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SKELETON AND FEATHERS: examination of a mounted bird skeleton and dried and mounted feathers will highlight many of the specializations of birds for flight. Your drawings and notes:

ALLOMETRY (COMPARATIVE MEASUREMENTS):

These will help you to appreciate the differences in bird/human hand and structure and function. From a pigeon skeleton (less messy than from the pigeon wing), make the following measurements in cm for both bird and person.

WING DISSECTION: although this laboratory will concentrate on dissection of internal viscera, try to highlight major features of the wing as well.

1. You should be able to palpate (feel) many of the bones of the wing in your exploration, including humerus, radius, ulna, etc.
2. Examine and dissect the skin. How are feathers attached? Do wings show different types of feathers?
3. Handling individual muscles, you should be able to find the biceps brachii m. and triceps brachii m. along the shaft of the humerus. You also might note the large tendon of the supracoracoideus m. near the humeral head. From lecture and from your reading, what is the function of the supracoracoideus m.? Note that ligaments, in contrast to tendons, connect bone to bone.
4. While the muscles of the forearm are small and difficult to distinguish, they do offer the excellent opportunity to test their actions on the wrist and hand. Tug on muscles to see what action results. Some muscles, particularly will extend the hand at the wrist, while others will flex the hand at the wrist. Can you note a general location for muscles that perform one or the other action?

1. Dispose of your dissected chicken wing in the provided plastic bags, not the yellow preserved animal bin or the regular garbage container. The"lovely" odor of rotting meat will remind you if you don't do this!
2. Please wash your instruments, your dissecting pan, and your hands with warm water and soap after dissecting.
3. You may need to pay more attention to keeping structures such as the skin moist with wet paper towels during your dissection. Without preservation, delicate structures run the risk of drying out.

1. Fresh muscle and other tissue has a different texture, appearance (and smell!) than preserved. Keep that in mind as we progress through this dissection. The greasiness will be from adipose tissue (fat). Why is there so much fat in these chicken wings?
2. First, determine what are the anterior/posterior/dorsal/ventral surfaces of your wing (hint: the thumb and the flap of skin between humerus and forearm known as the patagium should be anterior).
3. The patagium contains a muscle (patagialis m.) in its anterior cord-like edge that assists in helping the bird fold its wing when not flying.
4. You should be able to palpate (feel) many of the bones of the wing in your initial exploration, including humerus, radius, ulna, etc. Do you see a thumb with a nail on it?
5. Dissect the skin, starting from the ventral side, from the shoulder to past the wrist. Try to lift up the skin as you peel it away so that you do not cut many of the muscles
6. The skin of the bird has follicles from which contour feathers have been plucked. Some small pinfeathers (sensory) may be left. Around the elbow, you may remove a fat pad, but try not to cut or remove the tendons and other strip of connective tissue around the elbow. As you pull skin away, note the slight webbiness (from loose connective tissue) connecting the skin (epidermis and dermis) to deeper structures.
7. Note that muscles are covered by a shiny, silvery connective tissue layer called the epimysium. If you track the epimysium back to the bone, you will note that it blends into the tendon for that muscle.
8. Handling individual muscles, it is easy to find the biceps brachii m. and triceps brachii m. along the shaft of the humerus. You also might note the cut large tendon of the supracoracoideus m. near the humeral head. From lecture and from your reading, what is the function of the supracoracoideus m.? Note that ligaments, in contrast to tendons, connect bone to bone.
9. Also in the humerus one may find the brachial artery and vein in between the biceps brachii m. and triceps brachii m. The artery will be the rounder one keeping its shape better. If you are careful, you may also see a whitish thin band of a nerve nearby.
10. While the muscles of the forearm are small and difficult to distinguish, especially in fresh specimens, they do offer the excellent opportunity to test their actions on the wrist and hand. Tug on individual muscles to see what action results. Some muscles, particularly will extend the hand at the wrist, while others will flex the hand at the wrist. Can you note a general location for muscles that perform one or the other action?
11. Cut into the joint capsule of the elbow, noting collateral ligaments that surround and support the joint. When you look into the elbow, note the articular cartilage (hyaline cartilage). What three bones make up the elbow joint? Can you see them in your opening?
12. By using bone cutters at the humeral midshaft, or by looking at the cut proximal end, examine the bone marrow. What does bone marrow do?
13. Dispose of your wing and other parts in the designated plastic bags, and wash your intruments, your dissecting dish, and your hands in warm, soapy water.

|main page| |background| |03028: Physiology| |03048: Anatomy|

|03050: Invertebrate Zoology| |03051: Vertebrate Zoology| |03074: Economic Botany|

Please send comments and questions to: cronewil@hvcc.edu

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This web page last updated on March 14, 2000