it looks bad, you should have taken lower extremity anatomy much more seriously. but what's done is done, just make sure you really really really know it and review it before you start externships.
a C in LEA looks bad, but yes with a 3.4 gpa you are still a competitive applicant for residency and the C should not be the deal breaker for landing you a spot in residency.
If I'm interviewing you, and I see that on your transcript, I am going to pound you with anatomy questions. If you don't have that fundamental down, it makes it a whole lot more difficult to train you. Just make sure you continue to study LEA or it could ruin you on your externships.