A 4-month-old infant has undergone surgical treatment for meningo myelo encephalocele. A CT tomogram of head was made immediately after birth (see Figure below). At birth, an operation was carried out in the posterior cranial fossa to partially replace brain cerebellar contents to an intracranial position. In investigations for progressive hydrocephalus, it is noted that there is herniation of the cerebellar tonsils through the foramen magnum, and a diagnosis of Arnold-Chiari syndrome is established. This syndrome may also include which of the following?Tomogram from CT head taken 4 months previously (immediately after birth). Opening in the posterior cranial fossa showing brain and meninges protruding into sac (axial view).
Abnormal elongation of the medulla and lower cranial nerves may be evident in Arnold- Chiari syndrome. Additional features include fusion of the corpora quadrigemina, leading to a "beaked" tectum; partial or complete absence of the corpus callosum; and microgyria. The corpora quadragemina are relay stations for hearing (inferior corpora quadragemina) and the light reflex (superior copora quadragemina), and they form the posterior surface of the midbrain.
Fusion of the frontal lobes
Fusion of the temporal, parietal, and occipital lobes
Abnormal elongation of the medulla and lower cranial nerves
Partial or complete absence of the pituitary gland
Nervous System