In Ether 15:31 we find an interesting description of decapitation: And it came to pass that after [Coriantumr] had smitten off the head of Shiz, that Shiz raised upon his hands and fell; and after that he had struggled for breath, he died.
According to research by Gary Hadfield and John Welch, people have long wondered how Shiz could raise himself up, fall, and gasp for breath if his head had been cut off. Dr. Gary M. Hadfield, M.D., professor of pathology (neuropathology) at the Medical College of Virginia in Richmond Virginia has recently published in BYU Studies, 33 (1993): 324-25:
"Shiz's death struggle illustrates the classic reflex posture that occurs in both humans and animals when the upper brain stem (midbrain/mesencephalon) is disconnected from the brain. The extensor muscles of the arms and legs contract, and this reflect action could cause Shiz to raise up on his hands. . . In many patients, it is the sparing of vital respiratory and blood pressure centers in the central (pons) and lower (medulla) brain stem that permits survival.
The brain stem is located inside the base of the skull and is relatively small. It connects the brain proper, or cerebrum, with the spinal cord in the neck. Coriantumr was obviously too exhausted to do a clean job. His stroke evidently strayed a little too high. He must have cut off Shiz's head through the base of the skull, at the level of the midbrain, instead of lower through the cervical spine in the curvature of the neck . . . Significantly, this nervous system phenomenon (decerebrate rigidity) was first reported in 1898, long after the Book of Mormon was published.
In addition, the words "smote off" need not mean that Shiz's head was completely severed by Coriantumr. In Judges 5:26 Jael, the wife of Heber "put her hand to the nail, and her right hand to the workmen's hammer; and with the hammer she smote Sisera, she smote off his head, when she had pierced and stricken through his temples." Surely Jael did not cleanly chop off Sisera's head using a hammer. Indeed, both the Hebrew and Greek words translated as smote off mean "to hammer" or "to strike down with a hammer or stamp," but not generally to smite off. No more necessarily does Joseph Smith's translation in Ether 15:30 need to mean that Shiz's head was completely cut off. Fifty or sixty percent off would easily have been enough to get the job done, leaving Shiz to reflex and die. [Gary M. Hadfield and John W. Welch, The "Decapitation" of Shiz, in F.A.R.M.S. Update, Number 97, November, 1994]