The autopsy, conducted at the City Mortuary, also showed that he suffered severe bruises on his chest and hands.
The accident at the Manguo blackspot on Nairobi-Nakuru highway also left nine others injured.
Musumba passed on at Cherangany Nursing Home, where he had been hospitalised since he was involved in a road accident last week and sustained serious injuries.
Seven people lost their lives in a grisly road accident on Friday along Nakuru-Nairobi highway at Kamandura.
Bodaboda riders in Kapenguria are up in arms over increased accidents along the Kitale–Lodwar highway, which they blame on reckless and speeding truck drivers transporting clinker.
The family, staring at portraits displayed on each of the caskets, was overcome with disbelief, shock and tears. Leaders, friends and residents gathered to pay their last respects.