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

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

FLEXION

Anterior deltoid Pectoralis major (upper fibers) Coracobrachialis

EXTENSION

Inferior movement of the humerus in the sagittal plane

Coracobrachialis

EXTENSION

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 (11th 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 (11th 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

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

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

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

EXTERNAL ROTATION

Supraspinatus Teres minor