Mark Cavendish has withdrawn from the Tour de France after he suffered a fractured shoulder blade in a horrendous crash 200 metres from the finish line on stage four. Cycling’s governing body quickly disqualified the world champion, Peter Sagan, for a dangerous move in the sprint finish in which he appeared to elbow the British rider to the floor.

Tour de France: Arnaud Démare wins stage four after late crashes – live! Read more

Cavendish also sustained a heavy cut to his hand and was taken to hospital for x-rays to investigate injuries to the shoulder he damaged in a similar pile-up at the end of the first stage of the Tour in Harrogate in July 2014. In a chaotic finale, the yellow jersey holder, Geraint Thomas, also fell – but to no ill effect.

On Tuesday night it was confirmed that Cavendish’s Tour is over. “I’m obviously massively disappointed to get this news about the fracture,” he said. “I feel I was in a good position to win [the stage] and to lose that and even having to leave the Tour, a race I have built my whole career around, is really sad.”

Cavendish’s sporting director at Dimension Data, Roger Hammond, described the move that led to Sagan’s expulsion as “a flick of the elbow which was completely outrageous”. He added: “No one comes out of it well. This is a sad, sad day for the sport, Sagan is a hero and an idol of mine but a precedent has to be set.”

Facebook Twitter Pinterest Peter Sagan and Mark Cavendish during the final sprint of the 4th stage of the Tour de France. Photograph: Yoan Valat/EPA

Sagan was initially relegated to 115th place on the stage – last place in the lead bunch – and received the standard sanction of a 30-second time penalty but the president of the jury, Philippe Marien, said the referees applied a sterner sanction because the world champion “had put several other riders involved in the crash in danger”.

Sagan’s Bora-Hansgrohe team announced they had officially protested about the Slovak’s expulsion. The German team said Sagan “rejected [the claim] to have caused, or in any way intended to cause, the crash of Mark Cavendish”. On Wednesday morning, Sagan appeared to have accepted his fate.

“I can accept the decision but for sure I do not agree with them, because I think I have done nothing wrong,” Sagan said in a statement delivered outside the team hotel.

“It is very bad that Mark fell down, it is important he can recover well, I am sorry for that,” he added. “As you saw it was a crazy sprint, it was not the first one like that or the last one. I wish that Mark recovers well.”

In two crashes in the final kilometres involving about 20 riders, it was Cavendish who came off worst, being the first of three sprinters to hit the deck. He lay prone on the tarmac as the rest of the group passed and crossed the line several minutes after the stage winner, Arnaud Démare. Cavendish was holding his right shoulder, with his skin suit ripped from shoulder to waist, and with heavy bandaging on his right hand.

Facebook Twitter Pinterest Mark Cavendish crosses the line in obvious pain following the crash. Photograph: Christophe Ena/AP

“I’m going to go and get it checked out,” he said. “I will definitely need stitches in this finger, it’s bleeding a lot. With the shoulder, it might be something to do with a previous injury, it’s sat backwards, so I’m not sure if I’ve done something to the ligament. I’m not a doctor but from the feelings, I’m not optimistic.”

The Guardian understands he hit the road so hard he folded the spider and the chainring of his chainset so that they were pointing backwards. Sagan was one of several riders, including Cavendish, who launched their sprints in the wake of the Norwegian Alexandr Kristoff and were accelerating to full speed with around 250m to go. Cavendish was following Démare through a gap between Sagan and the crowd barriers when the Slovak moved to his right, making contact with the Manxman.

Sagan then lifted his elbow up and Cavendish was forced into the barriers in a split second and fell heavily on his right side. “There was no reason for that elbow,” said Hammond. “As a former professional bike rider I know the way it is done.” The German John Degenkolb, who was close behind, rode over Cavendish’s body and helmet and also fell, while the Briton Ben Swift performed a somersault over Cavendish’s bike as it lay on the ground but later told the Guardian he had no injuries.

Facebook Twitter Pinterest Mark Cavendish awaits assistance by medics after the crash on the finish to stage four. Photograph: Robert Ghement/EPA

“I get on with Peter well; if he came across that’s one thing but I’m not a fan of him putting his elbow in me like that,” Cavendish said. “A crash is a crash but I would just like to know about the elbow. I have a good relationship with Peter but I would like to speak to him about it.”

The world champion apologised to Cavendish afterwards but offered no real explanation. “I didn’t know Mark was behind me, he was coming from the right side and I wanted to take the wheel of Kristoff, I think. I wanted to go on his wheel but Mark was coming pretty fast from the back. I didn’t have time to react to go left, he just came to me and then to the barriers.”

Sagan added: “When I was told after the finish that Mark had crashed, I went straight away to find out how he was doing. We are friends and colleagues in the peloton and crashes like that are never nice. I hope Mark recovers soon.”

Philippe Marien, the head UCI commissaire [race official], said: “Before the Tour de France we warned the sprinters that we would look very closely at every sprint, that is what we did today. It was not an easy decision, but this is the beginning of the Tour and now is the moment to set our boundaries. And that is what we did today. It was not about Sagan, but about the act the rider made. What happens here, it looks like it was on purpose and it almost looks like hitting a person. It’s not about Cavendish and Sagan, it could be anybody, the names won’t matter.”

Better known as a sedate spa town and a still mineral water, Vittel does things when the Tour comes to visit. In 1968 this was the start town for a Tour de Santé, supposedly to relaunch the sport in the wake of Tom Simpson’s death, but which ended in two positive drug tests over the three weeks.

On Tuesday, what should have been a decorous celebration of 10 years in which Vittel has been the ‘eaufficiel’ du Tour, ended in Sagan’s disqualification.

This was a massive event, partly because of Sagan’s profile as the most popular rider in cycling, but also because this was the first time a world champion had been thrown off the race since Laurent Brochard was given his marching orders during the Festina drug scandal of 1998. And it is rare indeed for the race’s referees to decide that any of the plethora of dodgy manoeuvres and dirty tricks that happen in sprints is sufficiently life-threatening to merit expulsion.

The last time such a thing happened was in 2010 when the mild-mannered Australian Mark Renshaw decided to use his head as well as his legs at Bourg les Valence, not once, but several times, while in 1997 the otherwise utterly genteel Belgian Tom Steels was sent home for bunging a bidon at a fellow fast man.

The problem boils down to this: sprinters are usually as pleasant as they come, but the scent of the line causes a red mist to descend. This is part of their makeup, but just occasionally there is an attempt to draw a line. Unfortunately the fast men will be butting up against that line – if that is not an unfortunate choice of words – soon, probably as early as Thursday.

Facebook Twitter Pinterest Arnaud Demare celebrates as he crosses the finish line to win stage four of Le Tour de France. Photograph: Chris Graythen/Getty Images

Sagan’s expulsion left the race for the green jersey wide open, and the favourite now will be the Frenchman Demare, who emerged from the chaos here to give France its first bunch sprint stage winner since Jimmy Casper. Demare is the national champion and rides for the national favourite Francaise des Jeux, whose patriotic manager Marc Madiot refuses to sully the tricolour by letting it be daubed with his sponsors’ logos.

France will delight in Demare’s win, which reflected well on his turn of speed and it will follow his quest for the green jersey with bated breath in the next 17 days. If there was a slight false note, it came when he was accused of misbehaviour by fourth-placed Nacer Bouhanni, who alleged he had cut him up in the finale. Then again, nor is Bouhanni a stranger to the referees’ communiques. Where sprinting is concerned, earning the right to throw the first metaphorical stone is a big ask.

On Wednesday, the race gets serious with the finish at La Planche des Belles Filles ski resort in the Vosges mountains north of Belfort. The Tour has finished here twice, in 2012 and 2014, and on each occasion the race leader at the summit – in 2012 Bradley Wiggins, in 2014 Vincenzo Nibali – has worn yellow all the way to Paris, and perhaps more importantly that the finishing order at the summit strongly reflects the eventual standings at the end of the Tour.

In both years, seven of the first 10 finishers on top of the 20% wall that concludes the six-kilometre climb also finished in the first 10 in Paris. The chances are that either Geraint Thomas or his leader Chris Froome will retain the lead for Team Sky, although the Welshman hinted that Team Sky may give free rein to a long-distance escape. In Vittel, Thomas fell in a 15-man pile-up in the final kilometre, while Froome was held up, but did not fall.

That would happen if there are no riders up front who are a threat to Froome in the overall standings, as relinquishing the lead to another team will relieve them of the need to expend energy in defence of the maillot jaune. “I don’t think we will waste a lot of energy to bring back a big break if there is no one dangerous in it, and if it goes to someone who is not a threat overall, it’s not a big deal. If we are all together on the climb Froome is our main goal, so I will do what I can to help him. If he gets the jersey, great, if I keep it, that’s even better.”