Chapter 2. Prehension

Appendix A. Human Upper Limb Anatomy
"...Nature has admirably contrived the actual shape of
the hand so as to fit in with this arrangement. It is not
all of one piece, but it branches into several pieces;
which gives the possibility of its coming together into
one solid piece, whereas the reverse order of evernts
would be impossible. Also, it is possible to use the
pieces singly, or two at a time, or in various ways.
Again, the joints of the fingers are well constructed for
taking hold of things and for exerting pressure."
--Aristotle, Parts of Animals, IV, X.
349
In this appendix, we summarize information relevant for following
terminology used in the text. We consider the entire upper limb,
including the shoulder girdle, since moving the human hand to
different spatial locations requires these structures. For more detailed
information, we refer the reader to excellent anatomy references. Our
primary sources for this information included Basmajian (1970),
Tubiana (198 l), Hollinshead (1982), and Ranney and Grainger
(1987).
A.l Planes of the Body, Terms for Direction
For clarity, anatomists use a standard anatomical position for
descriptive accounts of the human body, regardless of its position and
orientation. In anatomical position, the body is standing erect, with
the face and eyes looking straight ahead, feet together, arms by the
sides with the palms facing forwards.
Figure A.l shows the planes of the bodv, defined in anatomical
position. The sagittal plane is any vertical plane which divides the
body into right and left halves. The median sagittal plane divides the
body into right and left halves at the body midline. The frontal or
coronal plane is any vertical plane dividing the body into anterior and
posterior portions. The horizontal or transverse plane divides the
body into upper and lower parts.
Directional terms explain exactly where a structure is located on the
body. The following terms are used in the text wherever possible, for
clarity of communication.