Image Based Question – 65243

Which of the following pharyngeal arch give rise to the structure marked as “A”in embryological life in the picture below?

A. 1st pharyngeal arch.

B. 2nd pharyngeal arch.

C. 3rd pharyngeal arch.

D. 4th pharyngeal arch.

Show Answer

Correct Answer » D Explanation

Ans:D. 4th pharyngeal arch.

The structure marked as A in the picture above represents the epiglottis.

DERIVATIVES OF PHARYNGEAL ARCH

Pharyngeal arch	Muscular contributions	Skeletal contributions	Nerve	Artery
1st (also called “mandibular arch”)	Muscles of mastication, anterior belly of the digastric, mylohyoid, tensor tympani, tensor veli palatini	Premaxilla, maxilla, mandible (only as a model for mandible not actual formation of mandible), zygomatic bone, part of the temporal bone,the incus, and the malleus of the middle ear, also Meckel’s cartilage and the sphenomandibular ligament.	Trigeminal nerve(part of V2 and V3)	Maxillary artery, external carotid artery
2nd (also called the “hyoid arch”)	Muscles of facial expression, buccinator, platysma, stapedius, stylohyoid, posterior belly of the digastric, auricular	Stapes, temporal styloid process, hyoid bone (lesser horns and upper part of body), stylohyoid ligament, Reichert’s cartilage	Facial nerve (VII)	Stapedial artery, hyoid artery
3rd	Stylopharyngeus	Hyoid bone (greater horns and lower part of body), thymus	Glossopharyngeal nerve (IX)	common carotid, internal carotid
4th	Cricothyroid muscle, all intrinsic muscles of soft palate (including levator veli palatini) except tensor veli palatini	Thyroid cartilage, epiglottic cartilage	Vagus nerve (X), superior laryngeal nerve	Right 4th aortic arch: subclavian arteryLeft 4th aortic arch: aortic arch
6th	All intrinsic muscles of larynx except the cricothyroid muscle	Cricoid cartilage, arytenoid cartilages, corniculate cartilage, cuneiform cartilages	Vagus nerve (X), recurrent laryngeal nerve	Right 6th aortic arch: pulmonary arteryLeft 6th aortic arch: pulmonary artery and ductus arteriosus