14. Dissection of the Anterior Forearm and Hand Practical

Question 1

Answer 1

Question 2

Can you find:
The pisiform bone
The trapezium
The flexor pollicis longus tendon
The flexor digitorum profundus tendon

Answer 2

Question 3

Name the structures

Answer 3

1 = palmar aponeurosis
X = muscles of thenar eminence
Y = adductor pollicis

Question 4

Name the structures

Answer 4

5 = Flexor digitorum superficialis tendons
6 = Flexor digitorum profundus tendons

Question 5

Name the structures

Answer 5

2 = lumbricals (originateattendonsofflexordigitorumprofundusandinsertatthelateral sides of the extensor expansions of 2nd-5thdigits)​
3 = palmar interossei muscles (origin is metacarpals, insertion is the proximal phalanges)​
4 = dorsal interossei muscles (origin is the metacarpals, insertadjacent sides of metacarpals to the bases of proximal phalanges & extensor expansions of digits 2-4)​
Y = adductor pollicis (originbases of metacarpals 2 and 3, insert base of 2/3rdmetacarpals and proximal phalanx of thumb)

Question 6

Answer 6

Question 7

Answer 7

Question 8

Where do the following insert:
flexor pollicis longus
flexor digitorum profundus

Answer 8

FDP - M. flexor digitorum profundus
FDS - M. flexor digitorum superficialis
FPL - M. flexor pollicis longus
FPB - M. flexor pollicis brevis
LL - Mm. lumbricales
FCR - M. flexor carpi radialis
FCU - M. flexor carpi ulnaris

Question 9

What does the carpal tunnel contain?

Which tendons and which nerve?

Answer 9

The carpal tunnel contains the following structures, from superficial to deep:

Four flexor digitorum superficialis tendons
Median nerve (laterally)
Flexor pollicis longus tendon (laterally)
Four flexor digitorum profundus tendons

Question 10

Answer 10

Question 11

Where are the flexor muscles?
What bones can be seen?

Answer 11

Question 12

Find the brachial, the radial, the ulnar and common interosseous arteries…

Answer 12

Brach A = brachial

RadA = radial
UlnA = ulnar

CommInterossA = common interosseous

Question 13

Which vein passes superficially over the roof of the cubical fossa and is a bridging vein between the cephalic vein and basilic vein?

Answer 13

Median cubital vein

Question 14

Which side is
(a) cephalic vein
(b) basilic vein
on in the anterior forearm?

Answer 14

Cephalic vein = lateral
Basilic vein = medial

Question 15

What are the boundaries of the cubital fossa?

Answer 15

Medially = pronator teres

Laterally = brachioradialis

Superiorly = imaginary line between the epicondyles of the humerus

Floor = brachial and supinator

Roof = bicipital aponeurosis and antebrachial fascia

Question 16

What is the content of the cubital fossa?

Where are they found within?

Answer 16

Biceps brachii tendon

Brachial artery - found medial to biceps brachii tendon

Median nerve - found medial to the brachial artery

TAN

Venae comitantes - veins which accompany the brachial artery (aka brachial veins)

Question 17

Which compartment does the brachioradialis muscle lie within and why do you think it belongs there?

Answer 17

1. Brachioradialis – lies in extensor compartment, embryological origin

Question 18

What is the action of brachioradialis?

Answer 18

Flexion of forearm at elbow joint in mid-pronation

Question 19

What is the innervation of brachioradialis?

Answer 19

Radial nerve

Question 20

What accompanies the radial nerve in the arm?

Answer 20

Radial artery

Question 21

What does the radial artery bifurcate into?

Where do the branches go?

Answer 21

Superficial and deep branches.

Superficial - continues distally underneath brachioradialis muscle.

Deep - pierces supinator muscle to pass to the posterior compartment of the forearm.

Question 22

What does the deep radial artery become in the posterior compartment?

Answer 22

The posterior interosseous nerve

Question 23

Answer 23

Question 24

Answer 24

Question 25

Answer 25

Question 26

Answer 26

Question 27

What do the basilic and cephalic veins arise from?

Answer 27

The dorsal venous arch

Question 28

What muscle is immediately lateral to the brachioradialis muscle?

Answer 28

Extensor carpi radialis longus muscle (ECRL)

Question 29

What is lateral and more superficial to the extensor carpi radialis longus muscle?

Answer 29

Extensor carpi radialis brevis (ECRB)

Question 30

What muscles arise from the common extensor tendon?

Answer 30

ECRB Extensor digitorum Extensor digit minimi Extensor carpi ulnaris

Question 31

What is the origin of there common extensor tendon?

Answer 31

Lateral epicondyle of the elbow

Question 32

Answer 32

Question 33

Why does the extensor digitorum muscle give off?

Answer 33

4 tendons which attach to the digits (not thumb) and assists in extension of the fingers.

Question 34

Which is the most medial muscle of the posterior compartment?

Answer 34

Extensor carpi ulnaris

Question 35

What does the posterior interossous nerve arise from, and what does it travel with?

Answer 35

Arises from the deep radial nerve. Travels with the posterior interosseous artery

Question 36

What are the boundaries of the anatomical snuffbox?

Answer 36

Medial - Extensor Pollicis Longus tendon Laterally (radial aspect) - Extensor Pollicis Brevis & Abductor Pollicis Longus tendons

Question 37

What important structures lie in the floor of the anatomical snuffbox?

Answer 37

Radial artery, superficial branch of radial nerve, cephalic vein

Question 38

Which of the forearm muscles are not present in 100% of the population?

Answer 38

Palmaris longus

Question 39

What does the radial artery lie lateral to in the forearm?

Answer 39

The flexor carpi radialis

Question 40

Which two tendons are used as landmarks when palpating the radial arterial pulse?

Answer 40

Flexor carpi radialis and brachioradialis

Question 41

What does lies medial to palmaris longus at the wrist?

Answer 41

Median nerve

Question 42

Which is the only muscle of the intermediate layer of the anterior compartment of the forearm?

Answer 42

Flexor digitorum superficialis (FDS)

Question 43

What is the purpose of the tendinous arch of the flexor digitorum superficialis?

Answer 43

Allows the ulnar artery and median nerve to pass deep to it.

Question 44

What lies between the median nerve and the ulnar artery at the wrist?

Answer 44

flexor digitorum superficialis

Question 45

What does the ulnar nerve branch into?

Answer 45

The common interossoeous artery (which further divides into anterior and posterior interosseous arteries)

Question 46

Answer 46

Question 47

Answer 47

Question 48

Answer 48

Question 49

Why is the anatomical snuffbox clinically relevant?

Answer 49

Carpal fracture (scaphoid) may result in vascular injury and can lead to avascular necrosis of the carpal bones

Question 50

What is the function of the dorsal interosseous muscles?

Answer 50

Abduction of the digits

Question 51

Answer 51

Question 52

Answer 52

Question 53

The middle layer of the muscles in the anterior compartment of the forearm contain a single muscle - which one is it?

Answer 53

Flexor digitorum superficialis

Question 54

The cubital fossa is bound by which muscle on the lateral border?

Answer 54

Brachioradialis

Question 55

Which nerve passes through the carpal tunnel and when compressed results in symptoms distributed over the hand?

Answer 55

Median nerve

Question 56

Which muscle acts on the thumb and is not innervated by the recurrent branch of the median nerve?

Answer 56

Adductor pollicis

Question 57

Which nerve lies in the cubital fossa and may be damaged during venipuncture if the needle is inserted in the wrong location?

Answer 57

Median nerve

Question 58

The common flexor origin is located on the medial epicondyle of the humerus? True or False.

Answer 58

Yes

Question 59

The ulnar nerve passes posteriorly to the lateral humeral epicondyle at the elbow joint. True or False?

Answer 59

False

Question 60

The palmaris longus is not always present in each individual, but it is normally located in the superficial muscle layer of the anterior compartment of the forearm. True or False?

Answer 60

True

Question 61

The roof of the carpal tunnel is formed by the extensor retinaculum. True or False?

Answer 61

False - the roof of the carpal tunnel is formed by the flexor retinaculum.

Question 62

The lumbricals act to flex the digits at the metacarpophalangeal joints whilst maintaining extension in the interphalangeal joints. True or False?

Answer 62

True