Download Skeletal System Take

Skeletal System Take-Home Assignment
If you do not have time to work on this last part of the chapter in lab, then complete it on your
own before the next lab. Your instructor may wish to have you turn it in for a grade. If so, then
you can print a copy of this part of the chapter from the PGCC A&P web site.
Objective 4: Define terms used to describe common structural features of bones.
When identifying bones, we are going to look at features visible from the surface, without having
to break the bone open. Most of the time, we are going to look at structures that protrude from
the surface of the bone, or we are going to look at depressions or holes in the bone. In the
following chapters you are going to be asked to learn many specific terms for these protrusions,
depressions, and holes. It will often seem that these names are completely random and
meaningless, but there are some generalities that will help you.
When a structure protrudes from the surface of a bone, it typically has one of two functions: to
articulate (make a joint) with another bone, or to serve as an attachment site for a muscle. If the
articulation (joint) is able to move, then the articulating surface will be smooth. A smooth
articulating protrusion often has one of the following names:
1. A condyle is a rounded projection.
2. A head is a rounded end of a bone.
Joints that are immoveable, such as where your hip joins your spine, are generally roughened.
However, most of the roughened projections that we will observe are for muscle attachment. A
projection for muscle attachment often has one of the following names:
1. A tubercle is a small, roughened projection.
2. A tuberosity is a larger, roughened projection.
3. A trochanter is a very large, roughened projection found only on the femur.
4. A spine is a slender ridge of bone.
5. A line is a long, narrow ridge.
6. A crest is a ridge that usually forms a border of the bone.
7. An epicondyle is a roughened projection superior to a condyle.
8. A process may have just about any shape. (Some “processes” we will study are for
immoveable articulations.)
Depressions and holes have a wide variety of functions:
1. A facet is a shallow, smooth indentation for articulation.
2. A fossa is a deeper indentation, often for articulation.
3. A meatus is a tube-shaped cavity.
4. A foramen is a hole that goes through the bone.
5. An alveolus is a socket for a tooth, found only in the maxillae and mandible.
6. A sinus is a cavity within a bone.
ACTIVITY 4
• If you are working on this activity outside of the lab, then refer to figures in your lab
manual, your textbook, or online. If you have a chance to work on this in the laboratory,
then by all means look at the real bones!
Temporal bone: Look at a picture of a temporal bone (or the real thing). How many
structures can you find on the temporal bone that are named using terms on the previous
page? Make a list of them in the space below:
Humerus: Repeat the exercise above for the humerus.
Femur: Repeat the exercise above for the femur.
• In the space below, list two terms from the previous page that cannot be found on any of
the three bones listed above. Next to each, write the name of one bone that has such a
structure. One example is given, but you still have to do two more.
Spine–scapula
QUESTIONS
7.
Why are surfaces for moveable articulations smooth?
8.
Why are surfaces for muscle attachment rough?