Some facts about ganglion

• Primary neurons responsible for taste sensation in anterior 2/3rd of tongue is supplied through geniculate ganglion.
• Superior cervical ganglion is the largest ganglion in the head and neck region. Major salivary gland receives post-ganglionic sympathetic fibres from this ganglion.
• Parasympathetic fibres to pterygopalatine ganglion come from greater petrosal nerve. The lesser petrosal nerve carries pre-ganglion fibres to the otic ganglion.
• Salivary glands receive innervation by way of general visceral efferent nerve fibres from salivatory nucleus.

A. TRIGEMINAL GANGLION

Crescentic or semilunar shaped sensory ganglion of 5^th cranial nerve.

The ganglion lies on the trigeminal impression on the anterior surface of petrous part of temporal bone near its apex and occupies a special space of dura mater called the trigeminal or Meckel's cave.

The central process of the ganglion cells from the large sensory root while the peripheral processes of the ganglion cells forms the three divisions of the trigeminal nerve.

B. CILIARY GANGLION

Parasympathetic ganglion placed in course of the oculomotor nerve.

It lies near apex of orbit between the optic nerve and tendon of the lateral rectus muscle.

It has sensory, motor, and sympathetic roots.

1) The sensory root comes from nasociliary nerve. It contains sensory fibres from the eyeball.

2) The motor root arises oculomotor nerve. It carries preganglionic fibres from Edinger-Westphal nucleus to supply the sphincter pupillae and ciliary muscle

3) The sympathetic root carries postganglionic fibres of superior cervical ganglion to supply the blood vessels of eye ball and the dilator pupillae.

C. PTERYGOPALATINE GANGLION (SPHENOPALATINE GANGLION)

This is the largest parasympathetic peripheral ganglion.

It lies in the pterygopalatine fossa just below the maxillary nerve.

Topographically it is related to the Maxillary nerve, but functionally it is connected to the Facial nerve.

The motor or parasympathetic root is formed by the nerve of pterygoid canal. It carries preganglionic fibres of superior salivary nucleus through the nervus intermedius, facial nerve, geniculate ganglion, the greater petrosal nerve, and the nerve of pterygoid canal to reach the ganglion. The postganglionic fibres supply the lacrimal glands, mucous glands of nose, paranasal sinuses, the palate and the nasopharynx.

The sympathetic root is also derived from nerve of pterygoid canal. It carries post-ganglionic fibres of superior cervical sympathetic ganglion to supply the nose the paranasal sinuses, the palate and the nasopharynx.

The sensory root comes from maxillary nerve and continues as branches of maxillary nerve.

D. SUBMANDIBULAR GANGLION

Topographically it is related to the Lingual nerve but functionally it is connected to the Facial nerve.

It is a relay station for secretomotor fibres to the submandibular and sublingual glands. The parasympathetic preganglionic fibres that arise in the superior salivatory nucleus pass through the facial nerve, the chorda tympani, and the lingual nerve to reach the ganglion.

Post ganglionic fibres for the submandibular gland reach the gland through branches of the ganglion. Post ganglionic fibres for the sublingual and anterior lingual gland are supplied through lingual nerve.

The sympathetic fibres carry the post ganglionic fibres of superior cervical ganglion to supply to submandibular and sublingual glands,

(Note: Sympathetic fibres pass through the submandibular ganglion without relay)

E. OTIC GANGLION

Topographically it is related to Mandibular nerve, but functionally it is a part of the Glossopharyngeal nerve.

It is situated in the infratemporal fossa, just below the foramen ovale and surrounds the origin of nerve to medial pterygoid.

The preganglionic parasympathetic fibres from the inferior salivary nucleus are passed through the glossopharyngeal nerve, its tympanic branch, the tympanic plexus and the lesser petrosal nerve to reach the ganglion.

The post ganglionic fibres reach the parotid gland through auriculotemporal nerve.

F. GENICULATE GANGLION

The geniculate ganglion is located on the first bend of the facial nerve. It is a sensory ganglion.

The taste fibres present in the nerve area peripheral processes of pseudounipolar neurons present in the geniculate ganglion.

(Note: The three ganglions associated with facial nerve are geniculate, submandibular and pterygopalatine)

Cervical sympathetic ganglion:

Cervical parts of right and left sympathetic trunks are situated one on each side of the cervical part of the vertebral column.

Origin: From fibres of T1 to T4 of spinal cord that ascend into the neck.

Due to fusion of 3 ganglia, superior, middle, inferior branches of superior ganglia:

To ventral rami of upper 4 cervical nerves

Plexus around internal carotid artery. Apart of this plexus supplies dilator pupillae.

Plexus around external carotid artery

Pharyngeal branches form pharyngeal plexus.

Left superior cervical cardiac goes to superficial cardiac plexus while the right goes to deep cardiac plexus.

Middle cervical ganglion: Formed by 5th & 6th cervical ganglia

Branches: Branches to ventral rami of 5th & 6th cervical nerves, thyroid, parathyroid, tracheal, oesophageal and to deep cardiac plexus.

Inferior cervical ganglia: Formed by fusion with first thoracic ganglion and 7 and 8 cervical ganglion is called stellate ganglion.

Branches: To ventral rami of C7 & C8 plexus around vertebral artery & Subclavian artery deep cardiac plexus.