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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] |
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] |
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] |
Mastoid Cells
The mastoid cells (also called air cells of Lenoir or mastoid cells of Lenoir) are air-filled cavities within the mastoid process of the temporal bone of the cranium. The mastoid cells are a form of skeletal pneumaticity. Infection in these cells is called mastoiditis. The term ''cells'' here refers to enclosed spaces, not cells as living, biological units. Anatomy The mastoid air cells vary greatly in number, shape, and size; they may be extensive or minimal or even absent. The cells are typically interconnected and their walls lined by mucosa that is continuous with that of the mastoid antrum and tympanic cavity. Extent They may excavate the mastoid process to its tip, and be separated from the posterior cranial fossa and sigmoid sinus by a mere slip of bone or not at all. They may extend into the squamous part of temporal bone, petrous part of the temporal bone zygomatic process of temporal bone, and - rarely - the jugular process of occipital bone; they may thus c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epitympanic Recess
The epitympanic recess is the portion of the tympanic cavity (of the middle ear) situated superior to the tympanic membrane. The recess lodges the head of malleus, and the body of incus. The mastoid antrum is situated posterior to the recess and opens into the recess at the posterior wall of the recess via the aditus to mastoid antrum. The ampulla of the lateral semicircular canal creates a prominence upon the medial wall of the recess. Clinical significance This recess is a possible route of spread of infection to the mastoid air cells located in the mastoid process of the temporal bone of the skull. Inflammation which has spread to the mastoid air cells is very difficult to drain and causes considerable pain. Before the advent of antibiotics, it could only be drained by drilling a hole in the mastoid bone, a process known as mastoidectomy A mastoidectomy is a procedure performed to remove the mastoid air cells near the middle ear. The procedure is part of the treatment for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Ear
The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea (of the inner ear). The mammalian middle ear contains three ossicles (malleus, incus, and stapes), which transfer the vibrations of the eardrum into waves in the fluid and membranes of the inner ear. The hollow space of the middle ear is also known as the tympanic cavity and is surrounded by the tympanic part of the temporal bone. The auditory tube (also known as the Eustachian tube or the pharyngotympanic tube) joins the tympanic cavity with the nasal cavity ( nasopharynx), allowing pressure to equalize between the middle ear and throat. The primary function of the middle ear is to efficiently transfer acoustic energy from compression waves in air to fluid–membrane waves within the cochlea. Structure Ossicles The middle ear contains three tiny bones known as the ossicles: '' malleus'', ''incus'', and '' stapes''. The ossicles were given their Latin names f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aditus To Mastoid Antrum
The aditus to mastoid antrum (otomastoid foramen) is a large, irregular opening upon the posterior wall of the tympanic cavity by which the mastoid antrum (situated posteriorly) communicates with the epitympanic recess of the tympanic cavity (situated anteriorly). The walls of the antrum are lined by mucosa which is continuous with that lining the mastoid cells and tympanic cavity. The medial wall of the aditus features a ridge created by the underlying facial canal, and a bulge created by the underlying ampulla of the lateral semicircular canal. The short limb of incus is lodged in a shallow fossa upon the posterior wall of the tympanic cavity just inferior to the aditus. The pyramidal eminence The pyramidal eminence is a hollow conical projection upon the posterior wall of the tympanic cavity of the middle ear. The stapedius muscle arises in the hollow of the eminence and its tendon exits through its apex. The pyramidal eminence is si ... is situated inferior to the aditus. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tegmen Tympani
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 posterius (ape ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Cranial Fossa
The middle cranial fossa is formed by the sphenoid bones, and the temporal bones. It lodges the temporal lobes, and the pituitary gland. It is deeper than the anterior cranial fossa, is narrow medially and widens laterally to the sides of the skull. It is separated from the posterior cranial fossa by the clivus and the petrous crest. It is bounded in front by the posterior margins of the lesser wings of the sphenoid bone, the anterior clinoid processes, and the ridge forming the anterior margin of the chiasmatic groove; behind, by the superior angles of the petrous portions of the temporal bones and the dorsum sellae; laterally by the temporal squamae, sphenoidal angles of the parietals, and greater wings of the sphenoid. It is traversed by the squamosal, sphenoparietal, sphenosquamosal, and sphenopetrosal sutures. Anatomy Features Middle part The middle part of the fossa presents, in front, the chiasmatic groove and tuberculum sellae; the chiasmatic groove ends o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mastoid Air Cell
The mastoid cells (also called air cells of Lenoir or mastoid cells of Lenoir) are air-filled cavities within the mastoid process of the temporal bone of the cranium. The mastoid cells are a form of skeletal pneumaticity. Infection in these cells is called mastoiditis. The term ''cells'' here refers to enclosed spaces, not cells as living, biological units. Anatomy The mastoid air cells vary greatly in number, shape, and size; they may be extensive or minimal or even absent. The cells are typically interconnected and their walls lined by mucosa that is continuous with that of the mastoid antrum and tympanic cavity. Extent They may excavate the mastoid process to its tip, and be separated from the posterior cranial fossa and sigmoid sinus by a mere slip of bone or not at all. They may extend into the squamous part of temporal bone, petrous part of the temporal bone zygomatic process of temporal bone, and - rarely - the jugular process of occipital bone; they may thus come t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facial Nerve
The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue. The nerve typically travels from the pons through the facial canal in the temporal bone and exits the skull at the stylomastoid foramen. It arises from the brainstem from an area posterior to the cranial nerve VI (abducens nerve) and anterior to cranial nerve VIII (vestibulocochlear nerve). The facial nerve also supplies preganglionic parasympathetic fibers to several head and neck ganglia. The facial and intermediate nerves can be collectively referred to as the nervus intermediofacialis. The path of the facial nerve can be divided into six segments: # intracranial (cisternal) segment (from brainstem pons to internal auditory canal) # meatal (canalicular) segment (with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bones Of The Head And Neck
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility. Bones come in a variety of shapes and sizes and have complex internal and external structures. They are lightweight yet strong and hard and serve multiple functions. Bone tissue (osseous tissue), which is also called bone in the uncountable sense of that word, is hard tissue, a type of specialised connective tissue. It has a honeycomb-like matrix internally, which helps to give the bone rigidity. Bone tissue is made up of different types of bone cells. Osteoblasts and osteocytes are involved in the formation and mineralisation of bone; osteoclasts are involved in the resorption of bone tissue. Modified (flattened) osteoblasts become the lining cells that form a protective layer on the bone surface. The minerali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otorhinolaryngology
Otorhinolaryngology ( , abbreviated ORL and also known as otolaryngology, otolaryngology–head and neck surgery (ORL–H&N or OHNS), or ear, nose, and throat (ENT)) is a surgical subspecialty within medicine that deals with the surgical and medical management of conditions of the head and neck. Doctors who specialize in this area are called otorhinolaryngologists, otolaryngologists, head and neck surgeons, or ENT surgeons or physicians. Patients seek treatment from an otorhinolaryngologist for diseases of the ear, Human nose, nose, throat, base of skull, base of the skull, head, and neck. These commonly include functional diseases that affect the senses and activities of eating, drinking, speaking, breathing, swallowing, and hearing. In addition, ENT surgery encompasses the surgical management of cancers and benign tumors and reconstruction of the head and neck as well as plastic surgery of the face, scalp, and neck. Etymology The term is a combination of Neo-Latin classic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
