In this anatomy lesson, I’m going to demonstrate protrusion, retrusion, and excursion, which are special body movement terms in anatomy that refer to forward (anterior), backward (posterior), or side to side movements.
Protrusion in Anatomy
Protrusion refers to the movement of a structure in an anterior (forward) direction. In fact, the word protrude means “projecting something forward.”
I call protrusion the kissing movement because it occurs when you pucker your lips like you’re going to give someone a kiss or stick out your tongue. Moving the mandible (lower jaw) forward is also an example of protrusion.
Retrusion in Anatomy
Retrusion is the opposite of protrusion. It refers to the movement of a structure in a posterior, or backward, direction. Putting your tongue back in your mouth, moving the lips back, or moving the mandible back are all examples of retrusion in anatomy.
Excursion in Anatomy
Finally, we have excursion, which refers to the side-to-side movement of the lower jaw (mandible). If you’ve ever heard of a character named Ernest P. Worrell, then you’ve definitely seen the excursion movement. He’s the character in those movies such as Ernest Goes to Camp, Ernest Goes to Jail, etc. When Ernest saw something nasty, he’d move his jaw back and forth and say, “Ewwww.”
Excursion can occur in either direction, and anatomists use directional terms to specify the type of excursion. When the mandible moves to either the left or right, it’s moving away from the body’s midline, so it’s called lateral excursion. When the mandible moves closer to the midline of the body, it’s called medial excursion.
Protrusion and Retrusion vs Protraction and Retraction
What about protraction and retraction? Some anatomy textbooks will refer to the forward movement of the mandible, lips, or tongue as protraction (instead of protrusion), and the backward (posterior) movement will be called retraction (instead of retrusion). The terms are sometimes used interchangeably, so use whatever method your anatomy professor suggests (they give you the grade, not me!).
However, some anatomists today use protraction and retraction to refer almost exclusively to the scapulae, as it is a combined movement (protraction is anterolateral, and retraction is posteromedial). In contrast, protrusion and retrusion are more of an anterior/posterior movement. Then again, some anatomists prefer not to use protraction and retraction at all, even when describing shoulder blade movement.
Protrusion, Retrusion, and Excursion in Healthcare
Healthcare professionals use protrusion, retrusion, and excursion when documenting, performing assessments on patients, or treating disorders. For example, in her head-to-toe assessment, Nurse Sarah asked me to stick out my tongue (an example of protrusion), to assess cranial nerve twelve.
In addition, something called a mandibular protrusion test (MPT) is sometimes used by anesthesiologists to predict difficult airways in patients.
Free Quiz and More Anatomy Videos
Take a free protrusion vs retrusion quiz to test your knowledge, or review our protrusion vs retrusion video. In addition, you might want to watch our anatomy and physiology lectures on YouTube, or check our anatomy and physiology notes.