Corpus: Submandibular ganglion

The submandibular ganglion is a small, spindle-shaped ganglion located in the submandibular triangle of the head. It is one of the parasympathetic ganglia in the head region.

2.1. Topography

The submandibular ganglion is situated just above the submandibular gland. It is bordered by the hyoglossus muscle and the posterior edge of the mylohyoid muscle. The ganglion is connected to the lingual nerve via two nerve fiber bundles.

2.2. Fibers

The submandibular ganglion is traversed by both sympathetic and parasympathetic fibers, though only the parasympathetic fibers synapse within the ganglion. The sympathetic fibers pass through the ganglion without synapsing, serving as a transit pathway.

2.2.1. Parasympathetic fibers

The preganglionic parasympathetic fibers that enter the submandibular ganglion originate from neurons in the superior salivatory nucleus. These fibers reach the ganglion via the facial nerve, specifically through the chorda tympani and the lingual nerve. After synapsing within the ganglion, the postganglionic fibers travel as glandular branches to innervate the submandibular and sublingual salivary glands with visceromotor functions. Additionally, some postganglionic fibers also innervate the minor salivary glands within the oral mucosa.

2.2.2. Sympathetic fibers

The submandibular ganglion also receives postganglionic sympathetic fibers from the superior cervical ganglion. These fibers reach the ganglion via the external carotid plexus and the facial artery. They pass through the ganglion without synapsing and continue to the aforementioned salivary glands.

2.2.3. Wide fibers

Some textbooks suggest that sensory fibers from the lingual nerve pass through the submandibular ganglion without synapsing. However, other sources claim that the submandibular ganglion is unique among parasympathetic head ganglia in that it does not transmit any somatic fibers.