Dental neuroanatomy and pain pathways

Why this matters

A patient sits down and says one sentence: "this tooth is killing me." Everything you do next depends on how much of that sentence you believe, and this lesson is the anatomy that tells you how much you should. Start with localisation, because every other decision rests on it. In 79 patients presenting to an endodontic emergency clinic, the painful tooth was correctly identified 73.3% of the time overall — but that splits into 89% when periradicular symptoms were present and 30% when the pain had no periradicular component (p<0.0001) [R65].

The big picture

One nerve carries almost everything you will ever do to a patient, and it is built in a way that makes a tooth hard to find. The first-order neurons sit mostly in one ganglion inside a dural pocket at the skull base, arranged as three overlapping agglomerations rather than three neat territories [R11].

The 15 cards in this lesson

1. 01Neuron one: the trigeminal ganglion, and what is not in it
2. 02The sensory column from midbrain to neck
3. 03Subnuclei, and why caudalis is not the gate for toothache
4. 04Up to thalamus and cortex — maps softer than the diagrams
5. 05What actually innervates a tooth
6. 06The hydrodynamic theory, audited
7. 07Inflammation rewires the pulp — and what tests can still tell you
8. 08Why the pulp localises badly and the ligament localises well
9. 09Convergence: how a tooth is felt in the ear
10. 10Clinical alert — in the lesson
11. 11Descending control, the gate, and central sensitisation
12. 12Pain that outlasts the tooth
13. 13Four ganglia, four hitch-hikes, one taste twist
14. 14Why a block works, why it fails, and the real numbers
15. 15Clinical alert — in the lesson

You have got it when

You can trace one signal end to end and say, at every relay, what is measured and what is assumed. At the tooth you can state the fibre populations with their species labels kept apart: 72% of axons unmyelinated and 28% myelinated at the apical level of normal HUMAN pulps, from one cross-section per tooth in a series whose specimen count is not recoverable [R36]; and separately 228 A fibres and 122 C fibres among…