1. PHARYNX Dr. Shawky M. Tayel
- Professor of Anatomy, Embryology & Human Genetics
Anatomy Dep., Alexandria Faculty of Medicine,
- Genetics Consultant, Clinical Genomic Center ,
- Genetics Consultant, Suzanne Mubarak Regional Centre for Women's Health & Development ,
- Fellow, Medical College of Ohio, USA,
- Member, American Society of Human Genetics.

2. PHARYNX
Definition:
It is a musculo-membrenous tube lying behind the nose, mouth and larynx.
It is about 12 cm long.
It extends from the base of the skull and ends opposite 6th cervical vertebra (level of lower border of cricoid cartilage)

3. Relations of the pharynx
Anteriorly:
Nasal cavity, mouth and larynx.
Posteriorly:
Vertebral column, prevertebral fascia and muscles.
Superiorly:
Sphenoid and basilar part of occipital bones.
Inferiorly:
It is continuous with esophagus.

4. Divisions of the pharynx:
The pharynx is divided into 3 parts from above downwards;
Nasopharynx
Oropharynx.
Laryngopharynx.

5. Oropharynx It is the middle part of the pharynx.
It extends from soft palate to upper border of epiglottis.
It communicates with the mouth through the oropharyngeal isthmus.

6. Structures in the oropharynx:
Palatine tonsil enclosed between the palatoglossal fold (ant.) and palato-pharyngeal fold (post.)

7. Palatine tonsil
It is a collection of lymphoid tissue on the lateral wall of the oropharynx on each side.
It lies in a triangular depression called tonsillar fossa.
This fossa is bounded by palatoglossal arch (fold) anteriorly and palatopharyngeal arch (fold) posteriorly.

8. Relations of palatine tonsils
Anteriorly: Palatoglossal arch.
Posteriorly: Palatopharyngeal arch.
Superiorly: Soft palate.
Inferiorly: Posterior third of the tongue.
Medially: Cavity of the oropharynx.
Laterally (tonsillar bed): Superior constrictor muscle, paratonsillar vein
and tonsillar artery.

9. Arterial supply of tonsil:
Tonsillar branch of facial artrey.
Twigs from dorsalis lingulae artery.
Twigs from ascending pharyngeal artery (from ECA).
Twigs from ascending palatine artery (from facial).
Venous drainage:
Paratonsillar vein to pharyngeal plexus.

10. Lymph drainage:
Upper deep cervical lymph nodes mainly jugulodigastric lymph nodes.
Nerve supply:
Tonsillar branch of glossopharyngeal nerve.
Lesser palatine nerve.

11. Laryngopharynx: It is the lower division of the pharynx.
It extends from the lower border of epiglottis to the upper border of cricoid cartilage.
Inferiorly it is continuous with the esophagus at level of 6th cervical vertebra.
It shows a depression on each side of the laryngeal inlet called piriform fossa.

12. Wall of the pharynx
From inside outwards, the wall of the pharynx is formed by:
Mucosa.
Inner fibrous coat (pharyngobasilar fascia). From base of skull to esophagus
Muscles.
Outer fibrous coat (buccopharyngeal fascia)

13. Muscles of the pharynx:
It consists of:
The 3 constrictors:
Superior constrictor.
Middle constrictor.
Inferior constrictor.
Stylopharyngeus muscle.
Palatopharyngeus muscle.
Salpingopharyngeus muscle.

14. Constrictor muscles of the pharynx
Origin:
Superior constrictor; posterior border of medial pterygoid plate.
Pterygoid hamulus.
Pterygomandibular raphe.
Posterior end of mylohyoid line.
Middle constrictor:
Lower part of stylohyoid ligament.
Lesser and greater cornu of hyoid bone.
Inferior constrictor:
Thyroid and cricoid cartilages.

15. Insertion:
Pharyngeal raphe:
A strong median fibrous raphe that receives the insertion of all constrictors on the back of the pharynx.
Its upper end is attached to the pharyngeal tubercle.

16. Nerve supply of constrictor muscles:
Pharyngeal plexus
Action of constrictor muscles:
During swallowing, contraction of the upper fibres of the superior constrictor will pull the pharyngeal wall forwards. This will help the soft palate to close the nasopharyngeal isthmus (between the nasopharynx and oropharynx).
The successive contractions of the superior, middle and inferior constrictor muscles propel the bolus of food downwards to the oesophagus.

17. Stylopharyngeus muscle:
Origin: from styloid process of the temporal bone.
Insertion: into the posterior border of thyroid cartilage.
Nerve supply: Glossopharyngeal nerve (IX).
Action: Elevation of the larynx and pharynx during swallowing.

18. Origin: cartilaginous part of auditory tube.
Salpingopharyngeus muscle:
Origin: cartilaginous part of auditory tube.
Insertion: It blends with palatopharyngeus muscle.
Nerve supply: Pharyngeal plexus.
Action: It helps in elevation of the pharynx.

19. Palatopharyngeus muscle:
Origin: Hard palate and palatine apponeurosis.
Insertion: The lamina of thyroid cartilage.
Nerve supply: Cranial part of accessory nerve through the pharyngeal plexus.
Action: Depression of the palate and narrowing the nasopharyngeal isthmus during deglutition.

20. Motor:
All muscles of pharynx are supplied by cranial part of accessory nerve through pharyngeal branch of vagus except Stylopharyngeus m. (glossopharyngeal nerve).

21. Pharyngeal plexus:
It is nerve plexus on the outer wall of the pharynx.
It is formed by:
Pharyngeal branch of vagus carrying the fibers of cranial part of accessory nerve (motor component).
Pharyngeal branch of glossopharyngeal (sensory component).
Branches of superior cervical sympathetic ganglion (sympathetic component).

22. Blood supply of the pharynx:
Arterial:
Ascending pharyngeal artery.
Ascending palatine artery.
Facial artery.
Lingual artery.
Pharyngeal branch of maxillary artery.
Venous drainage:
Pharyngeal plexus of veins into internal jugular vein.

23. Lymph drainage: Upper deep cervical lymph nodes.
Lower deep cervical lymph nodes.
Retropharyngeal lymph nodes.
Para tracheal lymph nodes.

24. Gapes of the pharynx:
1. A gap between the upper border of the superior constrictor and the skull base
- It gives passage to levator palati, ascending palatine artery, and auditory tube.
2. A gap laterally between the superior and middle constrictors
- It gives passage to the following:
a. Stylopharyngeus passing down to the pharynx.
b. Glossopharyngeal nerve passes forwards to the tongue.

25. 3. A gap laterally between the middle and inferior constrictors
- The structures passing through this gap are:
a. Internal layryngeal nerve.
b. Superior laryngeal artery.
4. A gap at the lower border of the inferior constrictor
- It is pierced by:
a. Inferior laryngeal artery. b. Recurrent laryngeal nerve.

26. Thank You