Massarwah, an Israeli Arab physician, stood at a gate of the fence that Israel is building to separate itself from the West Bank, arguing with a Border Police officer. The doctor was explaining that he and a group of colleagues were on their way to a West Bank village whose people were in dire need of medical care. The policeman was explaining that he was not authorized to let them through without proper orders.

When the discussion began, voices were calm and the discourse courteous. But after 40 minutes, Massarwah was losing patience.

"I told him we have medicines that can be spoiled. It's nothing for him," Massarwah said, referring to a policeman who was trying to devour an ice cream bar before it melted in the midday sun.

Arguments were pursued, phone calls made and orders sought. After waiting nearly an hour, the mobile clinic operated by Physicians for Human Rights-Israel was waved through the gate.

The ritual is a familiar one for the volunteers who travel into the West Bank each Saturday in a program run jointly by the physicians' group and the Union of Palestinian Medical Relief Committees. Sometimes the delays are longer; sometimes the group reaches its destination without a hitch. But the doctors say the system of checkpoints that Israel has set up in the West Bank has had a devastating effect on the lives of the estimated 2 million Palestinians who live there.

The Palestinian Health Ministry reported last month that in the past three years, more than 90 people have died in ambulances waiting at checkpoints. Israeli and Palestinian human rights groups have documented cases in which pregnant women gave birth, heart-attack victims died and others bled to death while held up at checkpoints.

The International Committee for the Red Cross, the World Health Organization, Doctors of the World, Amnesty International and Physicians for Human Rights all have warned that continued restrictions will worsen the existing crisis, though most acknowledge that continued violence by Palestinian militants limits the solutions available to Israel.

Israel defends its actions, saying controlling movement in the West Bank is essential to Israeli security in the midst of a Palestinian uprising in which more than 800 Israelis and 2,200 Palestinians have been killed. Officials acknowledge that such restrictions often hold up ambulances and other emergency vehicles, but they also say Palestinian ambulances have been used to smuggle arms, ammunition and explosives.

The Israeli military said in response to a report by Physicians for Human Rights-Israel that extensive efforts are made "to allow Palestinian populations that are not involved in terrorism to conduct a basic life pattern" and that "uncoordinated and spontaneous" movement would be allowed in medical emergencies.

In practice, said Massarwah, the anxious doctor, "they do their best to humiliate human beings."

When Massarwah and the other volunteers reached Atara, a hilltop village of about 1,800 residents 35 miles north of Jerusalem, the welcome was warmer than the one at the checkpoint. A few dozen patients -- mostly women and young children -- were waiting at a school, where classrooms would serve as examining rooms. Over each door was a sign, hand-lettered in Arabic, reading "family medicine" or "pediatrics" or "ear, nose and throat."

In one room, Mustafa Yassil, an orthopedic surgeon who normally works at the Menachem Begin Medical Center in Tel Aviv, tended to a succession of patients complaining of sore shoulders and bad backs. Yassil, 35, an Israeli Arab with a face like movie star Ray Liotta and a self-assured manner like specialists the world over, worked quickly and efficiently until two men appeared carrying a young woman in a chair.

The woman said she had been sick for two years and unable to walk for three months. Speaking in a weak voice and wincing each time she gasped for breath, she said she had been to specialists in several West Bank cities and in Jordan, and had undergone CT scans and an MRI. But no one could tell her what was wrong.

Yassil spoke with her and pored over her medical charts, looking more and more exasperated with each page. He said it was clear that the problem was not with her bones but with her muscles -- and that it was serious, perhaps muscular dystrophy. He wrote a referral to a medical center in Israel where she could undergo further tests. Down the hall in the room marked "pharmacy," freshly stocked with more than $4,000 worth of medicines that the physicians' group had brought with them, Wael Saifi, an internist from the West Bank's biggest hospital, al Wattan, said it was common for rural Palestinians to go undiagnosed until an ailment reached an advanced stage. "Most of them ask for medical help only after they have complained for a long time," he said. The current restrictions on movement may not have created that problem, Saifi said, but they clearly exacerbated it. "Most of them come to the hospital in ambulances," he said. "They have a long time to wait for the ambulances, and then sometimes soldiers delay them at checkpoints for an hour or two hours." In such conditions, mobile clinics such as the one visiting Atara are crucial, doctors say. Traveling just once a week, the Physicians for Human Rights volunteers probably won't return here for a year, said Miri Weingarten, the group's coordinator for the territories. But teams from the Palestinian medical relief committees are in constant circulation and generally reach each West Bank village every two weeks, she said. After the last patient was examined and the unused medicines were placed in the trailer, the villagers barbecued hamburgers and chicken breasts for their visitors on the school's unfinished second floor. As he munched a burger, Yassil, the orthopedist, talked about the woman who had been carried into his examining room. "It's muscular dystrophy," he said. "She will live a year, maybe two. It's very sad."   © 2003 The Washington Post Company