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The end of the hip and thigh
lectures
Femoral triangle
The piriformis muscle and the
sciatic nerve
Femoral Triangle
• Located on anterior medial superior thigh
• Can be more easily seen when the hip is
flexed
– Contains important muscular, vascular, and
neural structures
Boundaries of Femoral Triangle
• Superior
– Inguinal ligament
• Medial
– Medial border of adductor longus
• Lateral
– Medial border of sartorius
Floor of femoral triangle
• Concave anteriorly (gutter shaped)
• Muscles in floor medial to lateral
– Adductor longus muscle
– Pectineus muscle
– Iliopsoas muscle
Contents of Femoral Triangle
• Lateral to medial
– Femoral nerve
– Femoral artery
– Femoral vein
Relationship of the sciatic nerve to
the piriformis muscle
• The sciatic nerve is the largest nerve in
the body
– 2 cm wide where it leaves the pelvis through
the inferior part of the greater sciatic foramen
• Anterior rami of L4, L5, S1, S2, S3
• The sciatic nerve consists of the tibial and
the common fibular (peroneal) divisions
– The divisions usually separate about ½ way
down the thigh
Divisions of the Sciatic Nerve
• The divisions usually separate about ½
way down the thigh
• Tibial division
– Semitendinosus muscle, semimembranosus
muscle, and long head of the biceps femoris
muscle
• Common fibular division
– Short head of the biceps femoris muscle
• Both divisions continue down into the leg
The most common relationship
between the piriformis muscle and
the nerve
• The whole sciatic nerve passes inferior to
the piriformis muscle as it enters the
gluteal region
• The sciatic nerve is the most lateral
structure emerging inferior to the muscle
Structures medial to the sciatic
nerve
• Inferior gluteal nerve (L5-S2) to gluteus
maximus muscle
• Pudendal nerve to perineal muscles
• Various vessels
• Inferior gluteal vessels
• Pudendal vessels
In 12% of cases
• The sciatic nerve splits into its two
divisions before entering the gluteal region
– The tibial division
• Below piriformis muscle
– The common peroneal division
• Through the piriformis muscle
• What muscle does this nerve supply?
0.5% of cases
• The sciatic nerve splits into its two
divisions before entering the gluteal region
– The tibial division
• Below piriformis muscle
– The common peroneal division
• Superior to the piriformis muscle
• Nerve is more susceptible to injury during an im
injection