ICL 4.2: Hand Anatomy & Common Conditions

Question 1

what keeps the distal radial-ulnar joint stable?

Answer 1

triangular fibro-cartilage complex (TFCC)

it lets everything in the wrist rotate

it’s at the tip of the ulnar styloid so if someone says it hurts there the TFCC is probably torn

Question 2

which bone moves during pronation?

Answer 2

radius

the ulna is stable

Question 3

what are the characteristics of a normal radial-ulnar joint?

Answer 3

1. ulna and radius are about equal length
2. radial inclination from the radial styloid to the ulna is about 20 degrees down
3. volar tilt of the distal surface of the radius is about 10 degrees down
4. no gaps in the joint

Question 4

what is a Colles’ fracture?

Answer 4

most common fracture

an extra-articular dorsally angulated fracture from a FOOSH that causes the distal radius to get bent backwards

if the radius gets bent backwards, you lose the volar tilt

Question 5

what’s the pneumonic for the carpal bones?

Answer 5

some lovers try positions that they can’t handle

proximal: scaphoid, lunate, triquetrum, pisiform
distal: trapezium, trapezoid, capitate, hamate

Question 6

how are your carpals connected?

Answer 6

there’s a distal and proximal row of carpals that are held together by strong ligaments

this means there’s no significant motion within the rows and they all move together as one unit

Question 7

what causes a scaphoid fracture? how do you treat?

Answer 7

FOOSH

you’ll be tender in the anatomic snuff box

these are unstable and you should be worried because the scaphoid gets it blood supply distal to proximal so the more proximal the fracture, the harder it is to heal

Question 8

what is carpal instability?

Answer 8

the distal row or proximal row of carpals aren’t moving as a unit, they’re moving on their own

a common thing is tearing the scaphoid-lunate ligament

Question 9

what is SLAC wrist arthritis?

Answer 9

this is what happens after a scaphoid-lunate ligament tear

over the years the scaphoid is out there unaligned and you get arthritis after 20 years

to treat you take the scaphoid out to prevent scaphoid from rubbing against the radius

Question 10

what kind of joint is the carpal metacarpal joint of the thumb? what is a common complication with it?

Answer 10

saddle joint

lets your thumb move in any direction!

however, this means that there’s a lot of wear and tear of the thumb CMC joint and usually leads to arthritis –> can take the trapezium out to treat and then a tendon to stabilize the base of the thumb

more common in women

Question 11

what is a Boxer’s fracture?

Answer 11

5th metacarpal-carpal neck fracture (pinky knuckle break)

usually with young, drunk males that get punching injuries

you don’t do much to treat these because there’s so much motion with the pinky

however, deformity in the more radial MC joints need to be fixed

Question 12

what is the shape of the metacarpal phalangeal joint?

Answer 12

cam shaped = wider in volar direction

Question 13

what is Skier’s thumb?

Answer 13

aka Gamekeeper’s thumb

it’s a rupture of the ulnar collateral ligament (UCL) of the thumb in between the thumb and pointer finger

you won’t be able to grip things

often needs to be repaired

Question 14

what are the different phalanges?

Answer 14

3 in each digit; only 2 in the thumb

proximal = P1

middle = P2

distal = P3

Question 15

what is a PIP joint dislocation?

Answer 15

most common joint dislocation; usually dorsally

there’s a rupture of the volar plate

Question 16

what causes MP arthritis vs. IP arthritis?

Answer 16

MP = autoimmune disease (ex. rheumatoid)

IP = osteoarthritis

Question 17

what are the 4 groups of intrinsic hand muscles?

Answer 17

1. interosseous
2. lumbricals
3. thenar
4. hypothenar

Question 18

what are the interosseous muscles?

Answer 18

they’re between the metacarpals

dorsal ones abduct while palmar adduct

all innervated by ulnar nerve and let you do fine motor skills like typing and playing piano

Question 19

what are the lumbricals?

Answer 19

the only muscle in the body that originates from a tendon and inserts into a tendon –> flexor digitorum profundus to the radial side of the extensor tendon

they help your hand with power grasp

the ones on the ulnar side are called bipenate and come from 2 tendons; so the lumbricals from the ring and pinky finger come from two tendons and this makes sense because most of your grip strength comes from your pinky and ring finger

the lumbricals of the index and long finger are unipenate

Question 20

what is the ROM for the thenar and hypothenar muscles?

Answer 20

abductor, flexor, opponens

Question 21

what is the extensor digitorum communis?

Answer 21

it extends into the MPs of all 4 fingers

it’s 1 muscles with 4 tendon slits

it extends the MP joints but not so much the IP joints

Question 22

what is the extensor indices proprius?

Answer 22

EIP extends the index MP which lets you point your finger

Question 23

what is the extensor digit minimi?

Answer 23

EDM extends the pinky MP joint which is what lets you do the bull horn sign with your hand

Question 24

which tendons are in the 1st extensor compartment?

Answer 24

1. abductor policus longus
2. extensor policus brevis

they pull your thumb out;abducts

Question 25

which tendons are in the 2nd extensor compartment?

Answer 25

1. extensor carpi radialis longus 2. extensor carpi radialis brevis pull your wrist up

Question 26

which tendons are in the 6th extensor compartment?

Answer 26

extensor carpi ulnas

Question 27

what is DeQuervain's tendonitis?

Answer 27

1st compartment tendonitis: 1. abductor policus longus 2. extensor policus brevis

Question 28

what is intersection syndrome?

Answer 28

tendonitis of the 2nd compartment where the APL and EPB from 1st compartment cross over the ECRL and ECRB of the second compartment: 1. extensor carpi radialis longus 2. extensor carpi radialis brevis

Question 29

how do you diagnose tendonitis?

Answer 29

1. anywhere in the body, the tendon will have point tenderness 2. if you stretch the tendon it'll hurt 3. pain with resistance

Question 30

what is the Finklestein test?

Answer 30

stretching tendons --> the examiner grasps the thumb and ulnar deviates the hand sharply. If sharp pain occurs along the distal radius, de Quervain's tenosynovitis is likely specifically used for Dequervain's tendonitis of the 1st extensor compartment

Question 31

what is the extensor mechanism?

Answer 31

your long extensor tendon goes right over your MP joint and it extends the MP joint it does this via the little bands that come off of the extensor tendon called sagittal bands that wrap around the base o the proximal phalanx which lift the finger up --> your extensor tendon doesn't have any insertion at all on the proximal phalanx the sagittal bands also keep the extensor tendon on the midline then the extensor tendon keeps going and divides into 3 slips --> the central slip inserts on the base of the middle phalanx P2 and extends the PIP joint the lateral two slips run along the edges then come together and insert on P3 and they extend the DIP

Question 32

what is a mallet deformity?

Answer 32

avulsion of the extensor tendon from P3 so you lose extension at the DIP joint ex. when you jam your finger and the tendon rips off P3 so nothing is keeping your DIP straight so your finger droops the good news is that the tendon doesn't retract so you can just treat it with splints

Question 33

what is a Boutonniere deformity?

Answer 33

avulsion of the central slip of the extensor mechanism from the P2 base so you get loss of extension at the PIP PIP joint will flex but the extensor mechanism at the DIP joint is fine so it'll overflex and the tip of your finger will start to curve up

Question 34

what is a swan neck deformity?

Answer 34

hyper-extension at the PIP and flexion of the DIP could be caused by chronic mallet finger that doesn't get fixed and eventually causes hyper-extension of PIP usually because of autoimmune diseases like lupus and rheumatoid arthritis

Question 35

what is your flexor digitorum profundus?

Answer 35

starts in the forearm and then it inserts on P3 of digits 2-5 but the long, ring and small fingers usually function together while the index finger is independent flexes DIP joint of the fingers involved in power grip

Question 36

what is your flexor digitorum superficialis?

Answer 36

inserts on the P2 of digits 2-5 and flexes the PIP joint it splits into two slips over P1 area and then the flexor digitorum profundus goes through that and that's called Camper's chiasm involves in fine motor skills

Question 37

what are annular pulleys?

Answer 37

part of the flexor sheath of the fingers = flexor digitorum superficialis and profundus annular pulleys 1,3,5 are tendons at the joints of your fingers that let your joints bend annular pulleys 2 and 4 are functionally important to prevent bowstringing; they hold the tendons next to the bones when you extend your fingers

Question 38

what is the function of the flexor sheath?

Answer 38

1. stabilizes the tendons and allows them to slide 2. gives the nutrition and makes synovial fluid tendons = flexor digitorum superficialis and profundus

Question 39

what is jersey finger?

Answer 39

flexor digitoum profundus avulsion common on ring fingers pt. won't be able to make a fist flexor injuries always get fixed with surgery!

Question 40

what are trigger fingers?

Answer 40

a tendonitis that happens where the tendon enters the flexor sheath the tendon gets irritated as it's going through the sheets and as it's going through A1 pulley it gets caught and your finger gets caught and stays flexed at PIP just stretch it out or sometimes you have to cut A1 pulley

Question 41

what is carpal tunnel?

Answer 41

transverse carpal ligament is the roof and the carpals are the base of the carpal tunnel where median nerve passes through median nerve gives you sensation and fine motor and lets you oppose your thumb!!! causes numbness, night pain, and lots of dropping things *numbness is ONLY in the fingers, not in the palm

Question 42

what's inside the carpal tunnel?

Answer 42

10 structures: 4 FDP tendons 4 FDS tendons FPL median nerve your FCR tendon is NOT in your carpal tunnel

Question 43

how do you diagnose carpal tunnel?

Answer 43

1. Tinnel's test 2. Phalen's test 3. Durkin's test (squeeze the nerve)

Question 44

how do you treat carpal tunnel?

Answer 44

1. splints 2. stretching 3. corticosteroid injection 4. surgical release

Question 45

what are the long term effects of carpal tunnel?

Answer 45

hour glass contristriction and then the nerve stops working and then the muscles stop working = thenar muscle wasting

Question 46

what is cubital tunnel syndrome?

Answer 46

cubital tunnel aka your funny bone you'll get numbest in the ulnar distribution = pinky you'll also have pain, waking up at night, loss of motor skills you diagnose with Tinnel's test on ulnar nerve in the elbow area

Question 47

how do you treat cubital tunnel syndrome?

Answer 47

1. splint so you don't bent elbow 2. avoid pressure on elbow 3. usually get surgical release to decompress

Question 48

how can the radial nerve get injured? what is Wartenberg syndrome?

Answer 48

1. injury with humeral fracture along surgical neck | 2. Wartenberg syndrome = compression of the superficial radial nerve at the wrist (handcuffs)

Question 49

which artery mainly supplies the hand?

Answer 49

ulnar nerve (78%)

Question 50

what's the path of the radial artery through the hand?

Answer 50

goes dorsal through the anatomic snuff box, dorsal to thumb metacarpal and forms deep arch

Question 51

what is the path of the ulnar artery through the hand?

Answer 51

goes through Guyon's canal with ulnar nerve then forms the superficial arch of the palm

Question 52

what is ulnar hammer syndrome?

Answer 52

clotting of the ulnar artery in Guyon's canal you'll get pain in hypothenar region and numbness in ulnar distribution you get it from using your hand as a hammer like carpenters

Question 53

what is Raynaud's disease?

Answer 53

vasospasm of the digital arteries more common women and in the cold associated with lots of autoimmune diseases

Question 54

what is the function of the palmar fascia?

Answer 54

it sticks your skin to your palm!

Question 55

what is Dupuytren's disease?

Answer 55

thickening and contracture o the palmar fascia and you get nodules in the palm causes flexion usually of the ring finger more common in white males

Question 56

what kinds of incisions are done during hand surgery?

Answer 56

avoid straight longitudinal incisions on flexor surfaces scars that are straight don't bend well when you bend your fingers

Question 57

what is cellulitis?

Answer 57

superficial soft tissue infection; red, swollen, tender can treat with IV antibiotics, rest, etc

Question 58

what is Felon infection?

Answer 58

subcutaneous abscess of distal pulp space of fingertips

Question 59

what is paronychia?

Answer 59

infection around the nail bed you get it from picking at your nails or biting them

Question 60

what is pyogenic flexor tenosynovitis?

Answer 60

infection that goes along the flexor you have the flexor sheath that surrounds your flexor tendon so it can spread up your forearm

Question 61

what are the 2 parts of the nail bed?

Answer 61

1. germinal matrix = white part = makes nail (nails doesn't stick to germinal matrix) 2. serile matrix = pink part = this is what sticks to nail plate

Question 62

what is a ganglion?

Answer 62

sac of fluid that comes from your joint can happen anywhere in the body but wrist is the most common

Question 63

what is bursitis?

Answer 63

inflammation of bursa bursa is a thin fluid filled sac that allows soft tissues to move smoothly over bony prominences; usually very thin ex. olecran bursitis treat with rest, avoid direct pressure, ice, drainage