Mateusz Gładysz FESSH prep

FESSH prep Anatomy Third compartment and Lister's tubercle, extensor indicis position, juncturae tendinum types, the first compartment septum, proximal intersection syndrome

The dorsal extensor compartments and intersection syndromes

Last reviewed v1.0

FESSH-050Anatomy●○○ basic

Regarding the extensor compartments of the wrist:

  1. 1.The extensor pollicis longus is the only tendon of the third compartment; it passes on the ulnar side of Lister's tubercle, which acts as a pulley redirecting it radially across the extensor carpi radialis tendons.

  2. 2.The extensor indicis proprius tendon normally lies on the radial side of the extensor digitorum communis tendon to the index finger at the metacarpophalangeal level.

  3. 3.In the von Schroeder–Botte classification, juncturae tendinum become thicker from radial to ulnar: filamentous type 1 predominates in the second intermetacarpal space, tendon-slip type 3 in the fourth (about 80 %), and the extensor indicis proprius receives no junctura.

  4. 4.A septum dividing the first extensor compartment into separate abductor pollicis longus and extensor pollicis brevis tunnels is a rare variant found in fewer than 10 % of cadaver wrists.

  5. 5.Proximal intersection syndrome is a stenosing tenosynovitis of the second extensor compartment where the muscle bellies of abductor pollicis longus and extensor pollicis brevis cross the radial wrist extensors, about 4 cm proximal to Lister's tubercle.

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Question ID
FESSH-050
First published
Last reviewed
Version
v1.0
Answer key and explanations — open after answering

  1. 1. The extensor pollicis longus is the only tendon of the third compartment; it passes on the ulnar side of Lister's tubercle, which acts as a pulley redirecting it radially across the extensor carpi radialis tendons.

    True

    The third compartment contains only extensor pollicis longus, which turns around the ulnar side of Lister's tubercle before crossing the second-compartment tendons; Parellada attributes distal intersection tenosynovitis to this pulley effect at the crossover, with MRI showing tenosynovitis of both the second and third compartments. An MRI classification of 360 wrists found a radial peak larger than the ulnar peak in 69 % (the classical configuration, type 1A, in 41 %) and rare variants (9.5 %) in which the tendon courses along the radial aspect of the tubercle.

    • Parellada AJ, Gopez AG, Morrison WB, Sweet S, Leinberry CF, Reiter SB, et al.. Distal intersection tenosynovitis of the wrist: a lesser-known extensor tendinopathy with characteristic MR imaging features. Skeletal Radiol. 2006;36(3):203-8. PMID 17177022
    • Chan WY, Chong LR. Anatomical Variants of Lister's Tubercle: A New Morphological Classification Based on Magnetic Resonance Imaging. Korean J Radiol. 2017;18(6):957-963. PMID 29089828

  2. 2. The extensor indicis proprius tendon normally lies on the radial side of the extensor digitorum communis tendon to the index finger at the metacarpophalangeal level.

    False

    In Yammine's meta-analysis of 29 cadaver studies (3,858 hands) a single-slip extensor indicis was inserted on the ulnar side of the communis tendon to the index finger in 98.3 %; von Schroeder and Botte's 43-hand dissection likewise gives a single extensor indicis inserting ulnar to the communis as the commonest pattern. A radial position is a variant (17 % of double-slip tendons lie on the radial side), and the ulnar position is what the surgeon uses to identify the tendon for transfer.

    • Yammine K. The prevalence of the extensor indicis tendon and its variants: a systematic review and meta-analysis. Surg Radiol Anat. 2014;37(3):247-54. PMID 25096501
    • von Schroeder HP, Botte MJ. Anatomy of the extensor tendons of the fingers: variations and multiplicity. J Hand Surg Am. 1995;20(1):27-34. PMID 7722260

  3. 3. In the von Schroeder–Botte classification, juncturae tendinum become thicker from radial to ulnar: filamentous type 1 predominates in the second intermetacarpal space, tendon-slip type 3 in the fourth (about 80 %), and the extensor indicis proprius receives no junctura.

    True

    In 40 cadaver hands von Schroeder, Botte and Gellman found type 1 juncturae (filamentous regions within the intertendinous fascia) in 88 % of second and 28 % of third intermetacarpal spaces, type 2 (thicker connecting bands) in 40 % of third and 23 % of fourth spaces, and type 3 (tendon slips, 'y' or 'r' shaped) in 33 % of third and 80 % of fourth spaces; juncturae were absent from all first spaces and from 12 % of second spaces, the extensor indicis proprius received none and the extensor digiti quinti did. This is why an isolated communis laceration proximal to a junctura may still extend the finger.

    • von Schroeder HP, Botte MJ, Gellman H. Anatomy of the juncturae tendinum of the hand. J Hand Surg Am. 1990;15(4):595-602. PMID 2380523
    • von Schroeder HP, Botte MJ. Anatomy of the extensor tendons of the fingers: variations and multiplicity. J Hand Surg Am. 1995;20(1):27-34. PMID 7722260

  4. 4. A septum dividing the first extensor compartment into separate abductor pollicis longus and extensor pollicis brevis tunnels is a rare variant found in fewer than 10 % of cadaver wrists.

    False

    Lee's systematic review (1,901 cadaver wrists and 470 operated De Quervain patients) found a septum in 43.7 % of normal wrists and 62.2 % of De Quervain patients, 58.5 % of them incomplete; Bonczar's meta-analysis of 5,229 wrists confirms that a double abductor pollicis longus and a single extensor pollicis brevis are the commonest pattern and that a septum is much more common in De Quervain disease. The separate extensor pollicis brevis subcompartment explains failed injections and incomplete releases.

    • Lee ZH, Stranix JT, Anzai L, Sharma S. Surgical anatomy of the first extensor compartment: A systematic review and comparison of normal cadavers vs. De Quervain syndrome patients. J Plast Reconstr Aesthet Surg. 2016;70(1):127-131. PMID 27693273
    • Bonczar M, Walocha J, Pasternak A, Depukat P, Dziedzic M, Ostrowski P, et al.. Anatomical variations in the first dorsal compartment of the wrist: meta-analysis. Folia Morphol (Warsz). 2022;82(4):766-776. PMID 36165900

  5. 5. Proximal intersection syndrome is a stenosing tenosynovitis of the second extensor compartment where the muscle bellies of abductor pollicis longus and extensor pollicis brevis cross the radial wrist extensors, about 4 cm proximal to Lister's tubercle.

    True

    Grundberg and Reagan's operative series of 13 patients showed that the basic pathology of intersection syndrome is stenosing tenosynovitis of the sheath of the common radial wrist extensors (extensor carpi radialis longus and brevis) beneath the crossing bellies of the first-compartment muscles. De Lima's MR-anatomic study located the intersection 3.5–4.8 cm (mean 4.2 cm) proximal to Lister's tubercle — outside a standard wrist protocol, so the MRI must be tailored to include the distal forearm. It is distinct from distal intersection syndrome, where extensor pollicis longus crosses the same tendons distal to the tubercle.

    • Grundberg AB, Reagan DS. Pathologic anatomy of the forearm: intersection syndrome. J Hand Surg Am. 1985;10(2):299-302. PMID 3980951
    • de Lima JE, Kim HJ, Albertotti F, Resnick D. Intersection syndrome: MR imaging with anatomic comparison of the distal forearm. Skeletal Radiol. 2004;33(11):627-31. PMID 15365785
    • Parellada AJ, Gopez AG, Morrison WB, Sweet S, Leinberry CF, Reiter SB, et al.. Distal intersection tenosynovitis of the wrist: a lesser-known extensor tendinopathy with characteristic MR imaging features. Skeletal Radiol. 2006;36(3):203-8. PMID 17177022