Neuroanatomy
Muscles And Pharyngeal Arches
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Get accessImportant embryological structures across vertebrate species
- There are six in humans (but no fifth arch!)
The first three arches contribute to structures above the larynx while the last two contribute to the larynx and trachea
- First pharyngeal arch: muscles of mastication supplied by CNV3
- Temporalis
- Masseter
- Medial and lateral pterygoid
- Second pharyngeal arch: muscle of facial expression supplied by CNVII
- Frontalis
- Orbicularis oris
- Orbicularis oculi
- Platysma
- The exceptions are
Buccinator: derived from the second pharyngeal arch and is supplied by the facial nerve but plays a role in mastication
Digastric: derived from both arches. Anterior belly supplied by trigeminal and posterior belly by facial.
| First pharyngeal arch (mandibular) | Second pharyngeal arch (hyoid) | |
| Skeletal | Malleus | Stapes |
| Incus | Temporal styloid process | |
| Maxilla | Stylohyoid ligament | |
| Mandible | Lesser cornu of hyoid | |
| Spine of sphenoid | ||
| Sphenomandibular ligament | ||
| Palatine | ||
| Squamous temporal | ||
| Muscles | Masseter | Frontalis |
| Medial and lateral pterygoids | Orbicularis oris and oculi | |
| Temporalis | Platysma | |
| Mylohyoid | Occipitofrontalis | |
| Anterior belly of digastric | Stylohyoid | |
| Tensor veli palatini and tensor tympani | Posterior belly of digastric | |
| Stapedius | ||
| Auricular | ||
| Buccinator | ||
| Nerve supply | Mandibular and maxillary branches of trigeminal | Facial |
| Arteries | Maxillary | Stapedial artery |
| External carotid | Hyoid artery | |
| Other | Thyroid (derived from both.C-cells are derived from the fourth laryngeal pouches) |
Third arch
- Hyoid bone
- Thymus
- Common carotid
- Internal carotid
- Glossopharyngeal nerve: innervates the third arch
Fourth arch
- Cricothyroid muscle
- Thyroid cartilage
- Epiglottic cartilage
- Vagus nerve: innervates the fourth and sixth arches
- Subclavian
- Aortic arch
Tongue
- Developed from first, third and fourth pharyngeal arches
- Intrinsic muscles derived from occipital myotomes
- Sulcus terminalis divides the tongue into anterior two-third and posterior one-third
- Has vallate papillae anterior to the sulcus
- Supplied by:
- Hypoglossal nerve (almost all muscles)
- Vagus nerve (supplies palatoglossus)
Parasympathetic and sensory/taste fibres to the posterior third derived from the otic ganglion (from glossopharyngeal)
- Taste supply to the anterior two-thirds from the chorda tympani
- Sensory supply to the anterior two-thirds from the mandibular branch of the trigeminal