The use of âholidayâ to mean âa missed spotâ appears to be that rarity in English etymology, a word or phrase that actually has a nautical origin. The original use of âholidayâ in the âmissed a spotâ sense, back in the 18th century, was in reference to crew members painting the decks of a ship or âpayingâ (sealing seams with tar or pitch) its hull.
The knee jerk reflex is when a tendon above the kneecap is tapped with a reflex hammer, which causes the whole leg to involuntarily jerk.
Your doctor taps your knee with a small rubber hammer, and the lower part of your leg kicks out as if it has a mind of its own. Itâs called the knee-jerk reflex. The tap of the hammer stretches a tendon and the connected muscle in your thigh. The knee-jerk reflex is important: It helps you keep your balance. 1  Previous.