Anatomy Lab Presentation- Forearm Posterior Compartment

Question 1

What are the Superficial Muscles of the Forearm Posterior Compartment?

Answer 1

1. Extensor Carpi Radialis Longus
2. Extensor Carpi Radialis Brevis
3. Extensor Carpi Ulnaris
4. Extensor Digitorum
5. Digiti Minimi
6. Anconeus
7. Brachioradialis

Question 2

The Forearm Posterior Compartment is also called what?

Answer 2

“Extensor Compartment” because all but one muscle (Brachioradialis) perform Extension

Question 3

What nerve innervates the Superficial Muscles of the Forearm Posterior Compartment?

Answer 3

Radial Nerve

Question 4

What is the lone muscle that performs Flexion in the group of Superficial Muscles of the Forearm Posterior Compartment? Why is it considered Posterior?

Answer 4

1. Brachioradialis
2. Innervated by Radial Nerve

NOTE: It is considered to be posterior, BUT it is located very laterally between the anterior and posterior compartments

Question 5

Extensor Carpi Radialis Longus:

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 5

1. Lateral Supracondylar Ridge (Right above Lateral Epicondyle) of the Humerus
2. Base of Second Metacarpal (Index Finger)
3. Wrist Extension and aBduction
4. Radial Nerve

Question 6

Extensor Carpi Radialis Brevis:

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 6

1. Lateral Epicondyle of Humerus
2. Base of Third Metacarpal (Middle Finger)
3. Wrist Extension and aBduction
4. Radial Nerve

Question 7

Extensor Carpi Ulnaris:

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 7

1. Lateral Epicondyle of Humerus AND Posterior Border of Ulna
2. Base of the Fifth Metacarpal (Pinky)
3. Wrist Extension and aDduction
4. Radial Nerve

Question 8

Extensor Digitorum:

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 8

1. Lateral Epicondyle of the Humerus
2. Inserts on Middle and Distal Phalanges of Digits 2-5
3. Extension of Digits 2-5
4. Radial Nerve

Question 9

Extensor Digiti Minimi:

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 9

1. Lateral Epicondyle of the Humerus
2. Phalynx of Digit 5 (Pinky)
3. Extension of Pinky
4. Radial Nerve

Question 10

Anconeus:

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 10

1. Lateral Epicondyle of Humerus
2. Lateral aspect of Olecranon on Ulna
3. Accessory to Extension of the Elbow
4. Radial Nerve

Question 11

Brachioradialis:

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 11

1. Lateral Supracondylar Ridge (Right above Lateral Epicondyle) of the Humerus
2. Radius (Lateral side of Distal end)
3. Accessory to Flexion of the Elbow
4. Radial Nerve

Question 12

What are the Deep Muscles of the Forearm Posterior Compartment?

Answer 12

1. Abductor Pollicis Longus
2. Extensor Pollicis Longus
3. Extensor Pollicis Brevis
4. Extensor Indicis
5. Supinator

Question 13

What nerve innervates the Deep Muscles of the Forearm Posterior Compartment?

Answer 13

Radial Nerve

Question 14

Abductor Pollicis Longus:

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 14

1. Posterior of Radius and Ulna
2. Base of Thumb Metacarpal and Trapezium
3. Extension (Hitchhike) and aBduction (U Miami with Palms facing) of Thumb
4. Radial Nerve

Question 15

Extensor Pollicis Brevis:

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 15

1. Radius and Ulna (Dorsally)
2. Proximal Phalynx of Thumb
3. Extends Thumb (hitchhiking)
4. Radial Nerve

Question 16

Extensor Pollicis Longus:

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 16

1. Radius and Ulna (Dorsally)
2. Distal Phalynx of Thumb
3. Extends Thumb (hitchhiking)
4. Radial Nerve

Question 17

Extensor Indicis:

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 17

1. Ulna (Distally)
2. Second Digit Phalanges (Index)
3. Extension of the Index Finger
4. Radial Nerve

Question 18

Supinator:

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 18

1. Lateral Epicondyle of Humerus AND Ulna (Proximally)
2. Radius (Proximally)
3. Supination of the Forearm
4. Radial Nerve

Question 19

What is the difference in orientation of the Superficial and Deep Muscles of the Forearm Posterior Compartment?

Answer 19

“FaDDDy” (in Forearm Dorsal Deep run Diagonally):

1. Deep Muscles run Diagonally
2. Superficial Muscles run Vertically

Question 20

Forearm posterior compartment, superficial: extensor carpi radialis longus and brevis, extensor carpi ulnaris, extensor digitorum and extensor digiti minimi, anconeus, brachioradialis

Forearm posterior compartment, deep: abductor pollicis longus, extensor pollicis longus and brevis, extensor indicis, supinator

Answer 20

KNOW

Question 21

On the Arm Model

Answer 21

Superficial:
27- Brachioradialis
42- Extensor Carpi Radialis Longus
43- Extensor Carpi Radialis Brevis
44- Extensor Digitorum
45- Extensor Digiti Minimi
46- Extensor Carpi Ulnaris
47- Anconeus

Deep:
48-Supinator
49- Abductor Pollicis Longus
50- Extensor Pollicis Brevis
51- Extensor Pollicis Longus
52- Extensor Indicis

55- Superior Ulnar Collateral Artery??
56- Posterior Interosseous Artery??
57-Radial Nerve

Question 22

What 6 muscles Originate on the Lateral Epicondyle of the Humerus?

Answer 22

5 of the 7 Superficial Muscles of the Forearm Posterior Compartment AND 1 Deep Muscles of the Forearm Posterior Compartment:

1. Extensor Carpi Radialis Brevis
2. Extensor Carpi Ulnaris
3. Extensor Digitorum
4. Anconeus
5. Supinator
6. Extensor Digit Minimi