Robert Davis, 66, a patient at St. Elizabeths Hospital since 1943, had been lying on the floor for two hours, passing notes under a cafeteria door, when he was approached by nursing assistant Janice Little, the government prosecutor told a D.C. Superior Court jury yesterday.

"She told him to get up and get back to the ward," said assistant U.S. Attorney Harry R. Benner, who described Davis as a weak, feeble old man who could be a "troublesome" patient.

Little contends that Davis punched her in the stomach. She admitted to investigators that she kicked him in return, Benner said in his opening statement. But the government will prove, he said, that Little kicked the man "a number of times" and that the beating resulted in Davis' death hours after the incident on Sept. 18, 1976.

Little, 24, is charged with second degree murder. Following Davis' death, Little was transferred to a job as a hospital supply clerk, but was discharged from St. Elizabeths following her indictment in December, 1976, according to her attorneys, Jay Bernstein and Stanton Gildenhorn.Her dismissal has been appealed to the Civil Service Commission, the attorneys said.

Bernstein told the jury yesterday that the evidence would show that Davis was not "a feeble little old weak man" but that he had the body of a man "five to 10 years younger" and that his health varied from good to bad.

He described Davis as a former boxer, who was an "assaultive type person" in the hospital ward, and had been known to attack other staff members.

The defense attorneys said they would attempt to prove that Little acted in self defense and that the "minor altercation" with Davis did not result in injuries that would have caused his death.

Following the incident with Little, which occurred around 5 p.m., the prosecutor said the evidence will show, Davis was put in a locked, "special treatment room," a small cell with bars on a single window, furnished only with a mattress, that is used to seclude disruptive patients.

At 9 p.m., Benner said, Little, who was in charge of the hospital ward that night and had checked Davis periodically, summoned a doctor to Davis' cell after she observed that Davis' face was "grossly swollen."

At that point, Benner said the evidence will show, Davis passed a note to the doctor that said "she hit me" in what the government contends was an apparent reference to Little. She denied to the doctor that she had struck the man, Benner told the jury.

Shortly before 11:30 p.m., a doctor again was called to Davis's cell after other employees noticed that Davis' body was "blown up like a balloon," Benner said in his opening statements.

A surgeon, on call to the hospital, was telephoned, Benner told the jury, but he fell asleep and did not report to the hospital until some time later.

Davis, who suffered from Parkinson's disease, a degenerative disorder of the central nervous system, was renounced dead at :45 a.m. on Sept. 19, 1976.

Benner told the jury that the city's medical examiner later found evidence that Davis had been beaten, including scratches on his face, a cut on his scalp and numerous bruises on his body. Two of Davis' left ribs were cracked, and apparently puncutred his lungs, resulting in the extensive swelling when air from the lungs "leaked into Davis') body." Benner said.

The prosecutor said the evidence will show that the injuries were caused by "five or six impacts (to Davis body) . . . consistent with kicking."