title: Anatomy of the Adductor Magnus Origin: Implications for Proximal Hamstring Injuries.
abstract: BACKGROUND
  The adductor magnus (AM) has historically been a potential source of confusion in patients with suspected proximal hamstring avulsion injuries.
  
  
  OBJECTIVE
  To investigate the anatomic characteristics of the AM, including its osseous origin, anatomic dimensions, and relationship to the proximal hamstring tendons.
  
  
  METHODS
  Descriptive laboratory study.
  
  
  METHODS
  Dissection of the AM origin was performed in 11 (8 cadavers) fresh-frozen hip-to-foot cadaveric hemipelvis specimens. The gross anatomy and architecture of the proximal hamstring and AM tendons were studied. After dissecting the hamstring tendons away from their origin, the dimension, shape, and orientation of the tendon footprints on the ischial tuberosity were determined.
  
  
  RESULTS
  The AM was identified in all cadaveric specimens. The mean tendon thickness (anterior to posterior [AP]) was 5.7 ± 2.9 mm. The mean tendon width (medial to lateral [ML]) was 7.1 ± 2.2 mm. The mean tendon length was 13.1 ± 8.7 cm. The mean footprint height (AP dimension) was 12.1 ± 2.9 mm, and mean footprint width (ML dimension) was 17.3 ± 7.1 mm. The mean distance between the AM footprint and the most medial aspect of the conjoint tendon footprint was 8.5 ± 4.2 mm. Tendon measurements demonstrated a considerable degree of both intra- and interspecimen variability.
  
  
  CONCLUSIONS
  The AM tendon is consistently present just medial to the conjoint tendon at the ischial tuberosity, representing the lateral-most portion of the AM muscle. This study found wide variation in the dimensional characteristics of the AM tendon between specimens. Its shape and location can mimic the appearance of an intact hamstring (conjoint or semimembranosus) tendon intraoperatively or on diagnostic imaging, potentially misleading surgeons and radiologists. Therefore, detailed knowledge of the AM tendon anatomy, footprint anatomy, and its relationship to the hamstring muscle complex is paramount when planning surgical approach and technique.
  
  
  CONCLUSIONS
  The reported data may aid surgeons in more accurate recognition, diagnosis, and repair of proximal hamstring avulsion injuries.
authors.affiliation: Mayo School of Graduate Medical Education, Rochester, Minnesota, USA.
authors.forename: Mitchel R
authors.initials: MR
authors.lastname: Obey
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Broski
authors.affiliation: Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Spinner
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Collins
authors.affiliation: Department of Orthopedics, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Krych
keywords: adductor magnus; anatomy; hamstring avulsion; hamstring repair; hamstring tendons; proximal hamstring