Posture and Balance

Question 1

What is the definition of “Posture”?

Answer 1

Relative position of various parts with respect to one another, the environment and gravity

Question 2

Maintaining posture requires what kind of tone?

Answer 2

Extensor tone

Question 3

What are the four descending tracts which comprise the Ventromedial pathways?

Answer 3

• Vestibulospinal Tract
• Tectospinal Tract
• Pontine Reticulospinal Tract
• Medullary Reticulospinal Tract

Question 4

The Vestibulospinal Tract receives sensory input from where..?

Answer 4

Inner ear

Question 5

The Tectospinal Tract receives sensory input from where..?

Answer 5

Retina of eye

Question 6

Where does the Vestibulospinal tract originate from?

Answer 6

Vestibular nuclei in medulla

Question 7

Where does the Tectospinal Tract originate from?

Answer 7

Super colliculus

Question 8

Where does the Pontine Reticulospinal Tract originate from?

Answer 8

Reticular formation

Question 9

Where does the Medullary Reticulospinal Tract originate from?

Answer 9

Reticular formation

Question 10

The Pontine Reticulospinal Tract receives sensory input from where..?

Answer 10

Cerebellum / cortex

Question 11

The Medullary Reticulospinal Tract receives sensory input from where..?

Answer 11

Cerebellum / cortex

Question 12

In humans with extensive cortical damage, why might a patient appear rigid with increased extensor tone?

Answer 12

Because brainstem action is highly extensor, however there is cerebral inhibition usually

Decerebrate Response / Rigidity

Question 13

Decerebrate Response / Rigidity can be seen in which condition?

Answer 13

Cerebral malaria

Question 14

State the names of the two main structures of the Vestibular System

Answer 14

Otolith organs

Semi-circular canals

Question 15

What do the Otolith organs detect?

Answer 15

Forces of gravity / tilting of head (linear acceleration)

Question 16

What do the Semi-circular canals detect?

Answer 16

Head rotations (rotational motion and angular acceleration)

Question 17

What are the two Otolith organs?

Answer 17

Utricle and saccule

Question 18

Describe the structure of the Utricle / Saccules

Answer 18

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

Question 19

What is the difference between the Utricle and Saccule?

Answer 19

The Utricle is oreintated horizonally, whereas the Saccule is orientated vertically

Question 20

What do the Utricle Otolith organs detect?

Answer 20

Horizontal linear acceleration

Question 21

What do the Saccule Otolith organs detect?

Answer 21

Vertical linear acceleration

Question 22

Semicircular canals are filled with a fluid called?

Answer 22

Endolymph

Question 23

What is Caloric testing?

Answer 23

Irrigation of ear with cold / warm water, with temperature setting up convection currents in the endolymph to induce the vestibulo-ocular reflex

Question 24

What can Caloric testing be used for?

Answer 24

As a means to test brainstem function

Question 25

If Caloric testing, and only one eye moves in direction but the other remains still - what does this mean?

Answer 25

Medial Longitudinal Fasciculus Lesion

Question 26

What is the Positive Supporting Reaction reflex?

Answer 26

Placing a limb on the ground initiates a set of reflexes which stiffen the limb

Question 27

Give an example of a condition which is a disorder of the Vestibular system.

Answer 27

Meniere’s Syndrome
Benign Paroxysmal Positional Vertigo
Migraine Associated Vertigo

Question 28

What is Meniere’s syndrome caused by?

Answer 28

Caused by increased endolymph

Question 29

What is Benign Paroxysmal Positional Vertigo caused by?

Answer 29

Dislodged calcium carbonate crystals from otolith organs