Anatomical research on the ciliary ganglion and eye muscle nerves of Stellagama stellio (Squamata – Lacertilia - Agamidae)

Abstract Background Using a variety of methods, including as gross dissection and histological preparations, the arrangement of the root, ganglia, and peripheral distribution of the eye muscle nerves in Stellagama stellio were investigated. The anatomical study of the cranial nerves (the eye muscle nerves) of a member of the Agamidae family is significant because they exhibit an evolutionary trend among animals in the same group and because their distribution is correlated with the habits and habitats of animals. Therefore, it was determined that it was crucial to investigate the eye muscle nerves and the ciliary ganglion of Stellagama stellio in order to clarify their anatomical features and conclude their neurological characteristics This may aid in understanding the phylogeny of this family. Results The present work deals with the eye muscle nerves and the ciliary ganglion of Stellagama stellio . The eye muscle nerves include the oculomotor (CN III), trochlear (CN IV) and abducens (CN VI) nerves. The CN III arises via one stout root and leaves the cerebral cavity through its own foramen. It provides parasympathetic fibers to the ciliary ganglion via the large radix ciliaris brevis and innervates the superior rectus, inferior rectus, medial rectus, and inferior oblique muscles. The ciliary ganglion gives a single ciliary nerve and is made up of both large and tiny neurons. Within the brain, the CN IV fibers fully decussate. It innervates the superior oblique muscle. The CN VI leaves the cerebral cavity to pass into the vidian canal. It innervates the lateral rectus, bursalis and the retractor bulbi muscles. The eye muscle nerves convey general somatic motor fibers and, in addition to these, the CN III also carries general visceral motor (parasympathetic) fibers to the ciliary muscles. Conclusion This study provided vital insights into the description and analysis, of the eye muscle nerves and ciliary ganglion, showing several neurological features that are essential for phylogeny, and taxonomy.