Shoulder Muscles Actions, O's & I's (Class # 4-A)

Question 1

1. Supraspinatus*

TG Pg. 74-81

> Name the Origin(s), Insertion(s) and Action(s) of this muscle.

(Note: The most commonly injured of all the rotator cuff (SITS) muscles)

Answer 1

Origin:
- Supraspinous fossa of the scapula

Insertion:
- Anterior facet of the Greater Tubercule of the humerus

Action:
- ABduction of the arm at the shoulder

Question 2

2. Infraspinatus*

TG pg. 74-81

> Name the Origin(s), Insertion(s) and Action(s) of this muscle.

Answer 2

Origin:
- Infraspinous fossa of the scapula

Insertion:
- Middle facet of the Greater Tubercule of the humerus

Action:
- Lateral rotation of the arm at the shoulder

Question 3

3. Teres Minor*

TG pg. 74-81

> Name the Origin(s), Insertion(s) and Action(s) of this muscle.

(Notes: Can be sensitive. It’s an antagonist to the Teres Major.)

Answer 3

Origin:
- Superior half of the lateral border of the scapula

Insertion:
- Posterior Facet of the Greater Tubercle of the humerus

Action:
- Lateral rotation of the arm at the shoulder

Question 4

4. Subscapularis*

TG pg. 74-81

> Name the Origin(s), Insertion(s) and Action(s) of this muscle.

(Note: Often involved in rounded shoulders)

Answer 4

Origin:
- Subscapular fossa

Insertion:
- Lesser tubercle of the humerus

Action:
- Medial rotation of the arm at the shoulder

Question 5

96. Trapezius*

TG pg. 68-70

> Name the Origin(s), Insertion(s) and Action(s) of this muscle.

Answer 5

Origin:
- EOP
- Superior nuchal line
- Nuchal Ligament (Ligamentum nuchae)
- Spinous processes of C7-T12

Insertion:
- Upper: Lateral third of the Clavicle
- Middle: Acromion
- Lower: Spine of the scapula

Action:
Upper:
- Elevation of the Scapula
- Extension of the head at the neck
Middle:
- ADDuction (retraction) of the Scapula
Lower:
- Depression of the Scapula

Question 6

95. Levator Scapulae*

TG Pg. 83-85

> Name the Origin(s), Insertion(s) and Action(s) of this muscle.

(Note: It’s often “angry”: overused, shoulders up at our ears)

Answer 6

Origin:
- Transverse processes of C1-C4

Insertion:
- Medial border superior angle of the scapula

Action:
- Elevation of the Scapula

Question 7

92. Serratus Anterior

TG Pg. 86-88

> Name the Action(s) of this muscle.

Answer 7

Action:
- ABduction (Protraction) of the Scapula

Question 8

94. Rhomboid Major*

TG Pg. 82-83

> Name the Origin(s), Insertion(s) and Action(s) of this muscle.

(Also commonly involved in rounded shoulders)

Answer 8

Origin:
- Spinous Processes of T2-T5

Insertion:
- Medial border of the scapula between the spine & inferior angle

Action:
- ADDuction (retraction) of the Scapula

Question 9

93. Rhomboid Minor*

TG pg. 82-83

> Name the Origin(s), Insertion(s) and Action(s) of this muscle.

Answer 9

Origin:
- Spinous processes of C7-T1
- Ligamentum nuchae

Insertion:
- Root of the spine of the scapula

Action:
- ADDuction (retraction) of the Scapula