The Shoulder Joint Anatomy and Physiology of Human Movement 420:050

The Shoulder Joint Glenohumeral joint Very mobile but unstable Glenoid fossa Some ligaments Lax until extreme ROM Labrum and rotator cuff Relationship with shoulder girdle

Objectives Bones, bony landmarks and joints Muscles Movements

The Shoulder Joint Multiaxial ball and socket joint Able to rotate freely in all three planes Sagittal Frontal Transverse

Objectives Bones, bony landmarks and joint Muscles Movements

Deltoid

Pectoralis Major

Coracobrachialis

Latissimus Dorsi

Teres Major

Rotator Cuff Supraspinatus Infraspinatus Teres Minor Subscapularis

Rotator Cuff Small muscles Critical for shoulder health Dynamic stabilization Especially important during overhead repetitious activities

Supraspinatus

Infraspinatus

Teres Minor

Subscapularis

Objectives Bones, bony landmarks and joint Muscles Movements

Flexion Movement of humerus straight anteriorly Extension Movement of humerus straight posteriorly

Movements Abduction Upward lateral movement of humerus out to the side, away from body Adduction Downward movement of humerus medially toward body from abduction

Movements Horizontal adduction Movement of humerus in a horizontal or transverse plane toward & across chest Horizontal abduction Movement of humerus in a horizontal or transverse plane away from chest

Movements External rotation Movement of humerus laterally around its long axis away from midline Internal rotation Movement of humerus medially around its long axis toward midline

Movements Diagonal abduction Movement of humerus in a diagonal plane away from midline of body Diagonal adduction Movement of humerus in a diagonal plane toward midline of body

LINE OF PULL

FLEXION Superior movement of the humerus in the sagittal plane

Coracobrachialis

FLEXION

Anterior deltoid Pectoralis major (upper fibers) Coracobrachialis

EXTENSION Inferior movement of the humerus in the sagittal plane

Coracobrachialis

EXTENSION

Exception  Pectoralis Major Lower Fibers Effective extensor from hyperflexed position

EXTENSION Latissimus dorsi Teres major Deltoid (posterior) Pectoralis major (lower fibers) From hyperflexed position

ABDUCTION Superolateral movement of the humerus in the frontal plane

?

ABDUCTION

The location of the line of pull in relation to the joint center determines the movement in this case Hamilton, N. & Luttgens, K. (2007). Kinesiology: Scientific basis of human motion (11 th ed.). McGraw-Hill: New York.

ABDUCTION Deltoid (all three) Pectoralis major (upper fibers) Abducted > 90 degrees

ADDUCTION Inferomedial movement of the humerus in the frontal plane

ADDUCTION

The location of the line of pull in relation to the joint center determines the movement in this case Hamilton, N. & Luttgens, K. (2007). Kinesiology: Scientific basis of human motion (11 th ed.). McGraw-Hill: New York.

ADDUCTION Latissimus dorsi Teres major Pectoralis major (lower fibers) Pectoralis major (upper fibers) Abducted < 90 degrees

HORIZONTAL ABDUCTION Movement of the humerus away from the midline of the body in the transverse plane

HORIZONTAL ABDUCTION

Deltoid (posterior) Latissimus dorsi Teres major Infraspinatus Teres minor

HORIZONTAL ADDUCTION Movement of the humerus towards the midline in the transverse plane

Coracobrachialis

HORIZONTAL ADDUCTION

Pectoralis major (upper and lower) Deltoid (anterior) Coracobrachialis

INTERNAL ROTATION Movement of the humerus towards the midline in the transverse plane along its long axis

Subscapularis

INTERNAL ROTATION

Pectoralis major (upper and lower) Latissimus dorsi Subscapularis Teres major

EXTERNAL ROTATION Movement of the humerus away from the midline in the transverse plane along its long axis

EXTERNAL ROTATION

Supraspinatus Teres minor