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Chorda Tympani
Chorda tympani is a branch of the facial nerve that carries gustatory (taste) sensory innervation from the front of the tongue and parasympathetic ( secretomotor) innervation to the submandibular and sublingual salivary glands. Chorda tympani has a complex course from the brainstem, through the temporal bone and middle ear, into the infratemporal fossa, and ending in the oral cavity. Structure Chorda tympani fibers emerge from the pons of the brainstem as part of the intermediate nerve of the facial nerve. The facial nerve exits the cranial cavity through the internal acoustic meatus and enters the facial canal. In the facial canal, the chorda tympani branches off the facial nerve and enters the lateral wall of the tympanic cavity inside the middle ear where it runs across the tympanic membrane (from posterior to anterior) and medial to the neck of the malleus. The chorda then exits the skull by descending through the petrotympanic fissure into the infrate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submandibular Gland
The paired submandibular glands (historically known as submaxillary glands) are major salivary glands located beneath the floor of the mouth. In adult humans, they each weigh about 15 grams and contribute some 60–67% of unstimulated saliva secretion; on stimulation their contribution decreases in proportion as parotid gland secretion rises to 50%. The average length of the normal adult human submandibular salivary gland is approximately 27 mm, while the average width is approximately 14.3 mm. Structure Each submandibular gland is divided into a superficial lobe and a deep lobe, the two being separated by the mylohyoid muscle: * The superficial lobe comprises most of the gland, with the mylohyoid muscle runs under it * The deep lobe is the smaller part Submandibular duct Secretions are delivered into the submandibular duct on the deep portion after which they hook around the posterior edge of the mylohyoid muscle and proceed on the superior surface laterally. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Auditory Meatus
The internal auditory meatus (also meatus acusticus internus, internal acoustic meatus, internal auditory canal, or internal acoustic canal) is a canal within the petrous part of the temporal bone of the skull between the posterior cranial fossa and the inner ear. Structure The opening to the meatus is called the porus acusticus internus or internal acoustic opening. It is located inside the posterior cranial fossa of the skull, near the center of the posterior surface of the petrous part of the temporal bone. The size varies considerably. Its outer margins are smooth and rounded. The canal which comprises the internal auditory meatus is short (about 1 cm) and runs laterally into the bone. The lateral (outer) aspect of the canal is known as the fundus. The fundus is subdivided by two thin crests of bone to form three separate canals, through which course the facial and vestibulocochlear nerve branches. The falciform crest first divides the meatus into superior and inferio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taste Buds
Taste buds are clusters of taste receptor cells, which are also known as gustatory cells. The taste receptors are located around the small structures known as papillae found on the upper surface of the tongue, soft palate, upper esophagus, the cheek, and epiglottis. These structures are involved in detecting the five elements of taste perception: saltiness, sourness, bitterness, sweetness and savoriness (umami). A popular assumption assigns these different tastes to different regions of the tongue; in actuality, these tastes can be detected by any area of the tongue. Via small openings in the tongue epithelium, called taste pores, parts of the food dissolved in saliva come into contact with the taste receptors. These are located on top of the taste receptor cells that constitute the taste buds. The taste receptor cells send information detected by clusters of various receptors and ion channels to the gustatory areas of the brain via the seventh, ninth and tenth cranial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Special Senses
In medicine and anatomy, the special senses are the senses that have specialized organs devoted to them: * vision (the eye) * hearing and balance (the ear, which includes the auditory system and vestibular system) * smell (the nose) * taste (the tongue) The distinction between special and general senses is used to classify nerve fibers running to and from the central nervous system – information from special senses is carried in special somatic afferents and special visceral afferents. In contrast, the other sense, touch, is a somatic sense which does not have a specialized organ but comes from all over the body, most noticeably the skin but also the internal organs (viscera). Touch includes mechanoreception (pressure, vibration and proprioception), pain (nociception) and heat (thermoception), and such information is carried in general somatic afferents and general visceral afferents. Vision Visual perception is the ability to interpret the surrounding environment usi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submandibular Ganglion
The submandibular ganglion (or submaxillary ganglion in older texts) is part of the human autonomic nervous system. It is one of four parasympathetic ganglia of the head and neck. (The others are the otic ganglion, pterygopalatine ganglion, and ciliary ganglion). Location and relations The submandibular ganglion is small and fusiform in shape. It is situated above the deep portion of the submandibular gland, on the hyoglossus muscle, near the posterior border of the mylohyoid muscle. The ganglion 'hangs' by two nerve filaments from the lower border of the lingual nerve (itself a branch of the mandibular nerve, CN V3). It is suspended from the lingual nerve by two filaments, one anterior and one posterior. Through the posterior of these it receives a branch from the chorda tympani nerve which runs in the sheath of the lingual nerve. Fibers Like other parasympathetic ganglia of the head and neck, the submandibular ganglion is the site of synapse for parasympathetic fibers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tongue
The tongue is a Muscle, muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for chewing and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper surface (dorsum) is covered by taste buds housed in numerous lingual papillae. It is sensitive and kept moist by saliva and is richly supplied with nerves and blood vessels. The tongue also serves as a natural means of cleaning the teeth. A major function of the tongue is to enable speech in humans and animal communication, vocalization in other animals. The human tongue is divided into two parts, an oral cavity, oral part at the front and a pharynx, pharyngeal part at the back. The left and right sides are also separated along most of its length by a vertical section of connective tissue, fibrous tissue (the lingual septum) that results in a groove, the median sulcus, on the tongue's surface. There are two groups of glossal muscles. The f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sublingual Space
The sublingual space is a fascial space of the head and neck (sometimes also termed fascial spaces or tissue spaces). It is a potential space located below the mouth and above the mylohyoid muscle, and is part of the suprahyoid group of fascial spaces. Location and structure Anatomic boundaries The sublingual space is V-shaped, with the apex pointing to the anterior. Its boundaries are: * the mucosa of the floor of mouth and the tongue superiorly * the mylohyoid muscle inferiorly * the medial surface of the mandible anterolaterally * the muscles along the base of the tongue ( geniohyoid and genioglossus muscles) posteriorly * medially, the intrinsic muscles of the tongue and genioglossus separate the two halves of the sublingual space. Communications The sublingual space communicates posteriorly around the posterior free border of the mylohyoid muscle with the submandibular space. Infections of the sublingual space may also erode through the mylohyoid, or spread via the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mandibular Nerve
In neuroanatomy, the mandibular nerve (V) is the largest of the three divisions of the trigeminal nerve, the fifth Cranial nerves, cranial nerve (CN V). Unlike the other divisions of the trigeminal nerve (ophthalmic nerve, maxillary nerve) which contain only Afferent nerve fiber, afferent fibers, the mandibular nerve contains both afferent and Efferent nerve fiber, efferent fibers. These nerve fibers innervate structures of the lower jaw and face, such as the tongue, lower lip, and chin. The mandibular nerve also innervates the muscles of mastication. Structure Course The large sensory root of mandibular nerve emerges from the lateral part of the trigeminal ganglion and exits the cranial cavity through the Foramen ovale (skull), foramen ovale. The motor root (Latin: ''radix motoria'' s. ''portio minor''), the small motor root of the trigeminal nerve, passes under the trigeminal ganglion and through the Foramen ovale (skull), foramen ovale to unite with the sensory root just out ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lingual Nerve
The lingual nerve carries sensory innervation from the anterior two-thirds of the tongue. It contains fibres from both the mandibular division of the trigeminal nerve (CN V) and from the facial nerve (CN VII). The fibres from the trigeminal nerve are for touch, pain and temperature (general sensation), and the ones from the facial nerve are for taste (special sensation). Structure Origin The lingual nerve arises from the posterior trunk of mandibular nerve (CN V) within the infratemporal fossa. Course The lingual nerve first courses deep to the lateral pterygoid muscle and superior to the tensor veli palatini muscle; while passing between these two muscle, it is joined by the chorda tympani, and often by a communicating branch from the inferior alveolar nerve. The nerve then comes to pass inferoanteriorly upon the medial pterygoid muscle towards the medial aspect of the ramus of mandible, eventually meeting the mandible at the junction of the ramus and body of mandibl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Styloid Process
The temporal styloid process is a slender bony process of the temporal bone extending downward and forward from the undersurface of the temporal bone just below the ear. The styloid process gives attachments to several muscles, and ligaments. Structure The styloid process is a slender and pointed bony process of the temporal bone projecting anteroinferiorly from the inferior surface of the temporal bone just below the ear. Its length normally ranges from just under 3 cm to just over 4 cm. It is usually nearly straight, but may be curved in some individuals. Its ''proximal'' (''tympanohyal'') ''part'' is ensheathed by the tympanic part of the temporal bone ''(vaginal process), whereas'' its ''distal (stylohyal)'' ''part'' gives attachment to several structures. Attachments The styloid process gives attachments to several muscles, and ligaments. It serves as an anchor point for several muscles associated with the tongue and larynx. * stylohyoid ligament * stylomandi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petrotympanic Fissure
The petrotympanic fissure (also known as the squamotympanic fissure or the glaserian fissure) is a fissure in the temporal bone that runs from the temporomandibular joint to the tympanic cavity. The mandibular fossa is bounded, in front, by the articular tubercle; behind, by the tympanic part of the bone, which separates it from the external acoustic meatus; it is divided into two parts by a narrow slit, the petrotympanic fissure. It opens just above and in front of the ring of bone into which the tympanic membrane is inserted; in this situation it is a mere slit about 2 mm. in length. It lodges the anterior process and anterior ligament of the malleus, and gives passage to the anterior tympanic branch of the internal maxillary artery. Eponym It is also known as the "Glaserian fissure", after Johann Glaser. Contents The contents of the fissure include communications of cranial nerve VII to the infratemporal fossa. A branch of cranial nerve VII, the chorda tympani, ru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malleus
The ''malleus'', or hammer, is a hammer-shaped small bone or ossicle of the middle ear. It connects with the incus, and is attached to the inner surface of the eardrum. The word is Latin for 'hammer' or 'mallet'. It transmits the sound vibrations from the eardrum to the ''incus'' (anvil). Structure The malleus is a bone situated in the middle ear. It is the first of the three ossicles, and attached to the eardrum (tympanic membrane). The head of the malleus is the large protruding section, which attaches to the incus. The head connects to the neck of malleus. The bone continues as the handle (or manubrium) of malleus, which connects to the tympanic membrane. Between the neck and handle of the malleus, lateral and anterior processes emerge from the bone. The bone is oriented so that the head is superior and the handle is inferior. Development Embryologically, the malleus is derived from the first pharyngeal arch along with the ''incus''. In humans it grows from Meckel's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
