Lower Limb - Anatomy, Biomechanics, Neural Control of Standing Flashcards

Question

What does the inverted pendulum model tell us for sway angle of more than 8 degrees?

Answer 1

The model predicts that the difference between the CofP and CofM is proportional to the horizontal acceleration of the CofM

Answer 2

CoP – CoM = -Ix/Wd = -Kx I = Moment of inertia of the total body about the ankle in the direction of interest x = Horizontal acceleration of the CoM in the direction of interest d = Vertical distance from the ankle joints to the CoM W = Total body weigh above the ankle joints

Answer 3

visual vestibular proprioceptive

Answer 4

Reticulo-spinal vestibulo-spinal

Answer 5

This system is involved in controlling posture

Answer 6

Medial - arises in Pons - responsible for extensor tone (decerebrate Rigidity) Lateral - arises in Medulla - more involved in muscle movement

Answer 7

Decerebrate rigidity is a condition that occurs when there is damage to the brain, specifically to certain areas that control movement and coordination. This damage leads to increased muscle stiffness and a specific posture where the limbs are extended and rigid. It's a neurological response indicating a lack of normal inhibitory control over muscle tone.

Answer 8

The brain has a system that sends signals (or "drive") to control and inhibit certain activities in the spinal cord. This control is important for maintaining balanced and coordinated movements.

Answer 9

The reticular formation is a part of the brainstem that plays a crucial role in regulating various bodily functions, including consciousness, arousal, and motor control.

Answer 10

refers to nerve pathways that carry signals using neurotransmitters like noradrenaline (noradrenergic) and serotonin (serotonergic). These pathways start in the brain (from the nuclei) and travel down (descending) to the spinal cord. They act as modulators, influencing and adjusting the activity of other nerve cells in the spinal cord.

Answer 11

The signals carried by these pathways are "excitatory," meaning they increase the activity of the nerve cells they interact with. In the context of motor control, this increased activity can enhance the transmission of signals that lead to muscle contractions and movement.

Answer 12

Decerebrate posture result from damage to the upper brainstem. The arms are adducted and extended, with the wrist pronated and the fingers flexed. the legs are stiffly extended with plantar flexion of the feet Decorticate posture results from damage to one of both corticospinal tracts. the arms are adducted and flexed, with the wrist and gingers flexed on the chest. the legs are stiffly extended and internally rotated, with plantar flexion of the fee

Answer 13

Vestibular Apparatus (Inner Ear) is comprised on two Otoliths (gravity sensing) and three semi-circular canals (rotational acceleration sensing)

Answer 14

lateral tract - involved in stabilization of body medial tract - involved in stabilization of head

Answer 15

-Involved in stabilization of head on body. Uses Medial Vestibulospinal pathway. - When the head rotates or tilts in one direction, contract neck muscles to oppose the motion. - Also, biomechanical components of the head have a characteristic resonance frequency of 2-3 Hz which oscillation would likely occur and this reflex will help dampen

Answer 16

- Involved in stabilizing body. Uses Lateral Vestibulospinal pathway. - When body rotates or tilts in one direction, contract ipsilateral extensor muscles to counteract.

Answer 17

- Sensory strategies of how the three systems (visual, vestibular and proprioceptive) interact and are organized for controlling posture. Enviromental conditions can have large effects on type of postural strategies used. - Sensorimotor strategies reflect how the sensory and motor systems combine to produce a co-ordinated postural response. - Attentional strategies determine the degree of attention given to a postural task while performing other tasks simultaneously. Can be modified depending on the degree of anticipation of upcoming disturbances, and on previous postural conditions (postural set)

Answer 18

Vestibular Loss - tend to rely solely on ankle strategy People with Distal Neuropathies (loss of sensation from proprioceptors) - tend to rely on hip strategy Different sensory inputs can weight the type of postural strategy chose

Lower Limb - Anatomy, Biomechanics, Neural Control of Standing Flashcards

(42 cards)