Flashcards in Development Disorders Deck (20):
What is a neurulation defect?
- The neural tube does not close during neurulation (the stage of embryogenesis that includes the formation and closure of the neural tube)
What is a myeloschisis?
- Developmental anomaly characterized by a cleft spinal cord due to a failure of the neuroplate to form a complete tube
What is the most common type of spina bifida?
- Spina bifida occulta
What is spina bifida occulta?
- The neural arches fail to fuse dorsally
Where does spinal bifida occulta typically occur on along the cord?
What are the effects of spina bifida occulta?
- A dimple in the back of the bertebrae where the spinous process should be
- A tuff of hair
What is a meningocele?
- Subarachnoid space bulges through unfused neural arches (mesodermal arch doesn't completely close at all)
What 2 protective layers of the the spinal cord bulge out in a meningocele?
- Dura and arachnoid
How is the spinal cord affected in meningocele?
- The spinal cord remains in tact
What is a meningomyelocele?
- Spinal cord and nerve root bulge through neural arches
What is the difference between a meningocele, and a meningomyelocele?
- The spinal cord grows into the cyst
What is the surgical procedure for a meningomyelocele?
- The cord may be pushed back into the vertebral column
What is a syringomyelocele?
- The spinal cord bulges through the neural arches, and develops abnormally
What is a myelocele?
- There is a gap in the neural arch, but there is no fluid filled cyst, so the cord is completely exposed to the environment.
Which types of spina bifida are incompatible with life?
What is Arnold-Chiari syndrome?
- Congenital anomaly in which the cerebellum and medulla protrude down into the spinal cord through the foramen magnum
What is anencephaly?
- The congenital absence of the cranial vault, with a failure of the cerebral hemispheres to develop as a result of a defect in the dvelopment of the rostral neural tube
What is a meningoencephalocele?
- Protrusion of part of the cerebellum that is covered by meninges and skin
How is a meningoencephalocele named?
By the partion of the skull through which it protrudes.
ex) Occipital, frontal, etc..