Labyrinth


Label 1-6.

  • 1 – Lateral semicircular canal
  • 2 – Superior semicircular canal
  • 3- Posterior semicircular canal
  • 4 – Utricle 
  • 5 – Saccule
  • 6 – cochlear

Which is responsible for linear motion?

  • Utricle

Which is responsible for vertical motion?

Saccule

Which semicircular canal is most commonly affected in BPPV?

Posterior semicircular canal

Name two manoeuvres to treat BPPV.

  • Torsional 

  • Geotropic

  • Latency

  • Fatigable

  • Lasts 20-60seconds 

Which semicircular canal is most commonly affected in BPPV?

  • Epley’s for posterior BPPV
  • Semont for posterior BPPV
  • Barbeque roll for horizontal BPPV
  • Gufoni / Appiani for horizontal BPPV

Supporting Information

Ref: British Audiology Society – Positioning Tests 

https://www.thebsa.org.uk/wp-content/uploads/2015/12/Positioning-Tests-Recommended-Procedure-09.12.2015.pdf

 

Information

 

Inner ear- labyrinth of canals embedded in the temporal bone. It is split into 2 parts:

  1. The vestibule and semicircular canal

  2. Cochlea

Membranous labyrinth- 

  • Encloses a hollow system filled with endolymph.

    • The endolymphatic system – The endolymph from this system passes into the endolymphatic sac/ saccus endolymphaticus (blind ending sac near the sigmoid sinus). 

  • Surrounded by the perilymphatic system and communicates with the subarachnoid space via the cochlear aqueduct. 

    • Perilymph is a filtrate of blood and CSF – Mainly sodium.

    • Endolymph is a filtrate of perilymph with a different sodium/potassium concentration- Mainly potassium

BPPV- utricle and posterior semicircular canal

Semicircular canals x 3

  • Canals are right angles to each other- posterior, superior and lateral

  • Each has a widening/ampullae containing gelatinous mass called cupula which surrounds a collection of hair cells in the underlying membrane. 

  • Movement of the endolymph by rotation –>movement of the cupular→ movement hair cells

  • Cells are depolarised – transmit to vestibular nerve

  • Saccule acts to detect acceleration and deceleration

15% balance comes from vestibular organs, 15% proprioception, 70% vision. All go to the brainstem to maintain balance.

 

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