- See:
extenal rotators:
- Discussion:
- divide trochanteric bursa & bluntly sweep it posteriorly to expose
short external rotators & posterior edge of medius;
-
anatomy:
- from superior to inferior external rotators include:
-
piriformis,
gemellus superior, obturator internus, gemellus inferior,
and
quadratus femoris;
- note posterior border of medius is almost in line w/ femoral shaft and
anterior border fans anteriorly;
-
positioning:
- flex knee & internally rotate hip to place short external rotators under tension;
- this also pulls the operative field farther from the
sciatic nerve;
- place a blunt homan retractor underneath the medius (and over the anterior
acetabular labrum) and retract the medius anteriorly;
- this will help expose the superior capsule;
- palpate
sciatic nerve as it passes superficial to
obturator internus
and the gemelli;
-
sciatic nerve emerges below piriformis & passes downwards superficial to
obturator internus & gemelli &
quadratus femoris;
- palpate tendinous insertions of
piriformis and
obturator internus and
place tagging suture in the tendon for identification at closure;
- tag piriformis tendon along w/ conjoined external rotators;
-
piriformis tendon,
obturator internus tendon (conjoint w/ gemelli
tendons) & tendon of obturator externus are identified & freed
w/ electrocautery from their insertions at greater trochanter;
- detach muscles close to femoral insertion & reflect backward
laying them over
sciatic nerve to protect it during the case;
- divide
external rotators, including at least proximal half of quadratus
femoris, at their insertion on femur;
- branches of
MFCA emerge above & below quadratus femoris;
- keep a retractor on cut edge of
external rotators for protection;
- keep folded posteriorly to protect the
sciatic nerve;
- develop plane between these muscles & underlying capsule;
- branches of
MFCA emerge above & below
quadratus femoris to
anastomose w/ inferior gluteal vessels & ascending branches from
profunda femoris (
cruciate anastomosis) and can be
ligated as required;
-
quadratus femoris is incised close to quadrate tubercle exposing terminal
branch of
medial femoral circumflex artery, which lies deep to proximal
third of quadratus femoris, accompanying inferior border of the
obturator externus;
- reflect short external rotators posteriorly protecting
sciatic nerve;
- turning medial cut ends of muscles backwards over nerve helps to protect it;
