An indentation in a leg muscle can be caused by skin pulling toward a minor hematoma, according to Dr. Ashish Verma from HealthcareMagic.com. The indentation typically goes away naturally in a few weeks, or a doctor can fix it cosmetically.
A hematoma is the result of a damaged vein or capillary, according to MedicineNet. When the vessel is broken, blood collects outside of it and becomes swollen. As the swelling grows, skin is pulled away from the muscle, and this creates the indentation. A doctor must diagnose the hematoma. Treatments for a hematoma include rest, ice, heat, compression and elevation, according to MedicineNet.