1 / 27

Anatomy and Embryology of the Pharynx

Anatomy and Embryology of the Pharynx. Jared Bradley Turner, MD January 7, 2005. Embryology. Components of branchial/pharyngeal apparatus: Pharyngeal arches Pharyngeal pouches Pharyngeal clefts/grooves. Pharyngeal (branchial) arches. Derived from neural crest cells

shelly-golden
Download Presentation

Anatomy and Embryology of the Pharynx

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Anatomy and Embryology of the Pharynx Jared Bradley Turner, MD January 7, 2005

  2. Embryology Components of branchial/pharyngeal apparatus: • Pharyngeal arches • Pharyngeal pouches • Pharyngeal clefts/grooves

  3. Pharyngeal (branchial) arches • Derived from neural crest cells • Resemble fish gills (branchia) • Begin to develop early in the 4th week • By end of 4th week, four pairs of arches are visible on the surface (not 5th and 6th ) and a buccopharyngeal membrane ruptures forming communication between primitive oral cavity and foregut

  4. Pharyngeal arches (cont.) • Contribute to the formation of the neck as well as the face. • Visible structures at 42 weeks: 1st arch: mandibular prominence, maxillary prominences, and the frontonasal prominence

  5. Pharyngeal arches (cont.) • Core of mesenchymal tissue covered by surface ectoderm (outside) and by endodermal epithelium (inside) • Ectoderm -> skeletal • Mesoderm -> muscles with accompanying nerve • Arterial component (aortic arches) • Therefore, each arch carries nerve, muscle, bone and blood supply

  6. First pharyngeal arch • Maxillary process (dorsal) • Premaxilla, maxilla, zygomatic bone, portion of temporal bone • Mandibular process (ventral) • Contains Meckel’s cartilage which disappears except for dorsal end (incus & malleus) and mandible

  7. First pharyngeal arch • Muscles of mastication, digastric (ant belly), mylohyoid, tensor tympani and tensor palatini • Therefore, the accompanying motor nerve is the mandibular branch of trigeminal (V2) and sensory are V1, V2, and V3 • 1st aortic arch practically disappears but forms the maxillary artery

  8. Second pharyngeal arch • Reichert’s cartilage – stapes, styloid process, stylohyoid ligament, lesser horn and upper part of the hyoid • Muscles include: stapedius, stylohyoid, digastric (post belly), auricular, and those of facial expression • Facial nerve (CN VII) • 2nd aortic arch – stapedial & hyoid arteries

  9. Third pharyngeal arch • Cartilaginous contributions include greater horn and lower part of hyoid • Sole muscle: stylopharyngeus • CN IX (Glossopharyngeal nerve) • 3rd aortic arch (quite large): common carotid, 1st portion of internal carotid (remainder dorsal aorta), and external carotid

  10. Fourth & sixth pharyngeal arch • Cartilaginous contributions to larynx derived from fusion: thyroid, cricoid, arytenoid, corniculate, and cuneiform • Muscles of 4th: cricothyroid, levator palatini, and pharyngeal constrictors are innervated by SLN (CN X) • Muscles of 6th: intrinsics of larynx are innervated by RLN (CN X) • 4th aortic arch: L->arch of aorta & R->subclavian • 6th aortic arch: L & R pulmonary with ductus arteriosus on left

  11. Pharyngeal pouches (5) • 1st:tubotympanic recess-> middle ear & eustacian tube -> TM • 2nd palatine tonsil/fossa • 3rd: inferior parathyroid (dorsal), thymus (ventral) • 4th: superior parathyroid • 5th: ultimobranchial body -> calcitonin producing C cells (parafollicular)

  12. Pharyngeal clefts/grooves (4) • 1st: external auditory meatus • 2nd-4th : epicardial ridge and cervical sinus (disappears)

  13. Anatomy of the pharynx

  14. Anatomy (cont.) • Extends from base of skull to inferior border of cricoid cartilage anteriorly and inferior border of C6 posteriorly • Widest portion (5cm) at hyoid • Narrowest portion (1.5cm) at caudal end • Divided into 3 parts: nasopharynx, oropharynx, and laryngo(hypo)pharynx

  15. Nasopharynx • Respiratory function • Anterior: choana (posterior nasal aperture) • Posterior: pharyngobasilar membrane and superior constrictor muscle • Superior: basilar portion of occipital bone • Inferior: soft palate

  16. Oropharynx • Digestive function • Anterior: anterior tonsillar pillar • Posterior: superior constrictor • Superior: soft palate • Inferior: base of tongue, superior epiglottis • Laterally: palatoglossal and palatopharyngeal arches

  17. Hypopharynx • Lies posterior to the larynx • Superior: superior border of epiglottis and pharyngoepiglottic folds • Inferior: inferior border of the cricoid • Posterior/lateral: middle & inferior constrictors, bodies of C4-C6 • Anterior: laryngeal inlet

  18. Pharyngeal muscles

  19. Pharyngeal muscles • External circular and internal longitudinal (opposite in remainder of GI tract) • External: 3 constrictors (CN XI via X and ELN/RLN for middle and inferior) function to constrict wall of pharynx during swallow • Internal: palatopharyngeus and salpingopharyngeus (CN XI via X) and stylopharyngeus (CN IX) act to elevate pharynx and larynx during speech/swallow

  20. Pharyngeal muscles • Tensor veli palatini (V3) tenses soft palate & opens ET during yawn/swallow • Levator veli palatini (CN XI via X) elevates palate during swallow/yawn • Palatoglossus (CN XI via X) approximates tongue and soft palate

  21. Pharyngeal muscles

  22. Oral cavity I, II, III Oro/hypopharynx deep II, III, IV Nasopharynx II, V, III Pharyngeal lymphatic drainage

  23. Pharyngeal vessels

  24. Afferent innervation of pharynx

More Related