Median Nerve: Anterior Interosseous Nerve Syndrome

  • John Lubahn
  • Nicolai Baecher


Anterior interosseous nerve syndrome is a rare form of median nerve compression. Along with pronator syndrome, it comprises a small percentage of compression neuropathies in the upper extremity. Symptomatically, these disorders can encompass a range of symptoms from disruptions of normal sensation through profound weakness of the forearm musculature innervated by the anterior interosseous nerve. Initial treatment is nonsurgical with good results from activity modification and muscle stretching. When nonoperative treatment fails, both open and endoscopic surgery may be considered. In general, an endoscopic approach offers decreased morbidity and quicker return to sport. The endoscopic approach is technically demanding, and surgeons should be comfortable with soft tissue endoscopy techniques before approaching release of the AIN in this manner. Good results can be expected from either approach with proper selection of surgical candidates. Patients can be anticipated to make a full return to sports.


AIN Pronator syndrome Median nerve Compression Lacertus fibrosus 



Conflicts of Interest: John Lubahn has no conflicts of interest to disclose; Nicolai Baecher has no conflicts of interest to disclose.

Supplementary material

Video 103.1

Preoperative exam demonstrating weakness of the FPL and FDP to the index, as well as weakness to the FCR (MP4 69120 kb)

Video 103.2

Demonstration of a completed open AIN release with concomitant release of the lacertus fibrosus (MP4 36530 kb)

Video 103.3

Endoscopic release of the pronator teres (WMV 17042 kb)

Video 103.4

Endoscopic release of the fibrous FDS arch. Part 1 (WMV 13159 kb)

Video 103.5

Endoscopic release of the fibrous FDS arch. Part 2 (WMV 21206 kb)

Video 103.6

Postoperative demonstration of FDS and FPL strength after open AIN release compared to symptomatic contralateral side (MP4 8103 kb)


  1. 1.
    Roy J, Henry BM, Pękala PA, Vikse J, Ramakrishnan PK, Walocha JA, Tomaszewski KA. The prevalence and anatomical characteristics of the accessory head of the flexor pollicis longus muscle: a meta-analysis. PeerJ. 2015;3:e1255. Scholar
  2. 2.
    Guo B, Wang A. Median nerve compression at the fibrous arch of the flexor digitorum superficialis: an anatomic study of the pronator syndrome. Hand (N Y). 2014 Dec;9(4):466–70. Scholar
  3. 3.
    Mackinnon SE, Novak CB. Compression neuropathies. In: Wolfe CS, Hotckiss R, Pederson WC, Kozin SH, editors. Green’s operative hand surgery. 6th ed. Philadelphia: Elsevier; 2011. p. 977–1014.CrossRefGoogle Scholar
  4. 4.
    Rodner CM, Tinsley BA, O'Malley MP. Pronator syndrome and anterior interosseous nerve syndrome. J Am Acad Orthop Surg. 2013;21(5):268–75. ReviewCrossRefPubMedGoogle Scholar
  5. 5.
    Damert HG, Hoffmann R, Kraus A, Stowell RL, Lubahn J. Minimally invasive endoscopic decompression for anterior interosseous nerve syndrome: technical notes. J Hand Surg Am. 2013;38(10):2016–24. Scholar

Copyright information

© ISAKOS 2020

Authors and Affiliations

  • John Lubahn
    • 1
    • 2
  • Nicolai Baecher
    • 3
  1. 1.University of Pittsburgh Medical Center HamotErieUSA
  2. 2.Hand, Microsurgery, and Reconstructive OrthopaedicsErieUSA
  3. 3.Sports Medicine and Orthopaedic CenterSuffolkUSA

Personalised recommendations