Malformation of the spine in which the posterior portion of the lamina of one or more vertebrae fails to fuse, with or without defective development of the spinal cord is called?

1. A

   Rachischisis

2. B

   Encephalocele

3. C

   Spina bifida

4. D

   Anencephaly

Appeared in: AIIMS Raipur - 2017 (shift-2)

Explanation

• Spina bifida is the correct term for a congenital defect where the posterior vertebral arches (laminae) fail to fuse during embryonic development.
• This definition encompasses a spectrum of conditions, from the mildest form, spina bifida occulta, to more severe forms like meningocele and myelomeningocele, as shown in the image.
• The key feature is the bony defect in the spine, which may or may not involve the protrusion of the spinal cord or its coverings (meninges).

Why Other Options Were Wrong

• Option A: Rachischisis is a more severe and specific type of spina bifida where the neural folds do not elevate and fuse, leaving a flattened, exposed plate of neural tissue. The question describes the general failure of lamina fusion, which is broadly termed spina bifida.
• Option B: Encephalocele involves the herniation of meninges and/or brain tissue through a defect in the skull (cranium), not the spine.
• Option D: Anencephaly is the absence of the cranial vault, cerebral hemispheres, and cerebellum. It results from the failure of the rostral (head end) of the neural tube to close.

Related Visual

• Visual 1: Infographic - An illustration comparing a normal spine with the three main types of spina bifida (occulta, meningocele, myelomeningocele). This helps visualize the anatomical differences described in the options.
• Visual 2: Diagram - A flowchart showing the development of the neural tube and indicating where defects like spina bifida and anencephaly occur.

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain This question tests knowledge of different types of neural tube defects (NTDs), specifically the definition of spina bifida as background academic context rather than a clinical decision trigger.
• A key nursing intervention is the prevention of neural tube defects through periconceptional folic acid supplementation (400 mcg/day for most women).
• For a newborn with an open defect like myelomeningocele, immediate nursing priorities include protecting the exposed sac from injury and infection by covering it with a sterile, moist, non-adherent dressing and placing the infant in a prone position.
• Nurses play a vital role in screening (maternal serum alpha-fetoprotein tests) and providing long-term, multidisciplinary care for children with spina bifida, addressing issues like mobility, bladder/bowel function, and skin integrity.

How to Approach the Question

• First, break down the question stem to identify the core definition: 'malformation of the spine,' 'posterior lamina... fails to fuse.'
• Analyze the provided image. Note that it shows different types of a single condition affecting the spine, labeled 'Spina Bifida.'
• Evaluate each option against the core definition. 'Spina bifida' is the umbrella term for the failure of vertebral arch fusion.
• Eliminate 'Encephalocele' and 'Anencephaly' as they relate to defects of the skull and brain, not primarily the spine.
• Differentiate between 'Spina bifida' and 'Rachischisis.' Recognize that Rachischisis is the most severe form, while Spina Bifida is the general term that fits the broad definition in the question.
• Conclude that 'Spina bifida' is the most accurate and comprehensive answer.

Concept Tested & Keywords

• Concept Tested: This question tests knowledge of different types of neural tube defects (NTDs), specifically the definition of spina bifida.
• Stem keywords: malformation of the spine, posterior portion of the lamina, vertebrae fails to fuse, spinal cord
• Lead-in keywords: is called

Question ID

QSq_Bzy0akGc1k1OdD5kPC

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