Brief Answer:
A small concavity may not be significant at all. Check if you have any pain

Detailed Answer:
Hello,

Welcome to Ask a Doctor Service.

If you could upload a clear photograph of the area so that I can get a better idea of what is going on.

Muscles are by nature soft, hence when try to feel them, they yield under your fingers, which you would perceive as concavity.

In such a case it is not at all concerning.

If you however have noticed this recently, and if you see that particular muscle becoming thinner over the days and concavity increasing, you would need a neurologist opinion and an orthopedic surgeon consultation to rule out nerve damage.

I would for now suggest you to wait and watch and check if you have any difficulty in movements in the foot and ankle.

Kindly consult your pcp or neurologist if you find any deficiency in movements or if it is of recent origin and if you notice worsening concavity.

I hope that answers your query.

Best regards

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