what is the sheath that runs up the outside of the leg?
Anterior Compartment Syndrome Anterior compartment syndrome, also known as anterior shin splints arises when the big muscle on the outside front of the lower leg becomes too big for the sheath that surrounds it causing pain. Anterior compartment syndrome can be acute or chronic. Acute compartment syndrome is sudden onset and causes considerable pain. It is often due to an injury or impact to the big tibialis anterior muscles at the front of the leg which swells up. Chronic anterior compartment syndrome comes on gradually and may be due to the muscle growing too big for the sheath surrounding it.