Temporal Bone and Ear Anatomy

View Right Ear
Total of 50 Slides

View Left Ear
Total of 10 Slides

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Temporal bone and ear anatomy can be divided into four parts: 
** View Diagram of Ear ** 
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View Abstract of Article Discussing the Methodology of the Ear-Anatomy Website.
World Wide Web-based temporal bone anatomic sections.
Otolaryngology Head Neck Surgery  2002 May;126(5):573-7
 
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ear infections and videos:
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New FLASH Presentation
Of Temporal Bone
Anatomical Slides  !!!!

  • External Ear:  Contains the external auditory canal and auricle (outer ear).
  • Middle Ear and Eardrum (tympanic membrane) and three ear bones or ossicles: malleus, incus and stapes.
  • Inner Ear:  Contains the cochlea, a snail-shaped bone which transforms sounds into nerve impulses, the vestibule, contains the utricle and saccule which sense motion in relation to gravity and three semicircular canals which sense rotational motion.
  • Mastoid Air Cells:  These are air cells which are behind the ear canal and middle ear.

The web pages contained in this section present 60 temporal bone anatomy slides.  Histology sections from both the right and left temporal bone are available.    There are 10 histological sections per page.  The first page starts in the mid-temporal bone at the level of the stapes.   Each histology section can be viewed in three sizes: thumbnail, 750 pixels wide and 3000 pixels wide.  The 3000 pixels format is approximately 400 Kbytes in size and may take 3 to 4 minutes to view using a 28 baud modem.  To view the 700 pixel format, click on the thumbnail, to view the 3000 pixel version click on the the "View Highest Resolution" option next to the thumbnail.   View Right Temporal Bone Slides    View Left Temporal Bone Slides
    

The three middle ear bones are called Ossicles.  They are the Malleus (attaches to the Ear Drum), Incus (transmits sound between the Malleus and Stapes), and stapes which transmits sound to the Vestibule of the inner ear.

ossicles.jpg (31470 bytes)

Slide of Stapes Footplate, Vestibule (Utricle and Saccule), Cochlea, dehiscent Facial (VII) Nerve,  Internal Auditory Canal, Malleus, Incus and Ear Drum.  The cochlea is composed of the Modiolus (Yellow) which transmits the Auditory Nerve (VIII Cranial Nerve) to the Organ of Corti.  The Spiral Lamina and Ligament is shown in blue.  (Macula of Saccule is shown in dark green)

CLICK ON ANATOMY SLIDE TO ENLARGE

Temporal Bone and Ear Anatomy
The Cochlea is the organ of hearing.  It is snail shaped and has nearly 2.75 turns.  A close up view is provided in this slide.  The Organ of Corti is shown in green, the Stria Vascularis which is thought to produce Endolymph is shown in brown, and the Vestibular (Reissner) Membrane is shown in black.  CD: Cochlear Duct which contains Endolymph. Cochlea and the Organ of Corti
The sense organs of the semicircular canals are called Crista Ampullaris.  They sense angular or rotational motion.  The Cupula extends from the tip of the Crista forming a diaphragm which is thought to be reflected with movement of the Endolymph.  Shown here is a Crista and its Ampullary groove, transmitting the Ampullary branch of the Vestibular Division of the Vestibulocochlear, VIII, Nerve.    

For more about Positional Vertigo Go To:
  
Crista_Lateral_Canal.jpg (51168 bytes)
http://www.entusa.com/dizziness.htm
The Macula Acustica Utriculi and Macula  Sacculi are the sense organs for gravity.  These sense organs have Otoconia which are little "rocks" that move in relationship to gravity.  These rocks can be dislodged by trauma and can enter the Posterior Semicircular Canal giving rise to positional vertigo.  Also note the Stapedial Footplate and dehiscent Facial, VII, Nerve. Saccule_Utricle.jpg (70981 bytes)

   

The Right Temporal Bone has better histopathology with Basilar Membrane, Vestibular (Reissners) Membrane, Spiral Ligament, Stria Vascularis, Utricule and Saccule seen in most specimens.  View Right Temporal Bone Slides

The Left Temporal Bone has better orientation with the gross anatomy better demonstrated. 
View Left Temporal Bone Slides   The Basilar Membrane, Utricle and Saccule are seen in most specimens.

In the performance of a Stapedectomy, the stapes footplate is fixed and must be removed.  The relationship between the footplate and inner ear structures is very important.  The distance between the stapedial footplate and the saccule varies from 1.0 to 1.4mm and from the footplate to the utricle varies from 0.7 to 1.4 mm.  In 25 specimens the shortest distance between the footplate and the saccule was 0.8 mm and between the footplate and the utricle was 0.38 mm.*  In patients with Meniere's disease the endolymph is under high pressure and the membranes of the utricle and saccule are distended.  Sometimes they reach the footplate.  Stapedectomy in these patients is very hazardous and there is a high risk of postoperative deafness.

* Anson B.J. and Donaldson, J.A.  Surgical Anatomy of The Temporal Bone and Ear.    W.B. Saunders Company  p 282, 1973
    

       
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