Musculoskeletal Radiology Practice Questions

Q: In ankylosing spondylitis, what are the first radiological changes seen?

Sacro-iliac joints. **Explanation:** **Ankylosing Spondylitis (AS)** is a chronic inflammatory seronegative spondyloarthropathy that primarily affects the axial skeleton. **1. Why Sacro-iliac (SI) joints are the correct answer:** The hallmark of AS is **bilateral, symmetrical sacroiliitis**. Radiologically, the SI joints are the **earliest** site of involvement. The changes typically begin in the lower two-thirds of the joint (the synovial portion) and progress from subchondral erosions and sclerosis ("pseudowidening") to eventual bony ankylosis (fusion). According to the Modified New York Criteria, radiological evidence of sacroiliitis is essential for a definitive diagnosis. **2. Why the other options are incorrect:** * **Vertebral bodies:** While "squaring" of vertebral bodies (due to enthesitis at the corners) is a classic sign, it occurs after the initial SI joint involvement. * **Intervertebral ligaments:** Ossification of the outer fibers of the annulus fibrosus (forming **syndesmophytes**) leads to the "Bamboo Spine" appearance, but this is a late-stage feature. * **Intervertebral discs:** AS primarily affects the entheses and synovial joints; the discs are involved secondarily through calcification or the Andersson lesion (inflammatory spondylodiscitis), not as a primary early event. **Clinical Pearls for NEET-PG:** * **Earliest Sign on MRI:** Bone marrow edema (STIR sequence) around the SI joints (detectable before X-ray changes). * **Earliest Sign on X-ray:** Blurring of the joint margins (Grade 1 sacroiliitis). * **HLA-B27:** Strongly associated (>90% of cases). * **Dagger Sign:** A single central radiodense line on X-ray due to ossification of supraspinous and interspinous ligaments. * **Trolley Track Sign:** Three vertical linear densities due to ossification of the central ligaments and lateral facet joint capsules.

Q: Raindrop skull is a characteristic finding in which of the following conditions?

Multiple myeloma. **Explanation:** The **Raindrop Skull** is a classic radiological sign of **Multiple Myeloma**. It refers to multiple, well-defined, small, "punched-out" lytic lesions of varying sizes scattered throughout the calvarium. These lesions occur due to the proliferation of malignant plasma cells in the bone marrow, which secrete osteoclast-activating factors (like RANKL), leading to focal bone destruction without any surrounding osteoblastic reaction (sclerosis). **Analysis of Incorrect Options:** * **Eosinophilic Granuloma (Langerhans Cell Histiocytosis):** Typically presents as a large, solitary, "punched-out" lesion with beveled edges (the "hole-within-a-hole" appearance) rather than multiple small "raindrop" lesions. * **Thalassemia & Sickle Cell Anemia:** These are hemolytic anemias that cause compensatory extramedullary hematopoiesis. This leads to widening of the diploic space and thinning of the outer table, resulting in a **"Hair-on-end"** or **"Crew-cut"** appearance on a lateral skull X-ray, not lytic drops. **Clinical Pearls for NEET-PG:** * **Multiple Myeloma:** The most common primary bone malignancy in adults. Key features include CRAB criteria (Calcium elevation, Renal insufficiency, Anemia, Bone lesions). * **Skull X-ray vs. Bone Scan:** In Multiple Myeloma, a **Technetium-99m bone scan is often false-negative** because there is no osteoblastic activity. A skeletal survey (X-rays) or MRI is preferred. * **Bence-Jones Proteins:** Light chains found in urine; they do not show up on a standard dipstick (which detects albumin). * **Pepperpot Skull:** Do not confuse "Raindrop Skull" with "Pepperpot Skull" (salt-and-pepper appearance), which is characteristic of **Hyperparathyroidism**.

Q: Shenton's line is a radiological line used to determine the pathology of:

Hip. **Explanation:** **Shenton’s Line** is a fundamental radiological landmark used in the evaluation of the **hip joint** on an Anteroposterior (AP) radiograph. It is an imaginary curved line formed by the continuous arc of the **inferior border of the superior pubic ramus** and the **medial margin of the femoral neck**. In a normal, healthy hip, this line is smooth and unbroken. A disruption or "step-off" in Shenton’s line indicates pathology, most commonly **Developmental Dysplasia of the Hip (DDH)**, femoral neck fractures, or slipped capital femoral epiphysis (SCFE). **Why other options are incorrect:** * **Ankle:** Key radiological lines include the *Tibiofibular clear space* and *Talar tilt*, used to assess syndesmotic injuries or fractures. * **Elbow:** The primary lines are the *Anterior Humeral Line* and the *Radiocapitellar Line*, crucial for diagnosing supracondylar fractures and radial head dislocations in pediatrics. * **Shoulder:** Evaluation focuses on the *Glenohumeral joint space* and the *Scapular 'Y' view* to detect dislocations. **High-Yield Clinical Pearls for NEET-PG:** * **DDH Triad:** Disruption of Shenton’s line is often seen alongside a shallow acetabulum and a lateralized femoral head. * **Hilgenreiner’s and Perkins’ Lines:** These are also used in hip radiography to calculate the acetabular index and determine femoral head position. * **Ward’s Triangle:** A radiolucent area in the neck of the femur (area of least resistance) important in osteoporosis assessment. * **Klein’s Line:** Specifically used to diagnose Slipped Capital Femoral Epiphysis (SCFE).

Q: All of the following are seen in rickets except?

Frenkels line. In musculoskeletal radiology, distinguishing between the features of **Rickets** (childhood vitamin D deficiency) and **Scurvy** (Vitamin C deficiency) is a high-yield topic for NEET-PG. ### **Why Option A is the Correct Answer** **Fraenkel’s line** (also known as the "White line of Fraenkel") is a classic radiological sign of **Scurvy**, not rickets. It represents a dense, radiopaque band at the metaphysis due to the accumulation of calcified cartilage matrix that cannot be converted into bone because of defective collagen synthesis. ### **Explanation of Incorrect Options (Features of Rickets)** * **Widening of epiphysis-diaphysis distance (Option B):** In rickets, there is a failure of mineralization of the osteoid. This leads to an accumulation of non-mineralized cartilage at the growth plate, which appears radiolucent, effectively increasing the distance between the epiphysis and the shaft. * **Cupping and splaying of metaphysis (Option C):** Due to the weight-bearing load on soft, unmineralized osteoid, the metaphysis becomes widened (**splaying**) and develops a concave, saucer-like appearance (**cupping**). Fraying (shaggy margins) is also typically seen. * **Rarefaction (Option D):** This refers to a generalized decrease in bone density (osteopenia) due to poor mineralization, making the bones appear more "transparent" on X-ray. ### **NEET-PG High-Yield Pearls** * **Rickets:** Look for "Cupping, Splaying, and Fraying." The earliest sign is the loss of the **Zone of Provisional Calcification**. * **Scurvy:** Look for **Fraenkel’s line**, **Wimberger’s ring** (dense circular epiphysis), **Pelkan spurs** (metaphyseal spurs), and the **Trummerfeld zone** (scurvy zone/lucent band). * **Key Distinction:** Rickets affects the **growth plate** (widening), while Scurvy primarily affects the **metaphysis** (fragility and hemorrhage).

Q: What is the finding seen on X-ray of the right shoulder?

Fracture of the clavicle. ***Fracture of the clavicle*** - **Clavicle fractures** are the most common shoulder injuries, typically showing a clear **discontinuity** of the cortical bone with possible **displacement** or **angulation**. - On X-ray, look for **cortical disruption**, **bone fragment overlap**, or **step-off deformity** along the clavicular shaft, most commonly in the **middle third**. *Fracture of the scapula* - Scapular fractures are **uncommon** and require significant **high-energy trauma**, typically from motor vehicle accidents or falls from height. - X-ray would show **cortical breaks** in the scapular body, neck, or glenoid, often requiring **CT scan** for detailed evaluation due to overlapping structures. *Fracture-dislocation of the acromioclavicular joint* - AC joint injuries present with **widening** of the **acromioclavicular space** and possible **superior displacement** of the clavicle relative to the acromion. - Associated with **coracoclavicular ligament disruption**, showing increased **coracoclavicular distance** on X-ray, not a discrete bone fracture. *Fracture of the 1st rib* - First rib fractures are **extremely rare** and typically associated with **severe thoracic trauma** or **neurogenic thoracic outlet syndrome**. - Would appear as a **cortical break** in the **curved first rib** near the thoracic apex, often requiring **dedicated rib views** or **CT** for visualization.

Q: Which of the following is the most common cause of sclerotic skeletal metastasis in a female patient?

Carcinoma breast. **Explanation:** Bone metastases are broadly categorized into **osteolytic** (bone-destroying), **osteoblastic/sclerotic** (bone-forming), or **mixed**. 1. **Why Carcinoma Breast is correct:** Breast cancer is the most common malignancy in females and the most frequent cause of skeletal metastases in this demographic. While breast cancer typically presents with **mixed** (lytic and sclerotic) lesions, it is the **most common cause of sclerotic/osteoblastic metastases in females**. The sclerotic appearance occurs when tumor cells secrete factors (like TGF-β) that stimulate osteoblasts to lay down new bone. 2. **Why the other options are incorrect:** * **Carcinoma Ovary & Endometrial Carcinoma:** These gynecological malignancies rarely metastasize to the bone. When they do, the lesions are predominantly **osteolytic**. * **Melanoma:** This is notorious for causing highly aggressive, purely **osteolytic** (expansile) metastases. **High-Yield Clinical Pearls for NEET-PG:** * **Most common sclerotic metastasis (Overall/Males):** Prostate Carcinoma (classically purely blastic). * **Most common sclerotic metastasis (Females):** Breast Carcinoma. * **Most common lytic metastasis (Adults):** Lung Cancer (specifically Small Cell and NSCLC) and Renal Cell Carcinoma (RCC). * **Purely Lytic "Blow-out" Metastases:** Classically seen in RCC and Thyroid carcinoma. * **Imaging Gold Standard:** **MRI** is the most sensitive for early detection; **Bone Scan (Technetium-99m MDP)** detects osteoblastic activity but may show a "cold spot" in purely lytic lesions (like Multiple Myeloma).

Question 1

A 48-year-old man with a long history of low back pain presents with similar symptoms. His previous X-ray 6 years ago showed degenerative disc changes. What should be done next?

Accepted Answer

X-ray should not be repeated

Answer

Repeat X-ray

Answer

If any systemic disease is suspected, MRI should be done

Answer

If neurological deficit is suspected, CT should be done

Question 2

Which of the following conditions is NOT associated with the 'bone within a bone' appearance?

Accepted Answer

Hyperthyroidism

Answer

Osteopetrosis

Answer

Acromegaly

Answer

Hypercalcemia

Question 3

In ankylosing spondylitis, what are the first radiological changes seen?

Accepted Answer

Sacro-iliac joints

Answer

Intervertebral ligament

Answer

Vertebral bodies

Answer

Intervertebral discs

Question 4

Raindrop skull is a characteristic finding in which of the following conditions?

Accepted Answer

Multiple myeloma

Answer

Eosinophilic granuloma

Answer

Thalassemia

Answer

Sickle cell anemia

Question 5

What is the earliest radiological sign indicative of sacroiliitis on X-ray?

Accepted Answer

Blurring of the sacroiliac joint

Answer

Osteophytes

Answer

Erosion

Answer

Sclerosis

Question 6

Shenton's line is a radiological line used to determine the pathology of:

Accepted Answer

Hip

Answer

Ankle

Answer

Elbow

Answer

Shoulder

Question 7

All of the following are seen in rickets except?

Accepted Answer

Frenkels line

Answer

Widening of epiphysis-diaphysis distance

Answer

Cupping and splaying of metaphysis

Answer

Rarefaction

Question 8

What is the finding seen on X-ray of the right shoulder?

Accepted Answer

Fracture of the clavicle

Answer

Fracture of the scapula

Answer

Fracture-dislocation of the acromioclavicular joint

Answer

Fracture of the 1st rib

Question 9

Which of the following is the most common cause of sclerotic skeletal metastasis in a female patient?

Accepted Answer

Carcinoma breast

Answer

Carcinoma ovary

Answer

Endometrial carcinoma

Answer

Melanoma

Question 10

A hair on end appearance of the skull is seen in all of the following conditions EXCEPT:

Accepted Answer

Paget's disease

Answer

Thalassemia

Answer

Sickle cell anemia

Answer

Cooley's anemia

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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