Hand-Finger pathology

Tenosynovitis

Ultrasound image- Tenosynovitis of the flexor digitorum tendon.
A complex effusion and thickened tendon.

Ultrasound image- Transverse view of tenosynovitis of flexor digitorum profundus and superficialis.  The marked hyperaemia visible with power doppler demonstrates the acute nature of the process.

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Dupuytren’s Contracture

What is it?

  • Fibrosis of the palmer fascia forcing the flexion of the 4th/5th fingers.
  • Gradual onset
    M>F
  • Often inherited.
  • Generally affects 4th and 5th fingers.

Scan in longitudinal from the base of the proximal phalanx down into the palm looking superficial to the flexor tendon

It 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).

Transverse ultrasound view of the focal thickening of the palmar fascia in Dupuytrens contracture.

Ultrasound image- Dupuytrens 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).

Trigger Finger

What is it?

Tenosynovitis of a flexor digitorum tendon causing forced flexion of a finger.

  • Initially in transverse, identify the flexor digitorum tendons at the metacarpal head level. Follow the common tendon proximally to the carpal tunnel. Then follow distally to the insertions: The Flexor digitorum superficialis divides, with two slips inserting onto the side of the base of the middle phalanx. Flexor digitorum profundus inserts onto the distal phalanx.
  • Look for fluid and/or tendon thickening.
  • In longitudinal ask the patient to try flexing and extending their finger. You may need to do this passively (within the patient’s pain limitations.)
  • Watch in the region of the metacarpal neck for tendon bunching.

Ultrasound image- Bunching of the flexor digitorum at approximately 45 degrees flexion of the PIPJ.

Pulley Pathology

The flexor tendons are secured in place by a series of pulleys which are fibrous bands wrapping over the tendons and attaching to the bone.

  • Annular pulleys: which wrap transversely over the tendons. Numbered A1 – A4 (proximal to distal).
  • Cruciate pulleys: which are paired and cross diagonally over the tendons.

Numbered C1 – C3. (see below).
The annular pulleys are readily visible with high resolution, high quality equipment. The cruciate pulleys are poorly seen.

Normal Pulley

Anatomy specimen showing the annular pulleys with the finger extended.

Courtesy of Dr Andreas Schweizer.

www.turntillburn.ch

Ultrasound image- Normal A2 pulley at the proximal phalanx.

Ruptured Pulley

Ultrasound image- Transverse comparison of the normlly positioned flexor digitorum tendon and the abnormally elevated tendon off the bone (orange arrow)

Ultrasound image- The flexor tendon can be seen ‘bowstringing’ across the flexed finger, secondary to a ruptured pulley. Note the distance of the tendon off the bone and the deep layer of gel required to visualise the area.

Ultrasound image- Comparison of the flexor digitorum tendon position.
Normal right V’s abnormal left.

Ultrasound image- The elevation of the flexor tendon off the proximal phalanx (indicated by the red arrows) confirms the rupture of the a2 pulley.

Pulley Ganglion cysts

Commonly seen small cysts superficially overlying a pulley.
Usually present as an inconvenient lump rather than due to pain.

Ultrasound image- A ganglion associated with the A1 pulley of the 3rd finger

Ultrasound image- Transverse view of the pulley ganglion.

Extensor Tendon & extensor hood pathology

Torn extensor longus tendon.

Ultrasound image- The separation of the fibres is evident.
The retracted tendon has remained taut and a thin section of fibres remain, consistant with a partial tear.

Mallet Finger

A rupture of the extensor hood at it’s distal insertion onto the base of the distal phalanx.

Miscellaneous

Gout

Can occur anywhere.
Traumatic, post-surgical or developmental

Ultrasound image- A complex effusion of the metacarpo-phalangeal joint secondary to gout.

Ultrasound image- The same joint showing marked erosion of the metacarpal head/neck. (see the following X-ray image). .

Xray image showing gout erosions of the 2nd MCPJ

Ultrasound image- Gout:
A large complex joint effusion on the palmar aspect of the metacarpo-phalangeal joint.

Arterio-venous malformation

  • Can occur anywhere.
  • Traumatic, post-surgical or developmental

Ultrasound image- An arteriovenous malformation (AVM) at the base of the 5th finger (see adjacent photo).

The AVM is present and visible at the base of the little finger. Note the pink blush in the hypothenor eminence which also is involved.

Subungual Exostosis

This patient had previously had an infection which had cleared with antibiotics. She noticed that the nail was not growing and there was a hard lump forming.

Xray and Ultrasound both could see there was a calcified area with the Xray showing it was arising from the bone.

  • These lesions are benign and are commonly seen on the foot where they resemble a callus. They are resectable.

X RAY 3rd Finger

Ultrasound 3rd Finger