anatomy · section one
the skeleton
206 bones · 237 joints
Point at the drawing, or search for a bone by any name you know it by. Choosing one marks it in ink and turns everything it joins onto green, because a bone on its own tells you almost nothing — what it does is decided by what it is attached to.
green marks what it joins onto
“scaphoid. two of them.”
appendicular skeleton · wrist and hand
Scaphoid
Os scaphoideum · two of them · also called navicular bone of the hand, boat bone
It lies across both rows of wrist bones and ties them together, so that the wrist moves as one unit instead of buckling in the middle. Hold your thumb out sideways and a small hollow appears at its base, called the anatomical snuffbox - the scaphoid is the floor of that dip, and pressing there is sharply painful when it is broken.
its blood enters from the thumb end only, so a break across its waist can starve and kill the half nearer the forearm
on the drawing: the wrist block lights as a whole — all eight carpals are packed into it
what it joins onto
- radiocarpal (wrist) jointsynovial ellipsoidbends the wrist up, down and side to side
- scapholunate joint, in the proximal rowsynovial planesmall glide as the two bones turn together
- scaphotrapeziotrapezoid jointsynovial planegliding under the base of the thumb
- scaphotrapeziotrapezoid jointsynovial planegliding under the base of the thumb
- midcarpal jointsynovial planegliding that adds to bending and tilting
62 entries, 206 bones