Tendon sheath of extensor digiti minimi manus
Vagina tendinis extensoris digiti minimi manus
- Latin synonym: Vagina tendinis musculi extensoris digiti minimi manus
- Synonym: Tendinous sheath of extensor digiti minimi manus muscle
- Related terms: Tendinous sheath of extensor digiti minimi brevis
Definition
The tendon sheath of extensor digiti minimi (EDM) is a synovial sheath that encloses the EDM tendon as it passes through the fifth dorsal compartment of the wrist, lying beneath the extensor retinaculum, in the interval between the radius and the ulna.
The tendon sheath begins slightly proximal to the wrist joint and continues distally to the dorsum of the hand, where the tendon joins the extensor expansion of the little finger. It allows the EDM tendon to glide smoothly within its fibro-osseous tunnel during extension of the little finger.
Please note that the extensor retinaculum sends fibrous septa to the underlying ulna and radius, to divide the dorsal wrist into six fibro-osseous compartments. Each compartment contains specific extensor tendons invested in their own synovial sheaths; the fifth compartment contains only the extensor digiti minimi tendon.
References
Gray, H. (2016) Gray’s Anatomy: The Anatomical Basis of Clinical Practice. 41st edn. Edited by S. Standring. New York: Elsevier. Chapter 50: Wrist and hand, pp. 879.
Drake, R.L., Vogl, A.W. and Mitchell, A.W.M. (2009). ‘Chapter 7: Hand’ in Gray’s anatomy for Students. (2nd ed.) Philadelphia PA 19103-2899: Elsevier, pp. 757; Fig. 7.95.
MickeyMed. (n.d.). Extensor retinaculum of hand. Available at: https://www.mickeymed.com/article/extensorretinaculumofhand (Accessed: 7 January 2026).
