Los Angeles (CNN) -- The doctor convicted in pop star Michael Jackson's death is suffering possibly life-threatening and permanent injuries after almost a year in a small jail cell, his lawyers are warning. 

Dr. Conrad Murray is housed in a high-security section of the Los Angeles County jail because of his notoriety, which isolates him from the general population for his protection but means he has "extremely limited access to exercise." 

"Death or injury at the hands of another prisoner, however, is no worse than a slow death caused by a loss of circulation and atrophy resulting from inhumane confinement of a large man in a tiny space," lawyers Valerie Wass and Michael Flanagan wrote in a letter addressed to Los Angeles County Sheriff Lee Baca Wednesday. 

Conrad Murray invites Katherine Jackson to visit him in jail 

Murray -- jailed since November 7, 2011, when he was convicted of involuntary manslaughter in Jackson's death -- is 6 feet 5 inches tall, but confined in a 5-foot-by-7-foot cell, the letter said. 

"If one were to keep a dog in a space just a few inches larger than the dog's length, for any extended period of time, contentions of animal cruelty possibly leading to prosecution would likely result," it said. 

The sheriff's office did not immediately return repeated calls from CNN for comment. 

Wass, who is overseeing the appeal of Murray's involuntary manslaughter conviction, told CNN Thursday his jail conditions "are the equivalent of a large individual flying coach in a middle seat for a period of a year." 
Was the Doctor injured?
 The doctor convicted in pop star Michael Jackson's death is suffering possibly life-threatening and permanent injuries after almost a year in a small jail cell