MSK Upper Arm and Forearm

Question 1

Okay lets start with the muscles of the anterior compartment of the upper arm.
Can you name them?

Answer 1

Biceps brachii- long and short head
Brachialis
Coracobrachialis

Question 2

What is the innervation for the nerves in the anterior compartment of the upper arm?

Answer 2

Musculocutaneous nerve

Question 3

What is the overall compartment function for the anterior compartment of the upper arm?

Answer 3

Flexion

Question 4

Time to get a bit more specific :)

Let’s start with the biceps brachii.
What is it’s action?

Answer 4

Flexion at the elbow joint
Supination of the forearm

Question 5

What is the action of the brachialis?

Answer 5

Flexion at elbow joint

Question 6

What is the function of the coracobrachialis?

Answer 6

Flexion at shoulder joint
Weak adduction at shoulder joint

Question 7

Yay, pretty simple :)

Now let’s move onto the posterior compartment of the upper arm.
What muscle is found here?

Answer 7

Triceps brachii- long, medial and lateral head

Question 8

One of the heads of the triceps is deep to the other two.
Which one?

Answer 8

Medial head lies deep to the lateral and long heads

Question 9

Where do the heads of the triceps originate from?

Answer 9

Lateral- superior to radial groove of humerus
Medial- inferior to radial groove of humerus
Long- infraglenoid tubercle of scapula

Question 10

The three heads of the triceps come together to form a common tendon. Where does this tendon insert?

Answer 10

Olecranon of ulna

Question 11

What is the innervation for the posterior compartment of the upper arm?

Answer 11

Radial nerve

Question 12

Oops let me go back for a minute
What are the nerve roots of the musculocutaneous nerve?

Answer 12

C5-7

Question 13

What are the nerve roots for the radial nerve?

Answer 13

C5-T1

Question 14

What is the action of the posterior compartment of the upper arm?

Answer 14

Extension of elbow joint

Question 15

Moving onto the forearm…
How many layers of muscles are there in the anterior compartment of the forearm?

Answer 15

Three- superficial, intermediate and deep

Question 15

Name the muscles in the superficial layer of the anterior compartment of the forearm.

Answer 15

Flexor carpi ulnaris
Flexor carpi radialis
Palmaris longus
Pronator teres

Question 16

What is the innervation of the superficial layer of the anterior compartment of the forearm and what is the exception to this?

Answer 16

Supplied by median nerve except for flexor carpi ulnaris which is supplied by the ulnar nerve

Question 17

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

Answer 17

Flexor digitorum superficialis

Question 18

What is the innervation of the flexor digitorum superficialis, the only muscle in the intermediate layer of the anterior compartment of the forearm?

Answer 18

Median nerve

Question 19

What are the muscles in the deep layer of the anterior compartment of the forearm?

Answer 19

Flexor pollicus longus
Flexor digitorum profunda
Pronator quadratus

Question 20

What is the innervation for the deep layer of the anterior compartment of the forearm and what is the exception to this?

Answer 20

Median nerve

EXCEPT for flexor digitorum profundus- medial half (right and little finger) get innervation from the ulnar nerve and lateral half (middle and index) gets innervation from median nerve

Question 21

Let’s talk about the actions of the muscles in the anterior compartment of the forearm, starting with the superficial layer.

What is the action of the flexor carpi ulnaris?

Answer 21

Flexion at wrist
Adduction of wrist

Question 22

Let’s talk about the actions of the muscles in the anterior compartment of the forearm, starting with the superficial layer.

What is the action of the flexor carpi radialis?

Answer 22

Flexion at wrist
Abduction of wrist

Question 23

Let’s talk about the actions of the muscles in the anterior compartment of the forearm, starting with the superficial layer.

What is the action of the palmaris longus?

Answer 23

Flexion at wrist

Question 24

Let's talk about the actions of the muscles in the anterior compartment of the forearm, starting with the superficial layer. What is the action of the pronator teres?

Answer 24

Pronation of the forearm

Question 25

Let's talk about the actions of the muscles in the anterior compartment of the forearm, continuing with the intermediate layer. What is the action of the flexor digitorum superficialis?

Answer 25

Flexion at MCP joints Flexion at PIP joints Flexion at wrist

Question 26

Let's talk about the actions of the muscles in the anterior compartment of the forearm, finishing with the deep layer. What is the action of the flexor digitorum profundus?

Answer 26

Flexion of DIP joints Flexion of MCP joints Flexion of wrist

Question 27

Let's talk about the actions of the muscles in the anterior compartment of the forearm, finishing with the deep layer. What is the action of the flexor pollicus longus?

Answer 27

Flexes IP joints and MCP joints of thumb

Question 28

Let's talk about the actions of the muscles in the anterior compartment of the forearm, finishing with the deep layer. What is the action of the pronator quadratus?

Answer 28

Pronation of the forearm

Question 29

Which muscle in the anterior compartment of the upper arm can be absent in approx. 15% of the population?

Answer 29

Palmaris longus

Question 30

Okay, let's move onto the posterior compartment of the forearm now :) Just to recap (mostly to help me making the flashcards haha), so far we have covered the anterior and posterior compartments of the upper arm and the three layers (superficial, intermediate and deep) of the anterior compartment of the forearm. So, what are the two layers of muscles in the posterior compartment of the forearm?

Answer 30

Superficial and deep

Question 31

What are the muscles found in the superficial layer of the posterior compartment of the forearm? There's quite a few!!

Answer 31

Brachioradialis Extensor Carpi Radialis Longus Extensor Carpi Radialis Brevis Extensor Carpi Ulnaris Extensor Digitorum Extensor Digiti Minimi Anconeus

Question 32

What is the innervation for the muscles of the superficial layer of the posterior compartment of the forearm?

Answer 32

Radial nerve

Question 33

Let's work out the actions of the muscles in the superficial layer of the posterior compartment of the forearm before moving onto the deep layer. What is the action of the brachiradialis muscle?

Answer 33

Flexion at elbow ->only muscle which breaks the rule that flexors are found in the anterior compartment

Question 34

Let's work out the actions of the muscles in the superficial layer of the posterior compartment of the forearm before moving onto the deep layer. What is the action of the extensor carpi radialis longus and brevis?

Answer 34

Extends the wrist Abducts the wrist

Question 35

Let's work out the actions of the muscles in the superficial layer of the posterior compartment of the forearm before moving onto the deep layer. What is the action of the extensor carpi ulnaris?

Answer 35

Extends the wrist Adducts the wrist

Question 36

Let's work out the actions of the muscles in the superficial layer of the posterior compartment of the forearm before moving onto the deep layer. What is the action of the extensor digitorum?

Answer 36

Extension of digits at interphalangeal joints and MCP joints

Question 37

Let's work out the actions of the muscles in the superficial layer of the posterior compartment of the forearm before moving onto the deep layer. What is the action of the extensor digiti minimi?

Answer 37

Extends little finger Contributes the extension at wrist

Question 38

Let's work out the actions of the muscles in the superficial layer of the posterior compartment of the forearm before moving onto the deep layer. What is the action of the anconeus?

Answer 38

Extends elbow joint Abducts ulna during pronation

Question 39

Right, onto the deep layer of muscles :) Name the muscles found in the deep layer of the posterior compartment of the forearm.

Answer 39

Supinator Abductor Pollicus Longus Extensor Pollicus Brevis Extensor Pollicus Longus Extensor Indicis

Question 40

Innervation of the muscles in the deep layer of the posterior compartment of the forearm?

Answer 40

Radial nerve

Question 41

Let's work out the actions of the deep muscles in the posterior compartment of the forearm! What is the action of the supinator muscle?

Answer 41

Supinates forearm

Question 42

Let's work out the actions of the deep muscles in the posterior compartment of the forearm! What is the action of the abductor pollicus longus?

Answer 42

Abducts thumb

Question 43

Let's work out the actions of the deep muscles in the posterior compartment of the forearm! What is the action of the extensor pollicus brevis?

Answer 43

Extension at MCP joints and carpometacarpal joints of thumb

Question 44

Let's work out the actions of the deep muscles in the posterior compartment of the forearm! What is the action of the extensor pollicus longus?

Answer 44

Extends all joints of thumb; CMC, MCP, IP

Question 45

Let's work out the actions of the deep muscles in the posterior compartment of the forearm! What is the action of the extensor inidicis?

Answer 45

Extension of the index finger

Question 46

Just more generally now, what is the point on the humerus where the tendon of the wrist flexor muscles attach?

Answer 46

Medial epicondyle of humerus

Question 47

Just more generally now, what is the point on the humerus where the tendon of the wrist extensor muscles attach?

Answer 47

Lateral epicondyle of humerus

Question 48

Borders of cubital fossa? Please sit and work them out on yourself, before or after flipping the card over x

Answer 48

Lateral- medial border of brachioradialis Medial- lateral border of pronator teres Superior- line between two epicondyles of humerus (imaginary) Roof- bicep aponeurosis, fascia, subcutaneous fat and skin Floor- brachialis and supinator

Question 49

Contents of cubital fossa?

Answer 49

Radial nerve Median nerve Brachial artery Biceps tendon (can feel if flex arm)

Question 50

What makes up the anatomical snuff box? Look at hand pls

Answer 50

Ulnar border- tendon of extensor pollicis longus Radial border- tendons of extensor pollicis brevis and abductor pollicis longus

Question 51

Muscles of the hand can be extrinsic or intrinsic. We have already covered the extrinsic ones as they are located within the anterior and posterior compartments of the forearm. What are the groups of intrinsic muscles of the hand?

Answer 51

Thenar muscles Hypothenar muscles Lumbricals Interossei

Question 52

Name the thenar muscles.

Answer 52

Opponens pollicis Abductor pollicis brevis Flexor pollicus brevis

Question 53

Innervation of thenar muscles?

Answer 53

Median nerve (but deep head of flexor pollicus brevis is innervated by ulnar nerve branch)

Question 54

Time for the action of the thenar muscles :) What is the action of the opponens pollicis?

Answer 54

Oposes thumb

Question 55

Time for the action of the thenar muscles :) What is the action of the abductor pollicis brevis?

Answer 55

You'll never guess it... it abducts the thumb

Question 56

Time for the action of the thenar muscles :) What is the action of the flexor pollicis?

Answer 56

Flexion of MCP joint of thumb

Question 57

Okay, where would you find the thenar muscles?

Answer 57

Base of thumb on palmar aspect of hand

Question 58

Where would you find the hypothenar muscles?

Answer 58

Base of little finger on palmar aspect of hand

Question 59

Name the hypothenar muscles.

Answer 59

Opponens digiti minimi Abductor digiti minimi Flexor digiti minimi brevis

Question 60

Innervation of the hypothenar muscles?

Answer 60

Ulnar nerve

Question 61

Right, time for the actions of the hypothenar muscles! What is the action of the opponens digiti minimi?

Answer 61

Opposition by moving little finger towards palm

Question 62

Right, time for the actions of the hypothenar muscles! What is the action of the abductor digit minimi?

Answer 62

Abduction of the little finger

Question 63

Right, time for the actions of the hypothenar muscles! What is the action of the flexor digiti minimi brevis?

Answer 63

Flexion of MCP joint of little finger

Question 64

How many lumbrical muscles are there?

Answer 64

Four- one for each finger

Question 65

What are the actions of the lumbricals?

Answer 65

Flexion at MCP joints Extension at IP joints

Question 66

Describe the innervation of the lumbricals.

Answer 66

Lateral two lumbricals (index and middle) = median nerve Medial two lumbricals (ring and little) = ulnar nerve

Question 67

RECAP- nerve roots of 1. Musculocutaneous 2. Radial 3. Ulnar 4. Median

Answer 67

1. C5-7 2. C5-T1 3. C8-T1 4. C6-T1

Question 68

What are the two types of interossei?

Answer 68

Dorsal and palmar

Question 69

What is the innervation of all the interossei?

Answer 69

Ulnar nerve ->C8-T1

Question 70

Action of the palmar interossei?

Answer 70

Adduction of digits (PAD) Assist with flexion at MCP joints and extension at IP joints

Question 71

Action of dorsal interossei?

Answer 71

Abduction of digits (DAB) Assists with flexion at MCP joints and extension at IP joints