Hypoplasia-Hyperplasia
Hypoplasia-Hyperplasia
Hypoplasia-Hyperplasia
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שת/<br />
תבט/<br />
ד"<br />
י•<br />
44•<br />
Pathophysiology<br />
Remains Unknown<br />
Brainstem Nuclei; Nerves or muscle Aplasia<br />
Involved CN: 6-12 except 8<br />
6 (Abducens) – 75%<br />
7 (Facial) – 100%<br />
8 (Vestibulocochlear) – Never<br />
9,10,11 – Variable<br />
12 (Hypoglossal) – Rare<br />
3,4 (Oculomotor, Trochlear)– Very rare<br />
Toxin induced (Moebius)<br />
Vascular etiology:<br />
Theories<br />
- Basilar artery insufficiency<br />
- Premature regression of trigeminal a.<br />
- Subclavian a. disruption sequence<br />
Mesodermal dysplasia of muscles from 1 0 & 2 0 Branchial<br />
arches<br />
CN Nuclei changes are 2 0 to retrograde atrophy<br />
Disruption sequence of normal morphology @ 4-7 wks<br />
(Explains simultaneous limb anomalies)
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