Guyon's Canal Syndrome

Upper Limb

Overview

Guyon's canal syndrome is a rare compression neuropathy of the ulnar nerve as it passes through Guyon's canal at the wrist, resulting in motor and/or sensory dysfunction of the hand. Unlike carpal tunnel syndrome affecting the median nerve, this condition specifically impacts the deep motor branch and superficial sensory branch of the ulnar nerve distal to the wrist. Clinical presentation varies depending on the level and extent of compression within the canal.

Pathophysiology

The ulnar nerve enters the hand through Guyon's canal, a triangular anatomical space bounded medially by the pisiform and triquetrum, laterally by the hook of hamate, and roofed by the volar carpal ligament and hypothenar fascia. Compression within this canal can result from space-occupying lesions (ganglion cysts, lipomas, anomalous muscles), trauma (handlebar palsy, repetitive compression), thrombosis of the ulnar artery, or hypothenar hammer syndrome. The resulting nerve compression leads to demyelination and axonal loss, causing motor weakness of intrinsic hand muscles (particularly the adductor pollicis and hypothenar muscles) and sensory loss in the ulnar nerve distribution if the superficial branch is affected.

Patient Education

Guyon's canal syndrome requires specific diagnosis and management; avoiding repetitive pressure to the hypothenar region and using padded gloves during activities can help prevent symptom progression while seeking appropriate medical evaluation.

Typical Presentation

Site

Hypothenar eminence, medial palm, and ulnar aspect of hand; symptoms typically spare the dorsal cutaneous distribution

Quality

Weakness and clumsiness of hand grip and finger manipulation; possible tingling or numbness in ulnar hand distribution depending on compression extent

Intensity

Variable; ranges from mild weakness with minimal sensory changes to significant functional impairment with marked muscle atrophy

Aggravating

Repetitive gripping activities, prolonged pressure on the hypothenar region (cycling, using hand tools, leaning on the palm), direct trauma to the wrist

Relieving

Rest from provocative activities, avoiding pressure on the ulnar aspect of the wrist, ice application for inflammation management

Associated

Hypothenar muscle atrophy (claw hand deformity in severe cases), reduced grip strength, difficulty with fine motor tasks, possible visible swelling if mass present, history of direct trauma or repetitive compression injury

Orthopaedic Tests

Test descriptions are written with AI assistance from standard clinical texts. Where a test lists Sources, its description has been checked against them; those sources are independent and do not endorse OsteoKit. Accuracy figures and grades (A–D) appear only when checked against the published study; tests without one are marked “No accuracy study”.

Further reading: full test procedures are described in standard clinical examination texts, e.g. Magee & Manske, Orthopedic Physical Assessment (7th ed.), and Cook & Hegedus, Orthopedic Physical Examination Tests: An Evidence-Based Approach (2nd ed.).

No accuracy study

Froment's Sign

Procedure

Ask the patient to hold a sheet of paper between the thumb and the side of the index finger in both hands while you try to pull it away.

Positive Finding

The thumb IP joint bends on the affected side as flexor pollicis longus takes over from a weak adductor pollicis.

Interpretation

Shows weakness of ulnar-supplied thumb adduction. It confirms an ulnar motor deficit but not where the nerve is compressed; the same sign occurs with compression at the elbow.

Sources

No accuracy study

Hypothenar Eminence Atrophy Assessment

Procedure

Look at and feel the hypothenar eminence on both hands, comparing muscle bulk.

Positive Finding

Visible or palpable wasting of the hypothenar muscles on the affected side.

Interpretation

Wasting means a longstanding ulnar motor deficit. Lesions of the deep motor branch beyond the hypothenar branches can spare these muscles, so the pattern of wasting helps show where in or beyond Guyon's canal the nerve is compressed.

Sources

No accuracy study

First Dorsal Interosseous Weakness Test

Procedure

Ask the patient to spread the index finger away from the middle finger against resistance, and feel the first dorsal interosseous muscle in the web space.

Positive Finding

Weakness or wasting of the first dorsal interosseous compared with the other hand.

Interpretation

Shows an ulnar motor deficit. This muscle is affected by compression at the elbow as well as at the wrist, so it does not separate the two. Testing sensation on the back of the hand (dorsal ulnar cutaneous branch) does.

Sources

No accuracy study

Intrinsic Hand Muscle Manual Strength Testing (Grade 3–5)

Procedure

Test finger abduction and adduction (interossei), little finger abduction (abductor digiti minimi) and thumb adduction, grading each 0–5 and comparing sides. Also test thumb abduction (abductor pollicis brevis, median nerve) for comparison.

Positive Finding

Weakness in one or more ulnar-supplied intrinsic muscles, with normal median-supplied thenar strength.

Interpretation

Confirms an ulnar motor deficit. Weakness of both ulnar- and median-supplied hand muscles instead points to a C8/T1 nerve root or lower brachial plexus problem.

Sources

No accuracy study

Claw Hand Deformity Assessment

Procedure

Look at the resting hand, then ask the patient to straighten all the fingers.

Positive Finding

The ring and little fingers rest with the MCP joints hyperextended and the IP joints flexed, and cannot be fully straightened actively.

Interpretation

Shows weakness of the ulnar-supplied intrinsic muscles. Clawing is often more obvious with compression at the wrist than at the elbow, because the long flexors to the ring and little fingers still work (the 'ulnar paradox').

Sources

No accuracy study

Two-Point Discrimination Test (Sensory Assessment)

Procedure

Test light touch and two-point discrimination on the palmar little finger and ulnar half of the ring finger, and separately on the ulnar side of the back of the hand. Compare with the other hand.

Positive Finding

Reduced sensation in the ulnar-supplied fingers on the palmar side.

Interpretation

Palmar sensory loss with normal sensation on the back of the hand fits compression at Guyon's canal, because the dorsal cutaneous branch leaves the nerve above the wrist. Loss on the back of the hand as well points to a more proximal lesion, such as at the elbow. Some Guyon's canal lesions are purely motor, so normal sensation does not exclude them.

Sources

⚠ Red Flags

  • •Rapidly progressive neurological deficit suggesting acute compression
  • •Severe pain with systemic features suggesting infection or malignancy
  • •Evidence of vascular compromise with colour changes or temperature changes in the hand
  • •Imaging findings suggestive of malignant mass or space-occupying lesion
  • •Bilateral symptoms suggesting systemic neuropathy or cervical myelopathy
  • •Sensorimotor deficit extending beyond ulnar nerve distribution

⚡ Yellow Flags

  • •Work-related injury with secondary gain factors
  • •Catastrophic thinking about hand function and disability
  • •Excessive focus on medico-legal aspects of injury
  • •Poor adherence to activity modification recommendations
  • •Significant psychological distress disproportionate to objective findings
  • •Belief that the condition is untreatable or will cause permanent disability

Osteopathic Techniques

Guyon canal syndrome with mild, recent symptoms and no space-occupying lesion is treated conservatively: avoiding repetitive wrist loading and prolonged pressure on the hypothenar eminence, ergonomic changes, and a neutral wrist splint. Nerve gliding is sometimes added, but its evidence is limited and borrowed from other nerve entrapments. No trials of osteopathic techniques were found.

Safety: Before any neck technique, screen for blood-vessel problems in the neck. If there are signs of myelopathy (see Red Flags), do not treat the neck manually: refer.

Region

Forearm flexors (incl. FCU), away from Guyon’s canal

Technique

Soft tissue, elbow and forearmNo trials found

Rationale

Soft tissue to the forearm flexor and extensor muscles that move the wrist and fingers.

How it's done, cautions & evidence

How it's done

Hands-on kneading, stroking and sustained pressure to the forearm extensor and flexor muscles, their tendon origins at the epicondyles, the supinator, the pronators and the triceps. Deep transverse friction across the tendon origin is part of the Cyriax method for lateral elbow pain.

Cautions

Avoid direct pressure on an olecranon bursitis. A red, warm, tender bursa, especially with fever, may be septic and needs medical review.

Evidence in Guyon's Canal Syndrome

Searched 26 Oct 2026: no trials of forearm soft tissue in Guyon canal syndrome.

Region

Carpal bones (pisiform, hamate, triquetrum)

Technique

Articulation, wrist and hand
Grade D
Low evidence: expert consensus or could not be verified against literature
No trials of carpal mobilisation in Guyon canal syndrome. In carpal tunnel syndrome it has only been tested as an add-on.

Rationale

Gentle glides of the wrist, carpal and hand joints to restore movement.

How it's done, cautions & evidence

How it's done

Passive, rhythmic, low-velocity glides of the radiocarpal, midcarpal and intercarpal joints, the distal radioulnar joint, the thumb carpometacarpal (CMC) joint and the finger joints, within or up to the end of the available range. In thumb-base osteoarthritis trials this was Maitland-style passive accessory gliding of the CMC joint.

Cautions

After a fall on the hand, rule out a fracture first: scaphoid fractures are often missed on the first X-ray, so snuffbox pain needs a splint and repeat imaging. Do not move a joint that is splinted for a tendon injury: the DIP in mallet finger, the PIP in a central slip (boutonnière) injury.

Evidence in Guyon's Canal Syndrome

Searched 26 Oct 2026: no trials of carpal mobilisation in Guyon canal syndrome. Indirect: Sault 2020 (SR): in carpal tunnel syndrome, joint mobilisation was only used as part of a wider programme and may be a useful adjunct.

Region

Wrist flexors (incl. FCU)

Technique

Muscle energy, elbow and forearmNo trials found

Rationale

Muscle energy technique to ease tight forearm muscles that act on the wrist (wrist extensors or flexors, pronators or supinators).

How it's done, cautions & evidence

How it's done

The wrist or forearm is taken to the barrier of the tight muscle group (wrist extensors or flexors, pronators or supinators). The patient pushes gently back, at about 10–20% effort, against resistance for 5–10 seconds, relaxes for 3–5 seconds, and the new barrier is taken up.

Cautions

Not used with an acute fracture, a joint infection or a bone malignancy; take care with severe osteoporosis or after surgery that limits muscle contraction. Use the least force needed: too much can tear a muscle or pull off a tendon, especially in older patients.

Evidence in Guyon's Canal Syndrome

Searched 26 Oct 2026: no trials of forearm muscle energy technique in Guyon canal syndrome.

Region

Ulnar nerve (neck to hand)

Technique

Neural mobilisation, upper limb
Grade D
Low evidence: expert consensus or could not be verified against literature
No trials of neural mobilisation in Guyon canal syndrome. Its effect is uncertain in other nerve entrapments.

Rationale

Gentle sliding of the nerve along its path through the neck, arm, forearm and hand.

How it's done & evidence

How it's done

A movement-based treatment aimed at the nerve and the tissues around it. Gentle, rhythmic neck and arm movements either slide the nerve along its path (sliders) or lightly tension it (tensioners), with a median, radial or ulnar bias. One review found sliders helped more in acute pain and tensioners in chronic pain.

Evidence in Guyon's Canal Syndrome

Searched 26 Oct 2026: no trials of neural mobilisation in Guyon canal syndrome. Indirect: Basson 2017 (SR/MA): the effect in cubital tunnel syndrome is uncertain, and it was not effective for most outcomes in carpal tunnel syndrome.

Region

Cervical spine (C8–T1)

Technique

Articulation, cervicalNo trials found

Rationale

Gentle cervical and upper thoracic articulation for the segments that supply the arm.

How it's done & evidence

How it's done

Rhythmic, low-velocity movement of a restricted cervical segment within its passive range, with no thrust. Usually done with the patient supine and the head supported; the amplitude can vary.

Evidence in Guyon's Canal Syndrome

Searched 26 Oct 2026: no trials of cervical mobilisation in Guyon canal syndrome.

Sources

Rehabilitation Exercises

Wrist Circumduction in Multiple Planes

Range of MotionBeginner

Forearm Flexor Stretch (Reverse Prayer Position)

StretchingBeginner

Ulnar Nerve Gliding Exercises (Median Nerve Mobilization)

StretchingBeginner

Intrinsic Hand Muscle Strengthening (Pencil Squeeze)

StrengtheningBeginner

Adductor Pollicis Strengthening (Thumb Abduction Resistance)

StrengtheningIntermediate

Hypothenar Muscle Strengthening (Finger Spreading Against Resistance)

StrengtheningIntermediate

Grip Strengthening with Progressive Resistance

StrengtheningIntermediate

Wrist Extension and Flexion Active Range

Range of MotionBeginner

Ergonomic Hand Positioning During Work Tasks

PosturalBeginner

Fine Motor Dexterity Training (Coin Pickup and Stacking)

BalanceIntermediate

Interosseous Muscle Strengthening (Card Finger Abduction)

StrengtheningAdvanced

Activity Modification Pacing for Repetitive Tasks

PosturalBeginner

Referral Criteria

  • •Persistent neurological deficit despite 6-8 weeks of conservative management
  • •Progressive motor weakness or muscle atrophy indicating ongoing nerve damage
  • •Diagnostic uncertainty requiring electrodiagnostic studies (EMG/NCS) or imaging (ultrasound, MRI)
  • •Suspected space-occupying lesion (ganglion cyst, lipoma, or tumor) visible on palpation or imaging
  • •Evidence of vascular compromise requiring vascular assessment
  • •Symptoms following acute trauma with suspected fracture or dislocation
  • •Failure to improve with activity modification and conservative treatment warranting surgical decompression consideration
  • •Bilateral presentation or symptoms extending beyond ulnar nerve distribution suggesting systemic neuropathy