Yup - tigerchick is right, you are describing the tibial tuberosity. This is the attachment of the patellar tendon, and point tenderness here generally indicates early patellar tendonitis (most commonly).
Causes are numerous, but one common cause is a bike seat that is too LOW (unusual, yes) 
or lots of kneeling (tiling a floor, etc.) causeing infrapatellar bursitis here (“clergyman’s knee”).
edit: just saw your title “running injury …” if from running only, this could be a location for a tibial stress fracture (although unlikely in that exact area). Likely from running hills (my favorite)