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Founded and led by Dr. Theodore Dimon, The Dimon Institute is a world-renowned center for the study of the Alexander Technique in New York City, providing the most comprehensive, in-depth training and Alexander Technique teacher certification (AmSAT certified) available. 

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Recent Posts

Do the Skull and the Head Have the Same Center of Gravity?

June 29, 2018

Many of our readers have contacted us about our recent blog post (June 17, 2018),  which describes a simple experiment for locating  the center of gravity of a model skull. They have pointed out the major differences between a skull and a head. Their question is this: you’ve measured a skull, but do the skull and the intact head have the same center of gravity? A skull is a skull, after all, and nothing but bone. It lacks a brain, eyes, blood vessels, and fluid of any kind. All this soft tissue that we neglect in our experiment has  mass--in fact more mass than the skull itself. Does the weight of the soft tissue change the distribution of weight in the head from that of the skull?

 

This  is not  an easy question  to answer, as the  head is  not amenable to the kind  of lay research described in  our blog. It was a simple matter  to hang our model skull from a string and trace plumb lines. Performing this experiment using an intact human head was, for us, impossible and undesirable. However, researchers in crash test laboratories have addressed this very question, developing elaborate preparations and methods to determine the center of gravity of cadaver heads. In a report submitted to the Office of Naval Research, Beier et al. (1979) calculated the average center of gravity of several dozen cadaver heads. They found an average location at “0.8 cm in front of the auditory meatuses and 3.1 cm above the Frankfort plane” (Beier et al, 1979, 21, 24), along the mid-sagittal plane. In plain English, this means that this point is on the midline of the skull, about an inch forward of the atlantooccipital joint, and another inch up from there. In other words, it's at the sella turcica. To read the report, follow this link. More recently, researchers have developed digital representations of the head and used them to make similar measurements. For an example, follow this link.

 

So it is a curious physiological fact that the center of gravity  of the skull is the same as the center of gravity of the intact head. 

 

We thank our readers for their input,  and welcome your comments.

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