Arch Hand Microsurg.  2024 Jun;29(2):65-74. 10.12790/ahm.24.0007.

Changes in force generation by two-finger striking methods: an experimental study

• Yun SM
• Kim H
• Hwang K
• Jung SG
• Hwang YJ

• KMID: 2556355
• DOI: http://doi.org/10.12790/ahm.24.0007

Abstract

Purpose
Acute sagittal injury in boxer’s knuckle causes extensor tendon subluxation. We analyzed anatomical measurements for posture-related hand parts and measured the force generated when striking the fingers.
Methods
In 120 healthy adults (55 males, 65 females), the palm area, finger length, finger length, finger circumference, and wrist circumference were measured. Using a digital force gauge, the force generated by striking with finger flexion (FFF) performed by the middle finger was measured. The forces generated during extension flicking (FEFs) by the index and ring fingers were also measured. The forces exerted by the hand and fingers was measured using a grip force meter. The relationships of measured values with sex and age were statistically analyzed.
Results
The FFF of the middle finger was 12.9±7.0 N, and the FEFs of the index and ring fingers were 6.8±2.5 N and 5.8±2.3 N, respectively. The grip force was 343.3±134.7 N in the four fingers excluding the thumb, 108.4±41.6 N in the index finger, 110.5±45.4 N in the middle finger, and 83.6±36.5 N in the ring finger. Males had higher FFF for the middle finger (17.9±6.6 N) than females (8.6±3.9 N) (p<0.001), and greater FEFs for the index (8.5±2.0 N) and ring fingers (7.1±2.2 N) compared to females (5.3±1.7 N and 4.7±.8 N, respectively) (p<0.001). Cross-analysis results showed differences by sex and age. The circumference of the index finger exceeded that of the ring finger.
Conclusion
The study findings shed light on the relationship between the forces generated in the process of finger flicking.

Keyword

Finger injuries; Joint dislocations; Tendons

Figure

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  Fig. 1. Measuring the force generated by flexion flicking of a middle finger (A) and the force generated during extension flicking of an index finger (B).

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  Fig. 2. Measuring the maximal force of exertion on grasping for the index, middle, ring, and little fingers.

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  Fig. 3. Forces generated during finger striking. , flexion angle of the metacarpophalangeal joint; Fe, the tensile force (blue arrow) exerted on the extensor tendon; Fsb, the force applied to the sagittal band when it slips to the radial or ulnar side.

Reference

References

1. Lopez-Ben R, Lee DH, Nicolodi DJ. Boxer knuckle (injury of the extensor hood with extensor tendon subluxation): diagnosis with dynamic US: report of three cases. Radiology. 2003; 228:642–6.

2. Elson RA. Dislocation of the extensor tendons of the hand: report of a case. J Bone Joint Surg Br. 1967; 49:324–6.

3. Catalano LW 3rd, Gupta S, Ragland R 3rd, Glickel SZ, Johnson C, Barron OA. Closed treatment of nonrheumatoid extensor tendon dislocations at the metacarpophalangeal joint. J Hand Surg Am. 2006; 31:242–5.

4. Ishizuki M. Traumatic and spontaneous dislocation of extensor tendon of the long finger. J Hand Surg Am. 1990; 15:967–72.

5. Hong IT, Oh CH, Sim YS, Han SH. Direct repair of the sagittal band for extensor tendon subluxation caused by finger flicking. Orthopade. 2017; 46:755–60.

6. Hwang K, Ma SH. A nasal bone fracture caused by a dog bite in an adult. J Craniofac Surg. 2021; 32:e630–2.

7. Langer D, Maeir A, Michailevich M, Luria S. Evaluating hand function in clients with trigger finger. Occup Ther Int. 2017; 2017:9539206.

8. Ramakrishnan B, Bronkema LA, Hallbeck MS. Effects of grip span, wrist position, hand and gender on grip strength. Proc Hum Factors Ergon Soc Annu Meet. 1994; 38:554–8.

9. Balogun JA, Akomolafe CT, Amusa LO. Grip strength: effects of testing posture and elbow position. Arch Phys Med Rehabil. 1991; 72:280–3.

10. Fransson C, Winkel J. Grip strength and leg design of power grip hand tools. J Biomech. 1989; 22:1012.

11. Kim YJ, Lee DH, Park H, Park JH, Bae JH, Baeg MH. Wrist and grasping forces estimation using electromyography for robotic prosthesis. J Korea Robot Soc. 2017; 12:206–16.

12. Chauhan A, Jacobs B, Andoga A, Baratz ME. Extensor tendon injuries in athletes. Sports Med Arthrosc Rev. 2014; 22:45–55.

13. ElMaraghy AW, Pennings A. Metacarpophalangeal joint extensor tendon subluxation: a reconstructive stabilization technique. J Hand Surg Am. 2013; 38:578–82.

14. Beck JD, Riehl JT, Klena JC. Anomalous tendon to the middle finger for sagittal band reconstruction: report of 2 cases. J Hand Surg Am. 2012; 37:1646–9.

15. Young CM, Rayan GM. The sagittal band: anatomic and biomechanical study. J Hand Surg Am. 2000; 25:1107–13.

16. Rayan GM, Murray D. Classification and treatment of closed sagittal band injuries. J Hand Surg Am. 1994; 19:590–4.

17. Peelman J, Markiewitz A, Kiefhaber T, Stern P. Splintage in the treatment of sagittal band incompetence and extensor tendon subluxation. J Hand Surg Eur Vol. 2015; 40:287–90.

18. Kang HJ, Yong SW, Shim DJ, Hahn SB, Kang ES. Dislocation of the extensor tendons at the level of the metacarpophalangeal joint. Arch Hand Microsurg. 2003; 8:148–52.