Forearm and hand II week 3 Flashcards Preview

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Flashcards in Forearm and hand II week 3 Deck (35):
1

What layers are the muscles in the posterior compartment of the forearm divided into? What are their general functions?

1. superficial and deep layers

2. movements of the wrist joint, extension of the fingers including the thumb, and supination of the forearm

2

What are the common origins of muscles in the posterior compartment of the forearm?

lateral epicondyle and supracondylar ridge

3

What muscle in the posterior compartment of the forearm is an exception to the extensor functions of the muscles in this group?

brachioradialis. it is a flexor of the forearm at the elbow when the forearm is in a neutral position btwn pronation and supination (picture a handshake). note that it does not cross the wrist joint

4

All muscles in the posterior compartment of the arm are innervated by the _____ nerve or one of its branches. 

radial

5

What muscles are in the superficial layer of the posterior compartent of the forearm?

from lateral to medial: brachioradialis, extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris

note that there is only a single extensor digitorum muscle (unlike the supericial and deep flexor digitorum muscles). therefore, we have less control over the extension of our fingers than flexion

also, note that tendons of the extensor digitorum are interconnected as they pass to individual digits

6

What muscles are in the deep layer of the posterior comparment of the forearm? 

note that there is no intermediate layer of the posterior forearm as there is in the anterior forearm

from lateral to medial: supinator (pierced by the deep branch of the radial nerve), abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, and extensor indicis

7

What is the origin, insertion, function, and innervation of the anconeus?

origin: lateral epicondyle of humerus

insertion: olecranon process of ulna

function: extension of the forearm at the elbow

innervation: radial nerve

8

What is the origin, insertion, function, and innervation of the brachioradialis?

origin: lateral supracondylar ridge of humerus

insertion: stlyoid process of radius (distal end of radius

function: flexes forearm at the elbow

innervation: radial nerve

 

9

What is the origin, insertion, function, and innervation of the extensor carpi radialis longus?

origin: lateral supracondylar ridge of humerus

insertion: base of 2nd metacarpal

function: extends and abducts the wrist at the radiocarpal joint

innervation: radial nerve

10

What is the origin, insertion, function, and innervation of the extensor carpi radialis brevis?

origin: lateral epicondyle of humerus

insertion: base of 3rd metacarpal

function: extends and abducts the wrist at the radiocarpal joint

innervation: radial nerve

11

What is the origin, insertion, function, and innervation of the extensor digitorum?

origin: lateral epicondyle of humerus

insertion: extensor hoods of digits 2-5 (extensor hood: expansion of the extensor tendon as it passes over the dorsal aspect of the proximal phalange)

function: extends digits and wrist

innervation: radial nerve

12

What is the origin, insertion, function, and innervation of the extensor digiti minimi?

origin: lateral epicondyle of humerus

insertion: extensor hood of 5th digit (little finger)

function: extends the 5th digit and wrist

innervation: radial nerve

13

What is the origin, insertion, function, and innervation of the extensor carpi ulnaris?

origin: lateral epicondyle and posterior ulna

insertion: 5th metacarpal

function: extends and adducts the wrist

innervation: radial nerve

14

What is the origin, insertion, function, and innervation of the supinator?

origin: lateral epicondyle of humerus, posterior ulna

insertion: proximal radius

function: supinates forearm at the radioulnar joints

innervation: radial neve

15

What is the origin, insertion, function, and innervation of the abductor pollicis longus?

origin: posterior ulna, radius, interosseus membrane

insertion: base of 1st metacarpal

function: abducts and extends thumb

innervation: radial nerve

16

What is the origin, insertion, function, and innervation of the extensor pollicis brevis?

origin: posterior radius, interosseus membrane

insertion: base proximal phalynx of thumb

function: extends thumb (does not extend DIP)

innervation: radial nerve

17

What is the origin, insertion, function, and innervation of the extensor pollicis longus?

origin: posterior ulna, interosseus membrane

insertion: base of distal phalynx of thumb

function: extends thumb

innervation: radial nerve

18

What is the origin, insertion, function, and innervation of the extensor indicis?

origin: ulna and interosseus membrane

insertion: extensor hood of the second digit (index finger)

function: extends index finger and wrist

innervation: radial nerve

19

Identify these muscles of the posterior forearm. What layer are they in?

Q image thumb

superficial layer

A image thumb
20

Identify these muscles of the posterior forearm. What layer are they in?

Q image thumb

superficial

A image thumb
21

Identify these muscles of the posterior forearm. What layer are they in?

Q image thumb

deep layer

A image thumb
22

What is lateral epicondylitis? What muscle is most often affected? What movements of the arm are affected? What are common signs and symptoms?

is also known as tennis elbow. involves extensor muscles and tendons of the forearm that have origins on the lateral epicondyle. the tendon most commonly affected is that of extensor carpi radialis brevis (inserts on base of 3rd metacarpal) which helps stabilize the wrist when the elbow is extended. common signs and sx are pain with wrist extension against resistance, point tenderness or burning on lateral epicondyle, weak grip strength. sx are intensified with forearm activity

23

Where do the posterior interosseus, anterior interosseus, and radial arteries travel in the forearm? What do they supply?

Note: The anterior and posterior interosseus arteries branch from the common interosseus artery which branches from the ulnar artery in the anterior forearm

posterior interosseus artery: contributes branches to the elbow joint and posterior compartment of the forearm

anterior interosseus artery: passes through anterior flexor compartment but has perforating branches that pass through the interosseus membrane to supply deep muscles of the posterior compartment in addition to supplying muscles in the anterior compartment

radial artery: contributes muscular branches to the extensor musculature on the radial side of the forearm as it courses toward the hand with the superficial branch of the radial nerve and is ultimately a primary source of blood supply to the thumb

24

Identify these structures of the anterior and posterior forearm.

Q image thumb

A image thumb
25

What is the anatomical snuffbox? What are the boundaries of the anatomical snuffbox? What passes through it?

anatomical snuffbox is a term given to the triangular depression on the posterior-lateral side of the wrist (most evident with extension of thumb)

boundaries:

lateral: abductor pollicis longus and extensor pollicis brevis

medial: extensor pollicis longus

floor: scaphoid and trapezium, distal ends of extensor carpi radialis longus and brevis tendons

the radial artery passes through the anatomical snuffbox!

A image thumb
26

How is the anatomical snuffbox clinically important?

the scaphoid may be palpated within the anatomical snuffbox to assess fracture of this bone after wrist injury. with a fracture accross the scaphoid, blood supply may be denied ot the proximal portion of the bone which could result in avascular necrosis. if disconnected from blood supply, would need surgical repair

27

The tendons of flexor digitorum superificalis and profundus enter what kind of sheath? What about the flexor pollicis longus? What is this sheaths function?

They enter a common synovial flexor sheath and subsequently fan out to enter their respective digital synovial sheaths. These sheaths allow the tendons to slide freely over each other during movements of the fingers. Note that the flexor pollicis longus has its own synovial sheath

28

What are fibrous digital sheaths? What is their function?

strong ligamentous tunnels that surround the tendons and their synovial sheaths and prevent the tendons from pulling away from the digits (bowstringing)

29

What is tenosynovitis?

puncture wounds to the fingers can cause infections of the synvovial sheaths. the painful inflammation of the tendon is tenosynovitis. also, repetitive movements can cause inflammation of the tendons and sheats resulting in thickening of the fibrous sheaths and decreased ability to move the fingers

A image thumb
30

Identify the portions of the extensor tendon.

Q image thumb

A image thumb
31

The tendons of the extensor digitorum and extensor pollicis longus pass onto the dorsal surface of the the and and expand over the proximal phlanges to form _____ ____. 

extensor hoods

A image thumb
32

Describe arterial supply to the dorsal surface of the hand.

Q image thumb

The radial artery gives off a dorsal carpal branch which anastamoses with a branch of the ulnar artery to form the dorsal carpal artery/arch. The dorsal carpal arch gives rise to dorsal metacarpal arteries which ultimately divide to become dorsal digital arteries. 

A image thumb
33

Describe the venous supply in the dorsal hand. 

Q image thumb

Superficial and deep veins drain into a dorsal venous network on the back of the hand located over the metacarpal bones. Both cephalic and basilic veins originate from this dorsal venous network.

note that deep veins follow arteries in the hand. 

A image thumb
34

What nerves of the hand have these innervation patterns?

Q image thumb

A image thumb
35

What nerve of the hand has this innervation pattern? (be specific)

Q image thumb

A image thumb