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Femoral Triangle

  • Boundaries
    • Inguinal ligament, medial border of sartorius & adductor longus
    • Contents
      • Femoral nerve & vessels
    • Floor
      • Iliacus, psoas, pectineus, adductor longus
  • Sartorius
      • Longest muscle in the body
    • Origin
      • ASIS & notch below it
      • Crosses thigh obliquely, along medial border of femoral triangle, on fascial roof of adductor canal
    • Insertion
      • Upper part of medial surface of tibia
      • Inserted in front of gracilis & semitendinosus
    • Nerve Supply
      • Branch of anterior division of femoral nerve
    • Action
      • Sitting tailor’s position – thigh flexed, laterally rotated & abducted, knee flexed
  • Iliacus
    • Origin
      • Iliac fossa, entering thigh beneath the lateral part of inguinal ligament
    • Insertion
      • Inserted in front of psoas tendon & small area of femoral shaft, just below the lesser trochanter
    • Nerve Supply
      • Femoral nerve (L2,3) in iliac fossa
    • Action
      • Powerful flexor of hip
  • Psoas major
    • Origin
      • Lumbar spine, passes deep to middle of inguinal ligament
    • Insertion
      • Lesser trochanter
      • Both iliacus & psoas pass across the front of the capsule of the hip joint, with the bursa intervening
      • burse may communicate with the joint thorugh a gap in the capsule that lies between the iliofemoral & pubofemoral ligaments
    • Nerve Supply
      • First 3 lumbar nerves (mainly L2)
    • Action
      • Powerful flexor of hip
  • Pectineus
      • Quadrilateral muscle
      • Covered anteriorly by infolding of fascia lata
      • Femoral vein & canal lie on top of it
      • Adductor brevis & anterior division of obturator nerve lie behind it
    • Origin
      • Pectineal line of pubis & narrow area if bone below
    • Insertion
      • Vertical line below lesser trochanter
    • Nerve Supply
      • Anterior division of femoral nerve (L2,3)
      • Occasionally twig from obturator nerve (L2,3)
    • Action
      • Flexes & adducts thigh
  • Quadriceps femoris
    • Nerve Supply
    • each muscle is supplied by its own branch from the femoral nerve (L3, 4)
    • Action
    • main extensor of knee
    • rectus femoris can assist iliopsoas flex the hip
  • Rectus femoris
    • Origin
      • Arises ilium by 2 heads
      • Reflected head – groove above acetabulum
      • Straight head – upper half of AIIS, above iliofemoral ligament
      • 2 heads unite to form the anterior lamina of quadriceps tendon
  • Vastus Lateralis
    • Origin
      • Extensive linear origin from upper part of intertrochanteric line, greater trochanter, lateral lip of linea aspera of femur, lateral intermuscular septum
      • descending branch of lateral circumflex artery & nerve to vastus lateralis lie between vast lateralis & intermedius
  • Vastus intermedius
    • Origin
      • ant & lateral surfaces of upper 2/3 of shaft of femur
  • Articularis genu
    • Origin
      • ant surface if lower femoral shaft, deep to vastus intermedius
    • Insertion
      • upper convexity of suprapatellar bursa
  • Vastus medialis
    • Origin
      • Lower part of intertrochanteric line, medial lip of linea aspera, tendon of adductor magnus below the hiatus for femoral vessels
    • Action
      • Lowest fibres are indispensable for stability of patella

Stability of the patella

    • sesamoid bone
    • mobile from side to side
    • pull of quadriceps is oblique, tending to draw the patella laterally
    • 3 factors act against this
      • bony – forward prominence of lateral condyle of femur
      • ligamentous – tension of medial patellar retinaculum
      • muscle – lowest fibres of vastus medialis
  • Adductor canal (subsartorial/hunter’s)
    • gutter shaped grove between vastus medialis & front of adductor muscles, below the apex of femoral triangle
    • roof –fascia which contains meshes of subsartorial plexus, sartorius
    • floor - adductor longus above, adductor magnus below
    • contents – femoral artery & vein, saphenous nerve, nerve to vastus medialis (upper part)
  • subsartorial plexus –
    • medial cutaneous nerve to thigh
    • saphenous nerve
    • anterior division of obturator nerve
    • supplies overlying fascia, skin above medial side of knee
  • femoral artery
    • leaves the canal by passing through the hiatus between the hamstring & adductor parts of adductor magnus
    • at all levels the artery lies between the saphenous nerve & femoral vein
  • femoral vein
    • distal part of canal it is posterolateral to artery
  • femoral triangle – medial to artery
  • descending genicular artery
    • arises from femoral artery just above adductor hiatus, divides into
    • superficial saphenous artery that accompanies the saphenous nerve
    • deep muscular branch that enters vastus medialis & joins anastomosis around knee
  • saphenous nerve
    • passes out of canal under sartorius, pierces fascia lata, passes behind great saphenous vein
    • infrapatellar branch - given off just before leaving canal, pierces sartorius, joins patellar plexus & supplies prepatellar skin