Ipad Muscle Action Lab
Using the Ipad app: Visual Body MUSCLE Premium, open the ACTIONS icon from the home menu.
Activity 1: Mandible Movements
Elevation: Select the Mandible elevation icon. Elevation is the movement of the bone in the superior
direction by the muscles. Select the ACTION info tab in the upper left corner. Highlight the temporalis
muscle on the model and view the action of that muscle. (NOTE: The masseter is also considered a
prime mover of elevation of the mandible.) Indicate the muscles involved as the agonists (prime
movers) in the table below. Now practice with yourself doing the action of mandible elevation. Can you
feel the muscles that are the prime movers contracting to perform the action?
Depression: Select the Mandible depression icon. Depression is the movement of the bone in the
inferior direction by the muscles. Select the ACTION info tab in the upper left corner. Highlight the
digastric muscle on the model and view the action of that muscle. Note the muscles involved as the
agonists (prime movers) in the table below. Now practice with yourself doing the action of mandible
depression. Can you feel the muscles that are the prime movers contracting to perform the action?
Retraction: Select the Mandible retraction icon. Retraction is the movement of the bone in the posterior
direction by the muscles. Select the ACTION info tab in the upper left corner. Note the muscles involved
as the agonists (prime movers) in the table below. Highlight the digastric and temporalis muscles on the
model and view the action of that muscle. Now practice with yourself doing the action of mandible
retraction. Can you feel the muscles that are the prime movers contracting to perform the action?
Protraction: Select the Mandible protraction icon. Protraction is the movement of the bone in the
anterior direction by the muscles. Select the ACTION info tab in the upper left corner. Note the muscles
involved as the agonists (prime movers) in the table below. Now practice with yourself doing the action
of mandible protraction. Can you feel the muscles that are the prime movers contracting to perform the
action?
Review Question: What role is the masseter playing in these actions?
The masseter is the muscle involved in mastication (Chewing) by acting as an agonist in mandible
elevation.
Complete the following table.
Action
Mandible Elevation
Mandible Depression
Mandible Protraction
Mandible Retraction
Prime Movers (Agonists)
Temporalis; medial pterygoid; masseter
Geniohyoid; mylohyoid; digastric; stylohoid
Lateral pterygoid; medial pterygoid
Temporalis; digastric
Activity 2: Shoulder/Arm Movements
Flexion: Select the Shoulder Flexion icon. Flexion is a bending movement (sagittal plane) that decreases
the angle of joint bringing articular bones together & bending the trunk, arm, or knee from straight to an
angled position. Select the ACTION info tab in the upper left corner. Highlight the deltoid, pectoralis
major, biceps brachii, and serratus anterior muscles (one at a time) on the model and view the action of
that muscle. Indicate the muscles involved as the agonists (prime movers) in the table below. Now
practice with yourself doing the action of shoulder flexion. Can you feel the muscles that are the prime
movers contracting to perform the action?
Extension: Select the Shoulder Extension icon. Extension is the opposite of flexion occurring at the same
joint resulting in Increases in the angle between articulating bones; often resulting in straightening the
limb to its anatomical position. Select the ACTION info tab in the upper left corner. Highlight the
deltoid, latissimus dorsi, triceps brachii, teres major, and pectoralis major muscles (one at a time) on the
model and view the action of that muscle. Indicate the muscles involved as the agonists (prime movers)
in the table below. Now practice with yourself doing the action of shoulder extension. Can you feel the
muscles that are the prime movers contracting to perform the action?
Abduction: Select the shoulder horizontal abduction icon. Abduction is the movement of a limb away
from the midline along the frontal plane. Select the ACTION info tab in the upper left corner. Highlight
the deltoid muscle on the model and view the action of that muscle. Indicate the muscles involved as
the agonists (prime movers) in the table below. Now practice with yourself doing the action of shoulder
abduction. Can you feel the muscles that are the prime movers contracting to perform the action?
Adduction: Select the shoulder horizontal adduction icon. Adduction is opposite of abduction or
movement of a limb toward the midline. Select the ACTION info tab in the upper left corner. Highlight
the deltoid and pectoralis major muscles (one at a time) on the model and view the action of that
muscle. Indicate the muscles involved as the agonists (prime movers) in the table below. Now practice
with yourself doing the action of shoulder adduction. Can you feel the muscles that are the prime
movers contracting to perform the action?
Rotation: Select the shoulder medial rotation icon. Rotation is the turning the bone around its own long
axis and may occur toward or away from the midline. Select the ACTION info tab in the upper left
corner. Highlight the deltoid, latissimus dorsi, subscapularis, teres major, and pectoralis major muscles
(one at a time) on the model and view the action of that muscle. Indicate the muscles involved as the
agonists (prime movers) in the table below. Now practice with yourself doing the action of shoulder
rotation. Can you feel the muscles that are the prime movers contracting to perform the action?
Review Questions: Explain circumduction of the shoulder. Which of the movements would
circumduction include?
Circumduction is moving a limb so that the distal end moves in a circle, while the point is more or less
stationary. Consists of flexion, abduction, extension, and adduction performed in succession; therefore,
quickest way to exercise many muscles that move ball-and-socket joints. Circumduction of the shoulder
would include all the muscles listed for flexion, extension, abduction, and adduction.
Complete the following table.
Action
Shoulder Flexion
Shoulder Extension
Shoulder Abduction
Shoulder Adduction
Shoulder Rotation
Prime Movers (Agonists)
Deltoid; pectoralis major; biceps brachii;
coracobrachialis; serratus anterior
Deltoid; latissimus dorsi; teres major; triceps
brachii; pectoralis major
Deltoid
Deltoid; pectoralis major
Deltoid; latissimus dorsi; teres major;
subscapularis; pectoralis major
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Ipad app lab written by Lori Hays PhD