The 18-year-old Petrasso has joined on an initial 28-day deal after impressing whilst on loan at Oldham earlier this season.
Boss Steven Pressley told the club's website: "Michael is one player we've been watching for a while so we are delighted to get him in the building.
"He played for Oldham against us and we were impressed by his work-rate and speed during that performance.
"He is young and hungry so we think he will be a valuable addition for us."
Akpom, also 18, had a spell at Brentford earlier this term and links up with the Sky Blues on a youth loan deal until the end of the season.
Pressley added: "We've been looking to add options to our forward line and Chuba is an exciting young player who we're delighted to bring in.
"He is a young player who is hungry to prove himself, and hunger is certainly a key attribute at this football club.
"We've got a lot of games left this season and I hope Chuba will be able to help us get the results we need."