Muscles of the Arm

Question 1

What is the anatomical arm?

Answer 1

The shoulder joint to the elbow joint

Question 2

What muscles are in the anterior arm?

Answer 2

Biceps brachii
Brachialis
Coracobrachialis

Question 3

What muscles are in the posterior arm?

Answer 3

Triceps

Anconeus

Question 4

What are muscles in the anterior compartment of the arm innervated by?

Answer 4

The musclocutaneous nerve

Question 5

What kind of muscle is the biceps brachii?

Answer 5

Two headed

Question 6

Where is nearly all the muscle mass of the biceps located?

Answer 6

Anterior to the humerus

Question 7

Does the biceps have an attachment to the humerus?

Answer 7

No

Question 8

How is the muscle belly of the biceps brachii formed?

Answer 8

By the combination of the two heads

Question 9

Where do the two heads of the biceps brachii combine?

Answer 9

At the level of the humeral shaft

Question 10

How do the two heads of the biceps brachii combine?

Answer 10

The tendon of the long head passes through the shoulder joint and intertubercular groove of the humerus to meet the short head

Question 11

What is the biceps brachii innervated by?

Answer 11

Musculocutaneous nerve (C5-7)

Question 12

What does a tap on the biceps tendon test?

Answer 12

Spinal cord segment C6

Question 13

What is the arterial supply of the biceps brachii?

Answer 13

Brachial artery

Question 14

What is the action of the biceps brachii?

Answer 14

Supinates forearm, and when it is supine, flexes forearm

Short head resists dislocation of the shoulder

Question 15

What happens as the biceps tendon enters the forearm?

Answer 15

A connective tissue sheet is given off, called the bicipital aponeurosis

Question 16

What does the bicipital aponeurosis form?

Answer 16

The roof of the cubital fossa

Question 17

What does the bicipital aponeurosis blend with?

Answer 17

The deep fascia of the anterior forearm

Question 18

How common is a complete rupture of a body tendon?

Answer 18

Rare

Question 19

What is one of more common tendons to rupture?

Answer 19

The long head of the biceps tendon

Question 20

What does the rupture of the biceps tendon produce?

Answer 20

A characteristic bulge where the muscle belly is on flexing at the elbow, called the ‘Popeye Sign ‘

Question 21

Would a patient with a rupture of the biceps tendon notice much weakness in the upper limb?

Answer 21

No, due to the action of the brachialis and supinator muscles

Question 22

Where does the coracobrachialis muscle lie?

Answer 22

Deep to the biceps brachii in the arm

Question 23

Where does the coracobrachialis pass?

Answer 23

Through the axilla

Question 24

What is the innervation of the coracobrachialis?

Answer 24

Musculocutaneous nerve (C5, C6, C7)

Question 25

What is the arterial supply of the coracobrachialis?

Answer 25

Brachial artery

Question 26

What is the function of the coracobrachialis?

Answer 26

Helps flex and adduct the arm  | Resists dislocation of the shoulder

Question 27

Where does the brachialis muscle lie?

Answer 27

Deep to the biceps brachii, more distally than the other muscles of the arm

Question 28

What does the brachialis form?

Answer 28

The base of the cubital fossa

Question 29

What is the innervation of the brachialis?

Answer 29

``` Musculocutaneous nerve (C5, C6) Small lateral portion by radial nerve (C5, C7) ```

Question 30

What is the arterial supply of the brachialis?

Answer 30

Brachial artery | Radial recurrent artery

Question 31

What is the action of the brachialis?

Answer 31

Flexes forearm in all positions

Question 32

What does the triceps brachii have?

Answer 32

Three heads

Question 33

Where does the medial head of the triceps lie?

Answer 33

Deeper than the other two

Question 34

When is the medial head visible?

Answer 34

When the other two heads have been dissected away

Question 35

What happens to the three heads of the triceps brachii?

Answer 35

They combine to make one muscle and converge to a tendon

Question 36

What is the innervation of the triceps brachii?

Answer 36

Radial nerve (C6-8)

Question 37

What is the arterial supply of the triceps brachii?

Answer 37

Deep brachial artery

Question 38

What is the action of the triceps brachii?

Answer 38

Chief extensor of forearm  Long head resists dislocation of humerus  Especially important during adduction

Question 39

What does a tap on the triceps tendon test?

Answer 39

Spinal segment C7

Question 40

What is the innervation of the anconeus?

Answer 40

Radial nerve (C7, C8, T1)

Question 41

What is the arterial supply of the anconeus?

Answer 41

Recurrent interosseous artery

Question 42

What is the action of the anconeus?

Answer 42

Assists triceps in extending the forearm  Stabilises elbow joint  May abduct ulna during pronation