Download Activity – Analyzing the Triceps Brachii Shoulder (Glenohumeral

Activity – Analyzing the Triceps Brachii
In this activity we will use the "3 Rules of Muscles" to determine the joint actions of the biceps
triceps. Answer the questions below:

Hints in Blue
http://upload.wikimedia.org/wikipedia/commons
Shoulder (Glenohumeral) Joint Actions Word Bank
Action
Plane
Flexion
Extension
Abduction
Adduction
Horizontal Abduction
Horizontal Adduction
Internal Rotation
External Rotation
Sagittal
Sagittal
Frontal
Frontal
Transverse
Transverse
Transverse
Transverse
© 2014 Brent Brookbush
Elbow (Humeroulnar) Joint Actions Word Bank
Action
Plane
Flexion
Extension
Sagittal
Sagittal
1. What joint or joints does this 3 headed muscle cross?
Elbow
2. What about the long head of the triceps, does it cross an additional joint?
Yes, Shoulder
3. Since the triceps runs up and down on the back of the elbow, what joint action will it contribute to?
Extension
4. Can the triceps contribute to forearm pronation or supination?
No - The radius is the “moving” bone of the forearm. The radius literally “revolves” or “spins”
around the stable ulna. A muscle can only contribute to supination or pronation if it has an
attachment to the radius.
5. Now, the tricky one - What actions will the long head of the triceps contribute to at the shoulder?
(Hint: the origin of the long head of the triceps is inferior and posterior aspect of the glenoid fossa)
Adduction and extension (due to the location of the origin the long head of the triceps can pull
the humerus down and back, i.e. adduction and extension)
© 2014 Brent Brookbush
6. Re-write your answers into one succinct table?
Triceps Brachii
o Joints crossed:
 Lateral & Medial Head: Elbow
 Long Head: Elbow and Shoulder
o Actions:
 Extension
 Long head will contribute to shoulder adduction and extension
Check your answers!
© 2014 Brent Brookbush