Download the-wrist-and-handsession-8

Session 8
• Focus on wrist and hand
• Anatomy – structure and function
• Movements
• Conditions such as Colles fracture, De Quervain’s, Carpal tunnel
syndrome, OA base of the thumb, trigger finger, Dupuytren’s
contracture and more!
content
• Wrist – radiocarpal joint, midcarpal joint, muscles and nerves
• Conditions of the wrist
• Carpometacarpal joints focusing on the thumb, muscles
• Conditions of the thumb
• Metacarpophalangeal joints and interphalangeal joints, muscles of
the fingers
• Conditions of the fingers
Bones of the wrist
• The wrist is a vital link in the upper limb for hand
function
• Lost function cannot be replaced by the shoulder or
elbow
• Its main function is to make minor adjustments to grip
• Made up of two compound joints radiocarpal and
midcarpal
• Radio carpal joint – radius and disk with the scaphoid,
lunate and triquetrum
• The proximal surfaces of the carpal bones are covered
with articular cartilage
• The bones are linked with interosseous ligaments
• The bones together form a bi-convex surface which is
flexible to adapt to the demands placed upon it
• The pisiform acts as a sesamoid bone increasing the
angle of pull of flexor carpi ulnaris
Midcarpal joint structure
• Articulation between the scaphoid, lunate and
triquetrum proximally and the trapezium, trapezoid,
capitate and hamate distally
• The scaphoid, lunate and triquetrum have convex
surfaces whilst the distal row have concave surfaces
• Due to the shape of the articular surfaces more
extension occurs in the midcarpal whilst more flexion
occurs at the radiocarpal joint
• The wrist deconstructed
• Note that the scaphoid has extensive
coverage of articular cartilage making it
difficult for fractures of this bone to heal
• Note the hook of hamate and tubercle of
the trapezium for attachment of the
transverse carpal ligament. Cf later
Composite joints of the wrist complex
• The radiocarpal joint is enclosed by a single strong
capsule
• The capsule of the midcarpal joint is continuous
with each intercarpal articulation.
• The radial collateral ligament runs from the radius
and attaches to the scaphoid, trapezium and 1st
metacarpal
• The ulnar collateral ligament originates form the
ulna inserting onto the pisiform and triqeutrum
Ligaments of the dorsal (back) of the wrist
• The only major ligament is the dorsal radiocarpal
ligament
• It passes from the radial styloid to the lunate and
triquetrum
• It is considered to be a thickening of the joint
capsule
• Its main function is to maintain the lunate in
contact with the radius
Palmar or volar radiocarpal ligament
• This ligament is the most important for wrist
complex motion and stability
• 3 bands - radiocapitate, radio-triquetral and
radioscaphoid
• Radio-triquetral is the strongest, it also
attaches to and supports the lunate
• TFCC – triangular fibrocartilage complex
• Ulnocarpal ligament arises from this
attaching to the lunate and capitate
Movements of the wrist
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Normal range:
Flexion is 80 – 90 degrees from neutral
Extension 70 degrees
Radial deviation 20 degrees
Ulnar deviation 30-50 degrees
Biomechanics of flexion/extension
• Movement of the radiocarpal joint is a
gliding of the proximal row on the radius
and radioulnar disk
• Extension is initiated in the distal row with
the capitate at its centre
• Movement of the individual carpal bones
is complex with the ligaments between
the carpals acting as guy ropes and
stabilisers which pull the bones together
into a single unit
Biomechanics of radial and ulnar deviation
• A radial deviation – The distal row moves radially on the
proximal row until ligaments become tight and there is a
bony lock
• Continued radial deviation causes the carpals to move as
a unit towards the ulnar
• During this movement the lunate flexes and the distal
carpal row extends
• This allows the carpals to accommodate to the reduced
space between the trapezoid and radial styloid
• B ulnar deviation – active and passive forces from the
ligaments move the distal row towards the ulna until the
ligaments are taut
• At the same time the hamate is pulled down towards the
lunate which causes the proximal carpals to spread and
move towards the radius
• During the movement the scaphoid and lunate extend,
Capitate, trapezoid and trapezium flex
• Greatest ROM - wrist in neutral Flex/ext
• Dorsum of wrist crossed by 9 tendons
• 3 primarily wrist extensors:
• Extensor carpi radialis longus (ECRL), brevis
(ECRB) extensor carpi ulnaris (ECU)
• ECRL – from lateral supracondylar ridge to
base 2nd metacarpal
• ECRB – Common extensor tendon (CET) to
base 3rd metacarpal
• ECU – CET to base of 5th metacarpal
• Extensor carpi radialis brevis is active in all
grasp and release hand activities other than
when performed in supination
Example ECRL insertion
• 6 muscles have tendons crossing the front
of the wrist and can therefore produce
flexion
• 3 main flexors are - palmaris longus, flexor
carpi radialis (FCR) and flexor carpi ulnaris
(FCU)
• Palmaris longus – common flexor tendon
(CFT) to flexor retinaculum and palmar
aponeurosis Cf later
• FCR – CFT to base of 2nd metacarpal + slip to
3rd metacarpal. Greater contribution to
wrist flexion acting with palmaris longus
than radial deviation
• FCU – CFT also from ulna to pisiform and by
ligaments to hamate and 5th metacarpal.
Pisiform improves angle of pull so that FCU
acts as flexor and effective in ulnar
deviation
Extensor retinaculum
• Retinaculum is a 2.5cm wide fascial band
• Distal attachments to the pisiform and
triquetrum
• Tendon sheaths – likened to elongated
bursae, lined with synovial membrane
• Function is to reduce friction where the
tendon passes close to bone and
retinaculum
Flexor retinaculum or transverse carpal
ligament
• The transverse carpal ligament is
attached to pisiform and hook of
hamate arching over the carpal bones to
attach to trapezium and scaphoid on the
radial side of the palm
• The area under the ligament forms the
carpal tunnel cf later
• Note the tendon sheaths of the finger
flexors. The sheath of the little finger
communicates with the common flexor
sheath in the palm
Median and ulnar nerves in the hand
• The median nerves passes through the carpal
tunnel
• The ulnar nerve passes through Guyons canal
which is outside the carpal tunnel
• Regions of the hand supplied by the nerves are
shown below
Injuries to the triangular fibrocartilaginous
disc and ligaments
• Fractures of the wrist are common representing ¼ of
all limb fractures
• Children and young active people
• Older people associated with falls
• Colles fracture – wrist in extension, Smiths fracture
wrist in flexion
• More significant injuries the triangular cartilage can
also be damaged +/- involvement of other ligaments
• This can lead to instability of the wrist which is very
disabling
Scaphoid fracture
• Most common fractures of the carpus, accounting
for 79% of all carpal fractures[3].
• Most often in men aged 20-30 years.
• Vulnerability of blood supply therefore high risk of
non-union and avascular necrosis with subsequent
osteoarthritis; early diagnosis and treatment
minimise these risks.
• Usually associated with fall onto hand or direct
blow
• 20% fractures not seen on X-ray initially
• Immobilisation, occasionally surgery, rehabilitation
post immobilisation to regain wrist and hand
movement and function
Ganglions of the wrist
• Soft swelling can be associated with a joint or
tendon
• It is filled with thickened synovial fluid
• It is not known what causes them
• Traditional treatment – hit it with a heavy book to
disperse the fluid. This can be successful but it may
reform or you may cause other damage
• Sometimes the fluid can be aspirated but again it
may return
• If very troublesome surgical removal may be
considered
• Carpometacarpal joints more specialised 1st
CMC at the base of the thumb and 5th CMC at
the base of the 5th finger to allow opposition
of the tip of the thumb to tip of the 5th finger
• Metacarpophalangeal joint and
interphalangeal joint of the thumb
• 2-5 fingers MCP, proximal interphalangeal
(PIP) joint, and distal interphalangeal joint
(DIP)
CMC joint of the thumb
• Proximal surface of the trapezium saddle shaped
• Palm upwards thumb in line with the index
finger trapezium convex medial to lateral
• This allows the thumb to:
• Stretch outwards into extension, flex across the
palm,
• Bring the tip of the thumb to the tip of the little
finger – opposition
• Lie flat along the palm in line with the index
finger – adduction
• Stretch directly away from the index finger abduction
Ligaments of the CMC joint
• The capsule of the joint is relatively lax to
accommodate movement
• It is reinforced by radial, ulnar, volar and
dorsal ligaments
• There is also an intercarpal ligament tethering
the bases of the 1st and 2nd metacarpals
together
Movement at the saddle joint in abduction
• With the thumb flat to the palm in line with the index
finger movement away from the palm – abduction occurs
whilst the convex surface on the base of the metacarpal
slides backwards in the saddle. See cowboy below
Movement at the saddle joint in
flexion/extension
• Starting position of the thumb as before,
moving the thumb down and away from the
index finger into extension
• The concave surface on the base of the Ist
metacarpal moves over the trapezium in the
same direction as the carpal bone
• There is also some lateral rotation of the shaft
of the metacarpal
• Flexion, taking the thumb across the palm
occurs with medial rotation
• Note the cowboy leaning side to side in the
saddle
Opposition of the thumb
• Opposition of the thumb occurs with greater
axial or medial rotation of the metacarpal to
matched by flexion and rotation of the 5th
metacarpal to bring the tip of the thumb and
finger together
Ext pollicis longus and brevis
• Longus – middle 1/3 posterior ulna to base of
distal phalanx thumb
• Action - extends the tip of the thumb, assists with
extension MCP and CMC joints of thumb
• Brevis – posterior radius to base of proximal
phalanx of thumb
• Action – extends the MCP joint of the thumb,
• The intrinsic muscles of the thumb particularly
flexor and abductor pollicis form the thenar
eminence
• Flexor pollicis brevis flexes the MCP and CMC
joints. It assists in opposition of the thumb
towards the little finger
• Abductor pollicis longus – from the posterior
surfaces of the radius and ulna and the
interosseous membrane to the base of the first
metacarpal
• Action – abducts and extends CMC joint of
thumb
• Abductor pollicis brevis – flexor retinaculum,
trapezium and scaphoid to base of the proximal
phalanx of thumb and extensor expansion. Cf
later
• Action – abducts the CMC and MCP joints. Via
the dorsal expansion extends the tip of the
thumb
Adductor pollicis
• Transverse fibres – palmar surface 3rd
metacarpal to base proximal phalanx
• Oblique fibres – capitate, base 2nd and
3rd metacarpals to extensor expansion
• Action – adducts the CMC joint, adducts
and assists in flexion of the MCP joint
OA CMC joint of thumb
• 1 in every 6 people consulting for help with arthritis have
it in their wrist or
• 1.56 million people*, 6% of people aged 45 and over*
620,000 working-age women in the UK (45–64 years).*
• More women than men likely to seek treatment
• Women aged 45–64 twice as likely than men to seek
treatment
• Management – rest, ice or heat, NSAIDs
• Splinting may help when undertaking activities
• Must take it off and exercise thumb to avoid additional
stiffness
• Sometimes a trapeziectomy may be considered,
arthrodesis, joint replacement, interposition of soft tissue
into the joint space
• Discussion with the surgeon with particular emphasis on
outcome and complications
De Quervain’s (stenosing) tenosynovitis
• Pain and swelling radial side of thumb and wrist
• Worse with thumb and wrist movement,
associated with overuse and repetitive movement
• Reduced sliding of the tendons of extensor
pollicis brevis and abductor pollicis longus where
they run over the styloid of the radius and below
the extensor retinaculum
• Pain on extending the thumb, also when
stretching the tendon, thumb flexed across the
palm, wrist in ulnar deviation
• Rest, ice, splinting, NSAIDs, if not resolving steroid
injection
Gamekeepers thumb
• Used to be associated with gamekeepers wringing
the necks of birds between the thumb and index
finger
• Now more often associated with skiing injury, falling
whilst holding a ski pole
• Fall onto the hand whilst holding a stick
• Partial or complete tear of the ulnar collateral
ligament leading to instability of the thumb
• Important to get treatment early – referral to hand
surgeon for consideration of surgery
Metacarpophalangeal joints
• 4 MCP joints of the fingers – convex metacarpal head,
concave base of first phalanx distally
• The metacarpal has 180 degrees of articular surface.
Note the greater excursion towards the palm of the
hand to facilitate finger flexion
• The capsule is lax in extension
• The volar plate is a fibrocartilaginous structure which
blends with the capsule and it also blends with the
transverse metacarpal ligament
• The volar plate helps to limit extension it also prevents
pinching of the flexor tendons
• The collateral ligaments provide side to side stability of
the joint
• They are tight when the fingers are flexed
Proximal and distal interphalangeal joints
• PIP and DIP joints formed of the head of the
phalanx and the base of phalanx distal to it
• IP joint synovial hinge joint – joint capsule,
volar plate and two collateral ligaments
MCP joint flexion/extension
• The range of flexion at the MCP joint
increases from 90 degrees at the index
finger to 110 degrees at the little finger
• Hyperextension is consistent between
fingers but varies considerably between
individuals
• The range of ab and adduction is greatest in
extension
• The index and little fingers have the greatest
range of ab and adduction
• Note the A1 and A2 pulleys which prevent
the flexor tendons from bowstringing
outwards
Flexion at the PIP and DIP joints
• In the index finger the greatest range of flexion
extension is at the PIP joint (100-110 degrees)
• At the DIP joint the range is 80 degrees
• The range of motion at each joint increases towards
the little finger where PIP joint flexion is 135 degrees
and DIP joint flexion reaches 90 degrees
• The increasing range towards the ulnar side of the
hand angles the fingers towards the thumb
• Grip is therefore tighter on the ulnar side of the hand
• Extensor digitorum Longus – CET, insertion via 4 tendons
into the dorsal digital expansion
• Over the proximal phalanx the tendon splits into a medial
and 2 lateral bands
• The medial band inserts into the base of the middle
phalanx
• The lateral bands reunite over the middle phalanx and
insert into the base of the distal phalanx
• Extensor indicis has a separate muscle belly from the
posterior ulna inserting into the extensor expansion
• Extensor digiti minimi – CET to extensor expansion of the
little finger
• Splitting of flexor digitorum superficialis tendon with flexor digitorum profundus
tendon inserting into the terminal phalanx
Fibro-osseous tunnels
• To prevent the flexor tendons from
bowstringing out from the phalanges there
are a number of fibrous tunnels A1, A2 etc
pulleys
• To prevent excessive friction the tendons
are enclosed in a tendon sheath containing
synovial – like fluid which promotes sliding
of the tendon
Lumbrical muscles
Lumbricals
• Ist and 2nd lumbricals arise from the radial side of the
profundus tendon
• 3rd and 4th arise from the adjacent sides of the
tendon
• Insert into the radial side of the digital expansion
• Action – Extends the IP joints and simultaneously
flexes the MCP joints
Insertion of the lumbricals and dorsal
interossei into the extensor expansion
• Entrapment of median nerve as it passes
through the carpal tunnel at the wrist.
• Often cause unknown, may be associated
with flexor tendinitis, wrist arthritis
(especially inflammatory arthritis), previous
Colles' fracture, pregnancy, hypothyroidism,
diabetes, obesity
• Incidence peaks in the late 50s, particularly in
women, late 70s men and women =
• Pain and tingling thumb, index, middle ½ of
ring finger worse at night
• Severe cases wasting of the muscles of the
thenar eminence, weakness of grip
• Sustained wrist flexion may reproduce the
symptoms, tapping over the front of the wrist
• Treatment with resting splints at night
• Review of work station if excessive keyboard
usage may be a contributing factor
• Steroid injection may resolve the problem
Carpal tunnel release
• If conservative measures fail surgery may
be indicated
• If diagnosis uncertain nerve conduction
studies may be requested
• Surgery involves cutting the transverse
carpal ligament
• This can be performed as an open
procedure or endoscopically
Heberden’s nodes
• Swelling of the DIP joint associated with
arthritis
• Thought to be hereditary in 40-60% of
cases
• Management – ice, heat, maintaining
flexibility, avoiding over-stressing the joints
Mallet finger
• Rupture of the extensor tendon to the terminal joint
of the finger
• Direct blow to the finger, stubbing the finger as in
making the bed
• Mallet finger splint 6 weeks
• Ensure that when removed for washing the finger is
held in extension so that the ends of the tendon
remain in apposition
Trigger finger
• Nodule in the flexor tendon with constriction of the A1
pulley
• Usually the ring or middle fingers affected
• The finger is often stuck in flexion in the morning and
makes a popping sound as the finger is extended
• A steroid injection can relieve the problem in 70% of
cases
• If after 2 injections the problem is still significant
referral for surgery is indicated
Structure of the aponeurosis or fascia of the
hand
Dupytrens contracture
• Progressive disorder affecting palmar fascia,
causing the fibrous tissue to shorten and
thicken.[1]
• Excessive myofibroblast proliferation, altered
collagen matrix composition, thickened and
contracted palmar fascia. The resultant digital
flexion contractures may severely limit function
• Typically affects northern European men over
age 60, 25% prevalence
• 6x more common in men
• Genetic component, trauma, inflammatory
response, environmental
• Smoking, diabetes, excessive alcohol
• Management – not all come to surgery, early
stages injectable, collagenase appears to be
equivalent to surgery; however, recurrence
rates are still an issue, reported as 47% at five
years.
Next week
• Spine – mainly cervical but some thoracic
• Anatomy structure and function
• Disc degeneration, OA facet joints, nerve root irritation, spinal
stenosis, whiplash
• Presentation and management of conditions