I've stumbled on a construction that confused me in Kafka's Die Verwandlung where a definite article is used where I would expect to see a possessive pronoun.
wenn er den Kopf ein wenig hob
translation: (if he lifted his head a little)
my faulty translation: (if he lifted the head a little)
Could seinen also be used here, and if so, would it change the meaning in any way, and if not, how do I know when to use an article vs a possessive pronoun for these types of constructions.