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
“sternum. one of them.”
axial skeleton · chest
Sternum
Sternum · one of them · also called breastbone, chest bone
It is the shield at the front of the chest: the upper seven rib cartilages and both collarbones anchor onto it, and it covers the heart and the great vessels behind it. Run a finger down the midline from the soft notch between your collarbones and about two finger-widths down you will feel a firm ridge across the bone - the sternal angle, the joint between manubrium and body, and the level where the second rib cartilage joins.
about 1 in 20 people have a natural hole straight through it, the sternal foramen
what it joins onto
- sternocostal joints (via the costal cartilages)1st cartilaginous synchondrosis; 2nd-7th synovial planeslight glide - lets the chest widen as you breathe in
- sternoclavicular jointsynovial saddle with an articular discswivel - lets the collarbone lift, drop and swing
62 entries, 206 bones