Question
In face presentation, what is the presenting diameter?
| A. |
Mentovertical
|
| B. |
Submentobregmatic
|
| C. |
Occipitofrontal
|
| D. |
Suboccipitobregmatic
|
Show Answer
|
Correct Answer » B
Explanation
|
|
Face Presentation
Face presentation occurs due to complete extension of the fetal head, making the face the presenting part.
Denominator
Presenting/Engaging Diameter
Submentobregmatic diameter
- Extends from:
- Junction of chin and neck (submentum)
- To the center of bregma
- Measures:
This is the diameter that engages in a true face presentation.
Explanation of Other Options
A. Mentovertical — Incorrect
- Presenting diameter in brow presentation
- Extends from:
- Chin (mentum)
- To highest point of vertex
- Measures:
- Largest AP diameter of fetal skull
- Usually incompatible with vaginal delivery
C. Occipitofrontal — Incorrect
- Seen in partially deflexed vertex presentation
- Diameter:
D. Suboccipitobregmatic — Incorrect
- Diameter in well-flexed vertex presentation
- Measures:
- Smallest AP diameter for normal vaginal delivery
