Pharyngeal arch derivatives

The pharyngeal arches are key embryonic structures that contribute to the formation of the head and neck. Each arch is associated with specific cartilage, muscles, nerves, and clinical correlations. Below is a detailed breakdown of each pharyngeal arch to aid with understanding and memorization.

Quick Mnemonic for Memorization

Mnemonic: “Chew, Smile, Stylish Swallow, Simply Swallow, Speak”

Chew – 1st Arch
Smile – 2nd Arch
Stylish Swallow – 3rd Arch
Simply Swallow – 4th Arch
Speak – 6th Arch

Pharyngeal Arch Derivatives

Arch	Cartilage	Muscles	Nerve	Notes / Clinical Correlation
1st Pharyngeal Arch	– Maxillary Process: Maxilla, Zygomatic bone – Mandibular Process: Meckel cartilage, Mandible, Malleus, Incus, Sphenomandibular ligament	Muscles of Mastication (Temporalis, Masseter, Medial and Lateral Pterygoids), Mylohyoid, Tensor Tympani, Anterior Belly of Digastric, Tensor Veli Palatini	CN V3 (Mandibular Branch of Trigeminal Nerve) – Mnemonic: Chew	– Pierre Robin Sequence: Micrognathia, glossoptosis, cleft palate, airway obstruction – Treacher Collins Syndrome: Autosomal dominant neural crest dysfunction; leads to craniofacial abnormalities like zygomatic bone and mandibular hypoplasia, hearing loss, airway compromise
2nd Pharyngeal Arch	Reichert Cartilage: Stapes, Styloid Process, Lesser Horn of Hyoid, Stylohyoid Ligament	Muscles of Facial Expression, Stapedius, Stylohyoid, Platysma, Posterior Belly of Digastric	CN VII (Facial Nerve) – Mnemonic: Smile
3rd Pharyngeal Arch	Greater Horn of Hyoid	Stylopharyngeus	CN IX (Glossopharyngeal Nerve) – Mnemonic: Swallow Stylishly
4th and 6th Pharyngeal Arches	Arytenoids, Cricoid, Corniculate, Cuneiform, Thyroid Cartilages (Mnemonic: ACCCT)	– 4th Arch: Pharyngeal Constrictors, Cricothyroid, Levator Veli Palatini – 6th Arch: All Intrinsic Muscles of the Larynx except Cricothyroid	– 4th Arch: CN X (Superior Laryngeal Branch) – Mnemonic: Simply Swallow – 6th Arch: CN X (Recurrent/Inferior Laryngeal Branch) – Mnemonic: Speak	Arches 3 and 4 contribute to the posterior 1/3 of the tongue. Arch 5 does not contribute to major structures.

Key Points to Remember

Sensory and Motor Nerves: While sensory and motor nerves are associated with each pharyngeal arch, they are not derived from the arches themselves. They originate from neural crest cells (sensory) and neuroectoderm (motor).
Clinical Correlations:
- Pierre Robin Sequence (1st Arch): Involves micrognathia, cleft palate, and airway obstruction.
- Treacher Collins Syndrome (1st Arch): Autosomal dominant disorder leading to craniofacial deformities.
Muscle and Cartilage Derivatives: Each arch has unique muscle and cartilage derivatives that serve as important landmarks in clinical anatomy.
Mnemonics for Nerves and Actions:
- 1st Arch (Chew): CN V3 (Trigeminal, Mandibular Branch) – for mastication muscles.
- 2nd Arch (Smile): CN VII (Facial Nerve) – for facial expression.
- 3rd Arch (Stylish Swallow): CN IX (Glossopharyngeal) – Stylopharyngeus muscle.
- 4th Arch (Simply Swallow): CN X (Superior Laryngeal) – for pharyngeal constrictors.
- 6th Arch (Speak): CN X (Recurrent Laryngeal) – for laryngeal muscles.

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USMLE Step 1 Review Series

Curriculum

Pharyngeal arch derivatives

Quick Mnemonic for Memorization

Pharyngeal Arch Derivatives

Key Points to Remember

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