Apophyseal injuries can occur in children mainly during the second decade of life, so from about age 10 to 18 when the apophyseal areas will close. So an apophysis is a type of growth center on the bone where ligaments or tendons that are attached to muscle attach to the bone. Commonly in children that are playing repetitive sports.
Doing a high impact sport can get injuries to this apophysis and it can go misdiagnosed as a muscle sprain or a muscle strain or even tendonitis and this is actually a stress injury to that growth center. Now this growth center doesn’t affect the actual growth of long bones but it can lead to long term sequelae or pain if not properly identified and treated.
Occasionally, in rare events, this apophysis can actually have an avulsion fracture where it pulls off of the bone and those do need to be identified fairly early because they may need surgical correction depending on the degree of how far they’re pulled off the bone. Most apophyseal injuries do really well with just relative rests and appropriate physical therapy protocol and a good anti inflammatory medication.