The quad muscle dent, that scary groove that appears in your quadriceps muscle, has more than one possible cause. The quadriceps dent is often described as being one to two inches long, and sometimes horizontal, and other times diagonal. Occasionally a description for the quad muscle dent comes in as closer to vertical, and may exceed two inches in length, sometimes stretching for almost half the length of the thigh.
This article explains the causes of dents in your quad muscle. I’m a certified personal trainer, but I also consulted with Dr. Joseph J. Ruane, Medical Director, McConnell Spine, Sport & Joint Center, and Head Team Physician, Columbus Blue Jackets.
Dr. Ruane says, “First of all, any obvious or irregular change in tissue structure — such as ‘denting,’ is worth getting checked. Rarely (and I mean rarely) it may be a sign of something bad going on underneath.
“However, it may be reassuring to know that the dent is most often a loss of subcutaneous tissue (the fat under the skin) rather than loss of muscle tissue itself. This can result from local trauma (bumping hard into the corner of a desk). The fatty tissue is damaged in the impact, and sometimes shrivels and shrinks; leaving a dimple, or dent. Sometimes it fills back in, often it may not. Muscles do not atrophy in small, defined sections that leave dents.”
If you’ve been worried sick over the dent in your quad muscle, re-read Dr. Ruane’s last line: “Muscles do not atrophy in small, defined sections that leave dents.”
Oddly, people who have hypochondria related to MS or ALS have somehow formulated the idea that an early sign of muscle atrophy is some little depression or groove in the muscle. Nowhere in the annals of medical literature is muscle denting named as a sign of wasting muscle tissue or atrophy, or any kind of disease.
Another cause of the quad groove, in addition to local trauma, is a variation of this: prolonged leaning of the thigh into an object. A person who spends a lot of time at a counter of sorts may be unknowingly leaning (pressing) their thigh into a hard edge. Or, perhaps they are seated, and something weighted is resting atop their thighs, such as a heavy briefcase.
Later on, the person happens to notice a small impression or depression in their quadriceps while changing clothes, showering or working out. They fail to recollect earlier in the day when something was pressing into their leg and “molding” the dent.
Another cause of quad denting to consider is the natural anatomy of the muscle, if the fissure is more vertical than horizontal. A person who has toned thigh muscles, along with low body fat in that area, will likely see a horizontal dent in the middle of their quads, a few inches to several inches in length. This fissure may come and go, depending on body position.
If you’re not sure what the cause of your quadriceps dents, impressions or grooves are, check out a bodybuilding magazine to make a comparison of your anatomy with that of bodybuilders, whose muscle definition is acutely visible, so that you can learn what is a normal muscle dent, and what might be the result of local trauma.