Muscles of the shoulder
Terms
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- Biceps Brachii Action
- Flexes the elbow, Supinates the forearm, Flexes the shoulder
- Biceps Brachii Origin
- Short head: Coracoid process of scapula Long head: Supraglenoid tubercle of scapula
- Biceps Brachii Insertion
- Tuberosity of the radius and aponeurosis of the biceps Brachii
- Triceps Brachii Action
- All Heads: Extend the elbow Long Heads: Extend the shoulder, adducts the shoulder
- Triceps Brachii Origin
- Long Head: Infraglenoid tubercle of scapula Lateral head: posterior surface of proximal half of humerus Medial head: posterior surface of distal half of humerus
- Triceps Brachii Insertion
- Olecranon process of ulna
- Coracobrachialis Action
- Flexes the shoulder, Adducts the shoulder
- Coracobrachialis Origin
- Coracoid process of scapula
- Coracobrachialis Insertion
- Medial surface of mid-humeral shaft
- Deltoid Action (all fibers)
- All Fibers: abduct the shoulder
- Deltoid Origin
- Lateral one-third of clavicle, a acromion, and spine of scapula
- Deltoid Action (posterior fibers)
- Posterior Fibers: extends the shoulder, laterally rotates the shoulder, horizontally abducts the shoulder
- Deltoid Action (anterior fibers)
- Anterior Fibers: flex the shoulder, medially rotates the shoulder, horizontally abducts the shoulder
- Deltoid Insertion
- Deltoid Tuberosity
- Trapezuis Action (upper fibers bilaterally)
- Upper Fibers: bilateral- extend the head and neck,
- Trapezius Action (upper fibers unilaterally)
- unilateral- laterally flex the head and neck to same side, rotates the head and neck to the opposite side, elevates the scapula, upwardly rotates the scapula
- Trapezius Action (middle fibers)
- Middle Fibers: Adduct the scapula, stabilize the scapula
- Trapezius Action (lower fibers)
- Lower Fibers: depress the scapula, upwardly rotate the scapula
- Trapezius Origin
- external occipital protuberance, medial portion of superior nuchal line of occiput, ligamentum nuchae, and spinous process of C-7 to T-12
- Trapezius Insertion
- lateral one-third of clavicle, acromion, and spine of scapula
- Latissimus Dorsi Action
- Extends the shoulder, Adducts the shoulder, Medially rotates the shoulder
- Latissimus Dorsi Origin
- Spinous process of last six thoracic vertebrae, last three or four ribs, thoracolumbar aponeurosis and posterior iliac crest
- Latissimus Dorsi Insertion
- Crest of the lesser tubercle of the humerus
- Teres Major Action
- Extends the shoulder, Adducts the shoulder, Medially rotates the shoulder
- Teres Major Origin
- Lateral side of inferior angle and lower half of lateral border of scapula
- Teres Major Insertion
- Crest of the lesser tubercle of the humerus
- Supraspinatus Action
- Abducts the shoulder, Stabilizes head of humerus in glenoid cavity
- Supraspinatus Origin
- Supraspinous fossa of scapula
- Supraspinatus Insertion
- Greater tubercle of humerus
- Infraspinatus Action
- Laterally rotates the shoulder, Adducts the shoulder, Extends the shoulder, Horizontally abducts the shoulder, Stabilizes the head of humerus in glenoid cavity
- Infraspinatus Origin
- Infraspinous fossa of scapula
- Infraspinatus Insertion
- Greater tubercle of humerus
- Teres Minor Action
- Laterally rotates the shoulder, Adducts the shoulder, Extends the shoulder, Horizontally abducts the shoulder, Stabilizes head of humerus in glenoid cavity
- Teres Minor Origin
- Superior half of lateral border of scapula
- Teres Minor Insertion
- Lesser tubercle of the humerus
- Subscapularis Action
- Medially rotates the shoulder, Stabilizes head of humerus in glenoid cavity
- Subscapularis Origin
- Subscapular fossa of the scapula
- Subscapularis Insertion
- Lesser tubercle of the humerus
- Rhomboid Major and Minor Action
- Adducts the scapula, Elevates the scapula, Downwardly rotates the scapula
- Rhomboid Major and Minor Origin
- Minor: Spinous processes of C-7 and T-1 Major: Spinous processes of T-2 to T-5
- Rhomboid Major and Minor Insertion
- Medial border of the scapula between spine of the scapula and inferior angle
- Levator Scapula Action (unilateral)
- Elevates the scapula, Downwardly rotates the scapula, Laterally flexes the head and neck, Rotates the head and neck to the same side
- Levator Scapula Action (bilateral)
- Extends the head and neck
- Levator Scapula Origin
- Transverse processes of first through fourth cervical vertebrae
- Levator Scapula Insertion
- Medial border and superior angle of scapula
- Serratus Anterior Action
- Origin fixed: Abduct the scapula, Depress the scapula, Holds the medial border of scapula against rib cage Scapula stabilized: forced inhalation
- Serratus Anterior Origin
- Surfaces of upper eight or nine ribs
- Serratus Anterior Insertion
- Anterior surface of medial border of scapula
- Pectoralis Major Action (all fibers)
- Adducts the shoulder, Medially rotates the shoulder, May assist in elevating the thorax in forced inhalation ( if arm is fixed)
- Pectoralis Major Action (upper fibers)
- Flex the shoulder, Horizontally adduct the shoulder
- Pectoralis Major Action (lower fibers)
- Extend the shoulder
- Pectoralis Major Origin
- Medial half of clavicle, sternum, cartilage of ribs one thorough six
- Pectoralis Major Insertion
- Crest of greater tubercle of humerus
- Pectoralis Minor Action
- Depresses the scapula, Abducts the scapula, Tilts the scapula anteriorly, Assists in forced inhalation
- Pectoralis Minor Origin
- Third, fourth, and fifth ribs
- Pectoralis Minor Insertion
- Coracoid process of scapula
- Subclavius Action
- Draws clavicle inferiorly and anteriorly, Elevates first rib, Stabilizes the sternoclavicular joint
- Subclavius Origin
- First rib and cartilage
- Subclavius Insertion
- Inferior, lateral aspect of the clavicle