7. Anatomy of the forearm

Question 1

Skeletal features of the forearm

Answer 1

olecranon

trochlea

head of radius

radial tuberosity

ulna tubercle

interosseous membrane

styloid processes of radia and ulna

Question 2

What type of joint is the elbow joint and what kind of features does it have?

Answer 2

Synovial hinge joint Used for flexion/extension

Also proximal radioulnar joint

• pivot joint for supination/pronation

Question 3

Ligaments

Answer 3

Ligaments stabilise/strengthen the joint annular ligament radial collateral ligament ulnar collateral ligament

Question 4

Cubital fossa

Answer 4

Triangle region over anterior elbow

Borderred on bottom by pronater teres and brachioradialis

top made by line drawn from lateral epicondyle to medial epicondyle

Structures that pass through:

median nerve

lateral cutaneous nerve to the forearm

biceps tendon!

bicepital aponeurosis comes off from biceps tendon and over pronator teres

Question 5

Median cubital vein

Answer 5

Important for venepuncture

in middle of basilic vein and cephalic vein

Question 6

Forearm compartments

Answer 6

Two compartments: Flexor compartment Extensor compartment Long tendons enter hand

Question 7

Anterior forearm parts

Answer 7

superficial muscles

intermediate muscles ^(from common flexor origin)

deep muscles

Question 8

Superficial muscles of forearm

Answer 8

3 flexors of wrist (carpi)

1 pronator

Question 9

intermediate muscles of forearm

Answer 9

1 flexor of digits 2-5 (digitorum)

Question 10

deep muscles of forearm

Answer 10

1 flexor of digits 2-5 (digitorum)

1 flexor of thumb (pollicis)

1 pronator

Question 11

Superficial layer of forearm flexors

Answer 11

Common flexor origin at medial epicondyle

pronator teres

flexor carpi radialis (from CFO to 2nd metacarpal)

flexor carpi ulnaris (from CFO to pisiform and hamate to 5th metacarpal)

palmaris longus (from CFO to pisiform to 3rd metacarpal)

Question 12

Clinical aspect of superficial layer of forearm flexors

Answer 12

Golfers elbow - epicondylitis at CFO (common flexor origin)

Question 13

Intermediate layer of forearm flexors

Answer 13

common flexor origin Flexor digitorum superficialis Radial artery From medial epicondyle to medial phalanges

Question 14

Deep layer of forearm flexors

Answer 14

Interosseous membrane Flexor pollicis longus Flexor digitorum profundus pronator quadratus from medial epicondyle to distal phalanges

Question 15

Extensor compartment

Answer 15

Superficial muscles:

3 Extensors of wrist (carpi)

1 Extensor of digits 2-5 (digitorum)

1 Accessory extensor to digit 5 (digiti minimi)

Brachioradialis and anconeus

Deep muscles:

2 Extensors of thumb (pollicis)

1 Abductor of thumb (pollicis)

1 Accessory extensor to digit 2 (indicis)

1 Supinator

Question 16

Superficial layer of extensor

Answer 16

Common extensor origin Extensor carpi radialis longus/brevis Extensor digitorum Extensor digiti minimi (accessory to extensor digitorum) Extensor carpi ulnaris

Question 17

Clinical significance of superficial layer of forearm extensors

Answer 17

Tennis elbow Epicondylitis at CEO (tendon inflammation due to overuse/forceful extension)

Question 18

Brachioradialis

Answer 18

Flexor when half pronated supracondylar ridge to lateral epicondyle to styloid process of the radius

Question 19

Anconeus

Answer 19

stabilises elbow

Question 20

Deep layer of forearm extensors

Answer 20

Supinator Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus ^ all pass through anatomical snuffbox Extensor indicis (accessory to extensor digitorum) to 1st metacarpal, proximal phalanx and distal phalanx

Question 21

Wrist abduction and adduction

Answer 21

performed by the carpi muscles Together, abductor and adductor muscles splint wrist to allow fine movements of the hand

Question 22

Abduction of wrist

Answer 22

Flexor carpi radialis Extensor carpi radialis (longus and brevis)

Question 23

Adduction of wrist

Answer 23

Flexor carpi ulnaris Extensor carpi ulnaris

Question 24

Muscles involved in supination

Answer 24

biceps brachii supinator (superficial and deep branches)

Question 25

muscles involved in pronation

Answer 25

pronator teres pronator quadratus

Question 26

Supinated

Answer 26

proximal radioulnar joint distal radioulnar joint everythings chill

Question 27

pronated

Answer 27

radius rotates over ulna

Question 28

Carpal tunnel

Answer 28

tunnel for flexor tendons to digits and median nerve

Question 29

what does the flexor retinaculum do?

Answer 29

its a big sheath wrapping around all the flexor tendons aka transverse carpal ligament prevents bowing of tendons

Question 30

Contents of the carpal tunnel

Answer 30

median nerve flexor policis longus tendon flexor figitorum superficialis tendons flexor digitorum profundus tendons All these tendons are surrounded by synovial sheathes

Question 31

What is carpel tunnel syndrome?

Answer 31

compression of the median nerve due to increased pressure in carpel tunnel associated with trauma, obesity and pregnancy

Question 32

Extensor retinaculum

Answer 32

prevents bowing of tendons separates tendons into compartments Wraps around synovial sheaths of extensor tendons

Question 33

Long tendon insertion

Answer 33

Tendons to d2-5 extensor digitorum - into middle and distal phalanx flexor digitorum superficialis - into middle phalanx flexor digitorum profundus - into distal phalanx

Question 34

Arterial supply to forearm

Answer 34

Brachial artery divides at cubital fossa into: radial artery - under brachioradialis ulnar artery - under flexor carpi ulnaris, gives off common interosseous artery anastomosis around elbow joint

Question 35

Radial artery

Answer 35

lateral branch of brachial under brachioradialis runs alongside superficial branch of radial nerve winds to dorsum of hand

Question 36

ulnar artery

Answer 36

medial branch of brachial recurrent branches contribute to anastomosis gives off common interosseous artery

Question 37

common interosseous artery

Answer 37

from ulnar artery splits into posterior interosseous and anterior interosseous arteries

Question 38

nerve supply to forearm

Answer 38

musculocutaenous nerve median nerve radial nerve ulnar nerve

Question 39

median nerve

Answer 39

lies mid forearm between FDS and FDP branch: anterior interosseous nerve to deep flexor muscles passes thru carpal tunnel supplies: - motor to anterior compartment except FCU/medial part of FDP -sensory to lateral palm, d1, d2, d3, 1/2 d4

Question 40

Ulnar nerve

Answer 40

passes thru cubital tunnel posteriorily then goes anterior, between FCU and FDP supplies: -motor to FCU and medial part of FDP -sensory to medial hand 1/2 d4 and d5

Question 41

radial nerve

Answer 41

enters forearm on lateral side under brachioradialis divides into two branches: deep and superficial

Question 42

deep branch of radial nerve

Answer 42

deep branch - posterior interosseous nerve (motor) on posterior side (extensor side) passes through supinator muscle, enters extensor compartment supplies posterior compartment

Question 43

superficial branch of radial nerve

Answer 43

-superficial branch (sensory) under brachioradialis, winds to dorsum of hand on flexor side (anterior side) supplies lateral dorsum hand

Question 44

Clinical significance of radial nerve

Answer 44

wrist drop

Question 45

Answer 45