The placental abnormalities in which, a thin fibrous ring is present at the margin of the chorionic plate where the fetal vessels appear to terminate is?

1. A

   Circumvalate placenta

2. B

   Placenta membranecae

3. C

   Placenta marginata

4. D

   Placenta Supria

Appeared in: AIIMS Raipur - 2017 (shift-2)

Explanation

• Placenta marginata, also known as a circummarginate placenta, is an extrachorial placental variant.
• It is defined by the presence of a thin, flat, fibrous ring at the margin of the chorionic plate.
• In this condition, the fetal vessels appear to stop at the edge of this ring.
• Unlike a circumvallate placenta, the membranes are not folded back, and it is generally considered a benign finding with little to no clinical risk.

Why Other Options Were Wrong

• Option A: A circumvallate placenta is characterized by a thick, raised, and folded ring of fetal membranes, not a thin, flat ring. This feature is clearly visible in the provided image.
• Option B: Placenta membranacea is a condition where chorionic villi cover almost the entire surface of the fetal membranes, creating a very large, thin placenta. It is not defined by a fibrous ring.
• Option D: Placenta spuria (likely intended by the misspelling 'Supria') refers to the presence of one or more accessory placental lobes separate from the main placental disc. It does not involve a fibrous ring on the main placenta.

Related Visual

• Visual 1: Diagram - A comparative diagram showing a normal placenta, a circumvallate placenta (with its thick, folded ring), and a circummarginate placenta (with its thin, flat ring). This visual helps to clearly differentiate the key features of each condition.
• Visual 2: Gross Specimen Photograph - A photograph of a delivered placenta marginata, highlighting the flat, whitish ring at the edge of the chorionic plate.

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Placental abnormalities as background academic context rather than a clinical decision trigger.
• Placenta marginata is usually an incidental finding upon postpartum placental examination and does not typically require special antenatal monitoring.
• In contrast, a diagnosis of circumvallate placenta warrants closer surveillance for potential complications such as antepartum hemorrhage, placental abruption, fetal growth restriction, and preterm birth.
• Nurses should be able to differentiate these conditions upon placental inspection to ensure accurate documentation and to understand the potential risks associated with each, particularly the circumvallate type.

How to Approach the Question

• First, identify the key descriptive phrase in the question stem: 'a thin fibrous ring is present at the margin of the chorionic plate'.
• Analyze the provided image. The diagram clearly labels the structure with a 'thin, flat ring' as a 'Circummarginate placenta'.
• Recall or look up the definitions of the placental abnormalities listed in the options.
• Match the key descriptor from the question with the correct definition. 'Placenta marginata' is the clinical term for a circummarginate placenta.
• Differentiate this from 'Circumvallate placenta', which is characterized by a 'thick, raised ring', as also shown in the image.
• Eliminate the other options based on their definitions: 'Placenta membranacea' (villi cover all membranes) and 'Placenta spuria' (accessory lobe).

Concept Tested & Keywords

• Concept Tested: Placental abnormalities
• Stem keywords: placental abnormalities, thin fibrous ring, chorionic plate, fetal vessels
• Lead-in keywords: BEST, MOST RELEVANT CLUE
• Negative lead-in flag: false

Question ID

QI43lVrAInSDOxN_9weyNC

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