Ans. a (First branchial arch) (Ref Embryology by IB Singh 7th/113)Meckel's cartilage =first arch; and Reichert cartilage =second arch.First arch derivatives1) Meckel's cartilageMandible, Malleus, Incus, Sphenomandibular ligament, Anterior ligament of malleus.2) MusclesFour muscles of mastication (temporalis, masseter, lateral and medial pterygoids).Tensor tympani, Tensor veli palatini, Mylohyoid, Anterior belly of digastric.3) Nerve of first archMandibular nerve (post-trematic) and chorda tympani (pretrematic).4) Artery of first archMaxillary artery.Second arch derivatives1) Reichert's cartilageStapes, Styloid, Smaller (lesser) horn of hyoid & upper half of hyoid, Stylohyoid ligament2) MusclesMuscles of facial expression, Stapedius, Stylohyoid, Posterior belly of digastric.3) Nerve of second archFacial nerve4) Artery of second archStapedial arteryThird arch derivatives1) CartilageGreater horn of hyoid, lower half of hyoid.2) MuscleStylopharyngeus.3) Nerve of third archGlossopharyngeal nerve.Fourth arch derivatives1) CartilagesThyroid, cricoid, arytenoids, comiculate and cuneiform.2) MusclesMost pharyngeal constrictors, Cricothyroid, Levator veli palatini.3) Nerve of fourth archSuperior laryngeal branch of vagus nerve.Fifth arch makes no major development contributions. Sixth arch derivatives1) MusclesAll intrinsic muscles of larynx except cricothyroid.2) Nerve of sixth archRecurrent laryngeal branch of vagus nerve. Remember:Each pharyngeal arch is supplied by its own cranial nerve.# The trigeminal nerve supplying the first pharyngeal arch has three branches: the ophthalmic, maxillary, and mandibu- lar. The nerve of the second arch is the facial nerve; that of the third, the glossopharyngeal nerve. The musculature of the fourth arch is supplied by the superior laryngeal branch of the vagus nerve, and that of the sixth arch, by the recurrent branch of the vagus nerve.