Background: Avulsion of the proximal origin of the hamstrings has
become a more frequently recognized athletic injury. Most orthopaedic surgeons
rarely operate in this anatomic area. The purpose of the present study was to
define the anatomy of the proximal origin of the hamstrings and its
relationship to neurovascular and muscular structures encountered during a
repair of a complete avulsion.
Methods: Fourteen fresh-frozen hip-to-foot human cadaveric specimens
were dissected in the prone position. The proximal origin of the hamstrings
and its relationship to the surrounding neurologic and muscular structures
were documented and measured with use of digital calipers.
Results: Six of the fourteen specimens were from female donors. The
average age of the donors at the time of death was 68 ± 13 years. The
average height of the donors was 66 ± 3.5 in (167 ± 8.9 cm), and
the average weight was 142 ± 39 lb (64 ± 17.7 kg). The
semitendinosus and biceps femoris have a common tendinous site of origin on
the ischium. A number of measurements were obtained. The musculotendinous
junctions of the semitendinosus and biceps femoris separated at an average of
9.9 ± 1.5 cm from the most proximal origin site on the ischium. The
average distance from the proximal border of the semitendinosus/biceps femoris
origin to the inferior border of the gluteus maximus was 6.3 ± 1.3 cm.
At the lateral border of the ischium, the average distance from the inferior
gluteal nerve and artery to the inferior border of the gluteus maximus was 5.0
± 0.8 cm. The sciatic nerve was an average of 1.2 ± 0.2 cm from
the most lateral aspect of the ischial tuberosity. The site of origin of the
semitendinosus/biceps femoris was oval, with average measurements of 2.7
± 0.5 cm from proximal to distal and of 1.8 ± 0.2 cm from medial
to lateral. The site of origin of the semimembranosus was crescent-shaped,
with average measurements of 3.1 ± 0.3 cm from proximal to distal and
of 1.1 ± 0.5 cm from medial to lateral.
Conclusions: The semitendinosus and biceps femoris have a common
tendon of origin on the ischium, and the semimembranosus originates just
laterally. The proximal origin of the hamstrings has intimate relationships
with the inferior gluteal nerve and artery and the sciatic nerve, which may be
at risk during surgical dissection and retraction.