anatomy of the forearm

Question 1

What type of joint is the elbow joint and what are its actions

Answer 1

Synovial hinge joint and it does flexion/extension

Question 2

What type of joint is the radioulnar joint and what are its actions

Answer 2

Synovial pivot joint and it supinates/ pronates

Question 3

Outline the ligaments of the elbow joint, location and slips

Answer 3

Lateral side- radial collateral ligament which is under the annular ligament. comes from lateral epicondyle, 2 slips, one passes to the annular ligament and the other passes to the lateral epicondyle

Medial side- ulnar collateral ligament,
comes from the medial epicondyle, slips to coronoid process of ulna and olecranon

Question 4

What are the 2 compartments of the forearm

Answer 4

Anterior/flexor compartment

posterior/extensor compartment

Question 5

Outline the layers to the anterior compartment

Answer 5

Superficial layer:

• 3 flexors of the wrist (Carpi)
• 1 pronator

intermediate layer (Digitorum):
-1 flexor of digits 2-5

deep muscles (Digitorum):

• 1 flexor of digits 2-5
• 1 flexor of thumb (Pollicis)
• 1 pronator

Question 6

What are the muscles of the superficial layer of the anterior compartment

Answer 6

Pronator teres: inserts into the radius

all but pronator teres originate at the medial epicondyle

medial——>less medial
flexor carpi ulnaris: inserts into the 5th metacarpal

palmaris longus: inserts into the palmar aponeurosis, not everyone has it

flexor carpi radialis: inserts into the 2nd and 3rd metacarpal

Question 7

What are the muscles of the intermediate layer of the anterior compartment

Answer 7

Flexor digitorum superficialis, large muscle, the origin is medial epicondyle and the radius gives off 4 tendons which pass into the hand to digits 2-5

Question 8

What are the muscles of the deep layer of the anterior compartment

Answer 8

flexor digitorum profundus: origin at the ulnar and interosseous membrane and gives off 4 tendons which pass through carpal tunnel and inserts into distal phalynx, digits 2-5

laterally flexor pollicis longus: origin at radius and tendon inserts into the thumb

pronator quadratus:

Question 9

Outline the layers of the posterior compartment

Answer 9

mainly extensors

superficial muscles:

• 3 extensors of the wrist
• 1 extensor of digits 2-5
• 1 accessory extensor to digit 5
• brachioradialis and anconeus

deep muscles:

• 2 extensors of the thumb
• 1 abductor of the thumb
• 1 accessory extensor to digit 2
• 1 supinator

Question 10

Outline the superficial layer of the posterior compartment

Answer 10

medial—-> less medial, CEO (common extensor origin)

extensor carpi radialis longus/ brevis, origin above lateral epicondyle (supracondylar ridge) and CEO respectively and inserts into the base of the second metacarpal

extensor digitorum:
origin at CEO and gives off 4 tendons which inserts into middle and distal phalynx 2-5

extensory digiti minimi:
accessory to extensor digitorum and joins up to go to insert into digit 5

extensor carpi ulnaris:
from CEO and inserts into 5th metacarpal and extends wrists.

brachioradialis and anconeus.

Question 11

Outline brachioradialis and anconeus

Answer 11

muscles in the superficial layer of the posterior compartment.

origin at supracondylar ridge inserts into the styloid process of the radius

anconeus comes from lateral epicondyle and goes to the olecranon

Question 12

What are the deep muscles of the arm

Answer 12

Supinator muscle, abductor pollicis, extensor pollicis longus, extensor pollicis longus and extensor indicis

Question 13

What muscles form the borders of the anatomical snuffbox

Answer 13

Abductor pollic longus, extensor pollicis brevis and longus form the borders of the anatomical snuffbox and are all found in the deep layer of the posterior compartment of the arm

Question 14

What muscles abduct and adduct the wrist

Answer 14

Abduction (radial deviation) is done by flexor carpi radialis and extensor carpi radialis

adduction (ulnar deviation) is done by flexor carpi ulnaris and extensor carpi ulnaris

Question 15

What muscles supinate/ pronate the arm

Answer 15

supinate- biceps brachii and supinator muscle

pronate- pronator teres and pronator quadratus

Question 16

What is the carpal tunnel, what forms it and what are its contentes

Answer 16

formed by the carpal bones and the roof is formed by the flexor retinaculum, tendons and the median nerve runs through it

The components are the median nerve, tendons of flexor policies longus, flexor digitorum superficialis and flexor digitorum profundus.

Question 17

What is the pneumonic for carpal tunnel components and what do each represent

Answer 17

Tom, dick and very nervous harry

tibialis posterior, digitorum superficialis, artery, vein, median nerve and flexor hallucis

Question 18

Where is the extensor retinaculum

Answer 18

On the posterior aspect of the wrist and it prevents bowing of the tendons and separates them into compartments.

Question 19

What is the cubital fossa and what passes through

Answer 19

triangle region over the anterior elbow, bordered by a line created by the lateral and medial epicondyles, laterally bordered by the brachialis and medially bordered by pronator teres.

radial nerve, biceps tendon, brachial artery which splits into radial and ulnar artery, median nerve.