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UExcel Anatomy & Physiology: Study Guide & Test Prep19 chapters | 230 lessons
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Free 5-day trialSome people love to sleep on their side. Some are very particular, only preferring one side, while others are not picky and can sleep on one side or on the opposite side. If you know someone who sleeps on a side opposite your favorite side, there's a word for that side. If you know someone who sleeps on the same side as your favorite side, there's a word for that side, too. Had enough of the sides? Sides aside, let's get to the main part of this lesson instead.
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If you were to lie down in bed, on your back this time, and draw an imaginary line down the very center or middle of your body, stretching from the top of your head down to the soles of your feet, this would be called the midline of your body, with the word 'midline' referring to the fact that the line is in the middle of your body, or on what's known as the 'median plane.'
Now, draw a little dot just to the side of the midline and another dot almost all the way at the edge of your body, as far away from the midline as possible.
Something that is farther away from the midline is lateral, while something that is closer to the midline is termed medial. Hence, the dot farthest away from the midline is on the lateral aspect of your body and is lateral to the dot closest to the midline. On the other hand, the dot closest to the midline is medial to the dot farthest away from the midline. In simple terms, something lateral is to or on the side of something else, while something medial is toward the middle of something.
It should come as no surprise, then, that the inner part of your thigh, the inner thigh, is the medial part of your thigh, since it's closest to the imaginary midline we drew, while the outer thigh is the lateral part of your thigh.
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Another important couple of terms have to do with the specific side of the midline you're on. For example, the right leg and right arm are ipsilateral, meaning they're affecting, or on, the same side of the body. This is in contrast, or in direct opposition to, the right leg and left arm, which are contralateral, or affecting, or on, the opposite side of the body.
It should be easy to remember that contralateral means the opposite side of the body since contra in contralateral means 'opposite' or 'against,' whereas the term ipsi means 'the same' in Latin, hence 'ipsilateral' is on the same side!
Now that we've put that aside, let's quickly go over all of our terms an additional time.
Ipsilateral means something that's affecting, or on, the same side of the body, whereas contralateral means that something is affecting, or on, the opposite side of the body.
Something that is farther away from the midline of your body is lateral, while something that is closer to the midline is termed medial.
That's it - four simple terms all referencing their relationship to the midline, or their comparative relationship to the midline based on another point.
After watching this video in its entirety, you'll be able to explain the relative position of the parts of the body using the terms ipsilateral and contralateral as well as medial and lateral.
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UExcel Anatomy & Physiology: Study Guide & Test Prep19 chapters | 230 lessons