Musculoskeletal Radiology Practice Questions

Q: A wrist X-ray is shown. What is the probable diagnosis?

Rickets. ***Rickets*** - Classic X-ray findings include **widened, cupped, and frayed metaphyses** at the distal radius and ulna, indicating defective mineralization. - **Widened growth plates** and **delayed ossification** are characteristic features of rickets in growing children. *Colles fracture* - Shows a **dorsally angulated fracture** of the distal radius with characteristic **dinner fork deformity**. - Would demonstrate clear **cortical disruption** and **fracture lines**, not the smooth metaphyseal changes seen in rickets. *Scaphoid fracture* - Typically occurs in the **waist of the scaphoid bone** and may not be immediately visible on initial X-rays. - Presents with **tenderness in the anatomical snuffbox** and normal metaphyseal appearance of radius and ulna. *Osteoporosis* - Characterized by **generalized bone demineralization** and **cortical thinning** without specific metaphyseal changes. - Does not cause the distinctive **cupping and fraying** of metaphyses seen in metabolic bone disease.

Q: In which of the following diseases are the given X-ray findings typically seen?

Morquio disease. ***Morquio disease*** - Classic **skeletal dysplasia** findings include **platyspondyly** (flattened vertebrae), **odontoid hypoplasia**, and **genu valgum** (knock-knees). - Additional X-ray features show **flared iliac wings**, **epiphyseal dysplasia**, and **short stature** with disproportionate limbs. *Gaucher disease* - Primarily shows **Erlenmeyer flask deformity** of distal femur and **bone infarcts** rather than skeletal dysplasia. - **Hepatosplenomegaly** is prominent, but characteristic skeletal malformations of mucopolysaccharidoses are absent. *Fabry disease* - **X-ray findings are typically normal** as this lysosomal storage disease primarily affects cardiovascular and renal systems. - Clinical features include **angiokeratomas** and **corneal deposits**, not skeletal abnormalities. *Niemann Pick disease* - **Skeletal involvement is minimal** with normal bone architecture on X-rays. - Disease primarily causes **hepatosplenomegaly** and **cherry-red spot** on fundoscopy, not bone dysplasia.

Q: Wormian bones are features of all of the following conditions EXCEPT:

Pyle's disease. **Explanation:** **Wormian bones** (sutural bones) are accessory small bones found within the cranial sutures, most commonly in the lambdoid suture. Their presence is often idiopathic but can be a diagnostic marker for several genetic and metabolic bone disorders. **Why Pyle’s Disease is the Correct Answer:** Pyle’s disease (Metaphyseal Dysplasia) is characterized by a failure of remodeling of the long bones, leading to the classic **"Erlenmeyer flask deformity"** of the distal femur and proximal tibia. While it involves significant skeletal dysplasia, it is **not** typically associated with Wormian bones. **Analysis of Incorrect Options:** * **Hypophosphatasia:** A metabolic bone disease caused by low alkaline phosphatase levels, leading to defective mineralization. It is a classic cause of multiple Wormian bones. * **Down’s Syndrome (Trisomy 21):** Children with Down’s syndrome frequently exhibit delayed closure of sutures and the presence of Wormian bones. * **Menke’s Kinky Hair Syndrome:** This is an X-linked recessive disorder of copper metabolism. Radiologically, it presents with metaphyseal spurring and prominent Wormian bones. **NEET-PG High-Yield Pearls:** To remember the causes of Wormian bones, use the mnemonic **"PORK CHOP"**: * **P:** **P**yknodysostosis (also causes osteosclerosis and acro-osteolysis) * **O:** **O**steogenesis Imperfecta (most common pathological cause) * **R:** **R**ickets (healing phase) * **K:** **K**inky Hair Syndrome (Menke’s) * **C:** **C**leidocranial Dysostosis (absent clavicles + Wormian bones) * **H:** **H**ypophosphatasia / **H**ypothyroidism * **O:** **O**ne too many chromosomes (Down’s Syndrome) * **P:** **P**achydermoperiostosis

Q: Splaying and cupping of the metaphysis is seen in which condition?

Rickets. **Explanation:** The correct answer is **Rickets**. This condition is characterized by a failure of osteoid mineralization at the growth plate, leading to an accumulation of uncalcified cartilage. **1. Why Rickets is correct:** In Rickets, the lack of Vitamin D or calcium prevents the provisional zone of calcification from hardening. Under the mechanical stress of weight-bearing and muscle pull, the softened metaphysis becomes distorted. * **Cupping:** The metaphysis assumes a concave shape instead of being flat or convex. * **Splaying (Fraying):** The metaphysis widens and the margins become irregular or "brush-like" due to disorganized osteoid deposition. * **Widening of the Physis:** The radiolucent gap between the epiphysis and metaphysis increases. **2. Why other options are incorrect:** * **Scurvy (Vitamin C deficiency):** Characterized by defective collagen synthesis. Key radiological signs include the **White line of Frankel** (dense zone of provisional calcification), **Wimberger’s ring** (sclerotic margin of epiphysis), and **Pelkan spurs**. * **Paget’s Disease:** A disorder of bone remodeling. It presents with cortical thickening, coarsened trabeculae, and bone enlargement (e.g., **Picture frame vertebra** or **Cotton wool spots** in the skull), but not metaphyseal cupping. * **Lead Poisoning:** Characterized by **Lead lines**, which are dense transverse radiopaque bands at the metaphysis (increased density, not cupping). **Clinical Pearls for NEET-PG:** * **Earliest sign of Rickets:** Loss of the zone of provisional calcification. * **Rachitic Rosary:** Palpable/visible enlargement of costochondral junctions (rounded in Rickets, sharp/angular in Scurvy). * **Healing Rickets:** The first sign of healing on X-ray is the reappearance of the **zone of provisional calcification**.

Q: Flaring of the anterior ends of the ribs is characteristically seen in which condition?

Rickets. **Explanation:** **Rickets** is the correct answer because it is characterized by a failure of osteoid mineralization at the growth plates. In the thoracic cage, this occurs at the **costochondral junctions**. The accumulation of unmineralized osteoid leads to expansion and bulbous swelling of these junctions, which manifests radiologically as **flaring of the anterior ends of the ribs**. Clinically, this is known as the **"Rachitic Rosary."** Other classic radiological signs of Rickets include cupping, fraying, and splaying of the metaphyses (most prominent at the distal radius and ulna). **Analysis of Incorrect Options:** * **Neurofibromatosis (Type 1):** Characteristically shows **"rib ribboning"** (twisted, thinned appearance) and posterior vertebral scalloping, but not anterior flaring. * **Scurvy:** While it also involves the costochondral junctions (Scorbutic rosary), the swelling is due to subluxation of the cartilaginous plate. Radiologically, Scurvy is defined by the **White line of Frankel**, **Wimberger’s ring**, and **Pelkan spurs**, rather than generalized metaphyseal flaring. * **Hypothyroidism:** Typically presents with delayed bone age, epiphyseal dysgenesis (fragmented epiphyses), and "bullet-shaped" vertebrae, but does not cause anterior rib flaring. **High-Yield Clinical Pearls for NEET-PG:** * **Rachitic Rosary:** Broad and smooth (Rickets). * **Scorbutic Rosary:** Sharp and angular (Scurvy). * **Earliest sign of Rickets on X-ray:** Loss of the sharp zone of provisional calcification. * **Most sensitive site to detect Rickets:** Distal end of the ulna and the knee.

Q: An X-ray of the skull shows multiple lesions. What is the most likely diagnosis?

Multiple myeloma. ***Multiple myeloma*** - Causes multiple **punched-out lytic lesions** on skull X-ray, creating the classic **"raindrop skull"** or **"pepper-pot skull"** appearance. - These lesions have **well-defined margins** without sclerotic borders and represent plasma cell infiltration causing bone destruction. *Paget's disease* - Skull shows mixed **lytic and sclerotic lesions** creating the **"cotton-wool"** appearance, not purely lytic lesions. - May also present with **osteoporosis circumscripta** (flame-shaped lytic areas) but typically has bone expansion and thickening. *Eosinophilic granuloma* - Usually presents as a **solitary lytic lesion** with **beveled edges** creating a "hole-within-hole" appearance on lateral view. - Part of **Langerhans cell histiocytosis** and rarely causes multiple skull lesions in adults. *Osteomyelitis* - Shows **ill-defined lytic lesions** with **irregular margins** and associated **periosteal reaction**. - Often accompanied by **soft tissue swelling** and **sequestrum formation**, which are absent in purely lytic lesions.

Q: What is the diagnostic radiological finding in skeletal fluorosis?

Interosseous membrane ossification. ### Explanation **Skeletal Fluorosis** is a chronic metabolic bone disease caused by prolonged ingestion of high amounts of fluoride. The hallmark of the disease is an increase in bone density (osteosclerosis) and pathological calcification of soft tissue structures. **Why Option B is Correct:** The most characteristic and diagnostic radiological feature of skeletal fluorosis is the **ossification of the interosseous membrane**, particularly in the forearm (between the radius and ulna) and the lower leg (between the tibia and fibula). While osteosclerosis occurs in many diseases, the ectopic calcification of ligaments, tendons, and interosseous membranes is highly specific to fluorosis and often serves as a definitive diagnostic clue on X-rays. **Analysis of Incorrect Options:** * **Option A:** Sclerosis of the sacroiliac joint is more characteristic of **Ankylosing Spondylitis** or osteitis condensans ilii. In fluorosis, the joint space is usually preserved despite periarticular sclerosis. * **Option C:** While **osteosclerosis of the vertebral bodies** (chalky white appearance) is a common finding in fluorosis, it is non-specific. It can also be seen in Renal Osteodystrophy (Rugger-jersey spine), Myelofibrosis, and Osteopetrosis. * **Option D:** While ligaments do ossify in fluorosis, the **sacrotuberous and sacrospinous ligaments** are more commonly involved than those of the knee joint. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest Sign:** Osteosclerosis of the pelvis and lumbar spine. * **Classic Triad:** Osteosclerosis, Osteophytosis, and Calcification of ligaments/tendons. * **Dagger Spine:** Can mimic Ankylosing Spondylitis due to ossification of the supraspinous and interspinous ligaments. * **Dental Fluorosis:** Presents as "mottling of enamel" (occurs only if exposure happens during tooth development). * **Safe Limit:** Fluoride in drinking water should ideally be **<1.5 mg/L**.

Q: What is the characteristic finding on MRI described as a "double line sign"?

Avascular necrosis of the hip. **Explanation:** The **"Double Line Sign"** is a pathognomonic MRI finding seen on **T2-weighted images** in patients with **Avascular Necrosis (AVN)** of the femoral head. It represents the reactive interface between the necrotic bone and the viable reparative bone. * **The Inner Bright Line:** Represents hyperemic granulation tissue (high signal on T2). * **The Outer Dark Line:** Represents a rim of sclerotic bone (low signal on T2). **Why the other options are incorrect:** * **B. Slipped Capital Femoral Epiphysis (SCFE):** Characterized by the posterior and inferior displacement of the femoral head relative to the neck (best seen on "Frog-leg" lateral X-rays). MRI typically shows physeal widening and edema. * **C. Tuberculous Arthritis:** Presents with the **Phemister triad** (juxta-articular osteopenia, peripheral erosions, and gradual joint space narrowing). MRI would show synovial thickening and joint effusions, not a double line sign. * **D. Developmental Dysplasia of the hip (DDH):** A structural deformity involving an acetabular dysplasia or femoral head dislocation. Diagnosis is primarily via Ultrasound (in infants) or X-ray (Shenton’s line disruption). **High-Yield Clinical Pearls for NEET-PG:** * **MRI** is the most sensitive imaging modality for early detection of AVN (Stage 0/1). * **X-ray finding:** The **"Crescent Sign"** (subchondral fracture) indicates Stage II/III disease. * **Common Causes:** Corticosteroids (most common overall), Alcoholism, Trauma, and Sickle Cell Anemia. * **Classification:** The **Ficat and Arlet system** is commonly used to stage AVN based on imaging.

Question 1

Acro-osteolysis is a characteristic radiographic finding. Which of the following conditions is most commonly associated with acro-osteolysis?

Accepted Answer

Psoriatic arthropathy

Answer

Amyloidosis

Answer

Gout

Answer

Multiple myeloma

Question 2

A wrist X-ray is shown. What is the probable diagnosis?

Accepted Answer

Rickets

Answer

Colles fracture

Answer

Scaphoid fracture

Answer

Osteoporosis

Question 3

In which of the following diseases are the given X-ray findings typically seen?

Accepted Answer

Morquio disease

Answer

Gaucher disease

Answer

Fabry disease

Answer

Niemann Pick disease

Question 4

Radiographically, how can a bony neoplasm be differentiated from a cyst?

Accepted Answer

By peripheral bone formation.

Answer

By their sizes.

Answer

By their shapes.

Answer

By their location.

Question 5

Wormian bones are features of all of the following conditions EXCEPT:

Accepted Answer

Pyle's disease

Answer

Hypophosphatasia

Answer

Down's syndrome

Answer

Menke's kinky hair syndrome

Question 6

Splaying and cupping of the metaphysis is seen in which condition?

Accepted Answer

Rickets

Answer

Scurvy

Answer

Paget's disease

Answer

Lead poisoning

Question 7

Flaring of the anterior ends of the ribs is characteristically seen in which condition?

Accepted Answer

Rickets

Answer

Neurofibromatosis

Answer

Scurvy

Answer

Hypothyroidism

Question 8

An X-ray of the skull shows multiple lesions. What is the most likely diagnosis?

Accepted Answer

Multiple myeloma

Answer

Paget's disease

Answer

Eosinophilic granuloma

Answer

Osteomyelitis

Question 9

What is the diagnostic radiological finding in skeletal fluorosis?

Accepted Answer

Interosseous membrane ossification

Answer

Sclerosis of sacroiliac joint

Answer

Osteosclerosis of vertebral body

Answer

Ossification of ligaments of knee joint

Question 10

What is the characteristic finding on MRI described as a "double line sign"?

Accepted Answer

Avascular necrosis of the hip

Answer

Slipped capital femoral epiphysis

Answer

Tuberculous arthritis of the hip

Answer

Developmental dysplasia of the hip

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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