Physical Therapy Assistant Practice Exam

Which of the following describes the tonic labyrinthine reflex in a supine position?

1. Increased flexor tone

2. Increased extensor tone

3. Increased adductor tone

4. No tone exhibited

The correct answer is: Increased extensor tone

The tonic labyrinthine reflex (TLR) describes a significant postural response that is influenced by head position relative to gravity. When a person is in a supine position, the tonic labyrinthine reflex promotes increased extensor tone. This reflex is driven by the position of the head and body in relation to gravity, where the body tends to adopt postures that align with the head's orientation. In supine, the head is tilted back slightly, and this encourages the activation of extensor muscles to stabilize the body against gravitational forces. Consequently, we often observe that there is a facilitation of extensor muscle tone throughout the body, which helps maintain alignment and prevents excessive flexion or curling into a ball shape. In contrast, increased flexor tone would not be expected in the supine position, as this reaction typically occurs when the individual is in a prone position or when the head is flexed forward. Increased adductor tone, while still a possible response in certain situations, does not directly relate to the tonic labyrinthine reflex's characteristic response in supine. Additionally, an absence of tone is not indicative of a tonic reflex, as the tonic labyrinthine reflex specifically elicits a muscle tone response. Thus, increased extensor tone accurately captures the