Anatomy
Chicken Wing Dissection
Name:
Objectives:
1. Observe the different tissues that make up a bird's wing.
2. Relate the structure of a bird's wing joint to its function.
3. Compare and contrast the range of motion of a bird's wing with that of the human arm.
4. Observe the movement of the joint by opposing pairs of muscles.
CAUTION: Raw chicken may be contaminated by Salmonella bacteria. Keep your
hands away from your face and mouth throughout this investigation.
Follow precautions during this exercise, such as wearing gloves and washing with warm
soapy water, and there should be little or no chance of salmonella infection. You may be
working with wings soaked for several hours in 70% alcohol prior to dissection. The
alcohol treatment somewhat reduces the natural contrast between tissues that you get with
"fresh birds." Be sure to wash all tools and dissection pans with disinfectant soap and to
spray and dry your work area at the end of the period.
Work in pairs. There are several reasons for this; one of which is to reduce skin-removing
fatigue. The toughest thing about the chicken wing dissection is the time-consuming skin
removal. Allow about 20 minutes for this process. Read the entire lab before you start.
Take notes in the margins of this paper and answer questions in the space provided.
1. When the wings are removed the "butcher" may have made a clean slice and neatly
severed the upper wing bone from the body socket. If this is the case you can see the
shiny cartilage covering the end of the upper wing bone. If the cut is sliced into the
bone you can see the spongy bone tissue. If the cut is even deeper you will see the
bone marrow.
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If you have the first scenario with the whole end of bone showing you
might want to talk about the role of articular cartilage (hyaline cartilage) in
joint movement and the fluid that assists this movement.
If the spongy zone of the bone is showing, you may want to talk about this
network of bone strengthening struts and the effect of osteoporosis on this
area.
If the bone marrow is showing then you have one of the sites of red blood
cell production. Move around from group to group to see these different
views.
o
The most efficient way to remove the skin is to start at the top (proximal)
end of the upper wing with your scissors. Keep the point of the scissors up
as you cut down the middle on either the ventral or dorsal side. Cut down
to a joint and then trim to either side of your cut. When you do this you are
cutting below the dermis and above the muscle. The dermis is largely
composed of loose connective tissue that ordinarily anchors the skin to the
muscle layer. (Pinch up your skin on the back of your hand to show this
separation as well as the elastic recoil back to the original position.)
Adipose tissue (fat) is another form of connective tissue that can be seen
adhering to the underside of the skin. It is also apparent that the upper
wing has a single bone (like our humerus) and the lower wing has a double
bone structure (like our radius and ulna). This arrangement lends itself to
flexibility as well as coordination. Which joint in your body corresponds
to this joint in the chicken wing? _______________________________
Be careful not to cut any tendons or ligaments. How will you recognize
tendons and ligaments? ______________________________________
2. The muscles are contained within semi-transparent containers of connective tissue.
To demonstrate which muscles are extensors and which are flexors it is necessary to
loosely hold the wing by the upper wing bone in a horizontal manner. This will make
it easy to pull on the muscle with fingers or forceps and see what part of the wing
extends or flexes. You should be able to find a pair of extensor/flexors in both the
upper and lower wings.
3. The white tendons connecting muscle and bone can be seen in several upper and
lower wing muscle groups. Where these tendons run over joints--like the "elbow"-they are often in well developed sheathes.
4. Ligaments are not as easily seen as tendons. It may take a little digging to show these
bone to bone connections.
5. It is also possible to see blood vessels and nerves between muscle bundles and muscle
bundles and bones. It is necessary to do some teasing to see these structures and it is
worthwhile to share results at this point with the other lab groups.
6. If you sever a flexor muscle of a particular pairing it should further confirm the role
of the extensor that it was originally paired up with. (Possibly sever a flexor in the
upper wing and an extensor in the lower wing.)
7. Bend and straighten the joint and observe how the bones fit together. The shiny, white
covering of the joint surfaces is made of cartilage.
o What is the purpose of this cartilage?
8. See page 251 -265 in your text. Sketch your elbow joint, and label: the bone names,
the articular cartilage, articular capsule, synovial capsule, and the synovial membrane.
9. What is the structural class of the elbow?
10. What is the type of joint in the elbow (like hinge, ball and socket, or pivot)?
11. Name and describe the motions allowed by the elbow.
12. Using three different colors add a tendon/muscle to your sketch of the elbow and also
add a ligament. Make a key to show the color you use for each: tendon, muscle, and
ligament.
13. What is the difference between a tendon and a ligament?