Shoulder Musculature

Question 1

Serratus Anterior

Answer 1

origin - ribs 4-12

insertion - medial border of the scapula

isolated function - concentrically accelerates scapular protraction

integrated function -

• • eccentrically decelerates dynamic scapular retraction
• • isometrically stabilizes the scapula

Question 2

Rhomboid Major

Answer 2

origin - spinous processes c7-t5

insertion - medial border of the scapula

isolated function - concentrically produces scapular retraction and downward roation

integrated function -

• • eccentrically decelerates scapular protraction and upward rotation
• isometrically stabilizes the scapula

Question 3

Rhomboid Minor

Answer 3

origin - spinous processes c7-t1

insertion - medial border of the scapula superior to spine

isolated function - concentrically produces scapular retraction and downward rotation

integrated function -

• • eccentrically decelerates scapular protraction and upward rotation
• • isometrically stabilizes the scapula

Question 4

Lower Trapezius

Answer 4

origin - spinous processes of t6-t12

insertion - spine of the scapula

isolated function - concentrically accelerates scapular depression

integrated function -

• • eccentrically decelerates scapular elevation
• • isometrically stabilizes the scapula

Question 5

Middle Trapezius

Answer 5

origin - spinous processes of t1-t5

insertion -

• • acromion process of the scapula
• • superior aspect of the spine of the scapula

isolated function - concentrically accelerates scapular retraction

integrated function -

• • eccentrically decelerates scapular elevation
• • isometrically stabilizes the scapula

Question 6

Upper Trapezius

Answer 6

origin -

• • external occipital protuberance of the skull
• • spinous process of c7

insertion -

• • lateral third of the clavicle
• • acromion process of the scapula

isolated funciton -

• • concentrically accelerates cervical extension, lateral flexion, and rotation
• • concentrically accelerates scapular elevation

integrated function -
– eccentrically decelerates cervical flexion, lateral flexion, and rotation
eccentrically decelerates scapular depression
– isometrically stabilizes the cervical spine and scapula

Question 7

Pectoralis Major

Answer 7

origin -

• • clavicular- anterior surface of the clavicle
• • sternocostal- anterior surface of the sternum, cartilage of ribs 1-7

insertion - greater tubercle of the humerus

isolated function - concentrically accelerates shoulder flexion [clavicular fibers], horizontal adduction and internal rotation

integrated function -

• • eccentrically decelerates shoulder extension, horizontal abduction, and external rotation
• • isometrically stabilizes the shoulder girdle

Question 8

Pectoralis Minor

Answer 8

Origin - Ribs 3-5

Insertion - Coracoid process of the scapula

Isolated Function - concentrically protracts the scapula

integrated function -

• • eccentrically decelerates scapular retraction
• • isometrically stabilizes the shoulder girdle

Question 9

Anterior Deltoid

Answer 9

origin - anterior - lateral third of the clavicle

insertion - deltoid tuberosity of the humerus

isolated function - concentrically accelerates shoulder flexion and internal rotation

integrated function -

• • eccentrically decelerates shoulder extension and external rotation
• • isometrically stabilizes the shoulder girdle

Question 10

Medial Deltoid

Answer 10

origin - acromion process of the scapula

insertion - deltoid tuberosity of the humerus

isolated function - concentrically accelerates shoulder abduction

integrated function -

• • eccentrically decelerates shoulder adduction
• • isometrically stabilizes the shoulder girdle

Question 11

Posterior Deltoid

Answer 11

origin - posterior- spine of the scapula

insertion - deltoid tuberosity of the humerus

isolated function - concentrically accelerates shoulder extension and external rotation

integrated function -

• • eccentrically decelerates shoulder flexion and internal rotation
• • isometrically stabilizes the shoulder girdle

Question 12

Teres Major

Answer 12

origin - inferior angle of the scapula

insertion - lesser tubercle of the humerus

isolated function - concentrically accelerates shoulder internal rotation, adduction, and extension

integrated function -

• • eccentrically decelerates shoulder external rotation, abduction and flexion
• isometrically stabilizes the shoulder girdle