Shoulder region

• • • • Bones Joints Muscles Vessels & Nerves

Classifications of muscles that move the shoulder • • • A. muscles connecting scapula to humerus B. muscles connecting trunk to scapula C. muscles connecting trunk to humerus

Biceps & Triceps tendons

A. muscles connecting scapula to humerus 1. Supraspinatus 2. Infraspinatus 3. Teres minor 4. Subscapularis 5. Teres major 6. Coracobrachialis 7. Deltoid

Short muscles

• Function: abduction

Subscapularis • Function: Int. rotation

Rotator Cuff

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Rotator cuff function:

• only 25% of the humeral head is in contact with the glenoid fossa.

• The rotator cuff muscles compress and depress the humeral head within the glenoid fossa.

Rotator Cuff Disease photo

Quiz

supraspinatus infraspinatus teres minor subscapularis

Teres major

• • • Origin : – Inf angle of scapula Insertion : – Med lip of groove Actions: – Internal rotation and adduction of arm • Function: adduction of humerus med rotator • Why medial?

• Function: flex & adduct the shoulder joint

Coracobrachialis

Deltoid • • • Origin : – Clavicle, scapula Insertion : – Deltoid tuberosity of humerus Actions: – Abduction – Anterior deltoid: internal rotation – Posterior deltoid: external rotation

Classifications of muscles that move the shoulder • • • A. muscles connecting scapula to humerus B. muscles connecting trunk to scapula C. muscles connecting trunk to humerus

B. muscles connecting trunk to scapula 1. Serratus anterior 2. Levator scapula 3. Rhomboid major 4. Rhomboid minor 5. Trapezius 6. Pectoralis minor

Serratus Anterior

• • • Origin: – Ribs Insertion: – Medial border of scapula Actions: – Protraction and rotation of scapula

Winged scapula

Levator scapula

• • • Origin : – Cervical vertebrae Insertion : – Scapula Action: – Elevation of the scapula

Rhomboid major and minor

• • • Origin : – Cervical and Thoracic vertebrae Insertion : – Scapula Actions: – Retraction – Elevation

Trapezius

• • • Origin : – Occipital bone of skull, cervical and thoracic vertebrae Insertion : – Clavicle and Scapula Actions: – Elevation – retraction

Pectoralis Minor

• • • Origin : – Ribs Insertion : – Coracoid process of scapula Action: – Depression of scapula

Depression of scapula

Classifications of muscles that move the shoulder • • • A. muscles connecting scapula to humerus B. muscles connecting trunk to scapula C. muscles connecting trunk to humerus

C. muscles connecting trunk to humerus • • Pectoralis major Latissimus dorsi

Pectoralis Major

• • • Origin : – Clavicle, sternum, upper ribs Insertion : – Crest of greater tubercle and lat lip Action: – Add, med rotation

Latissimus Dorsi

• • • Origin : – Vertebrae, sacrum, ilium Insertion : – Medial lip Actions: – Adduction and med rotation of humerus

Latissimus Dorsi if humerus is fixed

• • • Covering th front and back of the trunk.

The pectoralis major and latissimus dorsi both adduct and medially rotate the Humerus.

Lower edge of the pectoralis major muscle on rib 7 = upper edge of the latissimus dorsi on vertebra T7.

Shoulder Girdle Movements