Muscles of the posterior scapular region

Question 1

Supraspinatus

Answer 1

Origin:

• Medial two thirds of the supraspinous fossa of the scapula
• The deep fascia that covers the muscle

Insertion:

• Most superior facet on the greater tubercle of the humorous

Innervation:

• Suprascapular nerve (C5, C6)

Function:

• Rotator cuff muscle;
• Initiation of abduction of arm to 15 degrees at glenohumeral joint

Question 2

Infraspinatus

Answer 2

Origin:

• Medial two thirds of the infraspinous fossa of the scapula
• The deep fascia that covers the muscle

Insertion:

• Middle facet on posterior surface of the greater tubercle of the humorous

Innervation:

• Supreascapular nerve (C5, C6)

Function:

• Rotator cuff muscle;
• Lateral rotation of arm at the glenohumeral joint

Question 3

Teres minor

Answer 3

Origin:

• Upper two thirds of a flattened strip of bone on the posterior surface of the scapula immediately adjacent to the lateral border of the scapula

Insertion:

• Inferior facet on the posterior surface of the greater tubercle of the humorous

Innervation:

• Axillary nerve (C5, C6)

Function:

• Rotator cuff muscle;
• Lateral rotation of arm at the glenohumoural joint.

Question 4

Teres major

Answer 4

Origin:

• Elongate oval area on the posterior surface of the inferior angle of the scapula

Insertion:

• Medial lip of the inter tubercular sulcus on the anterior surface of the humerus

Innervation:

• Inferior subscapular nerve (C5, c6, c7)

Function:

• Medial rotation and extension of the arm at the glenohumeral joint

Question 5

Long head of triceps brachii

Answer 5

Origin:

• Infraglenoid tubercle on scapula

Insertion:

• Common tendon of insertion with medial
• Lateral heads on the olecranon process of the ulna

Innervation:

• Radial nerve (C6, C7, C8)

Function:

• Extension of the forearm at the elbow joint
• Accessory adductor and extensor of the arm at the glenohumeral joint