2.1.3. Muscles of the Posterior (Extensor) Compartment of the Upper Arm

Question 1

What are the 2 Compartments of the Arm?

Answer 1

1. Anterior (Flexor)

2. Posterior (Extensor)

Question 2

What are the 2 Muscles of the Posterior (Extensor) Compartment?

Answer 2

1. Triceps Brachii

2. Anconeus

Question 3

What is the Arterial Supply to the Triceps Brachii?

Answer 3

Profunda Brachii Artery

Question 4

How many Heads does the Triceps Brachii have?

Answer 4

3

Question 5

What are the 3 Heads of the Triceps Brachii?

Answer 5

1. Medial Head
2. Lateral Head
3. Long Head

Question 6

1. Which of the Heads of the Triceps Brachii sits Deepest?

2. Where do the other 2 sit?

Answer 6

1. The Medial Head of the Triceps Brachii

2. They Lateral and Long Heads cover the Medial Head of the Triceps Brachii

Question 7

Where does the Medial Head of the triceps Brachii originate from?

Answer 7

The Humerus, inferior to the Radial Groove

Question 8

Where does the Lateral Head of the Triceps Brachii originate from?

Answer 8

The Humerus, superior to the Radial Groove

Question 9

Where does the Long Head of the Triceps Brachii originate from?

Answer 9

The Infraglenoid Tubercle

Question 10

What happens to the Triceps Brachii as they converge?

Answer 10

They form one Tendon

Question 11

Where does the Tendon of the Triceps Brachii attach Distally?

Answer 11

Olecranon of the Ulna

Question 12

What is the function of the Triceps Brachii?

Answer 12

Extension of the Arm at the Elbow

Question 13

What is the innervation of the Triceps Brachii?

Answer 13

1. Radial Nerve

2. In some individuals, the Triceps Brachii are innervated by the Axillary Nerve

Question 14

What is the Biceps Tendon Reflex testing?

Answer 14

C7

Question 15

Where is the Anconeus located?

Answer 15

Medially and Superiorly to the Extensor Compartment of the Forearm

Question 16

What are the Fibres of the Anconeus blended with?

Answer 16

The Fibres of the Triceps Brachii (The two muscles can be indistinguishable)

Question 17

Where does the Anconeus originate from?

Answer 17

Lateral Epicondyle of the Humerus

Question 18

What does the Anconeus attach to distally?

Answer 18

Posterior and Lateral Part of the Olecranon

Question 19

What is the function of the Anconeus?

Answer 19

1. Extends the Elbow Joint
2. Stabilizes the Elbow Joint
3. Abducts the Ulna during Pronation of the Forearm

Question 20

What is the innervation of the Anconeus?

Answer 20

Radial Nerve

Question 21

What does the Radial Nerve arise from?

Answer 21

It is the Terminal Branch Posterior Cord of the Brachial Plexus

Question 22

What is the function of the Radial Nerve?

Answer 22

It is the Nerve of the Extensor Compartment of the Forearm

Question 23

What does the Radial Nerve innervate?

Answer 23

All the Extensor Muscles of the Elbow and Wrist Joints

Question 24

How does the Radial Nerve enter into the Arm?

Answer 24

Anterior to the Long Head of the Triceps Brachii

Question 25

1. What does the Radial Nerve travel alongside? | 2. Where does the Radial Nerve travel?

Answer 25

1. Profunda Brachii Artery (Deep Artery of the Arm) | 2. Curves around the Midshaft Region of the Humerus, in the Radial Groove

Question 26

What is the Profunda Brachii Artery a Branch of?

Answer 26

Brachial Artery

Question 27

What is the Segmental (or Root) Value of this Nerve?

Answer 27

1. C5 2. C6 3. C7 4. T1

Question 28

Which Branch of the Brachial Artery accompanies the Radial Nerve in the Radial Groove?

Answer 28

Profunda Brachii

Question 29

1. What is the Characteristic Clinical Sign of a Radial Nerve Injury?

Answer 29

Wrist Drop (due to this Nerve Supplying the Extensors of the E;bows and Wrists)