TWENTY-FIVE children were injured in a pile-up in a school corridor triggered when a first-year pupil stopped to pick up her shoe.
Paramedics were called to the school to treat pupils for crush injuries, including ankle sprains, bruising and sore heads.
All the children were sent home following the incident, several were taken to hospital and five were kept off school the following day.
Stephen Miller, headteacher at Denny High School in Falkirk, said that investigations were ongoing into the incident, which happened outside the school library after morning break on Tuesday.
He insisted the corridors were supervised by both staff and senior pupils who had rushed to give immediate assistance.
He said: "It would appear that the cause of the crush was an innocent and accidental trip by a pupil, who paused to retrieve a shoe but was overtaken by the mass of following pupils unaware that there was a problem ahead.
"In the main, the injuries were soft-tissue damage, ankle sprains, dizziness and sore heads," said Mr Miller.
He added that all the injured were assessed by either a paramedic or a doctor who attended the incident.
"Parents and carers were then immediately notified and the majority of pupils were taken home as a result," the headteacher said. "A few were advised to attend hospital to check the extent of bruises and sprains."
A spokeswoman for Falkirk District council confirmed that the corridor had been supervised at the time and the crush was a freak accident.
A senior pupil at the school, which has 1,250 students, said: "The corridor was really busy, and people just kept walking, and they started to pile up.
"It was just a horrible accident, but I think the worst thing was the shock.
"We were helping the people who had been injured, and at one point it was like the scene in The Wizard of Oz when the witch is trapped underneath the house."
Denny High School is housed in a 1960s building, but staff and pupils are expected to relocate next year to a new building, which is currently under construction.
A council spokeswoman said that there was no design fault with the existing building and that the corridors are not particularly narrow.
Judith Gillespie, development manager of the Scottish Parent Teacher, said: "You don't expect it. Parents would be amazed, but these freak accidents do happen.
"And I would imagine there was some jostling at the back.
"It is very bizarre, and you can't ever legislate for the bizarre."
A spokesman for the Royal Society for the Prevention of Accidents said: "This was a significant incident in which children were injured.
"It is a timely reminder that a culture of safe thinking and safe behaviour in schools should be encouraged and subject to regular reminders.
"Young people in particular can be overcome with the excitement of the moment, and the consequences of such an event as this arising can be disproportionate to what started it."
A building project which is costing 115 million will replace the existing St Mungo's, Grangemouth, Denny and Falkirk High schools.
Denny High's new building is expected to be completed by February 2009.