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Tympanic Cavity
The tympanic cavity is a small cavity surrounding the bones of the middle ear. Within it sit the ossicles, three small bones that transmit vibrations used in the detection of sound. Structure On its lateral surface, it abuts the external auditory meatus (ear canal) from which it is separated by the tympanic membrane (eardrum). Walls The tympanic cavity is bounded by: * Facing the inner ear, the medial wall (or ''labyrinthic wall'', ''labyrinthine wall'') is vertical, and has the oval window and round window, the promontory, and the prominence of the facial canal. * Facing the outer ear, the lateral wall (or ''membranous wall''), is formed mainly by the tympanic membrane, partly by the ring of bone into which this membrane is inserted. This ring of bone is incomplete at its upper part, forming a notch (notch of Rivinus), close to which are three small apertures: the "iter chordæ posterius", the petrotympanic fissure, and the "iter chordæ anterius". The iter chordæ pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Branchial Pouch
In the embryonic development of vertebrates, pharyngeal pouches form on the endodermal side between the pharyngeal arches. The pharyngeal grooves (or clefts) form the lateral ectodermal surface of the neck region to separate the arches. Specific pouches First pouch The endoderm lines the future auditory tube (pharyngotympanic Eustachian tube), middle ear, mastoid antrum, and inner layer of the tympanic membrane. Derivatives of this pouch are supplied by Mandibular nerve. Second pouch * Contributes the middle ear, palatine tonsils, supplied by the facial nerve. Third pouch * The third pouch possesses dorsal and ventral wings. Derivatives of the dorsal wings include the inferior parathyroid glands, while the ventral wings fuse to form the cytoreticular cells of the thymus. The main nerve supply to the derivatives of this pouch is cranial nerve IX, glossopharyngeal nerve. Fourth pouch Derivatives include: * superior parathyroid glands and ultimobranchial body which forms the paraf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manubrium
The sternum (: sternums or sterna) or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, human lung, lungs, and major blood vessels from injury. Shaped roughly like a necktie, it is one of the largest and longest flat bones of the body. Its three regions are the manubrium, the body, and the xiphoid process. The word ''sternum'' originates from Ancient Greek στέρνον (''stérnon'') 'chest'. Structure The sternum is a narrow, flat bone, forming the middle portion of the front of the chest. The top of the sternum supports the clavicles (collarbones) and its edges join with the costal cartilages of the first two pairs of ribs. The inner surface of the sternum is also the attachment of the sternopericardial ligaments. Its top is also connected to the sternocleidomastoid muscle. The sternum consists of three main parts, listed from the top: * Manubr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tympanic Antrum
The mastoid antrum (tympanic antrum, antrum mastoideum, Valsalva's antrum) is an air space in the petrous portion of the temporal bone, communicating posteriorly with the mastoid cells and anteriorly with the epitympanic recess of the middle ear via the aditus to mastoid antrum (entrance to the mastoid antrum). These air spaces function as sound receptors, provide voice resonance, act as acoustic insulation and dissipation, provide protection from physical damage and reduce the mass of the cranium. The roof is formed by the tegmen antri which is a continuation of the tegmen tympani and separates it from the middle cranial fossa. The lateral wall of the antrum is formed by a plate of bone which is an average of 1.5 cm in adults. The mastoid air cell system is a major contributor to middle ear inflammatory diseases. Additional images File:Gray1209.png, Left temporal bone showing surface markings for the tympanic antrum (red), transverse sinus (blue), and facial nerve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squama Temporalis
The squamous part of temporal bone, or temporal squama, forms the front and upper part of the temporal bone, and is scale-like, thin, and translucent. Surfaces Its outer surface is smooth and convex; it affords attachment to the temporal muscle, and forms part of the temporal fossa; on its hinder part is a vertical groove for the middle temporal artery. A curved line, the ''temporal line'', or ''supramastoid crest'', runs backward and upward across its posterior part; it serves for the attachment of the temporal fascia, and limits the origin of the temporalis muscle. The boundary between the squamous part and the mastoid portion of the bone, as indicated by traces of the original suture, lies about 1 cm. below this line. Projecting from the lower part of the squamous part is a long, arched process, the '' zygomatic process''. This process is at first directed lateralward, its two surfaces looking upward and downward; it then appears as if twisted inward upon itself, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Bone
The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bones fuse. Each temple is covered by a temporal muscle. The temporal bones house the structures of the ears. The lower seven cranial nerves and the major vessels to and from the brain traverse the temporal bone. Structure The temporal bone consists of four parts—the squamous, mastoid, petrous and tympanic parts. The squamous part is the largest and most superiorly positioned relative to the rest of the bone. The zygomatic process is a long, arched process projecting from the lower region of the squamous part and it articulates with the zygomatic bone. Posteroinferior to the squamous is the mastoid part. Fused with the squamous and mastoid parts and between the sphenoid and occipital bones lies the petrous part, which is shaped li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petrous Part Of The Temporal Bone
The petrous part of the temporal bone is pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones. Directed medially, forward, and a little upward, it presents a base, an apex, three surfaces, and three angles, and houses in its interior the components of the inner ear. The petrous portion is among the most basal elements of the skull and forms part of the endocranium. Petrous comes from the Latin word ''petrosus'', meaning "stone-like, hard". It is one of the densest bones in the body. In other mammals, it is a separate bone, the petrosal bone. The petrous bone is important for studies of ancient DNA from skeletal remains, as it tends to contain extremely well-preserved DNA. Base The base is fused with the internal surfaces of the squamous, tympanic, and mastoid parts. Apex The apex, which is rough and uneven, is received into the angular interval between the posterior border of the great wing of the sphenoid bone and the basi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, '' Termin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cranial Cavity
The cranial cavity, also known as intracranial space, is the space within the skull that accommodates the brain. The skull is also known as the cranium. The cranial cavity is formed by eight cranial bones known as the neurocranium that in humans includes the skull cap and forms the protective case around the brain. The remainder of the skull is the facial skeleton. The meninges are three protective membranes that surround the brain to minimize damage to the brain in the case of head trauma. Meningitis is the inflammation of meninges caused by bacterial or viral infections. Structure The capacity of an adult human cranial cavity is 1,200–1,700 cm3. The spaces between meninges and the brain are filled with a clear cerebrospinal fluid, increasing the protection of the brain. Facial bones of the skull are not included in the cranial cavity. There are only eight cranial bones: The occipital, sphenoid, frontal, ethmoid, two parietal, and two temporal bones are fused to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Maxillary Artery
The maxillary artery (eg, internal maxillary artery) supplies deep structures of the face. It branches from the external carotid artery just deep to the neck of the mandible. Structure The maxillary artery, the larger of the two terminal branches of the external carotid artery, arises behind the neck of the mandible, and is at first imbedded in the substance of the parotid gland; it passes forward between the ramus of the mandible and the sphenomandibular ligament, and then runs, either superficial or deep to the lateral pterygoid muscle, to the pterygopalatine fossa. It supplies the deep structures of the face, and may be divided into mandibular, pterygoid, and pterygopalatine portions. First portion The ''first'' or ''mandibular '' or ''bony'' portion passes horizontally forward, between the neck of the mandible and the sphenomandibular ligament, where it lies parallel to and a little below the auriculotemporal nerve; it crosses the inferior alveolar nerve, and runs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tympanic Branch
The tympanic nerve ( Jacobson's nerve) is a branch of the glossopharyngeal nerve passing through the petrous part of the temporal bone to reach the middle ear. It provides sensory innervation for the middle ear, the Eustachian tube, the parotid gland, and mastoid cells. It also carries parasympathetic fibers destined for the parotid gland. Structure The tympanic nerve contains sensory axons to the middle ear (including the internal surface of the tympanic membrane) whose cell bodies are lodged in the superior ganglion of the glossopharyngeal nerve. It also contains parasympathetic axons which continue as the lesser petrosal nerve to the otic ganglion, which itself gives off postganglionic parasympathetic neurons. Origin The tympanic nerve arises from the inferior ganglion of the glossopharyngeal nerve (CN IX) in the jugular fossa. Course It passes through the petrous part of the temporal bone within the tympanic canaliculus that is situated within the bony r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior Ligament Of The Malleus
The ligaments of malleus are three ligaments that attach the malleus in the middle ear. They are the anterior, lateral and superior ligaments. The anterior ligament of the malleus also known as Casserio's ligament is a fibrous band that extends from the neck of the malleus just above its anterior process to the anterior wall of the tympanic cavity close to the petrotympanic fissure. Some of the fibers also pass through the fissure to the spine of sphenoid bone. The lateral ligament of the malleus is a triangular fibrous band that crosses from the posterior aspect of the tympanic notch to the head or neck of the malleus. The superior ligament of the malleus is a delicate fibrous strand that crosses from the roof of the tympanic cavity The tympanic cavity is a small cavity surrounding the bones of the middle ear. Within it sit the ossicles, three small bones that transmit vibrations used in the detection of sound. Structure On its lateral surface, it abuts the extern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
