Download cow bone dissection lab

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COW BONE DISSECTION LAB
Part A: Longitudinal Section
This is a section of the long bone, probably humerus or femur.
1. Find and describe the following:
___ articulating cartilage___ epiphyseal disk___ spongy bone___ compact bone___ yellow marrow2. What is the purpose of the articulating cartilage?
3. Is this cows’ bone fully developed? Justify your answer.
Part B: Elbow Joint
This is a synovial joint. Fat and muscle was cut away to be used as meat.
1. Define synovial joint.
Using the diagram below, orient your specimen so that it is in the position like the cow
was standing. Your joint should be resting on the radius and ulna.
2. Using the skeleton as a guide, determine the radius, ulna and humerus. What bone
protrudes posterior?
3. By pretending you’re a cow and standing on all fours, determine whether you are
looking at the left or right elbow? (hint: radius off the thumb and ulna off the pinkie.)
Which elbow:
Justify your answer.
4. The distal portion of the ulna and radius is fused in cows, but not in the humans.
Why is it better suited for the ulna and radius to be fused in cows and separate in
humans?
5. Find the periosteum by looking at a cross section. Describe its appearance.
6. Find the tendon of the triceps brachii (triceps) muscle attached to the olecranon of the
ulna. Draw the imaginary tricep muscle, tendon, and joint arrangement below. Label
each part.
7. Mimic the movement caused by the triceps by manipulating the joint. Describe this
movement.
8. Find the tendon of the biceps brachii muscle attached to the radial tuderosity. (Hint:
Look on the ventral side of the bone for the white tendon.) To what bone is the
tendon attached?
Draw the imaginary bicep muscle, tendon, and joint arrangement below. Label each
part.
9. Mimic the movement caused by the biceps by manipulating the joint. Describe this
movement.
10. Turn the joint so it “locks” into standing position. What is the purpose of this “lock”?
How is the arrangement different than humans?
11. Find the ligaments on the medial and lateral sides of the joint. What is the purpose of
these ligaments?
12. A ligament stretch is called a sprain. How could this happen?
13. Find the fat pad on the ventral/distal side of the humerus. Flex the joint and notice
where this fat pad is? Why is this fat pad present?
14. In a fresh specimen, the joint would be filled with synovial fluid. When you crack
your knuckles you are popping air bubbles in the synovial fluid. Why is it not
possible to crack your knuckles many times in a row?
*Make sure you are able to locate the following:
____ humerus
____ radius
____ ulna
____ triceps brachii tendon
____ biceps brachii tendon
____ ligaments
____ fat pad