Pharynx, palate and larynx

Why this matters

Everything a dentist does happens at the mouth of a tube that is shared with the airway, and that tube will always defend breathing before it defends anything else. Two of the emergencies most likely to arrive in a dental career come straight out of this anatomy. The first comes from above: an object leaves your instrument and enters a pharynx you cannot see into. In the only study denominated in patient VISITS — 39 events across 2,672,250 visits at one Korean dental hospital, 14.6 per million — the highest departmental rate was the predoctoral student clinic at 66.7 per million [R40].

The big picture

One muscular tube runs from the skull base to the cricoid, doing two incompatible jobs with equipment borrowed from three sensory territories and half a dozen cranial nerves. It is a food chute that must — roughly once a minute while a healthy younger adult is awake, and much less often in older people and in sleep (pooled means of 0.98 spontaneous swallows per minute under 60 and 0.21 per minute over 60, from a review whose authors decline to name a single normal value because the underlying studies disagree so…

The 15 cards in this lesson

1. 01Three pharynges in one tube: the boundaries that must be unambiguous
2. 02The muscular wall: three constrictors, three lifters, four gaps
3. 03Three midline landmarks that dissection does not support
4. 04The tonsillar bed, Waldeyer's ring and where sharp things stop
5. 05One nerve map for pharynx, palate and ear
6. 06Five muscles of the soft palate, and the one that is not vagal
7. 07The five palate muscles side by side
8. 08Velopharyngeal closure: what seals against what, and when it fails
9. 09Swallowing: the phases you were taught, and what people actually do
10. 10The epiglottis is not the valve
11. 11Clinical alert — in the lesson
12. 12Inside the larynx: cartilages, membranes, inlet and the intrinsic muscles
13. 13The cricothyroid membrane: small, vascular, and not the dentist's to cut
14. 14Clinical alert — in the lesson
15. 15Clinical alert — in the lesson

You have got it when

You can sketch the pharynx as three floors with named boundaries and say which of them you can actually inspect with a mirror. You can name the constrictors, the three longitudinal muscles and the four gaps, and say out loud that the gaps are a teaching scheme rather than measured anatomy.