The imprisoned Kremlin critic Alexej Navalnyj complains of increasing back pain due to the constant solitary confinement.
“You lock a person in an isolated punishment cell where they can either stand or sit on an iron stool for 16 hours a day.
In a month, under these conditions, even a healthy person's back will hurt," the opposition politician said on Monday via his social networks.
He himself has been in solitary confinement almost constantly for three months.
The prison doctor examined him, but did not tell him the diagnosis even after repeated requests, Navalny reported.
Since the injections she prescribed did not help either, he finally requested a copy of his medical file, which he was only given in an illegible condition.
He will now complain that he "can read" his medical records, the opposition politician said.
Because of alleged fraud, Navalny is in penal colony 6 in Melekhovo, about 260 kilometers northeast of Moscow - under particularly harsh prison conditions.
In May, a court upheld the nine-year prison sentence.
Internationally, he is considered a political prisoner and the harshest critic of Kremlin chief Vladimir Putin.
Navalny had recovered from a poison attack in Germany in August 2020, but then returned to Russia voluntarily and has been in prison ever since.