Hypopharynx anatomy

Hyphopharynx

1. Hypopharynx anatomy Dr S aheena N

2. PHARYNX  It is a funnel shaped fibro-muscular tube of about 13 cm . length  It extends form the base of the skull to the level of the 6th cervical vertebrae.  Its anterior wall is deficient and lies behind the cavities of the nose, mouth and larynx  Accordingly it is divided into 3 parts: Nasopharynx , oropharynx & laryngeopharynx . a)Base of skull (basioociput and basi sphenoid)  soft palate b)Plane of hard palate  hyoid bone c) Hyoid bone  lower border of cricoid cartilage Nasopharynx Oropharynxx Larygeopharynx

3. Hypopharynx/laryngopharynx The hypopharynx extend from the level of the hyoid bone above to that of the lower border of the cricoid cartilage below. Lies opposite the 4 th 5 th 6 th cervical vertebrae

4. Subdivisions of hypopharynx Pyriform sinus Post cricoid region Posterior pharyngeal wall

5. Pyriform fossa Lies on either side of larynx Extends from pharyngo epiglottic fold to the upper end of oesophagus Boundaries Superiorly- pharyngo epiglottic fold Laterally – thyrohyoid membrane & thyroid cartilage Medially – aryepiglottic fold ,posterolateral suface of arytenoid & cricoid cartilages Inferiorly – continues as esophagus

6. ..pyriform fossa

7. ..pyriform fossa Also known as smuggler’s fossa Forms the lateral channel for food Foreign bodies may lodge in the PF Internal laryngeal nerve –runs submucosally in the lateral wall of the sinus- accessible for local anesthasia Referred otalgia in pyriform fossa malignancy

8. ..pyriform fossa

9. Post cricoid region Part of anterior wall of laryngopharynx between the upper and lower border of cricoid cartilage It is the common site for ca in females with plummer – vinson syndrome

10. Posterior pharyngeal wall Extends from the level of hyoid bone to the level of cricoarytenoid joint The posterior hypo pharyngeal wall continuates the posterior oropharynx wall; It is composed of mucosa and the constrictor muscle. Smooth bulge of posterior pharyngeal wall with intact mucosa due to retropharyngeal malignancy .

11. WALLS OF THE PHARYNX Consists of the following from within outwards: Mucous coat lined by stratified squamous epithelium. Inner fibrous coat (pharyngo-basilar fascia). Muscular coat. Outer fibrous coat (buccopharyngeal fascia). Muscles of the pharynx Sup.constrictor mid.constrictor inf.constrictor  Outer circular layer : 3 constrictors of the pharynx.  Inner longitudinal layer: 3 longitudinal muscles. Constrictors of the pharynx. 1- Sup.constrictor 2- mid.constrictor N.B. All muscles of pharynx take nerve supply from pharyngeal plexus except stylopharyngeus from glossopharyngeal nerve 3- inf.constrictor longitudinal muscles. Stylo-pharyngeus Salpingo – pharyngeus 3-Palato-pharyngeus:

12. Hypopharyngeal diverticulum Zenker’s diverticulum Failure of cricopharyngeal sphincter relaxation when pharyngeal muscles are contracting Pharyngeal mucosa herniates through killian’s dehiscence- week area between two parts of inferior constrictor muscle Gateway of tears- perforation can occur at this site during oesophagostomy .

13. zenker’s diverticulum

14. Lymphatic drainage Pyriform sinus- richly supplied by lymphatics ( so nodal mets are common in ca pyriform fossa) - L ymphatics exit through the thyrohyoid membrane and drain into the upper jugular chain Post cricoid region- drain into para pharyngeal lymph nodes -Also drain into supraclavicular and para tracheal nodes Posterior pharyngeal wall- lateral or para pharyngeal nodes and then to deep cervical nodes

15. ..lymphatic drainage

16. Larynx and laryngopharynx

17. Video laryngoscopy