Posterior Compartment Of Forearm

Question 1

Muscles of posterior compartment has a common origin at?

Answer 1

Posterior (extensor) compartment:
Lateral epicondyl of humerus

Anterior (flexor) compartment:
Medial epicondyl of humerus

Question 2

The tendons of muscles of posterior compartment of forearm pass through?

Answer 2

Extensor retinaculum
(A fibrous band of connective tissue which holds the bands in place)

Question 3

Difference between flexor retinaculum and extensor retinaculum?

Answer 3

The flexor retinaculum is located on the palmar side of the wrist,
while the extensor retinaculum is located on the dorsal side of the wrist.

Question 4

Origin and insertion of extensor carpi radialis brevis?

Answer 4

Origin:
Lateral epicondyl of humeus

Insertion:
Base of 3rd metacarpal bone

Question 5

Insertion of extensor carpi radialis longus and extensor carpi radialis brevis?

Answer 5

Longus-
base of 2nd metacarpal

Brevis
Base of 3rd metacarpal

Question 6

Action of extensor carpi radialis brevis?

Answer 6

Same as longus:

Extends and abducts the wrist

Question 7

How many tendons of extensor digitorum?

Answer 7

4 tendons

Question 8

Medial to extensor carpi radialis brevis is?

Answer 8

Extensor digitorum

Question 9

Name the muscles of of posterior compartment of forearm?

Answer 9

Superficial layer

1. Extensor carpi radialis brevis
2. Extensor digitorum
3. Extensor digiti minimi
4. Extensor carpi ulnaris
5. Anconeus

Deep

6. Supinator
7. Abductor pollicis longus
8. Extensor pollicis brevis
9. Extensor pollicis longus
10. Extensor indicis

Question 10

Origin and insertion of extensor digitorum?

Answer 10

Origin:
Lateral epicondyl of humerus

Insertion:
Middle & Distal phalanges of medial 4 fingers

Question 11

Action of extensor digitorum?

Answer 11

Extends the fingers and hands

Question 12

Origin and insertion of Extensor digiti minimi?

Answer 12

Origin:
Lateral epicondyl of humerus

Insertion:
Extensor expansion of little finger

Question 13

Action of extensor digiti minimi?

Answer 13

Extends the MCP joint of little ginger

Question 14

Antagonist of flexor carpi ulnaris?

Answer 14

Extensor carpi ulnaris
It extends and adducts the wrist
( not flexion and adduction)

Question 15

Origin and insertion of extensor carpi ulnaris?

Answer 15

Origin:
Lateral epicondyl of humerus

Insertion:
Base of the 5th metacarpal bone

Question 16

Difference of action of extensor carpi ulnaris and extensor carpi radialis?

Answer 16

Extensor Carpi ulnaris
Adducts and extends the wrist

Extensor carpi Radialis
Abducts and extends the wrist

Question 17

Origin and insertion of anconeus muscle?

Answer 17

Origin:
Lateral epicondyl of humerus

Insertion:
Olecrannon process of ulna

Question 18

The origin of mucles of deep layer of posterior compartment of forearm?

Answer 18

Apart from supinator
One head - lateral epicondyl of humerus

All originate from shaft of radius
Ulna
Interosseous membrane

Question 19

Nerve supply for all the muscles of the posterior compartment of forearm?

Answer 19

Deep branch of the radial nerve

Anconeus - radial nerve

Question 20

Origin and insertion of supinator?

Answer 20

Origin:
1Lateral epicondyl of humerus (superficial head)
2. Annular ligament of the superior radioulnar joint
3. Ulna(deep head)

Insertion:
Neck and shaft of radius

Question 21

Supination of forearm is done by?

Answer 21

1.Supinator
2.Biceps brachii

Question 22

Distal to supinator is which muscle?

Answer 22

Abductor pollicis longus

Question 23

Origin and insertion of abductor pollicis longus?

Answer 23

Origin:
Shaft of radius and ulna

Insertion:
Base of the 1st metacarpal bone

Question 24

Action of abductor pollicis longus?

Answer 24

Abducts and extends the thumb

Question 25

Distal to abductor pollicis longus?

Answer 25

Extensor pollicis brevis

Question 26

Origin and insertion of extensor pollicis brevis?

Answer 26

**Origin** Shaft of the **radius** Interosseous membrane **Insertion** Base of **proximal** phalanx of thumb

Question 27

Action of extensor pollicis brevis?

Answer 27

Extends the MCP joint of thumb

Question 28

Extensor pollicis longus origin and insertion?

Answer 28

**Origin** Shaft of **ulna** Interosseous membrane **Insertion** Base of **distal** phalanx of thumb

Question 29

Action of extensor pollicis longus?

Answer 29

Extends the **distal**phalanx of thumb

Question 30

Difference in origin of extensor pollicis brevis and longus?

Answer 30

Brevis: Radius Longus: Ulna

Question 31

Origin and insertion of extensor indicis?

Answer 31

**origin** Shaft of **ulna** Interosseous membrane **Insertion** Extensor expansion of **index** finger

Question 32

Action of extensor indicis?

Answer 32

Extends the MCP joint of intex finger

Question 33

The only muscle of posterior compartment of forearm that that originates from shaft of radius and ulna both?

Answer 33

Abductor pollicis longus

Question 34

The only muscle of posterior compartment of forearm that that originates from shaft of **radius** and interosseous membrane?

Answer 34

Extensor pollicis brevis

Question 35

The muscles of posterior compartment of forearm that that originates from shaft of **ulna** and interosseous membrane?

Answer 35

1.Extensor pollicis longus 2.Extensor indicis

Question 36

Name the muscles of posterior compartment of forearm of thumb?

Answer 36

1. Abductor pollicis longus 2. Extensor pollicis brevis 3. Extensor pollicis longus

Question 37

The anconeus muscle is blended with which muscle?

Answer 37

Triceps brachii

Question 38

What is tennis elbow?

Answer 38

**Lateral epicondilytis** Or tennis elbow is the inflammation of the **periosteum** of the **lateral** epicondyle

Question 39

Which muscle forms the floor of the cubital fossa? And its roof?

Answer 39

**Brachialis** - floor **Bicipital aponeurosis** - roof

Question 40

How many heads of supinator and what passes through them?

Answer 40

2 heads Deep branch of **radial nerve** passes through them

Question 41

Which muscles form the lateral border of anatomical snuff box?

Answer 41

1. Abductor pollicis longus 2. Extensor pillicis **brevis**

Question 42

The tendon of which muscle forms the medial border of anatomical snuff box?

Answer 42

1.Extensor pollicis **longus**

Question 43

What happens in wrist drop?

Answer 43

Unopposed flexion at wrist joint Damage to: **Radial nerve** (Innervates all muscles in **extensor**compartment of forearm so extensor muscles paralysed) Flexor are unaffected so unopposed flexion

Question 44

What are 2 common characteristics sites of damage of radial nerve?

Answer 44

1. **Axilla** Humeral dislocation or fracture of proximal humerus 2. **Radial groove** Humeral shaft fracture