What is the shape of the placenta?

Appeared in: Uttarakhand CHO - 2021

Explanation

The human placenta at term is a flat, circular to oval organ, which is anatomically described as being discoid (disc-shaped).
This shape provides a large surface area for the exchange of nutrients, gases, and waste between the maternal and fetal circulation.
Textbook descriptions confirm that the typical placenta is a 'placental disc' that is round to oval, weighing about 470g with a diameter of 22 cm.

Option A: This is incorrect. A spherical shape implies a ball or globe, which does not describe the flat, plate-like structure of the placenta.
Option C: While the outline of the placenta can be oval, 'discoid' is a more precise anatomical term that describes its three-dimensional form as a flat, circular plate or disc.
Option D: This is incorrect. Fusiform means spindle-shaped, tapering at both ends. This shape is characteristic of certain muscles, like the biceps brachii, not the placenta.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy and morphology of the human placenta as background academic context rather than a clinical decision trigger.
After delivery, nurses and midwives must perform a thorough examination of the placenta to confirm its completeness. The expected finding is a single, intact discoid placenta.
If any cotyledons (lobes) or fragments appear to be missing from the maternal surface, it raises suspicion of retained placental tissue, which is a primary cause of postpartum hemorrhage and puerperal sepsis.
Identifying shape variations like a succenturiate lobe is critical. The vessels leading to this accessory lobe must be examined to ensure the lobe itself was not retained in the uterus, as this can lead to severe delayed bleeding.

How to Approach the Question

This is a factual recall question testing fundamental knowledge of obstetric anatomy.
Identify the core concept of the question: the 'shape' of the 'placenta'.
Recall the standard anatomical description of the placenta from your studies.
Evaluate the given options against this knowledge. 'Discoid' means disc-shaped, which is the correct term.
Eliminate the other options based on their definitions: 'Spherical' (ball-shaped), 'Oval' (egg-shaped outline, less precise), and 'Fusiform' (spindle-shaped) are incorrect descriptions of the placenta's structure.

Concept Tested & Keywords

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E6 Obstetrics Williams p. 10-26

Practise the full Uttarakhand CHO - 2021

Attempt every question from this paper in a timed mock, then review the full solution for each one.