wrist pathology

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for normal wrist anatomy and ultrasound scanning protocol

de quervains tenosynovitis

  • focal inflammation of the abductor pollicis longus and extensor pollicis brevis tendons (compartment 1)
  • the patient will have focal point tenderness over the lateral aspect of the wrist.

de quervain’s tenosynovitis scan plane.

ultrasound image- thickening of the apl and epb tendons with fluid and thickening of the tendon sheath.

ultrasound image- mild thickening of the apl and epb tendons with thickened overlying retinaculum (red arrows).
normal right. thickened left.

mild thickening of the apl and epb tendons with thickened overlying retinaculum (red arrow).

normal right. thickened, abnormal left.

ultrasound image- marked thickening of the apl/epb tendons with fluid in the sheath.
using power doppler the marked hyperaemia is easily seen.

finkelstein's test
the clinical test for de quervain’s tenosynovitis is finkelstein’s test. make a fist with the thumb on the inside. the ulnar/radial deviate (like a handshake movement). the test is positive for compartment 1 tendinopathy if there is focal pain at the radial styloid during ulnar deviation. differential diagnosis is 1st smcj arthritis, however the focal sharp pain with be further distal in cmcj disease.

dupuytren’s contracture

  • fibrosis of the palmer fascia.
  • gradual onset
  • m>f
  • inherited.
  • generally affects 4th and 5th fingers.

on ultrasound:

  • hypoechoic focal fusiform thickening of the palmar fascia at the level of the mc head.
  • don’t confuse with ‘trigger finger’ which involves the flexor tendon.

transverse ultrasound view of the focal thickening of the palmar fascia in dupuytrens contracture.

ultrasound image- dupuytren’s will appear as a hypoechoic focal fusiform thickening of the palmar fascia at the metacarpal head level. not to be confused with trigger finger (see below).

reference article

for detailed information on dupuytren’s contracture.

carpal tunnel syndrome.

involves compression of the median nerve as it passes under the flexor retinaculum.

note: a normal ultrasound does not exclude carpal tunnel syndrome.

common causes visible on ultrasound include:

  • tenosynovitis
  • joint effusions
  • ganglia
  • anomalous muscle belly protruding into the tunnel

ultrasound image- ts carpal tunnels.

arrows indicate the median nerves.
the right median nerve is visibly compressed compared to the left.

ultrasound image- compression of the median nerve with a thickened overlying retinaculum.

ultrasound image- bifid median nerve (normal variant)

ultrasound image- comparison:
on the right, a thin elongated muscle (red) extending into the carpal tunnel superficially.
the impression on the median nerve (green) is evident.

ultrasound image- transverse view of the same wrist showing the anomalous muscle belly (red) overlying the median nerve (green).

anomalous muscle in carpal tunnel ultrasound
longitudinal view of the carpal tunnel. during finger flexion, the muscle belly can be seen entering the space.
anomalous muscle in the carpal tunnel -transverse ultrasound
transverse view of the carpal tunnel. during finger flexion, the muscle belly can be seen entering the space.

ultrasound image- ganglia, synovial cysts or effusions may cause mass effect causing carpal tunnel syndrome.

ultrasound image- a joint effusion causing a mass effect in the carpal tunnel.

guyons canal syndrome

  • guyons canal is bordered by the pisiform & hamate and roofed by a reflection of the flexor retinaculum.
  • the ulnar nerve and artery pass through and may become entrapped or injured.
  • causes include repetitive injury such as cycling (handlebar palsy) or using heel of hand as hammer.

on ultrasound:

  • as with the carpal tunnel, look for ganglia, accessory muscles and asymmetry with the contra-lateral side.

ultrasound image- guyons canal.

ultrasound ulna nerve entrapment at the wrist
entrapment of the ulna nerve proximal to, not within, guyon’s canal. the ulna nerve (yellow) becomes entrapped and compressed between the extensor carpi ulnaris (ecu) and the extensor digitorum musculotendinous junctions. this was evident and reproduced the patient’s symptoms when re-enacting the patients painful movements. in this case, gripping and lifting a shopping bag.

intersection syndrome

wrist intersection syndrome anatomy.
ref: anatomylearning.com

proximal intersection syndrome

  • compartment 1 crossing compartment 2
  • occurs where the extensor pollicis brevis (epb) and abductor pollicis longus (apl) tendons cross the extensor carpi radialis (ecr) tendons. caused by repetitive rotational activities such as canoeing or weight lifting
  • not to be confused clinically with de quervain’s which is on the lateral aspect 1-2 cm more distal.

ultrasound image- the proximal intersection of the wrist..

proximal intersection ultrasound normal
ultrasound of the normal proximal intersection seen in transverse, as the probe is moved proximally along the ecr tendons. the apl musculo-tendinous junction is seen crossing over.

distal intersection syndrome

  • compartment 3 crossing compartment 2
  • the distal intersection is where the extensor pollicis longus (epl) tendon, crosses the extensor carpi radialis longus (ecr-l) and brevis (ecr-b) tendons.

ultrasound image- distal intersection syndrome: the distal intersection is where the extensor pollicis longus (epl) tendon, crosses the extensor carpi radialis longus (ecr-l) tendon.

ganglia and joint effusions

ganglia

synovial saccular out pouching from a joint or less commonly a tendon sheath.
look for the neck to the joint or tendon of origin.
may be simple or complex fluid.
intermittently focally tender.
look for any effect on surrounding structures

ultrasound image- markedly complex fluid in the extensor digitorum sheath with pannus consistent with the history of rheumatoid arthritis (ra).

ultrasound image- transverse view rheumatiod arthritis.

triangular fibrocartilage complex (tfcc)

  • a section of cartilage and ligaments at the distal ulna.
  • provides a continuous gliding surface along the forearm-carpal joint.
  • natural degeneration with age.

injuries from:

  • a fall onto an outstretched hand (foosh)
  • forced rotation (stuck drill)
  • racquet sports
  • direct blow to medial wrist

ultrasound cannot exclude tfcc pathology, but familiarity with the anatomy is important. mri and arthroscopy are the preferred modalities.

ultrasound image – triangular fibrocartilage complex (tfcc):  the blue arrows indicate the triangular fibrocartilage at the base of the ulna. the red arrow indicates the tfcc tear.