Instrinsic Muscles of the Thoracic Limb

Question 1

Deltoideus M.

Parts?
Action?
Innervation?

Answer 1

Acromion and Spinous

Action:
- to flex the shoulder

Innervation- axillary nerve

Question 2

Infraspinatus M.

Insertion?
Action?
Innervation?

Answer 2

Insertion- greater tubercle of the humerus

Action:

• Extend & flex joint
• Abduct shoulder & rotate humerus laterally
• Prevent medical rotation & provide lateral stability to shoulder

Innervation - suprascapular nerve

Question 3

Teres Minor M.
Action?
Innervation?

Answer 3

action:

• Flex shoulder
• Rotate shoulder laterally

innervation - axillary nerve

Question 4

Supraspinatus M.
Insertion?
Action?
Innervation?

Answer 4

Insertion - the greater tubercle of the humerus

Action:
Extend & stabilize shoulder

Innervation - suprascapular nerve

Question 5

Subscapularis M.
Insetion?
Action?
Innervation?

Answer 5

Insertion - the lesser tubercle of the humerus

Action:

• adduct, extend, stabilize shoulder joint
• Rotate shoulder joint medially
• Prevent lateral rotation w/ weight

Innervation - subscapular nerve

Question 6

Teres Major
Action?
Innervation?

Answer 6

Action:

• Flex shoulder joint
• Rotate shoulder joint medially
• Prevent lateral rotation w/ weight

Innervation - axillary nerve

Question 7

Coracobrachialis
Action?
Innervation?

Answer 7

Action:
-Adduct, extend, & stabilize shoulder joint

Innervation - musculocutanous nerve

Question 8

Tensor fasciae antebrachii m.

Action?
Innervation?

Answer 8

action - extend the elbow joint

innervation - radial nerve

Question 9

Anconeus m.

action?
innervation?

Answer 9

action- to extend the elbow joint

innervation- radial nerve

Question 10

Biceps brachii m.

origin?
insertion?
action?
innervation?

Answer 10

origin- supraglenoid tubercle

insertion- the ulnar and radial tuberosities

action:

• flex the elbow joint
• extend the shoulder joint

innervation- musculocutaneous nerve

Question 11

Brachialis m.

origin?
insertion?
action?
innervation?

Answer 11

origin- proximal 3rd of the lateral surface of the humerus

insertion- the ulnar and radial tuberosities

action- to flex the elbow joint

innervation- musculotaneous nerve

Question 12

Triceps brachii m.
Heads?
origin?
insertion?
action?
innervation?

Answer 12

origin:

• Long: caudal border of scapula
• Lateral: tricipital line of humerus
• Medial: crest of lesser tubercle of humerus
• Accessory: neck of humerus

insertion- olecranon tuber

Action: extend elbow joint

innervation- radial nerve