Download Muscles of the tongue

Tongue
Tongue
A human tongue
Latin
lingua
Gray's
subject #242 1125
Vein
lingual
Nerve
lingual nerve
Dorlands/Elsevier
l_11/{{{DorlandsSuf}}}
The tongue is the large bundle of skeletal muscles on the floor of the mouth that
manipulates food for chewing and swallowing (deglutition). It is the primary organ of
taste. Much of the surface of the tongue is covered in taste buds. The tongue, with its
wide variety of possible movements, assists in forming the sounds of speech. It is
sensitive and kept moist by saliva, and is richly supplied with nerves and blood vessels to
help it move.[1]
Etymology
The word tongue can be used as a metonymy for language, as in the phrase mother
tongue. In fact, Albanian (gjuha), Catalan (llengua), Portuguese (língua), French
(langue), Maltese, (ilsien), Arabic (‫ ل سان‬lisān), Romanian (limba), Russian (язык
yazyk), Bulgarian (ezik), Persian (zabaan), Greek (γλώσσα), Spanish (lengua), Polish,
Slovak, Czech, Slovene, Bosnian, Serbian, Croatian (jezik), Armenian (լեզու), Finnish
(kieli), Estonian (keel), Irish, Italian (lingua), Latin (lingua), Urdu (zabaan), Aramaic
(‫ܠ ܫ ܢܐ‬/‫ אנשל‬lišānā), Hungarian (nyelv), Hebrew (‫ לֹוׁשָל‬lashon), Turkish (dil), and Danish
(tunge), have the same word for "tongue" and "language".
Figures of speech
A common temporary failure in word retrieval from memory is referred to as the tip-ofthe-tongue phenomenon. The expression tongue in cheek refers to a statement that is not
to be taken entirely seriously; something said or done with subtle ironic humour. "Tongue
twisted" is a term used to described being unable to pronounce a word or phrase
correctly. A tongue twister is a phrase made specifically to be very difficult to pronounce.
"Tongue-tied" means being unable to say what you want to due to confusion or
restriction.
Anatomy
Structure
Drawing of an anterior view of the tongue and oral cavity, with cheeks removed for
clarity.
Lateral view of the tongue, with extrinsic muscles highlighted.
The tongue is made mainly of skeletal muscle. The tongue extends much further than is
commonly perceived, past the posterior border of the mouth and into the oropharynx.
The dorsum (upper surface) of the tongue can be divided into two parts:


an oral part (anterior two-thirds of the tongue) that lies mostly in the mouth
a pharyngeal part (posterior third of the tongue), which faces backward to the
oropharynx
The two parts are separated by a V-shaped groove, which marks the sulcus terminalis (or
terminal sulcus).
Since the tongue contains no bony supports for the muscles, the tongue is an example of a
muscular hydrostat, similar in concept to an octopus arm. Instead of bony attachments,
the extrinsic muscles of the tongue anchor the tongue firmly to surrounding bones and
prevent the mythical possibility of 'swallowing' the tongue.
Other divisions of the tongue, are based on the area of the tongue:
normal name anatomical name adjective
tongue tip
apex
apical
tongue blade lamina
laminal
tongue dorsum dorsum (back)
tongue root
radix
tongue body corpus
dorsal
radical
corporeal
Muscles of the tongue
The intrinsic muscles lie entirely within the tongue, while the extrinsic muscles attach the
tongue to other structures.
3/4 view of a 6.5 cm human tongue.
The extrinsic muscles reposition the tongue, while the intrinsic muscles alter the shape of
the tongue for talking and swallowing.
Extrinsic muscles
Extrinsic muscles of the tongue by definition originate from structures outside the tongue
and insert into the tongue. The four paired extrinsic muscles protrude, retract, depress,
and elevate the tongue:
Muscle
Genioglossus
muscle
Hyoglossus
muscle
Styloglossus
muscle
From
Palatoglossus
muscle
palatine
aponeurosis
mandible
hyoid bone
styloid
process
Intrinsic muscles
Nerve
hypoglossal
nerve
hypoglossal
nerve
hypoglossal
nerve
pharyngeal
branch of vagus
nerve
Function
protrudes the tongue as well as
depressing its center.
depresses the tongue.
elevates and retracts the tongue.
depresses the soft palate, moves the
palatoglossal fold towards the midline,
and elevates the back of the tongue.
Coronal section of tongue, showing intrinsic muscles
Four paired intrinsic muscles of the tongue originate and insert within the tongue, running
along its length. These muscles alter the shape of the tongue by: lengthening and
shortening it, curling and uncurling its apex and edges, and flattening and rounding its
surface.[2]




The superior longitudinal muscle runs along the superior surface of the tongue
under the mucous membrane, and elevates, assists in retraction of, or deviates the
tip of the tongue. It originates near the epiglottis, the hyoid bone, from the median
fibrous septum.
The inferior longitudinal muscle lines the sides of the tongue, and is joined to the
styloglossus muscle.
The verticalis muscle is located in the middle of the tongue, and joins the superior
and inferior longitudinal muscles.
The transversus muscle divides the tongue at the middle, and is attached to the
mucous membranes that run along the sides.
The tongue is often cited as the "strongest muscle in the body," a claim that does not
correspond to any conventional definition of strength.
Papillae and taste buds
See also: Taste bud
The oral part of the tongue is covered with small bumpy projections called papillae.
There are four types of papillae:




filiform (thread-shape)
fungiform (mushroom-shape)
circumvallate (ringed-circle)
foliate (leaf-shape)
All papillae except the filiform have taste buds on their surface.
Close-up view of a tongue with visible fungiform papillae (large bumps) scattered among
filiform papillae (small bumps).
The circumvallate are the largest of the papillae. There are 8 to 14 circumvallate papillae
arranged in a V-shape in front of the sulcus terminalis, creating a border between the oral
and pharyngeal parts of the tongue.
There are no lingual papillae on the underside of the tongue. It is covered with a smooth
mucous membrane, with a fold (the lingual frenulum) in the center. If the lingual
frenulum is too taut or too far forward, it can impede motion of the tongue, a condition
called Tongue-tie (Ankyloglossia).
The upper side of the posterior tongue (pharyngeal part) has no visible taste buds, but it is
bumpy because of the lymphatic nodules lying underneath. These follicles are known as
the lingual tonsil.
The human tongue can detect five basic taste components: sweet, sour, salty, bitter and
savory. The sense of taste is referred to as a gustatory sense. Contrary to the popular
myth and generations of schoolbooks, there are no distinct regions for tasting different
tastes. This myth arose because Edwin G. Boring replotted data from one of Wundt's
students (Hanig) without labeling the axes, leading some to misinterpret the graph as all
or nothing response.[3] The common conception of taste has a significant contribution
from olfaction.
Innervation of the tongue
Motor innervation of the tongue is complex and involves several cranial nerves. All the
muscles of the tongue are innervated by the hypoglossal nerve (cranial nerve XII) with
one exception: the palatoglossal muscle is innervated by the pharyngeal branch of vagus
nerve (cranial nerve X).
Sensory innervation of the tongue is different for taste sensation and general sensation.
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
For the anterior two-thirds of the tongue, general sensations and taste sensations
are carried via different nerves.
o Somatic sensations travel from the tongue via the lingual nerve, a major
branch of the mandibular nerve (itself a branch of the trigeminal nerve).
This nerve also carries general sensation from areas of the oral mucosa
and gingiva of the lower teeth.
o Taste sensation is carried to the facial nerve via the chorda tympani. The
chorda tympani also carries parasympathetic fibers from the facial nerve to
the submandibular ganglion.
The posterior one-third of the tounge has a more simple innervation, as both taste
and general sensations are carried by the glossopharyngeal nerve.
Vasculature of the tongue
The underside of a human tongue
The tongue receives its blood supply primarily from the lingual artery, a branch of the
external carotid artery. The floor of the mouth also receives its blood supply from the
lingual artery.
There is also secondary blood supply to the tongue from the tonsillar branch of the facial
artery and the ascending pharyngeal artery.