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A Review of the Shoulder Muscles and Their Actions. What muscle works closely with the anterior deltoid? Pectoralis major What muscle is involved in any lifting movements? Deltoid What is the major (strongest) extensor muscle? Latissimus Dorsi Name the four rotator cuff muscles. - PowerPoint PPT Presentation
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A Review of the Shoulder Muscles and Their Actions
Questions• What muscle works closely with the anterior deltoid?• Pectoralis major• What muscle is involved in any lifting movements? • Deltoid• What is the major (strongest) extensor muscle?• Latissimus Dorsi• Name the four rotator cuff muscles.• Subscapularis, Supraspinatus, Infraspinatus, and Teres
minor.• What muscle works closely with the infraspinatus?• Teres minor
Practice
• Name the muscles for Horizontal Adduction
• Pect Major (both)• Corachobrachialis• Deltoid (anterior)
• Name the muscles for Horizontal Abduction
• Deltoid (post)• Infraspinatus• Teres minor• Lats
Practice
• List the muscles that do flexion of the shoulder
• Coracobrachialis• Pectoralis major
(upper to 60°)• Anterior Deltoid
• List the muscles that do extension of the shoulder
• Latissimus dorsi• Teres major• Posterior deltoid• Pectoralis major
(lower fibers to neutral)
Practice
• List the muscles that do adductionadduction of the shoulder
• Pectoralis major (lower and upper below 90°)
• Coracobrachialis• Latissimus dorsi• Teres major
List the muscles that do abductionabduction of the shoulder
• Deltoid (all sections)• Supraspinatus• Pectoralis major
(upper past 90°)
Practice
• List the muscles that do internal rotation of the shoulder
• Subscapularis• Latissimus dorsi• Teres major• Anterior deltoid• Pect. major
• List the muscles that do external rotation of the shoulder
• Infraspinatus• Teres minor• Posterior deltoid
Name the muscle.
Coracobrachialis
Name the action
Adduction of the shoulder
Also, flexion and hor. add.
Name the muscle.
Pectoralis Major
Name the muscle.
Subscapularis
Name the action
Internal rotation of the shoulder
Name the muscle.
Deltoid
Name the action
Abduction of shoulder
Name the muscle.
Infraspinatus
Name the action
External rotation
Name the muscle.
Teres Major
Name the action
Adduction of scapula
Name the muscle.
Teres Minor
Name the action if the humerus move directly to the posterior
Extension of the shoulder
Name the muscle.
Supraspinatus
Name the action
Abduction of the shoulder
Coracobrachialis Pect. Major
SubscapularisDeltoid
Supraspinatus Teres Major
InfraspinatusTeres Minor
What position are her shoulders in?
Flexion
What position is his right shoulder in?
Horizontal Abduction andExternal Rotation
What rotation action is his shoulder performing as he continues to through the ball?
Internal Rotation
What position are her shoulders in?
Flexion
What position are his shoulders in?
Horizontal abduction or Extension
1.2.
FlexionExtension
Position of their shoulders?
What is the position of shoulders?
Extension
Shoulder Muscle Exercises
Major Muscles of the Shoulder
• Pectoralis major– Push-ups– Pull-ups– Bench press– Throwing– Tennis serve
• Latissimus dorsi– Chinning– Robe climb– Dips on parallel bars– Pullover exercises– Pulldown exercises– Rowing
Shoulder action = ?Shoulder muscle(s) = ? Abduction
DeltoidSupraspinatus
Shoulder action = ?Shoulder muscle(s) = ?
Flexion
Ant DeltoidUpper Pect MajorCoracobrach.
Shoulder action = ?Shoulder muscle(s) = ? Horizontal Add.
Ant. DeltoidPect. Major (both)Coracobrachialis
Shoulder action = ?Shoulder muscle(s) = ? Horizontal Abduction
Latissimus DorsiPost. DeltoidTeres MinorInfraspinatus
Shoulder action = ?Shoulder muscle(s) = ?
Adduction
Pect. Major (both)CoracobrachialisLatissimus DorsiTeres Major
Shoulder action = ?Shoulder muscle(s) = ?
Horizontal Add
Ant. DeltoidPect. Major (both)Coracobrachialis
Shoulder action = ?Shoulder muscle(s) = ?
Extension Lats Teres MajorPost. Deltoid Pectoralis Major (lower)Infraspinatus Teres minor
Shoulder action = ?Shoulder muscle(s) = ?
External Rotation
InfrspinatusTeres MinorPost. Deltoid
Name a shoulder muscle isolated with the following exercises.
• Side arm dumbbell raises
• Deltoid
• Push-ups
• Pectoralis major
• Rowing and pull-overs
• Latissimus dorsi
What is the action to the left? What muscles perform that action?
Internal RotationExternal Rotation
Internal Rotation
Subscapularis, Ant. Deltoid, Pect, Major, Lats. And Teres Major
Rotator Cuff ExercisesExternal Rotation
External Rotation
Internal Rotation
Abduction (to work the supraspinatus)
Shoulder Related Injuries
• The shoulder is built for motion, not stability
• Injury rate depends on…– Shallowness of glenoid
fossa– Laxity of ligaments– Strength of muscles
• Shoulder subluxation– Incomplete or partial dislocation
• Shoulder dislocation– Complete dislocation of the GH joint– Most common anteriorly and inferiorly
• Shoulder separation– Complete dislocation of the AC joint
Shoulder Dislocation
Impingement Syndrome
Impingement Syndrome• A condition that decreases
the subacromial space– Acromion process– Coracoacromial ligament
• Causes– Swelling– Bone spurs– Anatomical structure
Impingement Syndrome
Rotator Cuff Tears
Rotator cuff
• Subscapularis• Supraspinatus• Infraspinatus• Teres minor
Movement of RC Muscles• Subscapularis is an
internal rotator of the arm. • Supraspinatus assists the
deltoid in abducting the arm, with its greatest contribution being the initiation of abduction.
• Infraspinatus and teres minor muscles both externally rotate the arm.
Rotator Cuff Injury
• The throwing motion has been divided into five phases: wind-up, cocking, acceleration, and follow-through.
• Cocking phase– Subscapularis fires in late cocking phase
to decelerate the shoulder's external rotation. Also, it is stretched during the cocking phase.
Rotator Cuff Injury
• Follow-through (muscles fire most intensely)– Subscapularis internally rotates the shoulder, – The infraspinatus and teres minor contract
eccentrically to decelerate the arm and are stretched.
• During this repetitive eccentric loading, the rotator cuff is prone to overload, fatigue, tendinitis, and even a partial undersurface tear.
Note: Surgery needs to be performed within 3 months or the supraspinatus muscle will atrophy and be too short to reattach
Glenoid Labrum
Labral Tear
• The glenoid cavity makes up the “socket” of the shoulder joint.
• The labrum acts sort of like a gasket, turning the flat surface of the glenoid into a deeper socket that molds to the head of the humerus for a better fit.
• A tear of labrum can cause pain and a catching sensation with movement of the shoulder.
Labral Tear
• Most labral tears are probably the result of an injury to the shoulder, such as falling on an outstretched hand.
• There is reason to believe that the excess motion of the humerus moving around on the glenoid may cause damage to the labrum over time.
• An unstable shoulder may also cause injury to the labrum, if it repeatedly dislocates out of the glenoid.