9.3 Hand, Carpal & Compression Tests

Hand, Carpal & Compression Tests

Clinical Core: The hand and wrist represent an intricate kinetic terminal comprising 8 carpal bones, 5 metacarpals, 14 phalanges, and multiple fibro-osseous compartments. Accurate clinical testing requires isolating peripheral nerve compression syndromes from tenosynovitis of synovial sheaths, while verifying terminal arterial blood supply.

---

1. Carpal Tunnel Syndrome (CTS) Assessment

Carpal tunnel syndrome is the most prevalent compressive neuropathy of the upper extremity. The carpal tunnel is a rigid fibro-osseous canal bounded posteriorly, medially, and laterally by the carpal bones (forming the carpal arch) and anteriorly by the tough, non-compliant flexor retinaculum (transverse carpal ligament).

Transverse Carpal Ligament (Flexor Retinaculum)
                      ▲
                      │  [Carpal Tunnel Contents:]
                      │  - 1 Median Nerve
                      │  - 4 Flexor Digitorum Superficialis Tendons
                      │  - 4 Flexor Digitorum Profundus Tendons
                      │  - 1 Flexor Pollicis Longus Tendon
                      ▼
Carpal Bones Arch (Hamate, Capitate, Trapezoid, Trapezium)

In healthy wrists, resting hydrostatic tissue pressure within the canal ranges between 2 and 10 mmHg. In patients with carpal tunnel syndrome, resting pressures frequently exceed 30 mmHg. During active or sustained passive wrist flexion or extension, hydrostatic pressure surges above 90 to 110 mmHg, inducing mechanical deformation, microvascular ischemia, and conduction block within sensory and motor axons of the median nerve.

Phalen's Test (Wrist Flexion Test)

• Objective: Provoke median nerve ischemia and paresthesia by maximally elevating carpal tunnel hydrostatic pressure and compressing the nerve against the proximal edge of the transverse carpal ligament.
• Patient Position: Seated or standing.
• Therapist Execution: The patient is instructed to rest their elbows on a table or hold their forearms horizontally. The patient allows both wrists to fall into maximal unforced passive flexion (approximately 90°) with the dorsal surfaces of the hands approximated against each other. The patient maintains this position for a full 60 seconds.
• Positive Finding: Reproduction or worsening of numbness, tingling, burning, or pain along the cutaneous distribution of the median nerve (palmar aspect of the thumb, index, middle, and radial half of the ring finger) within the 60-second window.
• Diagnostic Pearl: A positive test supports, but does not confirm, carpal tunnel syndrome; findings are interpreted together with symptoms, sensory testing, and medical investigations such as nerve conduction studies.

Reverse Phalen's Test (Prayer Test)

• Objective: Provoke median nerve compression via passive wrist extension.
• Therapist Execution: The patient places the palmar surfaces of both hands together in a "prayer" position with fingers pointing upward and wrists extended to 90°. The patient maintains this posture with forearms horizontal for 60 seconds.
• Biomechanical Mechanism: Wrist extension increases carpal tunnel pressure to levels equal to or greater than flexion, while simultaneously elongating the median nerve across the anterior carpal canal.
• Positive Finding: Paresthesia reproduced within the median nerve distribution within 60 seconds.

Tinel's Sign at the Carpal Tunnel

• Objective: Identify regenerating or hypersensitive, irritable sensory axons of the median nerve.
• Therapist Execution: The patient's wrist is supported in a neutral, relaxed position with the palm facing upward. The therapist uses a fingertip (or neurological reflex hammer) to lightly tap (percuss) 4 to 6 times directly over the volar wrist crease, specifically over the course of the median nerve just deep to the transverse carpal ligament.
• Positive Finding: A sharp, electric shock sensation or tingling that shoots distally into the thumb, index, middle finger, and radial ring finger.
• Diagnostic Sensitivity: Tinel's sign demonstrates relatively low sensitivity (~38% to 60%) but moderate-to-high specificity (~67% to 87%). It is particularly valuable for monitoring axonal recovery following surgical decompression or manual treatment.

Durkan's Carpal Compression Test

• Objective: Directly compress the median nerve at the carpal tunnel inlet.
• Therapist Execution: The patient's forearm is supinated and resting on a table. The therapist places both thumbs directly over the median nerve at the proximal base of the palm, immediately distal to the distal wrist flexion crease (between the thenar and hypothenar eminences). The therapist applies constant, firm, even thumb pressure directly over the transverse carpal ligament for up to 30 seconds.
• Positive Finding: Reproduction of tingling, numbness, or burning pain along the median nerve sensory territory within 30 seconds.
• Diagnostic Accuracy: Durkan's original 1991 study reported sensitivity of 87% and specificity of 90%, better than Phalen's and Tinel's signs in that sample; later studies have reported lower and more variable values, so it is best used as part of a cluster.

---

2. Tenosynovitis of the Wrist: De Quervain's

The dorsal wrist is divided into six separate extensor compartments formed by fibrous septa extending from the extensor retinaculum to the dorsal radius and ulna.

First Dorsal Extensor Compartment:
- Abductor Pollicis Longus (APL)
- Extensor Pollicis Brevis (EPB)
Location: Directly over the radial styloid process

De Quervain's Tenosynovitis

• Pathoanatomy: Stenosing tenosynovitis characterized by fibrous thickening and myxoid degeneration of the common synovial sheath enclosing the Abductor Pollicis Longus (APL) and Extensor Pollicis Brevis (EPB) tendons as they traverse the fibro-osseous groove over the radial styloid process. Common in occupations requiring repetitive forceful thumb pinching combined with ulnar wrist deviation (e.g., new parents lifting infants, clerical workers, assembly technicians).

Finkelstein's Test

• Objective: Provoke tensile mechanical friction across the inflamed APL and EPB tendons within the first dorsal compartment.
• Classical Technique: The patient sits comfortably with the forearm in neutral rotation (thumb pointing up). The therapist grasps the patient's thumb with one hand, applies gentle longitudinal traction, and passively guides the wrist into sharp ulnar deviation while pulling the thumb across the palm.
• Eichhoff's Maneuver Comparison: Many clinicians confuse Finkelstein's test with Eichhoff's test (where the patient actively places the thumb inside a closed fist and actively ulnar-deviates the wrist). Eichhoff's maneuver generates a significant rate of false positives in healthy individuals due to excessive tensile strain. The true passive Finkelstein's test is significantly more specific.
• Positive Finding: Exquisite, sharp, familiar pain reproduced locally over the radial styloid process at the first dorsal compartment.
• Differential Diagnosis:
  • 1st Carpometacarpal (CMC) Osteoarthritis: Differentiated using the Grind Test (axial compression combined with rotation of the first metacarpal on the trapezium). CMC osteoarthritis reproduces pain at the base of the thumb without tenderness over the proximal radial styloid.
  • Intersection Syndrome: Produces pain and crepitus approximately 4 to 6 cm proximal to the wrist joint where the first compartment tendons cross over the second compartment tendons (ECRL and ECRB).

---

3. Motor Nerve Function & Vascular Supply

Froment's Sign (Paper Grip Test) — Ulnar Nerve Neuropathy

• Objective: Assess the motor function of the Adductor Pollicis muscle, innervated by the deep terminal motor branch of the ulnar nerve (C8–T1).
• Patient Position & Execution: The patient is instructed to grasp a flat, firm sheet of paper (or cardboard card) between the palmar pad of the thumb and the radial lateral border of the index finger (the "key pinch" position). The therapist then attempts to pull the paper firmly out of the patient's grasp while instructing the patient: "Don't let me pull the paper away; hold it as tightly as you can."
• Positive Finding: If the adductor pollicis is weak or paralyzed due to an ulnar nerve lesion (e.g., at the cubital tunnel or Guyon's canal), the patient cannot maintain the pinch using thumb adduction. To compensate and maintain grip on the paper, the patient involuntarily hyperflexes the interphalangeal (IP) joint of the thumb.
• Pathophysiological Mechanism: The patient recruits the Flexor Pollicis Longus (FPL) muscle. The FPL is innervated by the anterior interosseous nerve (a branch of the median nerve), which remains fully functional during isolated ulnar nerve palsy. The observable flexion of the distal thumb phalanx confirms Froment's sign.

Allen's Test (Palmar Arterial Patency)

• Objective: Objectively assess the patency of the radial and ulnar arteries and determine the integrity of the collateral circulation through the superficial and deep palmar arterial arches.
• Patient Position: Seated with forearm supinated and resting on a supportive surface.
• Therapist Execution:
  1. The patient is instructed to clench their hand into a tight fist 3 to 4 times consecutively to force blood out of the palmar capillary bed, and then hold the fist tightly clenched.
  2. The therapist uses both thumbs to apply firm digital pressure over both the radial artery (lateral volar wrist) and the ulnar artery (medial volar wrist) simultaneously, completely occluding arterial inflow.
  3. While maintaining continuous bilateral arterial compression, the therapist instructs the patient to open the hand into a relaxed, unclenched position. The palm and fingers will appear distinctly blanched and pale.
  4. The therapist releases digital pressure from ONE artery (typically the ulnar artery first) while maintaining firm, uninterrupted compression on the other artery.
  5. The therapist observes the time required for normal capillary refill and a warm erythema flush to return across the entire palm and fingertips.
  6. The test is repeated, releasing the opposite artery (radial artery) to evaluate its individual patency.
• Normal vs. Abnormal Thresholds:
  • Normal Finding: The palm and digits flush completely with red/pink erythema within 3 to 5 seconds, demonstrating excellent collateral arterial perfusion.
  • Abnormal (Positive) Finding: Delayed capillary refill persisting beyond 5 to 7 seconds, or patchy, incomplete flushing where digits remain pale. Indicates arterial occlusion, severe stenosis, or an incomplete palmar arch.

---

4. Hand, Carpal & Compression Test Matrix

---

5. Clinical Reasoning Vignette: Differential Diagnosis of First Ray Pain

Clinical Case Scenario

Patient Profile: A 31-year-old mother of a 4-month-old infant presents with severe, sharp pain localized to the radial aspect of her right dominant wrist and thumb. The pain is particularly acute whenever she scoops her baby up from the crib or turns a door handle. She reports no history of acute trauma.

Physical Assessment Findings:

• Observation: Mild localized swelling visible over the right radial styloid process. No thenar muscle atrophy is observed.
• AROM & PROM: Active thumb extension and abduction are painful; passive thumb adduction and wrist ulnar deviation elicit sharp pain.
• Finkelstein's Test: Strongly positive, eliciting severe, familiar pain precisely over the radial styloid at the first dorsal compartment.
• 1st CMC Grind Test: Negative; axial loading and circumduction of the first metacarpal on the trapezium produces no crepitus or deep joint pain, making basal thumb osteoarthritis less likely.
• Durkan's Carpal Compression Test: Negative after 30 seconds of sustained pressure; no tingling or numbness provoked in digits 1 to 4.
• Phalen's Test: Negative after 60 seconds; no neurological symptoms.
• Cervical Screen: Cervical spine movements are full and pain-free; Spurling's test is negative, making C6 radiculopathy less likely.

Clinical Decision-Making

1. Diagnostic Synthesis: The classic mechanical presentation (repetitive lifting with thumbs abducted and wrists ulnar-deviated), exquisite focal tenderness over the radial styloid, strongly positive Finkelstein's test, and negative carpal tunnel and CMC grind tests are strongly consistent with De Quervain's tenosynovitis.
2. Manual Therapy Treatment Plan: Deep, aggressive cross-fiber friction directly over the acute, inflamed radial styloid is avoided during early treatment. Instead, the therapist applies soothing lymphatic drainage, gentle myofascial release to the hypertonic bellies of the APL and EPB in the mid-forearm, and mobilizes the radiocarpal joint. Patient education focuses on lifting mechanics (scooping the infant with forearms in supination rather than grasping beneath the axillae with widely abducted thumbs).