Anat Cell Biol.  2018 Jun;51(2):71-78. 10.5115/acb.2018.51.2.71.

Morphometric study of pulleys of the thumb

• Gnanasekaran D
• Veeramani
• Karuppusamy A

• KMID: 2421169
• DOI: http://doi.org/10.5115/acb.2018.51.2.71

Abstract

Pulleys are thickened regions in flexor tendons sheaths of the digits. They are essential and act as fulcrum for the flexion and extension of the digits. The arrangement and number of pulley system differs greatly between the thumb and other digits. There is paucity of literature regarding the pulley system of thumb. We aimed to study the morphometry of the pulley system of the thumb in Indian cadavers. Dissection was carried out in 55 adult human cadaveric thumbs. The most common morphologic pattern of pulley observed in the thumb is type III (30 thumbs). The least observed is type I (4 thumbs). The mean width and standard deviation of A1, Av, oblique, and A2 pulleys are 5.06±0.87, 5.38±1.22, 4.68±1.13, and 6.04±1.41 mm, respectively. The gap distances between the pulleys were also measured. The results obtained from the present study may be helpful in surgical treatment of trigger thumb with less complication and also in reconstruction of the closed rupture of the pulley of the thumb.

Keyword

Pulleys; Thumb; Trigger thumb; Trigger finger; Flexor pollicis longus

MeSH Terms

Adult
Cadaver
Humans
Rupture
Tendons
Thumb*
Trigger Finger Disorder

Figure

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  Fig. 1 Measurements of width and gap distances of pulley of the thumb.

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  Fig. 2 Type I pulley.

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  Fig. 3 Type II pulley.

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  Fig. 4 Type III pulley.

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  Fig. 5 Type IV pulley.

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  Fig. 6 (A–D) Dot distribution graph of width of the pulleys.

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  Fig. 7 (A–D) Linear relationship of width of the pulleys with length of the thumb.

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  Fig. 8 (A–F) Linear relationship of gap distances of pulleys with length of the thumb.

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