Middle name of the Patient

How to read the middle name from Patient.Name when the first name contains two words or three words? I also noticed that the Patient resource does not have a field for middle name, does that mean this field is not available on FHIR R4 resources?

There’s a fair bit of uncertainty about first names with spaces in them. People doing data entry have problems with this. There’s a brief mention of this issue here: http://hl7.org/fhir/datatypes-examples.html#HumanName

basically, the same name might come either way from different systems or even in the same system, and you should be able to handle both