Femoral anatomy

Femoral canal anatomy

Boundaries

• Proximal opening: Femoral Ring
  • Boundaries of Femoral Ring:
    • Anterior: Medial part of Inguinal Ligament
    • Medial: Crescentic edge of Lacunar Ligament
    • Posterior: Pectineal Ligament
    • Lateral: Femoral Vein

• 25% of pts have an Aberrant Obturator Artery (Corona Mortis) which can cause significant bleeding if the Lacunar Ligament is stretched or divided during femoral hernia repair
  • Aberrant Obturator Artery a branch of the Inferior Epigastric Artery

Contents

• Lymph node (of Cloquet)

  • Female: Drains directly from Clitoris
  • Male: Drains from the Glans

• Lymphatic vessels draining Deep Inguinal Lymph Nodes

• Empty space

• Loose connective tissue

• NB: In Femoral Hernias, the Hernial Sac:

  • Passes behind the Inguinal Ligament
  • Passes medial to the Femoral Vein
  • Passes anterior to the Superior Pubic Ramus
  • Covered by the fascias of the Femoral Septum and Cribriform Fascia
  • Contains a large quantity of fat
  • More common in female than in male patients
  • Less common than inguinal hernias in female patients
  • Not able to be controlled by wearing a hernia truss
  • Classically associated with strangulation bowel obstruction of Richter type
  • Not more prone to recurrence after surgery than inguinal hernias

Femoral triangle

Boundaries

• Lateral: Sartorius (medial border)
• Medial: Adductor Longus (medial border)
• Superior: Inguinal Ligament
• Floor: Iliacus, Psoas, Pectineus and Adductor Longus
• NB: Roof: Fascia Lata of the Thigh

Contents

• Femoral Nerve
• Femoral Artery
• Femoral Vein
• Femoral Canal containing lymph nodes and lymphatics and loose connective tissue

Femoral Sheath

• Funnel shaped prolongation of the extraperitoneal fascia surrounding the femoral vessels
• Passing beneath the inguinal ligament
• Formed by
  • Transversalis Fascia anteriorly
  • Psoas fascia posteriorly
  • Both fuse with adventitia of Femoral Artery and Vein, one inch below inguinal ligament
• Sheath allows freedom of movement of these vessels
• Has three compartments
  • Lateral (Femoral Artery and Femoral branch Genitofemoral Nerve)
  • Intermediate (Femoral Vein)
  • Medial (Femoral Canal)
• NB: Femoral nerve is not within the Femoral Sheath
  • It’s lateral

Femoral Artery

Course

• Enters thigh at point midway between Anterior Superior Iliac Spine (ASIS) and Pubic Symphysis (Mid-Inguinal point)
• Lies on Psoas Major tendon, which separates it from capsule of hip joint
  • This is the point where its pulse can be felt and where arterial catheterization can occur
• Emerges from Femoral Sheath
• Courses downwards and enters Adductor Canal deep to Sartorius

Branches

• Four small branches below Inguinal Ligament
  1. Superficial Circumflex Iliac Artery
  2. Superficial Epigastric Artery
  3. Superficial External Pudendal Artery
  4. Deep External Pudendal Artery
• One large branch just below the termination of the Femoral Sheath
  • Profunda Femoris – chief artery of the thigh

Surface Marking

• With the hip slightly flexed and laterally rotated
• Midpoint between Pubic Symphysis and ASIS along the upper 2/3rd of a line towards the Adductor Tubercle

Surgical Approach

• In the Adductor Canal through an incision on the medial aspect of the lower thigh
  • Sartorius retracted medially and fascial roof of canal divided

Femoral Vein

• Enters lower angle of Femoral Triangle (where it lies posterior to artery)
• Ascends through Femoral triangle
• Comes to lie on medial side of Femoral Artery
• Receives Profunda Femoris vein posteriorly
• Receives Great Saphenous Vein anteriorly just below the Femoral Sheath
• Within the Femoral Sheath, it passes under the Inguinal Ligament
• Runs along the pelvic brim as the External Iliac Vein

Femoral nerve

Popliteal Artery

• Throughout course, it is the deepest neurovascular structure in the Popliteal Fossa
• Extends from Adductor Hiatus in Adductor Magnus (a hand’s breadth above the knee) to the fibrous arch of Soleus (a hand’s breadth below the knee)
• Enters Popliteal Fossa on medial side of Femur
  • Here, it lies deep and medial to Sciatic Nerve and its vertical continuation, the Tibial Nerve
• Convexes laterally as it passes downwards
• Comes to lie lateral to the Tibial Nerve
• Below fibrous arch of Soleus, (as the Posterior Tibial Artery) it returns to the medial side of the Tibial Nerve
• Below fibrous arch of Soleus, it immediately divides into Anterior tibial artery and Posterior tibial artery
• Artery lies successively on popliteal surface of Femur (separated from it by a little fat), on the Oblique Popliteal Ligament and on the fascia of Popliteus
• Palpation: Centre of the popliteal fossa (with the knee slightly flexed to relax the popliteal fascia)

Popliteal Fossa

• Diamond-shaped space behind the knee
• Boundaries:
  • Superior Medial: Semimembranosus, Semitendinosus
  • Superior Lateral: Biceps Femoris
  • Inferior: Heads of Gastrocnemius
  • Roof: Fascia Lata
    • Roof pierced by: Small Saphenous Vein and Posterior Femoral Cutaneous Nerve
• Floor (from above downwards)
  • Femur (popliteal surface)
  • Capsule of Knee Joint
  • Oblique Popliteal Ligament
  • Popliteus
• Small group of Popliteal Lymph Nodes lie alongside the Popliteal Vein

Contents (medial to lateral)

• Popliteal Artery
• Popliteal vein
• Tibial nerve
• Common peroneal nerve

Adductor Canal

• a.k.a. Subsartorial or Hunter’s Canal
• Extending from the apex of the femoral triangle to the Adductor Hiatus of the adductor magnus.
• Groove between Vastus Medialis and front of Adductor muscles below the apex of the Femoral Triangle
• Lateral: Vastus Medialis
• Anteriormedial: Sartorius
• Floor: Adductor Longus (above) and Adductor Magnus (below)
• Contents:
  • Femoral Artery
  • Femoral Vein
  • Saphenous Nerve
  • Nerve to Vastus Medialis