Posture and Balance Flashcards
What is the definition of “Posture”?
Relative position of various parts with respect to one another, the environment and gravity
Maintaining posture requires what kind of tone?
Extensor tone
What are the four descending tracts which comprise the Ventromedial pathways?
- Vestibulospinal Tract
- Tectospinal Tract
- Pontine Reticulospinal Tract
- Medullary Reticulospinal Tract
The Vestibulospinal Tract receives sensory input from where..?
Inner ear
The Tectospinal Tract receives sensory input from where..?
Retina of eye
Where does the Vestibulospinal tract originate from?
Vestibular nuclei in medulla
Where does the Tectospinal Tract originate from?
Super colliculus
Where does the Pontine Reticulospinal Tract originate from?
Reticular formation
Where does the Medullary Reticulospinal Tract originate from?
Reticular formation
The Pontine Reticulospinal Tract receives sensory input from where..?
Cerebellum / cortex
The Medullary Reticulospinal Tract receives sensory input from where..?
Cerebellum / cortex
In humans with extensive cortical damage, why might a patient appear rigid with increased extensor tone?
Because brainstem action is highly extensor, however there is cerebral inhibition usually
Decerebrate Response / Rigidity
Decerebrate Response / Rigidity can be seen in which condition?
Cerebral malaria
State the names of the two main structures of the Vestibular System
Otolith organs
Semi-circular canals
What do the Otolith organs detect?
Forces of gravity / tilting of head (linear acceleration)
What do the Semi-circular canals detect?
Head rotations (rotational motion and angular acceleration)
What are the two Otolith organs?
Utricle and saccule
Describe the structure of the Utricle / Saccules
Macula of sensory epithelium, which is made up of Hair cells and Supporting cells which penetrate into a Gelatinous cap. On top of this is Calcium carbonate crystals
What is the difference between the Utricle and Saccule?
The Utricle is oreintated horizonally, whereas the Saccule is orientated vertically
What do the Utricle Otolith organs detect?
Horizontal linear acceleration
What do the Saccule Otolith organs detect?
Vertical linear acceleration
Semicircular canals are filled with a fluid called?
Endolymph
What is Caloric testing?
Irrigation of ear with cold / warm water, with temperature setting up convection currents in the endolymph to induce the vestibulo-ocular reflex
What can Caloric testing be used for?
As a means to test brainstem function
If Caloric testing, and only one eye moves in direction but the other remains still - what does this mean?
Medial Longitudinal Fasciculus Lesion
What is the Positive Supporting Reaction reflex?
Placing a limb on the ground initiates a set of reflexes which stiffen the limb
Give an example of a condition which is a disorder of the Vestibular system.
Meniere’s Syndrome
Benign Paroxysmal Positional Vertigo
Migraine Associated Vertigo
What is Meniere’s syndrome caused by?
Caused by increased endolymph
What is Benign Paroxysmal Positional Vertigo caused by?
Dislodged calcium carbonate crystals from otolith organs
