Anatomic Description of the Origin of the Proximal Hamstring.

Purpose: To define the topographic anatomy of the footprint of the hamstrings origin on the ischium.

Methods: Dissection of the hamstrings origin in 6 cadaveric pelvises was performed. The hamstrings origin was isolated with sharp dissection, and it was noted whether the semimembranosus had a separate attachment or whether there was one confluent tendon attached at the footprint. The common hamstrings tendon was then sharply dissected from the ischium, and the footprint was outlined with surgical marker followed by radiopaque paint. Paint was prepared by mixing 0.25 g Daler-Rowney acrylic artists ink scarlet no. 567 (Daler-Rowney, Bracknell, England) per gram of EZ-HD 98% v/w barium sulfate (E-Z-EM Inc, Lake Success, NY). The paint was then applied to the area of the footprint, and the specimen underwent a 0.5-mm-slice computed tomographic (CT) scan of the pelvis with 3-dimensional (3D) reconstructions. Vitrea (Vital Images, Minnetonka, MN) software was used to determine the surface area of the ligament footprint as well as the distance from the ischial tuberosity to the center of the footprint. The thickness of the bone underlying the footprint was measured. Data are presented as means ± standard error.

Results: Five of 6 specimens had a common hamstrings tendon, whereas one had a separate attachment for the semimembranosus. The semimembranosus joined the common hamstrings tendon 2.33 ± 0.61 cm distal to the footprint. The average surface area of the hamstrings footprint measured 10.19 ± 0.75 cm(2). The distance from the tip of the ischial tuberosity to the center of the hamstrings footprint measured 3.73 ± 0.22 cm. The average thickness of the bone deep to the footprint was 3.77 ± 0.9 cm.

Conclusions: This study provides a topographic description of the origin of the hamstrings footprint and may assist surgeons in performing anatomic reattachment of this tendon.

Clinical Relevance: Our data will assist surgeons in performing anatomic repair of proximal hamstrings avulsions.