulnar deviation** and a **30-degree cranial angulation** (oblique orientation), which elongates the bone and opens the joint spaces. **Analysis of Options:** * **Scaphoid (Correct):** The oblique/specialized view is essential to identify fractures, especially at the waist, which are prone to avascular necrosis (AVN) due to retrograde blood supply. * **Capitate (Incorrect):** This is the largest carpal bone and is centrally located; it is typically well-visualized on standard PA and Lateral views. * **Navicular (Incorrect):** In modern terminology, "Navicular" refers to a bone in the foot. While the scaphoid was historically called the "carpal navicular," the term is now obsolete in hand anatomy to avoid confusion. * **Hamate (Incorrect):** While the body is seen on standard views, the "Hook of the Hamate" specifically requires a **Carpal Tunnel View**, not a standard oblique view. **High-Yield Clinical Pearls for NEET-PG:** * **Blood Supply:** The scaphoid receives its blood supply from the distal pole (radial artery branches). Therefore, a fracture at the **proximal pole** has the highest risk of **Avascular Necrosis (AVN)**. * **Clinical Sign:** Tenderness in the **Anatomical Snuffbox** is pathognomonic for a scaphoid fracture. * **Management:** If a fracture is clinically suspected but X-rays are negative, the wrist should be immobilized in a **thumb spica cast** and re-imaged in 10–14 days, or an MRI should be performed (the most sensitive investigation).

Q: Which radiographic view is considered the best for evaluating the mandible?

Orthopentomogram. ### Explanation **Orthopantomogram (OPG)**, also known as a panoramic radiograph, is the gold standard and most comprehensive screening tool for evaluating the mandible. **Why OPG is the Correct Answer:** The mandible is a curved, U-shaped bone. Conventional 2D radiographs often suffer from the "superimposition" of the cervical spine or the contralateral side of the jaw. The OPG utilizes **tomography** (specifically focal trough geometry) to provide a continuous, flattened view of the entire mandible from one condyle to the other. It is superior for visualizing the body, symphysis, angles, rami, and temporomandibular joints (TMJ) in a single image with minimal distortion. **Analysis of Incorrect Options:** * **Antero-posterior (AP) View:** This view is generally poor for the mandible because the dense occipital bone and cervical spine are superimposed over the mandibular body, obscuring detail. * **Lateral View:** A true lateral view causes the two halves of the mandible to overlap, making it nearly impossible to distinguish right-sided pathology from left-sided pathology. * **Oblique View (Lateral Oblique):** While historically used to visualize one side of the mandible without superimposition, it has been largely replaced by OPG as it provides a limited field of view and requires precise patient positioning. **High-Yield Clinical Pearls for NEET-PG:** * **Fracture Patterns:** The mandible behaves like a "sugar-tong" or a ring; if you see a fracture in one location (e.g., the symphysis), always look for a second fracture on the opposite side (e.g., the condyle). * **Towne’s View:** This is the specific radiographic view used to visualize the **mandibular condyles** and the neck of the mandible. * **PA Mandible:** Preferred over AP to reduce radiation dose to the lens of the eye and to decrease magnification of the facial bones.

Q: Rat bite erosions are seen in which condition?

Gouty Arthritis. **Explanation:** **Gouty Arthritis (Correct Answer):** Rat bite erosions (also known as **Martel’s sign** or punched-out erosions) are a hallmark radiographic feature of chronic tophaceous gout. These erosions occur due to the pressure effect of urate crystals (tophi) deposited in the periarticular soft tissues. They are typically characterized by **overhanging edges** (sclerotic margins) and are located away from the joint space, which helps distinguish them from the marginal erosions seen in Rheumatoid Arthritis. **Why other options are incorrect:** * **Psoriasis:** Characterized by the **"Pencil-in-cup" deformity**, asymmetric involvement, and "fluffy" periostitis. While erosions occur, they are typically marginal and lead to joint destruction rather than the eccentric "rat bite" appearance. * **Osteoarthritis:** This is a degenerative disease, not primarily erosive. Key findings include **joint space narrowing**, subchondral sclerosis, subchondral cysts (geodes), and **osteophyte** formation. * **Ankylosing Spondylitis:** Primarily affects the axial skeleton (Sacroiliitis). In peripheral joints, it presents with joint space narrowing and bony ankylosis (fusion), not eccentric rat-bite erosions. **NEET-PG High-Yield Pearls:** * **Earliest sign of Gout:** Soft tissue swelling. * **Joint Space:** In Gout, the joint space is characteristically **preserved** until very late stages of the disease (unlike RA or OA). * **Double Contour Sign:** Seen on Ultrasound (hyperechoic band over the hyaline cartilage), pathognomonic for Gout. * **Polarizing Microscopy:** Urate crystals are **needle-shaped** and show **strong negative birefringence** (yellow when parallel to the axis).

Question 1

Which sarcoma does not display the radiographic feature of Codman’s triangle?

Accepted Answer

Chondrosarcoma

Answer

Fibrosarcoma

Answer

Osteosarcoma

Answer

Ewing’s sarcoma

Question 2

The following X-ray is diagnostic of:

Accepted Answer

Rickets

Answer

Scurvy

Answer

Hairline fracture of radius and ulna

Answer

Osteopetrosis

Question 3

What are the radiological features seen in hyperparathyroidism?

Accepted Answer

All of the above

Answer

Loss of lamina dura

Answer

Osteitis fibrosa cystica

Answer

Erosion below the dura mater of the skull

Question 4

Salt-pepper skull is a characteristic radiographic finding in which of the following conditions?

Accepted Answer

Primary hyperparathyroidism

Answer

Paget's syndrome

Answer

Eosinophilic granuloma

Answer

Multiple myeloma

Question 5

Which imaging modality is NOT typically used for the detection of bone metastasis?

Accepted Answer

Ultrasound

Answer

MRI

Answer

CT

Answer

Radionuclide scan

Question 6

Which X-ray view is best for evaluating a patellar fracture?

Accepted Answer

Skyline view

Answer

Judet view

Answer

Water's view

Answer

Oblique view

Question 7

Clover leaf skull is seen in which condition?

Accepted Answer

Thanatophoric Dysplasia

Answer

Chiari Malformation

Answer

Eosinophilic Granuloma

Answer

Multiple Myeloma

Question 8

An oblique view is required for the diagnosis of which of the following carpal bones?

Accepted Answer

Scaphoid

Answer

Capitate

Answer

Navicular

Answer

Hamate

Question 9

Which radiographic view is considered the best for evaluating the mandible?

Accepted Answer

Orthopentomogram

Answer

Antero-posterior view

Answer

Lateral view

Answer

Oblique view

Question 10

Rat bite erosions are seen in which condition?

Accepted Answer

Gouty Arthritis

Answer

Psoriasis

Answer

Osteoarthritis

Answer

Ankylosing Spondylitis

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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