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Embryonic anastomosis between hypoglossal nerves.
J F Rodríguez-Vázquez1, J R Mérida-Velasco, S Verdugo-López
1Departamento de Anatomía y Embriología Humana II, Facultad de Medicina, Universidad Complutense, 28040 Madrid, Spain. jfrodvaz@med.ucm.es
Anatomical Science International
|March 31, 2009
Summary
This study observed a rare suprahyoid nerve variation in human embryos, detailing a hypoglossal nerve anastomosis. This finding provides insights into early human nerve development and anatomical variations.
Area of Science:
- Embryology
- Neuroanatomy
- Human Anatomy
Background:
- The hypoglossal nerve (CN XII) innervates tongue muscles.
- Variations in cranial nerve pathways can impact function.
- Understanding embryonic nerve development is crucial for diagnosing congenital anomalies.
Purpose of the Study:
- To document and describe a specific anastomosis of the hypoglossal nerve in the suprahyoid region of human embryos.
- To compare this variation with the typical arrangement of hypoglossal nerves during early development.
Main Methods:
- Microscopic examination of two human embryonic specimens (CR length 10.75 mm and 17.5 mm).
- Comparative analysis with established anatomical descriptions of normal hypoglossal nerve development at similar embryonic stages.
Main Results:
- Two cases of hypoglossal nerve anastomosis in the suprahyoid region were identified.
- The anastomotic branches were comparable in size to the main nerve trunks.
- The anastomosis was consistently located dorsal to the geniohyoid and caudal to the genioglossus muscles, overlying the hyoid bone anlage.
Conclusions:
- This suprahyoid anastomosis represents a significant variation in human embryonic hypoglossal nerve patterning.
- The formation of a suprahyoid nerve chiasm was noted in the smaller embryo, highlighting a potential midline developmental pathway.
- These findings contribute to the understanding of cranial nerve plasticity and variations during human development.
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