Deep transverse arrest occurs in …… pelvis :
**Core Concept**
Deep transverse arrest is a complication that occurs during the second stage of labor, where the fetal head fails to progress past the ischial spines and becomes arrested in a transverse position. This is often due to a mismatch between the fetal head and the maternal pelvis.
**Why the Correct Answer is Right**
In an android pelvis, the pelvic inlet is more oval and narrower, with a more pronounced sacrum and less room for the fetal head to move. The ischial spines are also more prominent, which can obstruct the fetal head's movement, leading to a deep transverse arrest. The android pelvis is one of the four main types of female pelvises, characterized by its narrow and deep shape.
**Why Each Wrong Option is Incorrect**
**Option A:** Gynaecoid pelvis is the most common type of female pelvis and is characterized by a round and spacious shape, which is not typically associated with deep transverse arrest.
**Option B:** Platypelloid pelvis has a wide and shallow shape, with a flat pelvis and a broad transverse diameter, which is less likely to cause deep transverse arrest.
**Option D:** Mixed pelvis combines features of different types of pelvises and does not have a distinct shape that would predictably lead to deep transverse arrest.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the shape and size of the pelvis can significantly impact labor progress. A thorough understanding of the different types of female pelvises and their characteristics can help obstetricians anticipate and manage potential complications.
**Correct Answer:**
✓ Correct Answer: C. Android. An android pelvis is more likely to cause a deep transverse arrest due to its narrow and deep shape.