Information about Tympanic Part

Bone: Tympanic part of the temporal bone
Left temporal bone. Outer surface. (Tympanic part at bottom center.)
Coronal section of right temporal bone.
Latinpars tympanica ossis temporalis
subject #34 145
Dorlands/Elsevier p_07/12618137
The tympanic part of the temporal bone is a curved plate of bone lying below the squama and in front of the mastoid process.

Surfaces

Its postero-superior surface is concave, and forms the anterior wall, the floor, and part of the posterior wall of the bony external acoustic meatus.

Medially, it presents a narrow furrow, the tympanic sulcus, for the attachment of the tympanic membrane.

Its antero-inferior surface is quadrilateral and slightly concave; it constitutes the posterior boundary of the mandibular fossa, and is in contact with the retromandibular part of the parotid gland.

Borders

Its lateral border is free and rough, and gives attachment to the cartilaginous part of the external acoustic meatus. Internally, the tympanic part is fused with the petrous portion, and appears in the retreating angle between it and the squama, where it lies below and lateral to the orifice of the auditory tube. Posteriorly, it blends with the squama and mastoid part, and forms the anterior boundary of the tympanomastoid fissure.

Its upper border fuses laterally with the back of the postglenoid process, while medially it bounds the petrotympanic fissure. The medial part of the lower border is thin and sharp; its lateral part splits to enclose the root of the styloid process, and is therefore named the vaginal process. The central portion of the tympanic part is thin, and in a considerable percentage of skulls is perforated by a hole, the foramen of Huschke.

The external acoustic meatus is nearly 2 cm. long and is directed inward and slightly forward: at the same time it forms a slight curve, so that the floor of the canal is convex upward. In sagittal section it presents an oval or elliptical shape with the long axis directed downward and slightly backward. Its anterior wall and floor and the lower part of its posterior wall are formed by the tympanic part; the roof and upper part of the posterior wall by the squama. Its inner end is closed, in the recent state, by the tympanic membrane; the upper limit of its outer orifice is formed by the posterior root of the zygomatic process, immediately below which there is sometimes seen a small spine, the suprameatal spine, situated at the upper and posterior part of the orifice.

Additional images


Left infratemporal fossa.

External and middle ear, opened from the front. Right side.


External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

The temporal bones are situated at the sides and base of the skull.

The temporal bone supports that part of the face known as the temple.

Parts

Each consists of five parts:
  • Squama temporalis
  • Mastoid portion
  • Petrous portion
  • Tympanic part

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Latin}}} 
Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
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The temporal bones are situated at the sides and base of the skull.

The temporal bone supports that part of the face known as the temple.

Parts

Each consists of five parts:
  • Squama temporalis
  • Mastoid portion
  • Petrous portion
  • Tympanic part

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Squama (or Squamous ) refers to a structure shaped like the scale of a fish. More specifically, it can refer to:
  • Squama occipitalis
  • Squama temporalis, the squamous portion of the temporal bone
  • Squamous cell
Squamous epithelium refers to epithelium, e.g.
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The mastoid process is a conical prominence projecting from the undersurface of the mastoid portion of the temporal bone. It is located just behind the external acoustic meatus, and lateral to the styloid process.
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The tympanic membrane, colloquially known as the eardrum, is a thin membrane that separates the external ear from the middle ear. Its function is to transmit sound vibrations from the air, conducted through the external acoustic meatus to the ossicles inside the
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In the temporal bone, the mandibular fossa (glenoid 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
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For the toad wart, see parotoid gland.

The parotid gland is the largest of the salivary glands. It is found wrapped around the mandibular ramus, and it secretes saliva through Stensen's duct into the oral cavity, to facilitate mastication and swallowing.
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The Eustachian tube (or auditory tube) is a tube that links the pharynx to the middle ear. In adults the Eustachian tube is approximately 35 mm long. It is named after the 16th century anatomist Eustachius.
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petrotympanic fissure (Glaserian 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.
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In anatomy, a styloid process (from Greek stylos, "pillar"), usually serving as points of attachment for muscles, refers to the slender, pointed process (protrusion) of :
  • temporal bone of the skull - Styloid process (temporal)

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The ear canal (external auditory meatus, external acoustic meatus), is a tube running from the outer ear to the middle ear. The ear canal extends from the pinna to the eardrum and is about 26 mm in length and 7 mm in diameter.
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The State University of New York Health Science Center at Brooklyn, better known as SUNY Downstate Medical Center, is an academic medical center and is the only one of its kind in the Borough of Brooklyn in New York City.
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Public domain comprises the body of knowledge and innovation (especially creative works such as writing, art, music, and inventions) in relation to which no person or other legal entity can establish or maintain proprietary interests within a particular legal jurisdiction.
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Henry Gray's Anatomy of the Human Body (or Gray's Anatomy as it has commonly been shortened) is an English-language human anatomy textbook widely regarded as a classic work on the subject.
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Bones are rigid organs that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red and white blood cells and store minerals.
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Head and neck anatomy focuses on the structures of the head and neck of the human body, including the brain, bones, muscles, blood vessels, nerves, glands, nose, mouth, teeth, tongue, and throat.
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skull is normally made up of 22 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, synarthrodial (immovable) joints formed by bony ossification, with Sharpey's fibres permitting some flexibility.
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The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoid in shape and curved on itself. It is pierced by a large oval aperture, the foramen magnum, through which the cranial cavity communicates with the vertebral canal.
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In anatomy, in the occipital bone, the foramen magnum (Latin: 'great hole') is one of the several oval or circular apertures in the base of the skull (the foramina), through which the medulla oblongata (an extension of the spinal cord) enters and exits the skull vault.
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The squama of the occipital bone, situated above and behind the foramen magnum, is curved from above downward and from side to side.

External surface

The external surface
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The inion is the most prominent projection of the occipital bone at the lower rear part of the skull. The ligamentum nuchae and trapezius muscle attach to it.

The term external occipital protuberance (protuberantia occipitalis externa
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The nuchal lines are four curved lines on the external surface of the occipital bone:
  • The upper, often faintly marked, is named the highest nuchal line, and to it the galea aponeurotica is attached.

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planum occipitale (or occipital plane), and is covered by the Occipitalis muscle.

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated.
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planum nuchale (or nuchal plane), is rough and irregular for the attachment of several muscles.

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated.
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cruciform eminence ( or cruciate eminence).
  • The upper two fossae are triangular and lodge the occipital lobes of the cerebrum.
  • The lower two are quadrilateral and accommodate the hemispheres of the cerebellum.

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internal occipital protuberance.

See also

  • external occipital protuberance

External links

  • Roche Lexicon - illustrated navigator, at Elsevier 34257.000-2
  • Diagram at uni-mainz.

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sagittal sulcus, the edges of which unite below to form a ridge, the frontal crest; the sulcus lodges the superior sagittal sinus, while its margins and the crest afford attachment to the falx cerebri.

It also is part of the parietal, and occipital bones.
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internal occipital crest; it bifurcates near the foramen magnum and gives attachment to the falx cerebelli; in the attached margin of this falx is the occipital sinus, which is sometimes duplicated.
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