Absence of both the sacral alae in the pelvis is called:

Appeared in: NHM UP Staff Nurse-2023 shift 1st

Explanation

Robert's pelvis is a rare congenital anomaly defined by the absence of the alae (wings) on both sides of the sacrum.
This bilateral absence causes the sacrum to fuse with the innominate bones.
The primary consequence is a severe reduction in the transverse diameter of the pelvis, creating an obstruction for vaginal delivery.
Due to this severe transverse contraction, a planned cesarean section is the only safe mode of delivery.

Option A: The rachitic pelvis is a deformity caused by rickets (vitamin D deficiency) during childhood, not a congenital absence of bony parts. It is characterized by a flattened pelvic inlet.
Option B: Naegele's pelvis is characterized by the absence or arrested development of only one sacral ala, not both. This results in an obliquely contracted pelvis.
Option D: A scoliotic pelvis is an asymmetrical deformity caused by severe curvature of the lumbar spine (scoliosis). It does not involve the congenital absence of the sacral alae.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomical abnormalities of the female pelvis as background academic context rather than a clinical decision trigger.
Severe pelvic deformities like Robert's pelvis and Naegele's pelvis create an absolute cephalopelvic disproportion, making vaginal delivery impossible and unsafe.
Antenatal identification of a contracted pelvis through clinical pelvimetry or imaging is crucial for planning a safe delivery, which is invariably a cesarean section in these cases.
A nurse's role includes identifying high-risk pregnancies through history (e.g., previous difficult labor, childhood diseases like rickets) and physical assessment, which may suggest the need for further pelvic evaluation.

How to Approach the Question

This is a factual recall question that tests your knowledge of specific medical terminology related to obstetrics.
First, identify the key defining feature in the question stem: 'Absence of both the sacral alae'.
Next, recall the definitions of the different types of pelvic deformities listed in the options.
Differentiate carefully between Robert's pelvis (absence of both alae) and Naegele's pelvis (absence of one ala).
Eliminate options like rachitic and scoliotic pelvis by remembering their causes (rickets and spinal curvature, respectively) are different from the congenital absence of a structure.
Select the option that precisely matches the description in the question.

Concept Tested & Keywords

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E6 Midwifery Obstetrics and Gynecology Nursing Sandeep Kaur p. 50-60

Practise the full NHM UP Staff Nurse-2023 shift 1st

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