Those trapped inside Syria's borders are sometimes more vulnerable than those that escape. We attempt to lift the lid on the humanitarian issues in Syria that you may not be aware of

The legacy of Syria's conflict may well be its refugees; they are by far the most prominent humanitarian consequence of the fighting so far, but they do not reflect the full scale of Syria's disaster. Other emergencies are going unnoticed in the country - here we discuss what they are, and why they remain invisible.

Refugees

When those affected by the fighting in Syria flee their homes and cross the country's borders they also step out from the darkness of a near total media blackout. Those who arrive in states like Lebanon, Jordan and Turkey instantly become more visible - the United Nations can attempt to count them, aid organisations can attempt to meet their needs and journalists can photograph them and speak to them in an attempt to record and relate their experiences.

That is not to say that refugees have it easy – far from it. They are viewed at best as a problem and at worst as a national threat by the countries that host them. However for every Syrian refugee, there are dozens more inside the country who are also vulnerable, albeit for different reasons.

IDPs

Internally displaced people (IDPs) are those that have fled their homes - often for very similar reasons that refugees have left theirs. They also frequently endure the same upheavals in terms of disrupted education, employment and family separation. But, unlike refugees, IDPs remain under the protection (or, as the case may be, at the mercy) of their own government. In the case of Syria, the government may be the very cause of their flight. Technically, the UN's refugee agency, UNHCR, is not responsible for protecting and assisting these individuals but it has traditionally done so nevertheless.

Of Syria's population of 21.9 million people, almost 1 in 5, a staggering 4.25 million are estimated to be displaced within their country's borders. Some of these had already been forced to leave their homes before the fighting began but the Internal Displacement Monitoring Centre (IDMC), which monitors displacement worldwide, believes that many Syrian IDPs are a direct result of the current conflict. More people are becoming internally displaced in Syria than anywhere else in the world.

Estimating the number of Syrian IDPs is particularly challenging. Individuals and families that have been displaced are often constantly on the move and unless they arrive in camps they are difficult to count. They may be living in out of reach areas, lack personal documentation or be frightened to make themselves known for fear of persecution. Just like refugees, they may be forced to move to areas where they are not welcome.

In the case of Syria, the largest challenge by far though is the simple fact that most aid agencies can't get in. As War Child puts it: "the government won't allow it and the security situation is too unstable." The UN's humanitarian chief, Valerie Amos, pleaded for cross-border access in April this year to no avail.

Sick and wounded

A lack of access doesn't just affect those who have left their homes. Sometimes, the most vulnerable people in a crisis are those that are trapped, unable to move to any kind of sanctuary. Fighting in the country continues, as does the bombing of towns. The Syrian government has claimed that half of all hospitals are now out of service but even those that are left standing are not always able to act as safe houses to the wounded as a series of shocking revelations has demonstrated.

A UN report in February this year found that "wounded and sick persons were refused treatment on sectarian or political grounds". The list of such incidents includes wounded children. In a separate address, the UN's high commissioner for human rights reported to the general assembly about the widespread destruction of hospitals that were being systematically attacked by military and security forces.

The commissioner also cited evidence that "hospitals had been used as detention and torture facilities". A report by Amnesty International in 2011 found that in some cases medical staff had been involved in the abuse. Even blood transfusions posed a risk according to the report, since the blood bank itself was controlled by the defence ministry and therefore assisted their ability to identify regime opponents.

Dr Fadi Al Khankan of the Syrian Expatriates Organisation claims that medical students that have protested against the regime have been prevented from receiving their certificates and that medical personnel had been targeted by security services.

With pharmaceutical factories in Syria down to a third of normal production, the long-term sick are also affected. Some pharmacies are rationing medication to individuals, which has increased demand for dangerous medication on the black market.

Invisibility

The problems that the vulnerable groups within Syria face are dramatically compounded by their inability to communicate them. Google's Transparency Report mentions two incidents where all Google products were blocked in the country – the first on 19 July 2012, the second for three days in November 2012 – but looking at web traffic reveals countless other disruptions to services.

Lack of access to electricity means that even when normal web activity is resumed, not everyone is able to gain information and communicate their concerns to others inside and outside the country.

Initiatives

A digital media project called Syria Deeply has attempted to collect together independent journalists and technologists and find new ways of telling the story of Syria's humanitarian disaster. They join the group of organisations attempting to use data and technology as a means of communicating to the outside world what is happening inside. In August Guardian data produced this animated map of deaths in the country.

The most comprehensive initiative by far however has been the Syria Tracker Crisis Map which was launched in 2011 just a few weeks after protests in the country began. The map collects online sources such as news articles and blog posts and checks these against first-hand reports that have been crowdsourced from websites like Facebook, Twitter and YouTube.

Though not perfect, the 3,346 reports they have collected – on rape, water tampering, revenge killings and chemical poisoning, as well as disease and epidemics – provide an unparalleled insight into the hidden disasters of a conflict whose cost is felt every bit as acutely inside the country as it is outside.