Worried about 20 week scan measurement

[Josie17]

Hello
Just had our 20 week scan today, all seemed fine but noticed in our notes that the TCD measurement was 16.6mm. That seems very low from what I can gather. The sonographer didn't mention anything and said all was good, all the other measurements are fairly standard. I just wondered if anyone knew what this means if anything?
The baby was being awkward and the sonographer found it difficult to get a good view of the head, could that be anything to do with it?

If there were any issue it would have been flagged up and you would know about it. Try not to worry (as hard as that is) there are many reasons why measurements may seem on the small side, and baby being at slightly wrong angle can certainly cause an "off" measurement.