Pterygopalatine Ganglion

1. Pterygopalatine Ganglion Preganglionic parasympathetic secretomotor fibers arise in the lacrimal nucleus of the facial nerve which lies in the lower pons. They run in the nervous intermedius of the facial nerve, then in its greater petrosal branch, then in the nerve of pterygoid canal. Postganglionic parasympathetic fibers reach the maxillary nerve by one of its ganglionic branches. They then run in the zygomatic nerve then to its zygomatico-temporal branch which joins the lacrimal nerve to lacrimal gland. Other postganglionicparasympathetic fibers run in the palatine nerves and nasal nerves to the palatine and nasal glands. Sympathetic postganglionic fibers from the superior cervical ganglion reach the ganglion via the internal carotid plexus, then in the deep petrosal nerve, then in the nerve of pterygoidcanal.

2. Branches: 1-The pharyngeal branch: It supplies the mucous membrane of the roof of the nasal part of the pharynx. 2-The greater; lesser palatine ns. They supply the mucousmembrane of the palate, tonsil and nasal cavity. 3- The nasal & nasopalatine ns: They enter the nose through the sphenopalatine foramen and supply the mucousmembrane and glands of the nasal cavity. 4-Orbital branches: They enter the orbit through the inferior orbital fissure to supply the smooth orbitalis muscle which bridges the fissure by sympathetic postganglionic fs Spheno-palatine foramen: It connects the posterior part of the superior meatus with the pterygo- palatine fossa.

3. Lymph drainage Regional Groups 1-Occipital lymph nodes They lie at the apex of the postetriortriangle. They receive lymph from the back of the scalp. The efferent vessels drain into the deep cervical lymph nodes.2- Retroauricular They are situated at the lateral surface of the mastoid process. They receive lymph from a strip of the scalp above the auricle and from the posterior wall of the external auditory meatus. 3- parotid They are situated on or within the parotid gland. They receive lymph from a strip of the scalp above the parotid salivary gland; lateral surface of the auricle; anterior wall of the external auditory meatus and lateral parts of theeyelids. Also, the nodes that are deeply placed in the gland, receive lymph from the middle ear.

4. 4- Buccal They are situated over the buccinator muscle, close to facial vein. They lie along the course of lymph vessels that drain into the submandibular nodes. 5- Submandibular They are situated on the superficial surface of the submandibular salivary gland beneath the investing layer of the deep cervical fascia. They can palpated just below the lower border of the mandible. They receive lymph from the frond of the scalp; nose and adjacent cheek; upper & lower lips( except the central part); upper & lower teeth ( except lower incisors); anterior twothird of the tongue ( except the tip );floor of the mouth; vestibule; gums and the frontal; maxillary and ethmoidal air sinuses.

5. 6- Anterior cervical They lay along the course of the anterior jugular veins and receive lymph from skin and superficial of the front of the neck tissue. 7- Submental They lay in the submental triangles between the anterior bellies of the digastric muscles. They receive lymph from the tip of the tongue; floor of the mouth beneath the tip of the tongue; incisor teeth and associated gums; central part of the lower lip and the skin over the chin. 8- superficial cervical They lay along the course of the external jugular vein. They receive lymph from the skin over the angle ofthe mandible; the skin over the apex of the parotid gland and the lobules ofthe ear.

6. 9- Retropharyngeal They are situated in the retropharyngeal space, in the interval between the pharyngeal wall and prevertebral fascia. They receive lymph from the nasal part of the pharynx, auditory tube and the upper part of the cervical vertebral column. 10- laryngeal They lay on the cricothyroidmembrane in front of the larynx. One or 2 nodes are found in front of the thyrohyoid membrane. They receive lymph from adjacent structures. 11- trachealThey lay lateral ( paratracheal ) or in front of the trachea ( pretracheal ) nodes. They receive lymph from thyroid and the other neighboring structure. N.B.All the previous nodes, theirefferent lymph vessels are drained into the deep cervical nodes. Also, the sub-mental drain into submandibular nodes

7. Deep Cervical Lymph Nodes They form a chain along the course of the internal jugular vein, from the skull to the root of the neck. The sternocleidomastoid muscle lies anterolaterally to it. They divided into upper & lower nodes. The upper deep are subdivided into: Anterosuperior group( jugulo-digastricnods ): They lay below and behind the angle of the mandible and just below the posterior belly of the digastric muscle . Their afferent lymph vessels from the posterior third of the tongue; tonsil; parotid; submandibular and retro- pharyngeal lymph nodes. Posterosuperior group: They are present in the posterior triangle of the neck. Their afferent lymph vessels from, deep muscles of the neck; mastoid and occipital lymph nodes.

8. The lower deep are subdivided into: Anteroinferior group ( jugulo-omohyoid nodes ): They are present on the intermediate tendon of the omohyoid muscle. Their afferent lymph vessels are mainly from the tongue; thyroidgland; prelaryngeal; tracheal and upper deep cervical lymph nodes. Posteroinferior group ( supraclavicular nodes ): They are present in the lower part of the posterior triangle of the neck. Their afferent lymph vessels are from deep muscles of the neck and upper deep cervical lymph nodes.

9. The efferent lymph vessels from the lower deep cervical nodes unite with efferent lymph vessels from the upper deep group and form the jugular lymph trunk. This trunk may end: 1- Right lymphatic duct on the right side. 2- Thoracic duct on the left side. 3- Subclavian lymph trunk or the brachiocephalic veins on both sides. N.B. There is no lymph nodes or lymph vessels in the orbital cavity; cranial cavity and central nerveous system ( drained by C.S.F. )