Intrinsic muscles of the tongue are derived from
occipital somites Most of the tongue muscles are derived from myoblasts that migrate from the occipital somites.Embryological Origin of the TongueThe tongue's embryonic orgin is derived from first 4 pharyngeal arches contributing different components.Anterior 2/3" or body of tongue: is derived from 3 lingual buds- the median tongue bud (tuberculum impar) and 2 lateral lingual swellings developing at each side of the median tongue bud. All arising from the la pharyngeal arch. The lateral tongue buds rapidly increase in size, merge with each other, and overgrow the median tongue bud. The merged distal tongue buds form the anterior 2/3rd of the tongue. The median tongue bud forms no recognizable pa of the adult tongue. Since the mucosa covering the ant. 2/3rd of the tongue originates from the first pharyngeal arch; sensory innervation to this area is by the mandibular branch of the trigeminal nerve. (Taste sensation to the anterior 2/3rd of the tongue is provided by the chorda tympani branch of the facial nerve).Post 1/3" or root of the tongue: is formed from two median elevations;- The copula arising from the 2"d pair of branchial arches, just caudal to the foramen ceacum.- The hypopharyngeal or hypobranchial eminence developing caudal to the copula from the 3rd and dh pair of arches.As the tongue develops the copula is gradually overgrown by the hypopharyngeal eminence and disappears. As a result, the post pa of the tongue develops from the hypopharyngeal eminence( the 3rd and 4th pharyngeal arches) . Thus the sensory nerve supply to this pa of tongue is from the glossopharyngeal nerve.(taste sensation is also carried by the glossopharyngeal nerve).Pharyngeal arch mesenchyme forms the connective tissue and vasculature of the tongue. Some of the tongue muscles probably develop in situ from mesenchyme, but most develop from myoblasts that migrate from the occipital myotomes. The hypoglossal nerve accompanies the myoblasts during their migration and innervates the tongue muscles.The Nerve Supply of the Tonguea. Motor nerve- All the intrinsic & extrinsic muscles, except the palatoglossus, are supplied by the hypoglossal nerve. The palatoglossus is supplied by the cranial pa of the accessory nerve through the pharyngeal plexus.b. Sensory nerves:- Anterior 2/3 of tongue - The lingual nerve is the nerve of general sensation and the chorda tympani is the nerve of taste for the anterior two-thirds of the tongue.- Posterior 1/3 of tongue - The glossopharyngeal nerve is the nerve for both general sensation and taste for the posterior 1/3 of the tongue.- The posterior-most pa of the tongue is supplied by the vagus nerve through the internal laryngeal branch. You can also see animated embryological development of tongue at following sites: class="Style2"> 1 2/animations/contents.htm
2 "d branchial cleft
Pharyngeal arch mesenchyme
Occipital somites
Cervical somites