Parasympathetic Ganglia Of Head And Neck
Parasympathetic ganglia of head and neck transmit three types of fibers (i) parasympathetic fibers, (ii) sympathetic fibers and (Hi) sensory fibers. These are called parasympathetic ganglia because only parasympathetic fibers synapse (relay) in the ganglia, other two types of fibers simply pass through without relay in the ganglia. Important parasympathetic ganglia in head and neck are :(i) otic ganglion, (ii) submandibular ganglion, (iii) pterygopalatine ganglion, and (iv) ciliary ganglion.
Topographically, it is connected to mandibular nerve, while functionally it is related to glossopharyngeal (IX) nerve. Its roots are:-
- Sensory root:-By Auriculotemporal nerve.
- Sympathetic root:-By sympathetic plexus around middle meningeal artery.
- Parasympathetic (secretomotor) root: - This root is by lesser petrosal nerve. Preganglionic fibres begin in inferior salivatory nucleus, pass through glossopharyngeal nerve, then its tympanic branch, tympanic plexus, and the lesser petrosal nerve and relay in otic ganglion. Postganglionic fibers pass through auriculotemporal nerve and supplies parotid gland.
- Motor root :- It is derived from nerve to medial pterygoid which passes unrelayed through ganglion and supplied tensor veli palatini and tensor tympani (Note :- Otic ganglion has a motor root, beside three standard roots of parasympathetic ganglion of head and neck: sensory, sympathetic and parasympathetic).
Functionally, submandibular ganglion is connected to facial nerve, while topographically it is connected to lingual branch ofmandibular nerve. Its roots are :-
- Sensory root: - It is from lingual nerve.
- Sympathetic root: - It is from sympathetic plexus around facial artery, which contains postganglionic fibers from superior cervical ganglion of sympathetic trunk.
- Secretomotor (parasympathetic) root: - Preganglionic fibers arise from superior salivatory nucleus pass through facial nerve then its chorda tympani branch which joins lingual nerve and relay in submandibular ganglion. Postganglionic fibers supply :-
- Directly submandibulargland.
- Through lingual nerveSublingual salivary gland and glands in oral cavity.