A failure of the vertebrae to close without protrusion of the meninges and the spinal cord is a form of:

DSSSB 12 August 2024

Applied Anatomy

Easy

Appeared in: DSSSB 12 August 2024

Explanation

Spina bifida occulta, which is defined as a midline defect of the vertebral bodies without protrusion of the spinal cord or meninges.
The term 'occulta' means hidden, which reflects that this defect is covered by skin and not externally visible as a sac.
In this condition, there is a failure of the posterior vertebral arches to fuse, but the spinal cord and its protective coverings (meninges) remain in their normal position within the spinal canal.
It is the mildest and most common form of spina bifida and is often discovered incidentally during an X-ray for other reasons.

Option B: Meningomyelocele is incorrect because it is the most severe form of spina bifida, characterized by the protrusion of a sac containing not only the meninges and cerebrospinal fluid but also a portion of the spinal cord and nerves. This contradicts the question's key phrase 'without protrusion'.
Option C: Meningocele is incorrect because it involves the protrusion of the meninges and cerebrospinal fluid into a sac through the vertebral defect. Although the spinal cord itself does not protrude, there is a visible external sac, which contradicts the 'without protrusion' part of the question.
Option D: Spina bifida cystica is a broad, general term that encompasses both meningocele and meningomyelocele. It refers to any form of spina bifida where there is a visible cystic sac protruding from the spinal column. This is the opposite of the condition described in the question.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of neural tube defects, specifically Spina Bifida as background academic context rather than a clinical decision trigger.
Spina bifida occulta is often asymptomatic and may go undetected. A nurse's assessment might reveal subtle signs over the lumbosacral area, such as a skin dimple, a tuft of hair, a birthmark (hemangioma), or a small fatty lump (lipoma).
While usually benign, spina bifida occulta can be associated with 'tethered cord syndrome,' where the spinal cord is abnormally attached, leading to neurological problems as the child grows. Nurses should be aware of symptoms like new-onset leg weakness, changes in gait, or bladder/bowel dysfunction.
What if? If a newborn presents with a visible, fluid-filled sac on the lower back, the immediate nursing priority is to protect the sac from rupture and infection. The nurse should cover it with a sterile, moist, non-adherent dressing and position the infant prone to minimize pressure on the sac. This is a surgical emergency, unlike spina bifida occulta.

How to Approach the Question

First, identify the key phrase in the question stem: 'without protrusion of the meninges and the spinal cord'.
Next, analyze the medical terminology in the options. 'Cele' refers to a protrusion or hernia. 'Meningo' refers to the meninges, and 'myelo' refers to the spinal cord.
Consider the term 'occulta,' which means 'hidden.' This implies a defect that is not externally visible as a sac.
Based on this, 'Meningocele' (meninges protrusion) and 'Meningomyelocele' (meninges and spinal cord protrusion) can be eliminated because they both involve protrusion.
'Spina bifida cystica' is a general term for types with a cyst, so it is also incorrect.
Conclude that 'Spina bifida occulta' is the only option that describes a vertebral defect without protrusion.

Concept Tested & Keywords

Concept Tested: Classification of neural tube defects, specifically Spina Bifida.
Stem keywords: failure of vertebrae to close, without protrusion, meninges, spinal cord
Lead-in keywords: is a form of

QIl8Pc4DLnQVq9doinV2KX

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 pp. 1369-1371, 1368-1370