wrist Flashcards
What is the wrist joint comprised of?
distal radius, ulna and carpal bones
What are the 3 joints that make up the wrist?
radiocarpal joint: distal radius and scaphoid & lunate bones
ulnocarpal joint: distal ulna and lunate & triquetral bones via articular disk
radioulnar joint
What is the name for the distal radial tubercle?
Lister’s tubercle
What is the ulnar styloid process the attachment site for?
UCL
Which carpal bone is embedded in a tendon and is not involved in wrist movement?
the Pisiform bone
Where is the triangular fibrocartilage
between the ulna and triquetral and lunate bones
allows forearm rotation
what mechanism is the dorsal wrist responsible for?
extensor mechanism for wrist, digits and thumb
What compartments is the snuff box made of?
compartment 1 and 3
(extensor pollicis brevis and extensor pollicus longus)
What 2 tendons are associated with De Quervain’s? (what is the compartment)
extensor pollicis brevis and abductor pollicis longus, compartment 1
what does compartment 2 contain?
extensor carpi radialis longus and brevis
what separates compartment 2 and 3?
what does compartment 3 contain?
Lister’s tubercle
extensor pollicis longus
When does the extensor pollicis longus commonly rupture?
in patients with rh arthritis due to the sharp radial deviation over Lister’s tubercle
what is contained within compartment 4 and 5?
4: extensor digitorum (superficial) and extensor indices (deep)
5: extensor digit minimi
what is contained within compartment 6?
extensor carpi ulnaris
what compartments are most commonly affected by tenosynovitis?
5th and 6th
what does the palmar wrist contain?
what tunnels does it contain?
flexor tendons, ulnar, median and radial nerve
contains the carpal tunnel and Guyon’s tunnel
What is contained within the carpal tunnel?
median nerve, flexor pollicis longus and eight flexor digitorum tendons (4 deep 4 superficial)
what forms the roof of the carpal tunnel?
flexor retinaculum?
what are the bony landmarks for the proximal carpal tunnel?
scaphoid on the radial side, and the pisiform on the ulnar side
what are the bony landmarks for the distal carpal tunnel?
trapezium on the radial size and hook of the hamate on the ulnar side
what is the Guyon’s tunnel and where is it?
on the ulnar side formed by the pisiform and hook of the hamate
contains the ulnar nerve and artery (nerve splits into superficial and deep branches)
what can cause most wrist pathologies?
tendon overuse or nerve compression
what systemic diseases can also cause wrist pathology?
rh arthritis
diabetes
lupus
osteoarthritis
psoriatic arthritis
what occurs with median nerve compression?
nerve paresthesia that causes burning/prickling sensation or numbness of the first 3 fingers
also called carpal tunnel syndrome
what is the most common entrapment syndrome of the upper limb?
CTS
what is the most common cause of CTS?
tenosynovitis of the flexor tendons
also ganglions, masses, thrombosed median artery, or accessory muscles
what is the appearance of CTS?
3x bigger in one axis compared to the other
loss of honeycomb appearance
abrupt contour changes
What can happen to the flexor retinaculum from CTS?
it may bulge outward due to intracanal pressure, best seen distally
if it extends more than 4mm above an imaginary line between the pisiform and scaphoid bone it is abnormal
what is the measurement for the carpal tunnel?
(CSA @ PQ) - (CSA @ CP) >2mm
what is a bifid median nerve associated with?
persistent median artery (important for sx) and with an increased association of CTS
what are the symptoms of ulnar nerve compression?
how can you recreate these symptoms?
paresthesia in last 2 windows
reproduced with probe pressure over hook of hamate (Guyons tunnel syndrome)
what is the most common cause of ulnar nerve compression in the wrist?
trauma
also chronic compression from long distance cycling or mass lesions
how does Guyon’s tunnel syndrome appear?
loss of honeycomb appearance
caliber change as it enters the tunnel
where is the radial nerve often compressed and assessed?
what is it called?
level of mid forearm where the nerve passes between the forearm muscles during pronation
Wartenburgs syndrome
how does joint fluid appear in the wrist?
anechoic distention of joint space representing simple fluid
collapses with pressure or movement, no internal flow**
how does synovial hypertrophy appear? (compared to joint fluid distention)
distention of the sheath around the tendon
will not collapse, has some flow with power doppler
what is rheumatoid tenosynovitis?
the immune system attacks the tendon sheaths in the wrists that causes inflammation of the synovium
what is the appearance of rheumatoid tenosynovitis?
hypoechoic pannus with fluid in the sheath
hypervascularity with power doppler of the pannus
thickened and heterogenous tendon with jagged edges (if involved)
what is the most affected tendon from rheumatoid tenosynovitis?
extensor carpi ulnaris
what causes general tenosynovitis of the wrist tendons?
what is seen?
overuse and friction
large amounts of fluid is seen around the tendons, increased CD signal if infected
What is the most common tendinopathy of the wrist? (what else is it called?)
De Quervain’s tenosynovitis (stenosing tenosynovitis) involving tendons in compartment 1
what setting is useful in identifying the inflammatory process of De Quervain’s?
colour doppler
what is the appearance of De Quervains?
swollen synovium with trace fluid around tendons and sheath, with restricted movement
colour doppler signals
bulge of the extensor retinaculum
What is intersection syndrome?
is a form of tenosynovitis involving where the 1st compartment tendons pass over the 2nd compartment tendons
how does intersection syndrome appear?
inflammation of the synovial sheath of the 2nd compartment
what is the triangular fibrocartilage complex?
dense connective tissue between the lunate and triquetrum carpal bones and ulnar head
how does a tear of the TFCC present?
(symptoms)
ulnar sided wrist pain, clicking with wrist movement and point tenderness
how does a TFCC tear appear?
hypoechoic, thinned or absent
what is the most common tendon in the wrist/hand to tear?
flexor digitorum longus
what causes tears of the extensor tendons?
usually from rheumatoid tenosynovitis
most commonly extensor pollicis longus and extensor digit minimi
what can cause a retinaculum tear?
after traction injuries
leads to instability
what causes a tear of the extensor retinaculum specifically?
occurs after a punch or from chronic inflammation
which tendon is prone to subluxation in the elbow?
extensor carpi ulnaris
diagnosed if >50% of the tendon moves out of the ulnar groove
how do rheumatoid nodules appear?
palpable, compressible masses on the fingers with NO vascularity
small, oval, well defined and hypoechoic
what is the most common expansible lesion of the wrist?
ganglion cyst
filled with gelatinous, mucoid thick fluid that may have septations and is non-compressible
communicates with the tendon sheath
where is the most common site for a ganglion?
dorsal wrist, from the scapholunate ligament and radiocarpal joint
what is a “dorsal occult ganglion”?
occurring dorsally to the lunate bone, very small (prevents detection), causes pain from compression on radial nerve
where does a palmar ganlgia arise from?
radioscaphoid joint, usually between radial artery and flexor carpi radialis
how does a palmar ganglion appear?
usually large, painless and can have transmitted pulsatility from radial artery
what can a palmar ganglion be mistaken for?
pseudoaneurysm
what is the 2nd most common mass of the wrist/hand?
giant cell tumor from the tendon sheaths
progessively enlarge and are benign
how do giant cell tumors appear?
solid hypoechoic masses WITH internal flow
cause pressure of bone and tendon displacement
what causes a pseudoaneurysm?
traumatic injury to blood vessel wall that can become thrombosed
how does a pseudoaneurysm appear?
anechoic mass with internal echoes, ying yang flow pattern on colour doppler that is continuous with vessel
