II. Anatomy: Vestibular Structures
- Semicircular canals
- Monitors head rotation and spatial positioning
- Three semicircular canals with endolymph fluid filled ampullae
- Canals lie at right angles to one another
- One for each direction (e.g. X,Y and Z axis)
- Fluid filled canals contain crista ampullaris
- Crista ampullaris is a sensory organ detecting sudden head rotation, acceleration and deceleration
- Hair cells within the crista ampullaris detect fluid motion
- Hair cells generate an impulse that is transmitted centrally via Vestibular Nerve (CN 8)
- Otolithic organs
- Utricle
- Contains otoliths (small stones) that settle with position changes
- Detects horizontal linear movement and Head Tilting
- Sacule
- Smaller, more globular organ without utricle communication
- Detects vertical linear movement (e.g. gravity)
- Both Utricle and Sacule contain a Macula (sack)
- Macula contains thick, gelatinous material and otoliths
- Otoliths (statoconia) are Calcium Carbonate crystals that move with gravity and head movement
- Hair cells within the Macula detect static head position as well as head movement
- Utricle
- Perilymphatic fluid
- Surrounds vestibular apparatus (semicircular canals and otolithic organs)
- Communicates with the perilymph of the Cochlea (from oval window to round window)
- Communicates with perilymphatic duct (and the subarachnoid space)
III. Anatomy: Neurologic Structures
- Cranial Nerve 8 (two tracts)
- Vestibular nucleii
- Located in the pons and Medulla and receive input from the respective tracts of Cranial Nerve 8
- Transmit signals to the rest of the Cerebrum, Cerebellum and spinal cord
- Combines with other inputs (e.g. occiptal lobe, dorsal columns)
- Medial Longitudinal Fasciculus and Oculomotor Nucleus
IV. Anatomy: Vascular Structures
- See Vertebro-Basilar CVA
- Posterior Circulation via the vertebrobasilar system
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Vertebral arteries
- Two arteries ascend in parallel from the subclavian artery via each transverse foramen
- Join to form the Basilar Artery
- Branches
-
Basilar Artery
- Arises from the joining of the two Vertebral arteries
- Courses anteriorly to join with the Anterior Circulation via the Circle of Willis
- Branches
V. Anatomy: Images
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Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
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Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
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Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
-
Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
-
Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
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Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
VI. References
- Goldberg (2014) Clinical Physiology, Medmaster, Miami, p. 118-9
- Ondrejka (2014) Crit Dec Emerg Med 28(10): 11-7
Images: Related links to external sites (from Bing)
Related Studies
| Definition (NCI) | The central cavity of the osseous labyrinth. |
| Definition (PSY) | Major organ of equilibrium which acts as a sensory receptor that detects the position and changes in the position of the head in space. |
| Definition (CSP) | structures of the inner ear concerned with reception and transduction of stimuli of equilibrium; they include the semicircular canals, the utricle, and the saccule. |
| Definition (MSH) | An oval, bony chamber of the inner ear, part of the bony labyrinth. It is continuous with bony COCHLEA anteriorly, and SEMICIRCULAR CANALS posteriorly. The vestibule contains two communicating sacs (utricle and saccule) of the balancing apparatus. The oval window on its lateral wall is occupied by the base of the STAPES of the MIDDLE EAR. |
| Concepts | Body Part, Organ, or Organ Component (T023) |
| MSH | D014722 |
| SnomedCT | 181188003 |
| English | Apparatus, Vestibular, Vestibular Apparatus, vestibular apparatus, Labyrinth Vestibules, Labyrinth, Vestibular, Labyrinths, Vestibular, Vestibules, Labyrinth, Vestibular Labyrinths, Vestibule, Labyrinth, Labyrinth Vestibule, Vestibular Labyrinth, vestibular labyrinth, Vestibular labyrinth, Labyrinthus vestibularis, Vestibulum Auris, Vestibules, Ear, Ear Vestibule, Vestibule, Ear, Vestibule of Ear, Ear Vestibules, Vestibule, Vestibule of the Ear, Vestibular apparatus, Vestibular apparatus (body structure) |
| French | Appareil vestibulaire, Système vestibulaire labyrinthique, Vestibule labyrinthique, Labyrinthe vestibulaire, Vestibule de l'oreille interne, Vestibulum auris |
| Swedish | Vestibularapparat |
| Czech | vestibulární aparát |
| Portuguese | Vestíbulo do Labirinto, Sistema Vestibular |
| Spanish | Vestíbulo del Laberinto, aparato vestibular (estructura corporal), aparato vestibular, Aparato Vestibular |
| Finnish | Sisäkorvan eteinen |
| Italian | Vestibolo, Apparato vestibolare, Labirinto vestibolare |
| Russian | ВЕСТИБУЛЯРНЫЙ АППАРАТ ЛАБИРИНТА, VESTIBULIARNYI APPARAT, VESTIBULIARNYI APPARAT LABIRINTA, ВЕСТИБУЛЯРНЫЙ АППАРАТ |
| Japanese | 前庭, 前庭(迷路), 前庭迷路, 前庭器 |
| Croatian | VESTIBULUM |
| Polish | Narząd równowagi, Aparat przedsionkowy, Narząd przedsionkowy błędnika, Narząd przedsionkowy |
| Norwegian | Vestibulum, Forgården, Vestibulum auris, Apparatus vestibularis |
| German | Apparatus vestibularis, Gleichgewichtsorgan, Statisches Organ, Vestibulum |
Ontology: Vestibular functions (C2370946)
| Definition (ICF) | Sensory functions of the inner ear related to position, balance and movement. |
| Definition (ICF-CY) | Sensory functions of the inner ear related to position, balance and movement. |
| Concepts | Physiologic Function (T039) |
| English | Vestibular functions, unspecified, Vestibular functions |
