About a dozen Soviet-American couples divided by the refusal of Soviet officials to let one partner leave the country are a small but highly emotional item on the human rights agenda as Moscow and Washington maneuver toward an expected summit meeting this fall.

The problem of these "divided spouses" has been raised repeatedly with the Soviets by U.S. officials, and it is expected to come up again when Soviet Foreign Minister Eduard Shevardnadze visits Washington this week for talks with Secretary of State George P. Shultz.

The "divided spouses" list was reduced by one couple last weekend, when Matvei Finkel of Moscow and Susan Graham of Spokane, Wash., married since 1979, left Moscow with their 9-month-old daughter.

Of the 10 couples remaining on the State Department's official list, the longest separation is that of Anatoly Michelson of Naples, Fla., who left his wife, Galina, and daughter, Olga, in Moscow when he defected in 1956. There is an additional list of four Soviet-American couples whose marriages have been blocked. All of these cases involve American citizens whose Soviet spouses or fiances have been turned down for emigration at least twice.

To U.S. officials, the issue is simple, a matter of basic human rights and compliance to the family reunification provisions of the 1975 Helsinki accords, which the Soviets signed. Because of the small number of cases involved, it is seen in Washington as an easy way for the Soviets to build good will.

"Why in the world can't people who want to get married be allowed to get married, and {those} who are married be accorded the privilege of living with each other, wherever it is they want to live?" Shultz asked in a wire service interview last week. "It just baffles me."

Soviet Embassy spokesman Igor Bulay also expressed bafflement. "This is a very queer subject for us," he said in a telephone interview.

"Soviet law does not forbid anyone to get married," Bulay said. "But there are Soviet persons, due to their occupation mostly, who possess state secrets . . . and five years should pass until such a person could be given permission to leave the country."

Until recently, most emigration requests were refused without even that much explanation. But when Assistant Secretary of State Richard Schifter, the State Department's human rights chief, discussed the divided spouses case by case with Soviet officials in Moscow last month, "for the first time they were reasonably specific" about denials," Schifter said in an interview last week.

The citing of "state secrets" to refuse emigration can be puzzling at times. According to Keith Braun, a Detroit lawyer whose Soviet wife, Svetlana, has been rejected five times, the Soviet Embassy told Sen. Carl Levin (D-Mich.) that the reason was "her previous access to highly classified information." Braun said his wife, who was 21 when they married in 1984, had studied low-temperature refrigeration at a chemical institute but never worked full time. Her father, Braun said, left a classified engineering job in 1978, when she was 15.

The Brauns' case is a high-profile one because of his role as spokesman for the Divided Spouses Coalition, an informal network that pools information on the cases and maintains contacts with U.S. government officials and the media. Several Soviet spouses have held meetings at the U.S. Embassy in Moscow with visiting members of Congress and State Department officials. Others in both countries, however, avoid publicity, hoping to avoid Soviet displeasure that might hurt their chances of being reunited.

Braun has been able to make eight visits to his wife in Moscow. But another coalition member who has made radio and television appearances, Dr. Galina Vileshina of Boca Raton, Fla., has been barred from visiting her husband, Pyatras Pakenas, whom she left behind in Vilnius, Lithuania, when she left in 1980 with her son from a previous marriage. Vileshina, a neurologist, said her husband needs heart bypass surgery.

The couple, married in 1977, first were refused visas in 1978. Pakenas, a lawyer in a meatpacking plant, has now been turned down 17 times, but he emphasized in an interview in Vilnius with Washington Post correspondent Jackson Diehl that "I am not a dissident. . . . I only want to leave because I want to be with my wife and family."

In order for his wife to leave, Pakenas said, they had to divorce for two weeks while she got her exit permit. Vileshina is Jewish and at first tried to have him join her in Israel. Pakenas said he believes local authorities have blocked his emigration because they fear setting a precedent of allowing ethnic Lithuanians to leave.

Keith Braun sees an ebb and flow in the Soviet treatment of these divided couples cases, as in the larger trends of Jewish emigration. He counts eight cases resolved in the fall of 1985, around the time of the Geneva summit between President Reagan and Soviet leader Mikhail Gorbachev, and eight more last fall, before and after the Reykjavik summit. This year, three cases were resolved by March, then none until this month's Finkel-Graham release.

Few new cases have been added to the divided spouses list, however. The State Department estimates that of about 90 new Soviet-American marriages each year, 80 percent of the Soviet spouses receive permission to leave.

The State Department's Schifter was told in Moscow last month that seven of the remaining cases are under review by a special panel of the Soviet parliament.

Braun suspects these are appeals of visa rejections, filed in mid-April after Shultz and Schifter met with a group of Soviet spouses in Moscow, and he notes that the six-month deadline for rulings would come in mid-October, perhaps just when final arrangements are being made for another Reagan-Gorbachev summit.

"We really have to impress on the Soviets that these individual cases mean a lot to us," Schifter said. "From a Marxist point of view, this is very difficult for them to understand, that the president of the United States, the secretary of state would consider these individual cases important."