Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology Indian Medical PG Practice Questions and MCQs

Question 301: Which of the following is true about osteoporosis?

A. Raised alkaline phosphatase
B. Cod fish vertebrae (Correct Answer)
C. Low calcium
D. Low phosphate

Explanation: **Cod fish vertebrae** - **Cod fish vertebrae** (or biconcave vertebral bodies) are a characteristic radiological sign seen in **osteoporosis**, resulting from weakened vertebral bodies bulging under pressure from disc material. - This appearance is due to the softening of the vertebral endplates, allowing the intervertebral discs to indent the adjacent vertebral bodies. - This is a classic finding in severe osteoporosis on lateral spine radiographs. *Raised alkaline phosphatase* - **Alkaline phosphatase (ALP)** levels are typically **normal in osteoporosis** because bone turnover, while unbalanced, does not involve a significant increase in osteoblastic activity that would elevate ALP. - **Elevated ALP** is more characteristic of conditions with increased osteoblastic activity, such as **Paget's disease of bone**, **osteomalacia**, or bone metastases. *Low calcium* - **Serum calcium levels** are typically **normal in osteoporosis** as the body maintains calcium homeostasis through hormonal regulation, even if bone density is low. - **Low calcium (hypocalcemia)** is more commonly associated with conditions like **hypoparathyroidism** or severe **vitamin D deficiency** leading to **osteomalacia**. *Low phosphate* - **Serum phosphate levels** are typically **normal in osteoporosis**, similar to calcium, due to tightly regulated homeostatic mechanisms. - **Low phosphate (hypophosphatemia)** can be seen in conditions like **osteomalacia** (especially those related to vitamin D deficiency or renal phosphate wasting) but not typically in osteoporosis.

Question 302: The earliest evidence of Rickets is seen by:

A. S. phosphorus level (Correct Answer)
B. Radiological examination of growing end of bone
C. S. calcium level
D. S. alkaline phosphatase level

Explanation: ***S. phosphorus level*** - **Low serum phosphorus** is one of the **earliest biochemical markers** of rickets, appearing before radiological changes become evident. - Hypophosphatemia results from **inadequate vitamin D** leading to decreased intestinal absorption of phosphorus and/or increased renal phosphate wasting. - Biochemical abnormalities **precede radiological manifestations** in the natural progression of rickets. - This makes serum phosphorus measurement critical for **early detection** and intervention. *S. alkaline phosphatase level* - Elevated serum alkaline phosphatase is an important biochemical marker indicating increased osteoblastic activity. - However, it is **less specific** than serum phosphorus and may be elevated in other conditions affecting bone growth. - While it rises early in rickets, serum phosphorus changes are typically detected first. *Radiological examination of growing end of bone* - Radiological findings such as **widening of growth plates**, **cupping**, and **fraying** of metaphyses are characteristic of rickets. - However, these changes represent **established disease** rather than earliest evidence. - Radiological changes become visible only **after biochemical abnormalities** have been present for some time. - X-ray findings confirm the diagnosis but are not the earliest detectable changes. *S. calcium level* - **Serum calcium levels** are often maintained within normal range in early rickets due to compensatory mechanisms. - Increased **parathyroid hormone (PTH)** secretion mobilizes calcium from bone to maintain serum levels. - Hypocalcemia typically occurs only in **severe or late-stage** rickets when compensatory mechanisms fail.

Question 303: The 'Search lines' to detect fracture line on occipitomandibular radiographic view of midfacial skeleton fracture was described by:

A. Rowe and Williams
B. Rene Le Fort and Guerin
C. McGrigor and Campbell (Correct Answer)
D. Andreason and Ravn

Explanation: ***McGrigor and Campbell*** - **McGrigor and Campbell** described the "Search lines" concept for identifying fracture lines on **occipitomandibular radiographic views** of midfacial skeleton fractures. - Their work focused on systematic radiographic interpretation for diagnosing complex facial trauma. *Rowe and Williams* - **Rowe and Williams** are well-known for their classification of **mandibular fractures**, not specifically for "Search lines" on occipitomandibular views. - Their contributions are primarily in the surgical management and classification of various facial bone fractures. *Rene Le Fort and Guerin* - **Rene Le Fort** is renowned for defining the classical **Le Fort fracture patterns** of the midface, which are crucial for classifying maxillary trauma. - **Guerin** is associated with early descriptions of facial fractures, but neither described "Search lines" for specific radiographic views. *Andreason and Ravn* - **Andreason and Ravn** are recognized for their work on **dental traumatology**, particularly related to classification and management of tooth injuries. - Their primary focus is on **dentoalveolar trauma**, not the radiographic interpretation of midfacial bone fractures using "Search lines."

Question 304: Investigation of choice for lumbar prolapsed disc -

A. CT Scan
B. Myelogram
C. X-ray
D. MRI (Correct Answer)

Explanation: ***MRI*** - An **MRI** provides the best visualization of **soft tissues**, including the intervertebral discs, spinal cord, and nerve roots, making it the **gold standard** for diagnosing lumbar prolapsed disc. - It can accurately show the **degree of disc herniation**, its impact on neural structures, and associated edema, which are crucial for treatment planning. *CT Scan* - While a **CT scan** provides good bony detail and can show disc herniation, its ability to visualize soft tissues is inferior to MRI for this specific condition. - It involves **ionizing radiation** and may miss subtle nerve root compression or spinal cord abnormalities apparent on MRI. *Myelogram* - A **myelogram** involves injecting contrast dye into the spinal canal and then performing X-rays or CT scans to outline the spinal cord and nerve roots. - Though effective in showing **nerve compression**, it is an **invasive procedure** with potential complications and has largely been replaced by MRI as a first-line diagnostic investigation. *X-ray* - **X-rays** primarily visualize **bony structures** and are useful for detecting fractures, spinal alignment issues, or severe degenerative changes. - They **cannot directly visualize intervertebral discs** or nerve compression, making them unsuitable for diagnosing a prolapsed disc.

Question 305: Not a radiological feature of Ankylosing spondylitis

A. Romanus sign
B. Fish mouth vertebrae (Correct Answer)
C. Trolley track sign
D. Dagger sign

Explanation: **Fish mouth vertebrae** - **Fish mouth vertebrae**, characterized by concave vertebral bodies, are typically seen in conditions like **osteoporosis** or **sickle cell anemia**, resulting from vertebral compression or infarction. - This appearance is not a characteristic radiological feature of **ankylosing spondylitis**, which primarily involves fusion and ossification of spinal ligaments. *Romanus sign* - The **Romanus sign** refers to erosions at the anterior and posterior corners of the vertebral bodies, an early and characteristic radiological feature of **ankylosing spondylitis**. - These erosions eventually lead to squaring of the vertebrae. *Trolley track sign* - The **trolley track sign** is a classic late-stage radiological finding in **ankylosing spondylitis**, indicating ossification of the interspinous and supraspinous ligaments, and the facet joint capsules. - This results in three parallel lines visible on an anteroposterior spinal radiograph. *Dagger sign* - The **dagger sign** is another characteristic radiological feature of **ankylosing spondylitis**, representing ossification of the supraspinous and interspinous ligaments. - It appears as a single central radiopaque line on an anteroposterior spinal radiograph.

Question 306: Sunburst appearance found in:

A. Ewing sarcoma
B. Giant cell tumor
C. Osteosarcoma (Correct Answer)
D. Chondrosarcoma

Explanation: ***Osteosarcoma*** - A classic radiographic feature of **osteosarcoma** is the **sunburst appearance**, which represents new bone formation radiating outwards from the cortex. - This aggressive tumor typically occurs in the **metaphysis of long bones** (e.g., distal femur, proximal tibia). *Ewing sarcoma* - Characteristically presents with an **onion-skin appearance** (concentric layers of periosteal reaction) due to rapid bone destruction and new bone formation. - It often affects the **diaphysis of long bones** and flat bones, unlike the metaphyseal involvement of osteosarcoma. *Giant cell tumor* - Known for its characteristic **soap-bubble appearance** on imaging, indicating a lytic lesion with thin septations. - Typically found in the **epiphysis of long bones** in young adults. *Chondrosarcoma* - Radiographically, it often shows a **lobulated lesion** with **calcified cartilage matrix** (popcorn or ring-and-arc calcifications). - While it can be destructive, it does not typically exhibit the radiating pattern seen in a sunburst appearance, which is primarily an osteoblastic phenomenon.

Question 307: Radiological findings of scurvy are A/E:

A. Pelkan spur
B. Epiphyseal widening
C. Metaphyseal infarction (Correct Answer)
D. Metaphyseal porosis

Explanation: ***Metaphyseal infarction*** - **Metaphyseal infarction** (bone infarcts) is NOT a feature of scurvy and is typically associated with conditions like **sickle cell anemia**, **Gaucher disease**, or following trauma/infection. - Scurvy primarily affects collagen synthesis, leading to issues with bone matrix and subperiosteal hemorrhages rather than ischemic necrosis. *Pelkan spur* - **Pelkan spur** (also known as the "corner sign" or "spur formation") is a **characteristic radiological finding in scurvy**, not rickets. - It results from metaphyseal corner fractures due to subperiosteal hemorrhages and weakened bone matrix at the metaphyseal edges. *Epiphyseal widening* - This is not a classic or characteristic finding of scurvy. - While scurvy affects the growth plate with features like **Wimberger ring sign** (dense calcification around epiphysis) and **epiphyseal separation**, generalized epiphyseal widening is not typically described. *Metaphyseal porosis* - **Ground glass osteopenia/porosis** is a recognized feature of scurvy due to impaired osteoid formation. - This results from defective collagen synthesis leading to decreased bone density, particularly evident in the metaphyseal regions.

Question 308: Beheaded Scottish terrier sign is seen in:

A. Osteoporosis
B. Spondylolysis (Correct Answer)
C. Spondylosis
D. Osteogenesis imperfecta

Explanation: ***Spondylolysis*** - The \"Beheaded Scottish terrier sign\" is **pathognomonic for spondylolysis**, which is a **fracture of the pars interarticularis**. - On oblique lumbar spine radiographs, the normal vertebra resembles a \"Scotty dog\" where the pars interarticularis forms the \"neck\"; when fractured, it appears \"beheaded\". - This defect occurs most commonly at **L5**, often due to repetitive stress in athletes (gymnasts, football players). - **Key distinction**: Spondylolysis is the pars fracture itself; if it progresses to anterior vertebral slippage, it becomes spondylolisthesis. *Spondylolisthesis* - This refers to **anterior displacement of one vertebra over another**, which can occur as a complication of spondylolysis. - While related to spondylolysis, the \"Beheaded Scottish terrier sign\" specifically indicates the **pars fracture** (spondylolysis), not the vertebral slippage. - Diagnosed on lateral radiographs showing vertebral step-off, not the oblique view Scotty dog sign. *Spondylosis* - Refers to **degenerative changes of the spine** including disc degeneration, osteophyte formation, and facet joint arthritis. - This is an **age-related process** and does not involve pars interarticularis fractures. - Not associated with the \"Beheaded Scottish terrier sign\". *Osteoporosis* - A systemic condition of **decreased bone mineral density** predisposing to fractures. - Does not produce the specific \"Beheaded Scottish terrier sign\" which is unique to pars interarticularis defects. *Osteogenesis imperfecta* - A **genetic collagen disorder** causing brittle bones and multiple fractures. - While it causes pathological fractures, it does not specifically manifest as the \"Beheaded Scottish terrier sign\".

Question 309: Cod-fish vertebrae are seen in:

A. Osteomalacia
B. Osteoporosis (Correct Answer)
C. Fractures
D. Spinal tumors

Explanation: ***Osteoporosis*** - **Cod-fish vertebrae**, or biconcave vertebral bodies, are characteristic of **osteoporosis**, resulting from the weakened vertebral body collapsing under the pressure of the intervertebral discs. - This specific vertebral deformity occurs due to the **loss of bone mineral density**, making the central portions of the vertebrae more susceptible to compression. *Osteomalacia* - While osteomalacia also leads to generalized bone softening, it typically presents with **Looser zones (pseudofractures)** and diffuse skeletal pain, rather than classic cod-fish vertebrae. - The primary defect in osteomalacia is **impaired mineralization of osteoid**, leading to softer bones that deform but do not typically collapse in the characteristic biconcave shape. *Fractures* - Fractures describe a break in the bone and do not inherently cause the typical **cod-fish deformity** unless it is a specific type of vertebral compression fracture in an already weakened osteoporotic bone. - While vertebral compression fractures can occur in severe osteoporosis, the term "fractures" alone is too broad and does not specifically lead to the characteristic biconcave shape of cod-fish vertebrae. *Spinal tumors* - Spinal tumors can cause bone destruction or compression, but they typically lead to **lytic lesions**, new bone formation, or more irregular vertebral deformities, often with neurological symptoms. - They do not typically result in the **symmetrical biconcave indentation** of the vertebral endplates seen in cod-fish vertebrae.

Question 310: Looser's zones are seen in:

A. All of the above
B. Paget's disease
C. Osteomalacia (Correct Answer)
D. Renal osteodystrophy

Explanation: ***Osteomalacia*** - **Looser's zones** (also called **pseudofractures** or **Milkman's fractures**) are **pathognomonic** radiological findings of **osteomalacia**. - These appear as **radiolucent bands perpendicular to the cortex**, typically bilateral and symmetrical, commonly seen in the **pubic rami, femoral necks, ribs, and scapulae**. - They represent **stress fractures with unmineralized osteoid seams** that fail to heal due to defective mineralization from **vitamin D deficiency** or **phosphate depletion**. *Paget's disease* - Characterized by **disorganized bone remodeling** with a "**cotton wool**" appearance on skull X-rays, **cortical thickening**, and **bone expansion**. - Shows increased bone density and deformities, **not** radiolucent pseudofractures. - Does not feature Looser's zones. *Renal osteodystrophy* - This is a **spectrum of bone disorders** in chronic kidney disease, which can include osteitis fibrosa cystica, osteomalacia, adynamic bone disease, and mixed patterns. - While the **osteomalacic component** of renal osteodystrophy could theoretically show Looser's zones, they are **not a characteristic or common finding** of renal osteodystrophy as a whole. - The question asks for the **classic association**, which is **primary osteomalacia**. *All of the above* - Incorrect because Looser's zones are **specifically pathognomonic for osteomalacia**, not for Paget's disease or the general spectrum of renal osteodystrophy.

Practice by Chapter

Radiographic Anatomy of Bones and Joints

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Imaging of Fractures and Dislocations

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Arthritides: Inflammatory and Degenerative

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Metabolic Bone Diseases

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Bone and Soft Tissue Tumors

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Congenital Skeletal Anomalies

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Spine Imaging

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Skeletal Infections

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Sports Medicine Imaging

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Imaging of Prostheses and Implants

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Musculoskeletal Ultrasound

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MSK Interventional Procedures

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