Shoulder

Question 1

Pectoralis major IO Innervation

Answer 1

Origin:
* Clavicular head: Anterior aspect of medial ½ of clavicle
* Sternocostal head: Manubrium and body of sternum; Superior 6 costal cartilages; 6th rib; Aponeurosis of external abdominal oblique muscle

Insertion:
* Lateral lip of intertubercular sulcus of humerus

Innervation
* Lateral and medial pectoral nerves

Question 2

Action of Pectoralis major

Answer 2

• Adduction of humerus
• Medial rotation of humerus
• Flexion of humerus
  Clavicular head:
• Flexion of extended arm
  Sternocostal head:
• Extension of flexed arm

Question 3

Pectoralis minor IO Action Innervation

Answer 3

Origin:
* Anterior ends of 3rd to 5th ribs

Insertion:
* Coracoid process of scapula

Action:
* Protraction of scapula
* Depression of scapula
* Downward rotation of scapula

Innervation:
* Lateral and medial pectoral nerves

Question 4

Serratus anterior IO Action Innervation

Answer 4

Origin:
* External surface of 1st to 9th ribs

Insertion:
* Medial border of scapula

Action
* Protraction of scapula
* Hold scapular against thoracic wall
* Upward rotation of scapula

Innervation
* Long thoracic nerve

Question 5

Subclavius IO Action Innervation

Answer 5

Origin:
* Superior surface of costal end of 1st rib and adjacent 1st costal cartilage

Insertion:
* Inferior surface of the middle 1/3rd of the clavicle

Action:
* Depression of clavicle

Innervation:
* Subclavian nerve

Question 6

Deltoid IO Action Innervation

Answer 6

Origin:
* Lateral third of clavicle
* Acromion
* Spine of scapula

Insertion:
* Deltoid tuberosity of humerus

Action:
Clavicular part:
* Flexion of humerus
* Medial rotation of humerus
Acromial part:
* Abduction of humerus
Scapular part:
* Extension of humerus
* Lateral rotation of humerus

Innervation:
* Axillary nerve

Question 7

Supraspinatus IO Action Innervation

Answer 7

Origin:
* Medial 2/3rd of supraspinous fossa of scapula

Insertion:
* Greater tubercle of humerus

Action:
* Abduction of humerus

Innervation:
* Suprascapular nerve

Question 8

Infraspinatus IO Action Innervation

Answer 8

Origin:
* Medial 2/3rd of infraspinous fossa of scapula

Insertion:
* Greater tubercle of humerus

Action:
* Lateral rotation of humerus

Innervation:
* Suprascapular nerve

Question 9

Teres major IO Action Innervation

Answer 9

Origin:
* Posterior aspect of inferior angle of scapula

Insertion:
* Anterior surface of humerus on medial lip of intertubercular sulcus

Action:
* Adduction of humerus
* Extension of humerus
* Medial rotation of humerus

Innervation
* Lower subscapular nerve

Question 10

Teres minor IO Action Innervation

Answer 10

Origin:
* Posterior aspect of superior 2/3rd of lateral border of scapula

Insertion:
* Greater tubercle of humerus

Action:
* Lateral rotation of humerus

Innervation:
* Axillary nerve

Question 11

Subscapularis IO Action Innervation

Answer 11

Origin:
* Medial 2/3rd of subscapular fossa of scapula

Insertion:
* Lesser tubercle of humerus

Action:
* Medial rotation of humerus

Innervation:
* Upper and lower subscapular nerves