42. The Dreaded Hand Chapter Flashcards
What are key parts of the history to ask for hand exam?
- age
- mechanism
- time occurred
- other injuries
- hand dominance
- occupation
What are key questions to ask for penetrating hand injuries?
Tetanus status
For surgical planning of the hand, what do you need to know?
- NPO status
For nonacute/ nontraumatic/more chronic hand complaints what are 6 key questions to ask pt?
- presence of contracture
- timing of sx
- pain
- palliating/provoking factors
- other extremity same sx?
- functional impairment
Hand physical exam: 4 key categories to assess?
- Inspection
- ROM
- Palpation
- NVS
What are key aspects of the hand exam: inspection phase?
A Skin - wounds, erythema, pallor, cyanosis
B Edema
C Deformity - rotation, angulation, cascade sign
ROM of the hand needs to be assessed both __ and __
passive, active
Palpation of the hand exam: what 4 things are you looking for ?
warmth
joint effusion
tenderness
masses - nodules, ganglions
NVS: what nerve tests flexion of the thumb and index finger (“OK” sign)
median
What nerve tests thumb extension against R?
radial
how to test median nerve - motor?
okay sign
which nerve assesses abduction of fingers against R?
ulnar
how to test radial nerve - motor?
ext thumb against R
How to test ulnar nerve abduction?
finger abduction against R
How to test sensation in the hand exam? Particularly important to test …
two point discrimination
How to test vascular aspect for hand exam (2 helpful test names)
Allen
Cap refill at nail bed
When might a CT scan be indicated in hand injuries?
- complex fractures
- high clinical suspicion of fracture with negative XR
When might an MRI scan be indicated in hand injuries?
ligaments, tendon, soft tissue injuries, particularly:
1. OM
2. Avascular necrosis
3. Bone tumors
Posterior surface of the hand __ surface
dorsal
Palmar surface of hand also referred to as ___ surface
volar
Which hand surface is more prone to swelling?
dorsal
Fingertip is defined as the area distal to DIP. What two muscles attach here?
fdp
extensor tnedons
Distal part of the nail is known as the __ __
nail body
Proximal part of the nail bed is knwon as nail __
root
What is the lunula of the nail?
white, crescent shaped area on nail bed
Represents the distal end of germinal matrix, important for generation of nail plate
Why do we care so much about the lunula?
if damaged, area of germinal matrix so may have perminent damage to nail plate
What tendons and m inserts distal as lunula?
extensor
FDP
Small area of skin covering proximal nail is known as cuticle or __
eponychium
Tge area of skin underlying the distal nail bed is the ___
hyponychium
The skin overlying the lateral portion of the nail bed is known as the __
paronychium
What is important to assess in physical exam of the nail?
cap refill
clubbing
spooning
splinter hemorrhage
discoloration
thickness
What does the flexor retinaculum do at the wrist?
holds the 8 carpal bones bound by ligaments to form carpal tunnel
what passes through the carpal tunnel?
median n
flexor tendons
Boundaries of the carpal tunnel?
volar - flexor retinaculum
medial and lateral - carpal bones
Where are the thumb metacarpal and phalangeal epiphyses? (prox vs distal)
vs
finger metacarpal epiphyses?
proximal
vs
distal
Ossification centres of phalnges and metacarpals appear when?
when do they fuse?
open 10-36mo
fuse by age 14-16y
How does one perform the cascade test?
palm up
gradual increase in flexion from radial to ulnar for joints in hand
*watch for abnormal rotation deformity of digits
DIP flexion (degrees) vs PIP
90 vs 105
What do collateral ligaments at the DIP and PIP joints serve to do?
function laterally both sides for lateral stability and R of lateral, oblique and rotational forces
Fibrocartilaginous plate on anterior surface of IP joint - which side? why?
volar
reinforce joint capsule, limit hyperextension
What does the cascade test tell you? Ie what is normal
fingers come together over thenar and hypothenar eminance, point toward scaphoid
Why are MCP joints less stable than IP?
rounded head metacarpal bone onto concave surface of proximal phalax
good for grasp by allowing some rotational and side-side movement
How does the MCP volar plate differ from IP?
interconnected by deep tranverse ligament
How to test the collateral ligaments of the MCP joint?
in flexion (full)
no ability to abduct or adduct phalanx
differnt than extension where limited s-s mobility is possible
What is the functional position of the hand? **
Wrist: 30 degrees extension
MCP 70-90 degree flexion
PIP and DIP full extension
Metacarpal 3 arches - what are they?
proximal (carpal)
distal (metaracarpal) transverse arch
longitional arch
How to differentiate from the intrinsic and extrinsic m of hands (general)
intrinsic origin and insertion within hand itself
vs extrinsic origin is proximal to hand with tendon insertions inside hand
Thumb: MCP extension and flexion range
ext 10 degrees hyper
70 degree flexion
IP flexion vs extension ability degrees
90 flex
15 hyper
What are the intrinsic muscles of the hand?
- thenar: abd pollicis brevis, flexor pollicis brevis, opponens pollicis
- hypothenar: opponens digiti minimi, flexor digiti minimi, abductor digit minimi
- adductor pollicis
- lumbricals
- interossei
What nerves controls thenar emin (abd pollicis brevis, flexor pollicis brevis, opponens pollicis)?
recurr branch of median n
What nerve adducts and rotates thumb medially (add pollicis)?
ulnar
what nerve innevates hypothenar: opponens digiti minimi, flexor digiti minimi, abductor digit minimi
ulnar
Lumbricals come from which muscle?
FDPLumb
Lumbricals insert at ? hood and base of…
extensor hood
proximal phalanx
Radial vs ulnar lumbricals (nerve innervation)
2-2 radial, ulnar
Dorsal interossei - action and nerve?
4 dorsal
abduct
deep branch ulnar nerve
Extensor tendons pass through dorsum of wrist at __ different compartments, innervated by __ nerve
6
radial
Palmar interossei action, nerve
3 aplmar in intermetacarpal spaces, insert at base 2, 4, 5 proximal phalanx
adduct
deep branch ulnar nerve
Compartment 1 extensors muscles of hand: most radial. What muscles do they contain? Innervation?
abd p longus
ext pollicis brevis
PIN - branch of radial n
Compartment 3 extensors muscles of hand: What muscles do they contain? Innervation?
EPL
radial n
What muscles form the borders of the anatomic snuff box
lateral: abd pl extensor polciis brevis
medial - EPL
Compartment 2 extensors muscles of hand: What muscles do they contain? Innervation?
extensor carpi radiali longus and brevis
insert at base fo second and third metacarpals resp
extend and abd hand at wrist
radial n
Compartment 4 extensors muscles of hand: What muscles do they contain? Innervation?
extensor indicis
etensor digitorum communis tendons
insert extensor hood
ext 4 digits of hand primarily at MCP jt
radial n
What forms the extensor hood/expansion (m)
Lumbrical and interosseous m connect with extensions of ext digitorum tendons to form extensor hood
divides further into 3 bands
what are the three bands of the extensor hood?
2 lateral bands
central tendon/slip
What holds the three bands of the extensor hood together? what does this prevent?
transverse retinacular lig
stops volar displacement of lateral bands
if extensor hood transverse retinacular ligaments become disrupted, what type of deformity will you see?
boutenniere - PIP flexion
Compartment 5 extensors muscles of hand: What muscles do they contain? Innervation?
extensor dig minimi
radial
Compartment 6 extensors muscles of hand: What muscles do they contain? Innervation?
extensor carpi ulnaris
adduct and extend wrist
radial n
Flexor muscles - what two compartments?
ant and post
What muscles are in charge of flexion of the hand at the wrist (3)
FCR
FCU
PL
FCR nerve?
median
FCR in addition of flexion of wrist, also in charge of ?
abduction of hand at wrist
FCU nerve?
ulnar
flexion and adduction of hand at wrist
PL nerve?
median
PL is absent in ?% of pt
25
Both PL and FCU insert at the __ retincaculum
flexor
What 3 m are responsible for flexion of digits and enter the hand via carpal tunnel?
fdp
FDS
FPL
median n (except one branch of fourth and fifth digits of fdp is ulnar)
FDP function
flex fingers at IP (?distal)
FDS functions to flex at __ joints
PIP
Testing FDS integrity - ensure…
flex assoc finger against R at PIP while holding other fingers in extension
Digital flexor sheath of the hand has mebranous and retinacular portion - why do we worry about infection in these moreso than extensor?
avascular - prone to infection
Digital flexor sheath - retinacular component akin to pulley system - overlies __ sheath
synovial
Digital flexor sheath - retinacular component akin to pulley system - made up of ?
palmar aponeurosis pulley
3 cruciform pulleys
5 annular pulleys
*thumb has its own
Digital flexor sheath - retinacular component akin to pulley system - what is the overall function of this system?
maintain tendons in axis with flexion of MPC and ICPs to prevent bowstringing
Digital flexor sheath - retinacular component akin to pulley system - most important pulleys to preserve?
A2 and 4
Path of radial a in hand
through anatomic snuff into deep palmar arch and superficial
deep palamr to anastomose with ulnar
superfiical also does
Ulnar a pathway hand
superficial flexor retinaculum through Guyon canal (pisiform and palmar carpal ligament space)
distal to this it branches into large superifical palmar arch
In the normal anatomy of the flexor pulley system, why are A2 and A4 essential?
narrowest portion of hand
Pulley system (flexor) of hand: A1- ?
C1 - ?
5
3
A1, 2, then C1, and alternates to A5 most distally
Reminder : The median nerve enters the hand via the carpal tunnel. It is respon- sible for sensation of the radial two-thirds of the volar surface of the hand as well as the flexor surface of fingers 1 through 3 and the radial half of the fourth (ring) finger (Fig. 42.15). The motor branch of the median nerve innervates five intrinsic muscles of the hand including the thenar muscles and two of the lumbricals. The extrinsic muscles of the hand innervated by the median nerve include the flexor tendons to the radial three digits and FCR.
Reminder
The ulnar nerve supplies sensation to the ulnar one-third of the hand at both the volar and dorsal surfaces. It is also responsible for sensation of the fifth finger and the ulnar half of the fourth finger. The ulnar nerve is responsible for the extrinsic motor function of the flexor carpi ulnaris (FCU) and the flexor digitorum profundus (FDP) tendons of the fourth and fifth digits. It also innervates the remaining intrinsic muscles of the hand and divides into a volar and dorsal branch at the wrist. The volar branch, along with the ulnar artery, enters the palm through the Guyon canal. It is responsible for movement of muscles of the hypothenar eminence, interosseus muscles, and the lumbricals of the fourth and fifth fingers. The deep branch innervates the adduc- tor pollicis. The ulnar nerve’s motor innervation of the fourth and fifth digits is largely responsible for grip power and injury can significantly alter normal use of the hand.
Reminder: The radial nerve contains superficial and deep branches and pro- vides sensation to the radial two-thirds of the hand on the dorsal sur- face excluding the fingertips. There are no motor function branches for the radial nerve within the hand, though its innervation of the dorsal forearm leads to hand function including extension of the wrist (exten- sor carpi radialis longus) as well as other extensor tendons (extensor digitorum communis, extensor digiti quinti proprius, extensor pollicis longus and brevis).
-
How do you know if sensation is intact? (most sn way)
two point discrim:
Sensation is deemed intact if a patient is able to distinguish between one and two points to a distance of 5 mm.
Rapid mo/sn testing of hand: each n and action?
function of the radial, ulnar, and median nerve is to have the patient make an “OK” sign with their thumb and index finger (testing the median nerve), while dorsiflexing the wrist (radial nerve) and spread- ing/abducting the third, fourth, and fifth fingers (ulnar nerve). For general sensory examination, a clinician can test the finger tufts of the index finger (median nerve), the little finger (ulnar nerve), and the dorsum of the proximal phalanx of the thumb (radial nerve) with two- point discrimination
How to perform a digital block? (general terms)
- skin adequately cleaned - web space each side of digit anesthetized mc
- aspirate to ensure no vessel
- vol 0.5-1ml injected and advanced to volar side phalanx for additional 0.5-1ml
repeat on other side
Advantages of a digital block
- fewer injection sites means less pain for pt
- local = greater edema and distortion which can be avoided with digital block
- less anesthesia is typically needed for regional procedure
Palmar approach of hand/digital block
- needle over metacarpal hed
- subcut, direct then on one side of metaracpal
- advance 1cm aspiration so not in vessel
- give 3cc of local
- withdraw partial and inject other side
If transthecal approach to palmar digital block - if significant R what likely hit? should be little to none in sheath
same idea as palmar apprach just 45 degree angle
if R then tedon, withdraw
Dorsal approach to digital block
- needle at one side dorsal surface approx 1cm prox to mcp joint
adv until palmar aponeurosos/volar edge metacarpal - 2ml here
- while withdrawing, additional 1ml injected along tract
- then repeat on dorsal surface of opp side of same metacarpal
Radial nerve block general recommendations
- volar surface wrist feel a
- lateral to this, after aspiration, give 2-5ml of local
Median n block general recommendations
- tendon FCR felt
- needle over m n which is 1cm ulnar from RCR (between this tendon and PL)
- adv into flexor retinaculum where feel pop (possible paresthesia complaint)
- then withdraw several cm to avoid avoid intraneural injection
In which pt may a median n block be CI?
carpal tunnel (due to BL constriction)
Ulnar n bloc basics at wrist
Needle between ulnar a and FCU tendon
adv ~1cm
Paresthesia? draw back few mm
then inject ~5cc
Pathophysiology of ring causing edema
torniquet - further restriction venous return then eventual arterial
How to first try to remove ring?
- Lubrication of finger and ice/elevation
- distal traction on ring with twisting movement
If there are no signs of neurovascular compromise, deep ring erosion or open wound, what kinds of ring removal attempts can be made
- ring wrap
- rubber band
-two rubber bands under ring and hemostat to pull distal traction - surgical glove - finger of glove over pt effected finger, proximal end of glove under ring
Proximal end of ring then pulled back over ring
followed by distal traction and twisting
When to go straight to a ring cutter, rather than using other methods?
signs of NV compromise, open wound, deep erosion
What should be considered/warned when using ring cutter
gets hot q30s so take breaks
When to use a forearm volar splint?
soft tissue hand/wrist injuries
most wrist, 2nd-5th metacarpal fractures
not for distal radius or ulnar fractures as some pronation is possible
When to use a burkhalter splint? what is this?
metacarpal neck #, MCP dislocation
volar slab 30 deg wrist ext or dorsal slab with 90 deg metacarpal flexion
When to use a forearm sugar tong splint?
distal radius and ulna # as prevents pro-supintation
When to use a thumb spica cast? position? allows…
scaphoid, thumb MCP; de quervain teno
wine glass position immob of 1st mcp, allows thumb dip free to oppose
When to use an ulnar gutter splint?
4-5th metacarpal, mcp joint # prox/middle
when to use a radial gutter splint?
sprains/fractures 2nd-3rd digital metacarpal, mcp jont.
when to use finger splints?
stable middle, distal phalanx #.
For PIP sprains, use ? splint
dynamic - buddy taping
Main 4 types/categories of hand injuries
fracture/bony
tendon
ligament
joint space
What type of fracture pattern are typically stable?
transverse
What hand injury concerns warrant immediate surgical consultation?
- open
- partial/complete amp
- displaced intra articular #
- # not maintaining reduction
What are the 3 mc complications for untreated fractures?
- malunion
- nonunion
- loss of motion
Middle phalanx/PIP injury DDX
head, neck, shaft or base # injury
dorsal/volar/lateral PIP dislocation or sublux
volar plate or collateral lig injury
central slip/extensory injury
fdp/fds injury
DDX for distal phalanx/DIP joint fracture?
tuft, shaft or avulsion #
seymour fracture
crush injury
nailbed injury
subungal hematoma
dip disloc/sublux
mallet finger (dorsal), jersey finger (volar)
collateral lig injury
extensor dig communis injury
FDP tendon injury
Proximal phalanx/MCP joint injury ddx
head, neck, shaft or base #
dorsal, volar or lat MCP dislocation or subluxation
volar plate or collateral ligament injury
trigger finger
clenched fist/fight bite injury
extensor complex injury
fdp or fds injury
Metacarpal/cmc joint injury ddx
head, shaft, neck or base #
crush injury
nail bed or subungal hematoma
mallet thumb
IP joint dislocation or sublux
volar plate or collateral lig injury
extensor pollicis longus injury
Thumb proximal phalamx/mcp joint injury ddx
head, neck, shaft or avulsion #
ulnar collateral lig injury
radial collateral ligament injury
Thumb metacarpal/cmc joint injury ddx
head, neck, shaft #
base - bennet or rolando #
cmc joint dislocation or sublux
oblique cmc lig injury
abd pollicis longuss tendon injury
What is a tuft fracture?
secondary to crush injury of distal phalanx
usually stable
can have lac or subungal hematoma
Transverse vs longitudinal fractures - more stable?
transverse
Fractures of this distal phalanx usually stable/un and __-articular
unstable
intra
Avulsion fracture of the finger base - dorsal injury is known as a ?
Mallet finger - inability to extend distal phalax at DIP