Dental records proved that the body of a woman that surfaced in the East River off Long Island City on Tuesday is Svetlana Aronov, the Upper East Side woman who went missing two months ago, officials said. Water in her lungs proved that she drowned.

The condition of her body and Cartier watch, which stopped at 4:17 p.m., provided a strong indication of when she died.

However, with only a few superficial bruises on her knees and the front of her legs, detectives were hard-pressed yesterday to determine how she ended up in the East River.

"At this point there are still a million scenarios," said a police source, speaking on condition of anonymity.

Detectives yesterday were measuring sections of the railing of the walkway along the FDR Drive above East 50th Street to see if it was low enough to have caused the bruising on Aronov's legs, the source said. Police Commissioner Ray Kelly said the bruises were about 15 inches above the soles of her feet.

The thinking behind the measurements, the source said, is that Aronov may have fallen in. Many detectives assigned to the case yesterday kicked around the possibility that her father's cocker spaniel, which she had been walking, jumped into the water and she fell over the railing trying to retrieve the dog, the source said.

Though her disappearance was originally thought by detectives to be a homicide, the lack of trauma on her body caused police yesterday to lean toward a suicide or accidental death, the source said.

Aronov, who would have turned 45 on Sunday, was last seen about 2:30 p.m. on March 3 as she left her York Avenue apartment building to walk her father's dog, Bim. Aronov, who was a rare-book dealer, was carrying only a cellular phone and a house key.

Security cameras on a building near East 66th Street captured her image as she walked north. Bloodhounds were later brought in and were able to trace Aronov's scent to York and 68th Street, four blocks from her home. Police interviewed a witness who told them he thought he saw a woman fitting her description get into a taxi at that location.

A series of events then led police to originally suspect foul play.

Aronov's mother-in-law picked up her granddaughter, Veronica, 9, at school and then walked her back to the family's apartment. Svetlana Aronov was supposed to have left the key with the doorman, but did not.

Aronov also was supposed to pick up her father, who was returning from St. Petersburg, Russia, at Kennedy Airport at 5 p.m. that afternoon. She never showed up.

When her husband, Dr. Alexander Aronov, arrived home from work that night, he found that a plant his wife had been watering for her father was placed with several of her father's items near the front door. Food for that night's dinner had been left out. Her wallet with her identification, cash and ATM card was also there.

With few leads, detectives looked into several possibilities - organized crime connections, Aronov's personal life, the problems with the doctor's practice - but nothing panned out.

Alexander Aronov, 45, could not be reached for comment yesterday. His lawyer, Ed Hayes, said his client has "no better sense" from detectives as to what happened.

"It's a complete mystery," Hayes said yesterday.

Hayes said the doctor's hiring him shouldn't be interpreted the wrong way. "I don't think anybody thinks he's a suspect," Hayes said.

Instead, the lawyer said the husband hired him for two reasons: to help in the investigation and because "under these circumstances no one can expect him to answer all the media questions or to always meet alone with the police and the district attorney."

Also, a dog found just after midnight yesterday not far from the Throgs Neck Bridge in Beechhurst was originally thought to be the one Svetlana Aronov was walking. However, the medical examiner later determined the dog was a Maltese poodle, not a cocker spaniel.