Anatomic variation of cranial parasympathetic ganglia

Abstract

Having broad knowledge of anatomy is essential for practicing dentistry. Certain anatomical structures call for detailed studies due to their anatomical and functional importance. Nevertheless, some structures are difficult to visualize and identify due to their small volume and complicated access. Such is the case of the parasympathetic ganglia located in the cranial part of the autonomic nervous system, which include: the ciliary ganglion (located deeply in the orbit, laterally to the optic nerve), the pterygopalatine ganglion (located in the pterygopalatine fossa), the submandibular ganglion (located laterally to the hyoglossus muscle, below the lingual nerve), and the otic ganglion (located medially to the mandibular nerve, right beneath the oval foramen). The aim of this study was to present these structures in dissected anatomic specimens and perform a comparative analysis regarding location and morphology. The proximity of the ganglia and associated nerves were also analyzed, as well as the number and volume of fibers connected to them. Human heads were dissected by planes, partially removing the adjacent structures to the point we could reach the parasympathetic ganglia. With this study, we concluded that there was no significant variation regarding the location of the studied ganglia. Morphologically, our observations concur with previous classical descriptions of the parasympathetic ganglia, but we observed variations regarding the proximity of the otic ganglion to the mandibular nerve. We also observed that there were variations regarding the number and volume of fiber bundles connected to the submandibular, otic, and pterygopalatine ganglia.

Cranial Nerves N‐VI

“…These variations include oval, quadrilateral, rectangular, egg, or irregular-shaped ganglia (Hallet 1847;Siessere et al 2008). Doubling and tripling of the ganglion has also been noted bilaterally (Hallet 1847;Whitnall 1979).…”

“…The otic ganglion can vary in location, 0-4 mm from the anterior section of the mandibular nerve (Siessere et al 2008). The otic ganglion may also send branches to the medial pterygoid muscle, sympathetic plexus of the middle meningeal artery, the lesser petrosal nerve, and the auricotemporal nerve (Siessere et al 2008).…”

“…The otic ganglion may also send branches to the medial pterygoid muscle, sympathetic plexus of the middle meningeal artery, the lesser petrosal nerve, and the auricotemporal nerve (Siessere et al 2008). The otic ganglion can also be completely absent unilaterally or bilaterally.…”

“…In unilateral absence, the contralateral ganglion will present with a small thickening. In bilateral absence, a nerve plexus containing ganglion cells sometimes replaces the otic ganglia (Weigner 1898;Siessere et al 2008).…”

Effect of streptozotocin-induced diabetes on the autonomic ganglia of albino rats

“…Sensory fibers from the maxillary branch of trigeminal nerve and sympathetic fibers pass through ganglia, but do not synapse in them. [9] The coeliac ganglia (ClG) are a well-defined prevertebral sympathetic ganglia located on the sides of the coeliac trunk having a varying number of neurons with extensive dendritic fields. [10] ClG receive convergent synaptic input from spinal preganglionic neurons and peripheral intestinofugal neurons projecting from the gut.…”