Teenage son - Growth spurt and bow legs.

[Babyroobs]

Just wondering if anyone can offer advice. My ds3 ( almost 14yrs) has had a big growth spurt and is very tall and thin, completely different stature to my other 2 older ds's. His legs just don't look right , they are slightly bowed and have knobbly bits sticking out at the sides of his knees that my other sons don't have( not sure whether this is just because he is so thin!) . He also has a bit of a funny gait. he has no pain or anything on walking and can run fast ( wins races at school )I want to take him to the Dr but just a bit worried they will think I am wasting their time. Would I be better off trying to speak to a school Nurse for advice? Do they do any routine growth checks on kids these days? I would be grateful if anyone can advise on the best course of action. Thanks.