Motion
Use the picture above to imagine the mentioned motions. Motion in the transverse plane will be about the longitudinal axis. Motion in the frontal plane will be about the anterior-posterior axis. Motion in the sagittal plane will be about the medial-lateral axis.
When reviewing this section, remember that muscles act only to pull during contraction. Take time to remember the location of each muscle and why it will produce each action.
When reviewing this section, remember that muscles act only to pull during contraction. Take time to remember the location of each muscle and why it will produce each action.
Motion in the Sagittal plane about the medial-lateral axis
Flexion for the shoulder joint consists of raising the arm from anatomical position to completely vertical with the fingers pointed stright upward. This motion takes place in the sagittal plane about the medial lateral axis.
The muscles that provide flexion at the shoulder include the anterior deltoid, the coracobrachialis and the pectoralis major. |
Extension at the shoulder joint is the motion produced when the hand moves from a fully flexed position back to anatomical position. Hyperextension is when the arm continues farther posterior than anatomical position. This motion is in the sagittal plane about the medial lateral axes.
The muscles that produce this motion about the shoulder joint include the posterior deltoid, the latissimus dorsi, the pectoralis major, and teres major. |
Motion in the frontal plane about the anterior-posterior axis
From anatomical position, abduction is the motion produced when the arm rotates in the frontal plane until it reaches a completely vertical position with the fingers pointed upward. The motion in the frontal plane rotates about the anterior-posterior axes. The muscles that produce this motion include the middle deltoid and the supraspinatus.
Adduction takes place when the arm moves from full abduction back to anatomical position in the frontal plane. This motion is about the anterior-posterior axes. The muscles that produce this action are the latissimus dorsi, pectoralis major, and teres major.
Adduction takes place when the arm moves from full abduction back to anatomical position in the frontal plane. This motion is about the anterior-posterior axes. The muscles that produce this action are the latissimus dorsi, pectoralis major, and teres major.
Motion in the Transverse plane about the longitudinal axis
Internal and external rotation take place in the transverse plane about the longitudinal axis. When producing this motion, the arm is in anatomical position, with the elbow bent at a 90degree angle, forearm parallel with the ground.
External rotation is created when the angle of the forearm, relative to the body, increases. For example, if the image above shows the arm's starting position at 90 degrees from the body, its ending position will be 180degrees from the body. The muscles that produce external rotation include the posterior deltoid, infraspinatus, and teres minor. Internal rotation takes place when the angle created between the forearm and body decreases. Using the same example, when the forearm is in full external rotation (180 degrees from the body) internal rotation will return it to its original position at 90degrees or all the way to 0degrees. The muscles that produce internal rotation include the anterior deltoid, latissimus dorsi, pectoralis major, subscapularis, and teres major. |
Horizontal adduction and abduction, similar to internal and external rotation, takes place in the transverse plane about the longitudinal axis. The difference between these motions include that horizontal adduction and horizontal abduction have the entire upper extremity (UE; arm and forearm) parallel to the ground.
Horizontal abduction is created when the angle of the UE relative to the body increases. For example, in the picture above, if the starting position has the UE 90 degrees from the body, abduction will increase that angle to its ending position at 180 degrees. The muscles that produce this motion include the middle and posterior deltoid, the infraspinatus and the teres minor. Horizontal adduction is created when the angle of the UE relative to the body decreases. Again, using the image from above, adduction would result in the UE moving from full abdution back to its starting position. The muscles that produce this motion include the coracobrachialis, the anterior deltoid and the pectoralis major. |