Standard drop hanging.
Where the standard drop proves inadequate to break the neck or cause unconsciousness, the prisoner seems to suffer a more cruel death than where little or no drop is used. The force generated by a drop of 5 or 6 feet is very considerable and does great damage to the skin, muscles and ligaments of the neck but does not necessarily induce asphyxia any sooner. This description of a hanging at San Quentin prison in California is from Clinton Duffy who was the warden there from 1942 to 1954 and relates to the execution of Major Raymond Lisemba on May 9th, 1942. "The man hit bottom and I observed that he was fighting by pulling on the straps, wheezing, whistling, trying to get air, that blood was oozing through the black cap. I observed also that he urinated, defecated, and droppings fell on the floor, and the stench was terrible". "I also saw witnesses pass out and have to be carried from the witness room. Some of them threw up."It took ten minutes for the condemned man to die. When he was taken down and the cap removed, "big hunks of flesh were torn off" the side of his face where the noose had been, "his eyes were popped," and his tongue was "swollen and hanging from his mouth. His face had turned purple."
Fortunately not all standard drop hangings were so gruesome and many prisoners did not show any signs of physical suffering as they were rendered unconscious by the force of the drop, even though their spinal cord was not severed.
See the description of the hanging of Westley Alan Dodd in Washington state in 1993. scroll to bottom of page.

The measured or long drop.
Here is an official government photograph of a long drop hanging in Kuwait.The hyperflexion of the neck caused by the British style eyelet noose is self evident.
It takes between a half and three quarters of a second for a person to reach the end of the rope after the trap opens, depending upon the length of drop given. The force produced by the prisoner's body weight multiplied by the length of fall and the force of gravity (some 1,100 ft lbs being normal in the U.K. after 1939), coupled with the position of the noose is designed to violently jerk the persons head backwards and sideways. In medical terms this is known as hyperflexion of the neck, which causes fracture-dislocation of the upper neck vertebrae, ideally between the C2 & C3 vertebrae, crushing or severing the spinal cord leading to immediate unconsciousness.This leads to a number of factors, all of which can cause death.The Phrenic nerve which controls the diaphragm emerges between the C3 and C4 vertebrae and thus if the fracture occurs above C4 the person's breathing ceases immediately, leading to asphyxia.The rope constricts the carotid arteries and the jugular veins, with the same results described in Short drop hanging above.Typically the neck is constricted by as much as five inches from its original circumference.In some of the photos of Kuwaiti hangings the leather or rubber washer is visible on the rope and one can get a good idea of the amount of constriction of the neck, as it was against the eyelet before the hanging and is designed not to move.Fractures of the hyoid bone and larynx typically occur which on their own can prove fatal as breathing is severely restricted or prevented.The normal cause of death is given as comatose asphyxia.Some slight movements of the limbs and body may occasionally occur but are almost certainly due to muscular reflexes.