Lower Extremity O/I/Inn/BS/A

• piriformis origin

  sacrum
• piriformis insertion

  greater trochanter of femur
• piriformis innervates

  branches of S1 and S2
• piriformis blood supply

  superior and inferior gluteal arteries, internal pudendal artery
• piriformis actions

  external rotation of hip
• superior and inferior gemellus origin

  Ischial spine (superior) and ischial tuberosity (inferior)
• Superior and inferior gemellus insertion

  Greater trochanter of femur
• Superior and inferior gemellus innervates

  Nerve to obturator internus (superior) and nerve to quadratus femoris (inferior)
• Superior and inferior gemellus blood supply

  Inferior gluteal and internal pudendal arteries (superior) and medial femoral circumflex artery (inferior)
• superior and inferior gemellus actions

  External rotation of hip and extension of hip  
• adductor brevis origin 


  inferior pubic ramus
• adductor brevis innervates

  obturator nerve
• adductor brevis insertion


  linea aspera of femur
• adductor brevis blood supply


  deep femoral, medial femoral circumflex and obturator arteries
• adductor brevis actions


  hip adduction
• rectus femoris origin


  anterior inferior iliac spine
• rectus femoris insertion


  tibial tuberosity via patella ligament
• rectus femoris innervates


  femoral nerve
• rectus femoris blood supply


  deep femoral artery and lateral femoral circumflex artery
• rectus femoris actions


  knee extension and hip flexion
• sartorius origin


  anterior superior iliac spine
• sartorius insertion


  medial proximal tibia
• sartorius innervates


  femoral nerve
• sartorius blood supply


  deep femoral artery and lateral femoral circumflex artery
• sartorius actions


  hip flexion, abduction and external rotation; knee flexion and internal rotation
• ilicus origin


  iliac fossa
• iliacus insertion


  lesser trochanter of the femur
• iliacus innervates


  femoral nerve
• iliacus blood supply


  iliolumbar artery
• iliacus actions


  hip flexion and external rotation
• psoas major origin


  lateral surface of vertebrae T12-L4 and costal facets of vertebrae L1-L5
• psoas major insertion


  lesser trochanter of the femur
• psoas major innervates


  direct branches of lumbar plexus (L1-L3)
• psoas major blood supply

  iliolumbar artery
• psoas major actions


  hip flexion and external rotation
• semimembranosus


  Origin: ischial tuberosity, Insertion: medial condyle of tibia and oblique popliteal ligament, Innervation: tibial nerve, Blood Supply: perforating branches of the deep femoral artery, Actions: hip extension, knee flexion and internal rotation
• semitendinosus


  Origin: ischial tuberosity, Insertion: medial proximal tibia, Innervation: tibial nerve, Blood Supply: perforating branches of the deep femoral artery, Actions: hip extension and knee flexion and internal rotation
• biceps femoris


  Origin: ischial tuberosity (long) and lateral lip of linea aspera (short), Insertion: head of the fibula, Innervation: tibial nerve, common fibular nerve, Blood Supply: perforating branches of deep femoral artery, Actions: hip extension, knee flexion and external rotation
• popliteus


  Origin: lateral condyle of femur and lateral meniscus, Insertion: posterior tibia, Innervation: tibial nerve, blood supply: popliteal artery, action: lateral rotation on the fixed tibia, "unlocks" extended knee
• Gluteus Maximus


  origin: sacrum, ilium, thoracolumbar fascia, sacrotuberous ligament; insertion: iliotibial tract and gluteal tuberosity; innervation: inferior gluteal nerve; blood supply: superior and inferior gluteal arteries; actions: hip extension and external rotation