First Post... My son who is 15 weeks old constantly had one thumb tucked very tight between his fingers in a fist. We only noticed today as he has only started untucking it. That one thumb only has one crease and is thinner than the other one. Took him to gp who suspected hypoplasia but an xray in the hospital dismissed this the same day. Consultant thinks it has lost muscle mass and is stiff from the way he had it gripped so tight 24 7. The past 2 days he has gained creases on the back of his thumb and with gentle pressure it can now bend, it is the same length as the other one but has a slight bend it. Would make sense as the bend is how he tucked it. Has anyone else had any experience of this? Paediatric consultant has referred him to a hand specialist but thinks it will have rectified itself by time appointment comes round.