Los Angeles (CNN) — The doctor convicted in Michael Jackson’s death is suffering possibly life-threatening and permanent injuries after almost a year in a small cell with “extremely limited access to exercise,” his lawyer said Wednesday.

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.

“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,” attorney Michael Flanagan wrote in a letter addressed to Los Angeles County Sheriff Lee Baca Wednesday.

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-feet-by-7-feet cell, Flanagan wrote.

“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,” attorney Michael Flanagan wrote.

Photos: Michael Jackson, King of Pop

Murray was taken to a hospital Sunday night for treatment of what his lawyer described as “marked venous stasis of his lower extremities” and “right shoulder pain and severe loss of motion.”

Flanagan’s letter suggested the sheriff has “alternatives available to protect society and punish offenders that would not likely result in causing permanent injury or death to an inmate.”

California law allows Baca, at his discretion, to release Murray under monitored home confinement. Otherwise, he is set to remain in jail for another year.

Murray was sentenced to the maximum four years in prison for the conviction, but he is eligible for parole after serving half of his sentence. A California law intended to relieve overcrowding in state prisons resulted in Murray being kept in the county jail.

His jail cell is so small that Murray has “no opportunity for physical movement throughout the day,” Flanagan wrote. “The only actual exercise that Dr. Murray received occurs on most Monday evenings when he is transferred in chains to an 8-by-8 cage on the roof of the facility.”

Murray, in a phone call to a friend Monday that was published Wednesday by the celeb news website TMZ, complained that he feared his illness would be permanent. “I may never be able to wear a boot again,” he said.

“The venous stasis gives rise to a high risk for deep vein thrombosis and/or migrating pulmonary embolism,” his lawyer wrote to the sheriff. “This condition may have developed to a chronic state which has become permanent and uncorrectable necessitating a lifetime of medication and treatment.”

Murray’s physical appearance has changed dramatically since he was taken into custody, his lawyer wrote.

“A review of earlier booking photos and bio-statistics of Dr. Murray, when compared to his current condition and appearance, would be shocking to persons not previously familiar with him,” he wrote. “To those who have known him for the last year or longer, the suffering that has obviously taken its toll on his health is unimaginable.”

He is allowed out of the small cell for just two and a half hours a week, he said.

“Dr. Murray’s cell is proportional to that of a travel cage used for short-term transportation of an animal,” he said.

Keeping a human in such conditions “would at the very least give rise to civil liability for negligent confinement resulting in a debilitating medical condition,” Flanagan wrote.

“Please consider this letter as notice of the life-threatening condition in which Dr. Murray currently exists,” he told the sheriff. “Correction of this intolerable situation is of extreme importance.”

Murray was found guilty of causing Jackson’s death on June 25, 2009, by administering a deadly overdose of sedatives and the surgical anesthetic propofol in what he told police was an attempt to cure his insomnia.