Body planes, look at this website for more info
https://www.google.co.uk/url?q=https://www.boundless.com/physiology/textbooks/boundless-anatomy-and-physiology-textbook/introduction-to-anatomy-and-physiology-1/mapping-the-body-33/body-planes-and-sections-289-1344/&sa=U&ved=0ahUKEwjQs8XR9YrUAhXHKcAKHapnD58QFggUMAI&usg=AFQjCNH0hXmL_w50JNtIeUTU7BDPw10XDg
Solid tipped IUPC design avoids pressure or becomes lodged against the uterine wall as may occur with fluid filled IUPC.
In fluid filled IUPC:
1. A catheter tip may become wedged against the uttering wall or fetal part preventing recording of pressure data or causing a distorted or truncated waveform.
2. A catheter tip in relation to external pressure transducer position may record inaccurate pressure readings.
3. Meconium, vernix, or blood may obstruct catheter
4. Air in catheter may change pressure waveform or provide inaccurate pressure data.
