It is the region's most advanced medical resource. Yet al-Arish hospital, in Sinai, is receiving only a trickle of patients from Gaza

Inside al-Arish hospital, a modern slab of stone and glass in the heart of northern Sinai's dusty administrative capital, doctors huddle in an office staring in silence at the latest scenes from Gaza flashing up on al-Jazeera TV.

Ahmed Ellabban, professor of surgery at Suez Canal University, shakes his head as he surveys the scene. "There are 4,000 injured people just 50km from here," he says quietly. "We're sitting in a very well-equipped hospital with more than 100 doctors on call, ready to deal with more than 400 emergency cases through the week. But they are not coming. We don't know why. We just wait."

Oscillating between silence and mayhem, al-Arish hospital – the receiving point for all wounded Palestinians who make it across the Egyptian border – is a surreal backdrop to Gaza's growing humanitarian crisis. With the number of patients making it through the contentious Rafah crossing each day rarely reaching double figures, the region's most advanced medical centre sits frozen in tense expectation most of the time, its tiled corridors empty save for the odd cleaner or local official doing the rounds. On some days, nobody arrives at all.

But each time a Palestinian ambulance does make it across the thin patch of sand and barbed wire marking no man's land between Gaza and Egypt, the hospital erupts into activity as staff prepare to receive their new case. They know it is unlikely to be a simple one. "Which body part haven't I seen missing?" says one para­medic when asked what type of shrapnel injuries he had witnessed in victims being transported to al-Arish. According to hospital records, one in six of those victims have been children.

Perched on a rickety stool outside the ER, her face illuminated by flickering blue ambulance beacons, Nawal Wasa prays for her teenage daughter's life as doctors fight to save her inside. "She's only 16 years old," Nawal says fiercely. "She wanted to finish high school and go to university. That's all she ever wanted."

Nawal's horror began the previous week, when she decided to retrieve Hanin from what she thought would be a safe refuge: her brother's house in the Gazan neighbourhood of Zeitoun. "My own house was riddled with bullet holes so I sent Hanin there to protect her. But that morning, I had a sudden fear of her not being near me, and I knew I had to have her in my arms as soon as possible. Destiny got to her before I could."

As Hanin and her uncle stood in the doorway, Israeli jets dropped a single bomb on the house. "He is a teacher; she is a student. We're not Hamas. We don't have anything to do with Hamas," says Nawal. "The rubble tore off my brother's legs and completely severed Hanin's right foot. By the time I reached the house, people were already telling me Hanin was dead."

In fact, Nawal's daughter was alive, but an endurance test of staggering proportions was awaiting her. Like all those who eventually pull up in al-Arish hospital's car park, her mother had to navigate a bureaucratic maze of Gazan medical officials, the Palestinian embassy in Cairo, Hamas border guards and Egyptian military brass before the go-ahead was given for Hanin to be driven down through the battered Gaza Strip.

The journey itself was made on roads torn up by Israeli mortar fire, each bump accentuating the pain of her injury. Ambulances often have to strike out into the desert and crawl through the sand, under constant risk of being bombed by F16 jets; two doctors and 12 ambulance drivers have been killed making just such a trip in recent days.

"They are murdering the innocent, and those whose try and help the innocent. It's criminal behaviour," says Ellabban of the attacks on medics. At the border, a whole new set of searches, registrations and document inspections begins before a transfer of stretchers takes place under the baking Sinai sun and an Egyptian orange ambulance begins the home leg to al-Arish.

As Hanin lies, conscious but silent under a mesh of tubes, the hospital lurches yet again from lethargy to frenzy. Planes have arrived in the nearby al-Arish airbase to ferry those closest to death on to specialist units in Cairo and Saudi Arabia, and paramedics leap up from the cafeteria to get their ambulances ready. Relatives spill out on to the steps of the ER as a stretcher is rushed past. It appears empty until you notice its small human cargo in the middle, buried under a mountain of blood bags and seemingly held together by wires.

The child on the stretcher is eight-year-old Zakaria Ahmed. His father, Hamada, a textiles worker in Zeitoun, can barely lift his eyes from the ground as the ambulance doors swing open and his son is loaded on.

Two days earlier, Zakaria had been playing in the street, making the most of the free time thrown up by his school's impromptu closure as a result of the bombardment. It was shortly after 9am when mortars began pounding the alleyway; within seconds, shrapnel had embedded itself in Zakaria's legs and skull. Despite his critical condition, though, Zakaria is one of the lucky ones.

"The hospitals at home are overflowing and there's no space for us, so thanks be to God that we reached here," says Hamada flatly. He gazes at the scrum surrounding his son in the car park. "Thirty people from my family are already dead. I hope the Israelis one day experience the same nightmares they have brought upon us."

Two more children are brought out for transfer. "My sister and two of my cousins were killed by an Israeli rocket as they drank tea on their roof," says Mahmoud Afana as a third cousin, 10-year-old Ibrahim, is wheeled past. "The Israelis, they have no targets. They just fire randomly, like crazy people."

Another young man, 24-year-old Mohammed Najwar, tells his story. "There were 20 of us sitting round the fire listening to the radio and wondering when we would ever be safe," he says, puffing furiously on a cigarette as a crowd surges in to listen.

"We only use the radio because there is no electricity for the television. Suddenly there were four huge explosions above us and I found myself trapped under a rock. By the time the dust cleared, I could see the bombs had taken away my father and two of my brothers. My other brother is here," he adds, jerking his thumb towards the hospital doors. He offers a hollow laugh when asked why the Israelis targeted his house. "Because there is nothing else left to target."

Political debate feels like an unaffordable luxury for relatives of the Gazan wounded, preoccupied as they are with the life and death of their children. But when recriminations are handed out, their focus varies. "Of course, Israel will always be our enemy," says Nawal Wasa.

"They are malicious and they are liars. Look around you – we are all civilians; we are all victims of our own houses crumbling upon us. I hope somebody gives me some explosives so I can give them what they have given me. But we must also look at the Arab regimes, even here in Egypt. Yes, the people here are good, but what about the government? What are they doing?"

For Mahmoud Afana, the problem lies closer to home. "I think this war will end only when Hamas gives up on some of its demands. And it is not only me praying they will do that – it's the whole of Palestine," he says. Pro-Hamas graffiti regularly appears on walls in this area, but Afana isn't afraid. "Hamas are in their hideouts; it's the people who are getting hurt."

The ambulances leave, the circus subsides, and as night falls on al-Arish, the hospital's small army of healthcare workers settle themselves back down for another extended bout of strained anticipation. Over in his office, Ellabban refuses to be drawn into the blame game. "Regardless of who is at fault, there are doctors and equipment on this side of the wall and sick patients on the other side. Who is responsible for this crime?"

He lights a stick of incense and mentions 45 Egyptian doctors still stuck at the Rafah border crossing, having been refused permission to enter Gaza and tend to the injured. "We are all medical professionals, with a duty to treat people regardless of politics or religion. Every single person here is ready to go into Gaza on our own responsibility to work and serve these people, and we're ready to die. We know what awaits us on the other side."

And with that, the professor leans back on his chair and returns his gaze to the television, preparing for a long night of examining dying Gazans – through a screen, powerless to help them.