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Bunnell Tightness Test (Intrinsic Tightness Test)

Exams and Signs

Historical Overview

  • The Bunnell tightness test is named after Sterling Bunnell, who is considered the “founding father” of American hand surgery. Bunnell’s Surgery of the Hand, first published in 1944, is still referenced by orthopedic practitioners.4

Description

  • Intrinsic tightness is caused by intrinsic muscle dysfunction. The Bunnell tightness test differentiates between intrinsic and extrinsic tightness of the muscles in the hand.

Pathophysiology

  • Intrinsic tightness may arise from an effect of rheumatoid arthritis (RA).

Instructions

  1. Passively flex the patient’s proximal interphalangeal (PIP) joint while holding the metacarpal (MP) joint in either full extension or full flexion.2
  2. Observe whether the patient demonstrates restricted flexion at the PIP joint.
  3. Compare these results with the results of the patient’s other hand.2

Variations

  • Flex the patient’s distal interphalangeal (DIP) joint by using a passive hook grip.

Related Signs and Tests

  • Dorsal tenosynovitis
  • Flexor tendon exam
  • Landsmeer test

Diagnostic Performance Characteristics

  • Because there is no conclusive evidence regarding the reliability of the Bunnell intrinsic tightness test, it is often used in conjunction with other physical tests in an examination of the hand.
Presentation Photos and Related Diagrams
  • Intrinsic Tightness (Bunnell Intrinsic Tightness Test); Extension intact.
    Intrinsic Tightness (Bunnell Intrinsic Tightness Test); Extension intact.
  • Intrinsic Tightness (Bunnell Intrinsic Tightness Test); Limited Flexion
    Intrinsic Tightness (Bunnell Intrinsic Tightness Test); Limited Flexion
  • Intrinsic Tightness (Bunnell Intrinsic Tightness Test); Marked limited PIP flexion with MP extended.
    Intrinsic Tightness (Bunnell Intrinsic Tightness Test); Marked limited PIP flexion with MP extended.
  • Intrinsic Tightness (Bunnell Intrinsic Tightness Test); With MP flexion PIP flexion improves.
    Intrinsic Tightness (Bunnell Intrinsic Tightness Test); With MP flexion PIP flexion improves.
Definition of Positive Result
  • A positive result occurs when the MP joint is hyperextended passively, and this restricts passive flexion at the PIP joint.3
Definition of Negative Result
  • A negative result occurs when the MP joint is hyperextended passively, and this does not restrict passive flexion at the PIP joint. 
Comments and Pearls
  • Intrinsic tightness in RA may not be due to disuse atrophy, but rather to direct muscular involvement in RA.1
  • It is improbable that intrinsic muscle dysfunction on its own is enough to produce ulnar drift.1
Diagnoses Associated with Exams and Signs
References
  1. Akhavani MA, Paleolog EM, Kang N. Muscle Hypoxia in Rheumatoid Hands: Does it Play a Role in Ulnar Drift? J Hand Surg Am 2011;36(4):677-85. PMID: 21463729
  2. Culp R, Jacoby S.  Musculoskeletal Examination of the Elbow, Wrist and Hand: Making the Complex Simple. New Jersey: SLACK Incorporated, 2012.
  3. Kenney RJ, Hammert WC. Physical Examination of the Hand. J Hand Surg Am 2014;39(11):2324-34. PMID: 25442747
  4. Newmeyer WL. Sterling Bunnell, MD: the founding father. J Hand Surg Am 2003;28(1):161-4. PMID: 12563656
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