The 3rd pharyngeal arch forms which specific structures in the adult?

• A Lesser cornua and upper body of hyoid; tensor tympani and tensor veli palatini (CN V)
• B Thyroid cartilage; cricothyroid muscle (CN X external laryngeal branch)
• C Greater cornua and lower body of hyoid bone; stylopharyngeus muscle (innervated by CN IX) ✓
• D Malleus, incus, and muscles of mastication (CN V)

Explanation

The 3rd pharyngeal arch is innervated by the glossopharyngeal nerve (CN IX). Its cartilaginous component (Reichert's cartilage equivalent at this arch) forms the greater cornua and the lower body of the hyoid bone. Its muscular component forms the stylopharyngeus, the only muscle supplied by CN IX. The 1st arch (Meckel's cartilage) forms the malleus, incus, anterior ligament of the malleus, sphenomandibular ligament, and muscles of mastication (CN V). The 2nd arch (Reichert's cartilage) forms the lesser cornua and upper body of hyoid, styloid process, stapes, and muscles of facial expression (CN VII). The 4th/6th arches form laryngeal cartilages and muscles (CN X).

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.