Expansion
Arch one, chew like a Trigeminal son
Mnemonic
“1, 5; 2, 7; 3, 9; 4 and 6, 10” pairs each arch with its cranial nerve:
- Arch 1 - trigeminal (V3). Muscles of mastication, mylohyoid, anterior belly of digastric, tensor tympani, tensor veli palatini
- Arch 2 - facial (VII). Muscles of facial expression, stapedius, stylohyoid, posterior belly of digastric
- Arch 3 - glossopharyngeal (IX). Stylopharyngeus only
- Arch 4 and 6 - vagus (X). Pharyngeal constrictors, soft palate, larynx
“The odd exceptions all follow the arch, not the region.” That is why palatoglossus is vagal in a tongue supplied by the hypoglossal, why tensor veli palatini is trigeminal in a palate supplied by the vagus, and why the digastric has two different nerves for its two bellies.
Arch 5 does not exist in humans, which is why the sequence jumps from 4 to 6.
Expansion
- Nerve - CN V, trigeminal
- Muscles - mastication, mylohyoid, anterior digastric