The submento-vertical diameter measures:
A. 9.5 cm
B. 10 cm
C. 11.5 cm
D. 14 cm
Explanation
Submento-vertical diameter is a fetal skull diameter measured in brow presentation.
Definition
It is the distance measured from the point of the chin (mentum) to the highest point on the vertex of the skull.
Measurement
➡️ Submento-vertical diameter = 11.5 cm
Explanation
- In brow presentation, the fetal head is partially extended.
- Because of this partial extension, the submento-vertical diameter becomes the presenting diameter.
- This diameter is large, making vaginal delivery difficult or impossible in most cases.
Key points to remember
- Submento-vertical diameter → 11.5 cm
- Seen in → Brow presentation
- Significance → Unfavourable for vaginal delivery
Correct Answer
✅ 11.5 cm
Other Options Details
Submento-vertical diameter is a fetal skull diameter seen in brow presentation (partial extension of the head).
Correct measurement
👉 11.5 cm
Now, explanation of all options:
A. 9.5 cm
- This measurement corresponds to the submento-bregmatic diameter
- Seen in face presentation with complete flexion
- It is the smallest AP diameter, therefore favorable for vaginal delivery
- ❌ Not submento-vertical
B. 10 cm
- This corresponds to the suboccipito-frontal diameter
- Seen in deflexed vertex presentation
- Intermediate size diameter
- ❌ Not submento-vertical
C. 11.5 cm ✅ (Correct Answer)
- This is the submento-vertical diameter
- Extends from:
- Submentum (chin) → highest point of the vertex
- Seen in brow presentation
- Large diameter → vaginal delivery is usually difficult or impossible
D. 14 cm
- This is the mento-vertical diameter
- Seen in incomplete extension (brow presentation)
- Largest AP diameter of the fetal skull
- ❌ Not submento-vertical
Final Answer:
✅ C. 11.5 cm
I hope that you liked this article.
Thanks!! 🙏 😊
Writer: Vandita Singh, Lucknow (GS India Nursing Group