Lecture 22: posterior forearm and hand

Question 1

Describe what pronation/supination also involves

Answer 1

Also involves humeroradial joint = radial head needs to rotate against something - humerus provides surface

Question 2

Name muscles of superficial layer of posterior forearm compartment

Answer 2

Brachioradialis
Anconeus
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor digitorum
Extensor carpi ulnaris
Extensor digiti minimi

Question 3

Brachioradialis attachments

Answer 3

Lateral supracondylar ridge of humerus to Styloid process of radius
Lat border cubital fossa

Question 4

Brachioradialis FUCNTION

Answer 4

Elbow flexion

Question 5

Brachioradialis Exceptions

Answer 5

Considered posterior forearm muscle bc of its innervation - radial nerve
But only crosses one joint = elbow, where acts as flexor - synergist of biceps brachii and brachialis

Question 6

Anconeus attchment

Answer 6

Lateral epicondyle humerus to olecranon process of ulna

Question 7

Anconeus Functions

Answer 7

Elbow extension and stabilization

Question 8

Extensor carpi radialis longus attachment

Answer 8

Lateral supracondylar ride of humerus to base of metacarpal 2

Question 9

Extensor carpi radialis longus Functions

Answer 9

Extension wrist
Abduction wrist

Question 10

Extensor carpi radialis brevis attachments

Answer 10

Lateral epicondyle of humerus to base of metacarpal iii

Question 11

Extensor carpi radialis brevis FUCNTION

Answer 11

Wrist extension and abduction

Question 12

Extensor carpi radialis brevis + Extensor carpi radialis longus + flexor carpi radialis = how do they work together

Answer 12

Work together on anterior and posterior aspects of wrist to produce abduction = radial deviation

Question 13

Extensor digitorum attachments

Answer 13

Lateral humeral epicondyle —> four tendons onto dorsum of digits ii-v

Question 14

Extensor digitorum Functions

Answer 14

Extension of wrist
Extension of mcp, pip and dip

Question 15

Extensor carpi ulnaris attachments

Answer 15

Lateral humeral epicondyle To base of metacarpal v

Question 16

Extensor carpi ulnaris Functions

Answer 16

Wrist extension and addution

Question 17

extensor digiti minimi Attachmnets

Answer 17

Lateral humeral epicondyle To dorsum digit v, medial to tendon from extensor digitorum to v

Question 18

extensor digiti minimi Functions

Answer 18

Independent extension of digit v joints
Wrist extension

Question 19

Extensor carpi ulnaris + flexor carpi ulnaris = work together

Answer 19

Work together to produce adduction of wrist = recruited
= ulnar deviation

Question 20

Name muscles of deep layer posterior forearm compartment

Answer 20

Supinator
Abductor pollicis longus
Extensor pollicis longus
Extensor pollicis brevis
Extensor indicis

Question 21

Supinator attachments

Answer 21

Ulna and interosseous membrane to proximal third of anterior surface of radius

Question 22

Supinator FUCNTION

Answer 22

Supination

Question 23

Abductor pollicis longus attachment

Answer 23

Ulna and interosseous membrane To base metacarpal 1
Most proximal

Question 24

Abductor pollicis longus FUCNTION

Answer 24

Abduction - thumb, cmc

Question 25

Extensor pollicis longus attachments

Answer 25

Ulna and interosseous membrane To distal phalanx digit 1 Dorsal tubercle of radius = pulley redirecting path of extensor pollicis longus onto thumb

Question 26

Extensor pollicis longus FUCNTION

Answer 26

Extension of thumb joints

Question 27

Extensor pollicis brevis atthcments

Answer 27

Ulna and interosseous membrane To Proximal phalanx digit 1

Question 28

Extensor pollicis brevis Functions

Answer 28

Thumb joints extension

Question 29

Extensor indicis attachment

Answer 29

Ulna and interosseous membrane To distal phalanx didgit 2 (medial and deep to extensor digitorum tendon)

Question 30

Brevis sandwich

Answer 30

Brevis tendon between 2 longus tendons L = extensor pollicis longus B = extensor pollicis brevis L = abductor pollicis longus Medial 2 = thumb extensors, lateral 1 = thumb abductor

Question 31

Summarize supinators of forearm - posterior compartment

Answer 31

Rotation of radius at humeroradial joint and radioulnar joint, radius uncrosses back over ulna to lie parallel to it Supinator Biceps brachii = retract when supinate, strong Supinator especially when elbow at 90 degrees= unrolls proximal pronate radius

Question 32

What provides motor innvertaion to anterior compartment forearm

Answer 32

Median nerve —> anterior interosseous nerve Ulnar nerve

Question 33

Describe median nerve - ant compartment motor

Answer 33

C6-t1 After cubital fossa = travels between intermediate and deep anterior muscles Motor to anterior compartment of forearm EXCEPT = flexor carpi ulnaris and medial 1/2 of flexor digitorum profundus

Question 34

Describe anterior interosseous nerve - ant compartment motor

Answer 34

Deep muscles = pronator quadratus and lateral 1/2 of flexor digitorum profundus (digit 2 and 3), flexor pollicis longus

Question 35

Describe ulnar nerve - ant compartment motor

Answer 35

C8-t1 Travels posterior to medial epicondyle then deep to flexor carpi ulnaris and medial 1/2 of flexor digitorum profundus (digits 4 and 5)

Question 36

Describe sensory innervation anterior compartment of forearm

Answer 36

Lateral antebrachial cutaneous nerve - from musculocutaneous medial antebrachial cutaneous nerve - from medial cord Radial nerve Median nerve = tiny piece sensory Ulnar nerve = ulnar side

Question 37

Describe motor innervation of posterior compartment of forearm - Gen

Answer 37

From radial nerve c5-t1 = 2 branches= deep radial nerve (posterior side) and superficial radial nerve (distal part forearm and hand)

Question 38

Describe deep radial nerve motor to posterior forearm

Answer 38

Pierces Supinator and Innervates it Motor to all other posterior muscles not covered by radial nerve

Question 39

Describe superficial radial nerve to posterior forearm

Answer 39

Travels deep to Brachioradialis - sensory only Along with Lateral and medial antebrachial cutaneous nerve

Question 40

Describe radial nerve motor to posterior forearm

Answer 40

Anconeus Brachioradialis Extensor carpi radialis brevis/longus

Question 41

Describe vasculature of anterior and posterior forearm - Gen

Answer 41

After travelling through cubital fossa = brachial artery splits into radial and ulnar arteries = supply forearm Brachial —> 2 branches = ulnar artery and radial artery

Question 42

Describe vasculature of anterior and posterior forearm - radial artery

Answer 42

Supply antero and posterior lateral muscles Travels posterior to thumb

Question 43

Describe vasculature of anterior and posterior forearm - ulnar artery

Answer 43

Supplies antero and postero medial muscles Stays on anterior surface arm Branches - early = common interosseous artery

Question 44

Describe vasculature of anterior and posterior forearm - common interosseous artery

Answer 44

Big, branches after travel through cubital fossa - ulnar artery branches Then common interosseous —> posterior interosseous artery and anterior interosseous artery

Question 45

Describe vasculature of anterior and posterior forearm - posterior interosseous artery

Answer 45

Supplies muscles of deep posterior compartment

Question 46

Describe vasculature of anterior and posterior forearm - anterior interosseous artery

Answer 46

Supplies deep muscles of anterior compartment

Question 47

Describe vasculature of anterior and posterior forearm - veins

Answer 47

Deep veins match arteries and may be paired - venae comitantes

Question 48

define anatomical snuff box

Answer 48

Formally radial fossa = depression on lateral side of wrist Between tendons of extensor pollicis longus and brevis (Sniff drugs)

Question 49

Describe contents of anatomical snuff box

Answer 49

Superficial radial nerve travels here (sensory) Radial artery travels deep within in = pulse can be detected

Question 50

Describe borders of anatomical snuff box

Answer 50

Above = tendon of extensor pollicis longus Below = tendon of extensor pollcis brevis (and abductor pollicis longus)

Question 51

Extensor indicis FUCNTION

Answer 51

independent extension of index finger - digit 2 - pointer finger