. Journal of comparative neurology . length. Trigeminal nerve The trigeminal nerve arises from the wall of the anterior regionof the rhombencephalon by a relatively small motor root and alarger sensory root upon which is located the semilunar ophthalmic and the maxillary divisions of the trigeminalnerve arise as fibrous outgrowths from the semilunar motor root of the trigeminus takes part only in the for-mation of the mandibular division. In embryos of the pig 5 to 2 See bibliography. 74 ALBERT KUNTZ 6 mm. in length, the neural crest has already become differen-tiated
. Journal of comparative neurology . length. Trigeminal nerve The trigeminal nerve arises from the wall of the anterior regionof the rhombencephalon by a relatively small motor root and alarger sensory root upon which is located the semilunar ophthalmic and the maxillary divisions of the trigeminalnerve arise as fibrous outgrowths from the semilunar motor root of the trigeminus takes part only in the for-mation of the mandibular division. In embryos of the pig 5 to 2 See bibliography. 74 ALBERT KUNTZ 6 mm. in length, the neural crest has already become differen-tiated into ganglionic masses. At this stage the anlage of thesemilunar ganglion appears as a somewhat irregular mass ofcells lying in close proximity with the lateral surface of theanterior region of the rhombencephalon and almost or quite incontact with the ectoderm. As development advances the posi-tion of this ganglionic mass is shifted ventrad until the entireanlage lies ventro-lateral to the rhombencephalon in the regionof the ^.,4j^ Fig. 1 Drawing made from a wax reconstruction of the third and the fifthcranial nerves in an embryo of the pig 27 mm. in length. Cil, ciliary ganglion;Lin, lingual nerve; Ma, maxillary nerve; Man, mandibular nerve; Oc, oculo-motor nerve; Oph, ophthalmic nerve; Ot, otic ganglion; S, semilunar ganglion;Sph, sphenopalatine ganglion; Subm, submaxillary ganglion. In embryos of the pig 8 mm. in length, the semilunar ganglionis quite definitely outlined. It still lies in close proximity withthe wall of the rhombencephalon. Its proximal surface is slightlyconcave, while its peripheral surface is irregularly convex. Theentire mass, therefore, is already roughly crescentic in fibers of the sensory root of the trigeminal nerve have alreadypenetrated the wall of the rhombencephalon and the motor root CRANIAL SYMPATHETIC GANGLIA IN THE PIG 75 is well differentiated. The nuclei of the cells composing theganglionic mass are identical in appeara
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmedicine, bookyear191
