In this article and video, I’m going to demonstrate opposition and reposition, which are special movements involving the thumb.
The thumb, also known as the pollex or digit one, articulates (forms a joint) with the trapezium bone of the wrist (carpus) via a saddle joint, which is a type of synovial joint featuring interlocking convex and concave surfaces. They call it a saddle joint because, well, it kinda looks like a saddle (yee-haw, cowboy!).
Thanks to this saddle joint, the thumb can perform circumduction, flexion and extension, abduction and adduction, as well as special movements called opposition and reposition.
Opposition of the Thumb
Opposition of the thumb occurs when the tip of the thumb comes to meet (and oppose) the tip of another finger from the same hand. A super easy way to remember this is that you’ve probably heard someone say that humans have opposable thumbs. Opposition is the special movement of our opposable thumbs.
In fact, think about this: when the opposition movement occurs, what happens? In the picture above, did you notice how the thumb and finger created a shape similar to the letter ‘O’? The ‘O’ stands for opposition! Now you can easily remember this motion of our opposable thumbs!
Reposition of the Thumb
Reposition is the opposite action of opposition. During reposition, the thumb and finger return to their original position.
Opposition and Reposition Anatomy Video
See a demonstration of opposition and reposition in the anatomy review video below:
Free Quiz and More Anatomy Videos
Take a free opposition and reposition quiz to test your knowledge, or review our opposition and reposition video. In addition, you might want to watch our anatomy and physiology lectures on YouTube, or check our anatomy and physiology notes.