1. POPLITEAL FOSSA AND CONTENTS

Popliteal Fossa — Concise Notes

Definition & Significance

• Diamond-shaped space posterior to knee joint
• Major transition zone between thigh & leg
• Key conduit for neurovascular structures

Boundaries

Superomedial

• Distal semitendinosus
• Distal semimembranosus

Superolateral

• Distal biceps femoris

Inferomedial

• Medial head of gastrocnemius

Inferolateral

• Lateral head of gastrocnemius
• Plantaris

Floor

• Knee joint capsule
• Popliteal surfaces of femur & tibia
• Popliteus muscle (inferior part)

Roof

• Deep fascia
• Continuous with:
  • Fascia lata (superiorly)
  • Deep fascia of leg (inferiorly)

Functional Importance

• Protects & transmits popliteal vessels and nerves
• Common site for vascular and nerve assessments (clinical relevance).

Popliteal Fossa — Contents (Concise Notes)

Major Structures

• Popliteal artery (deepest)
• Popliteal vein
• Tibial nerve
• Common fibular (peroneal) nerve

Tibial & Common Fibular Nerves

• Terminal branches of sciatic nerve
• Most superficial neurovascular structures

Tibial nerve

• Descends vertically
• Exits deep to plantaris
• Enters posterior compartment of leg

Common fibular nerve

• Follows biceps femoris tendon
• Passes along lower lateral margin
• Winds around neck of fibula
• Enters lateral compartment of leg

Popliteal Artery

• Continuation of femoral artery
• Begins at adductor hiatus (adductor magnus)

Course

• Appears upper medial fossa
• Descends obliquely
• Ends by dividing into:
  • Anterior tibial artery
  • Posterior tibial artery

Key Features

• Deepest structure → difficult to palpate
• Pulse detectable by deep midline palpation
• Gives:
  • Muscular branches
  • Genicular arteries (knee anastomosis)

Popliteal Vein

• Superficial to artery
• Travels with artery
• Passes through adductor hiatus → femoral vein

Roof Structures

• Covered by skin & superficial fascia

Small saphenous vein

• Ascends posterior leg
• Pierces deep fascia at knee
• Drains into popliteal vein

Posterior cutaneous nerve of thigh

• Passes through roof
• Continues with small saphenous vein
• Supplies upper posterior leg skin

Clinical Correlation — Popliteal Artery Aneurysm

• Aneurysm: Diameter > 7 mm
• Often associated with other large-vessel aneurysms

Complications

• Thrombosis (common)
• Distal embolization
• Limb ischemia → possible amputation
• Rupture less common

Diagnosis

• Duplex Doppler ultrasound (best initial test)
• Differentiates from Baker’s cyst

Management

• Typically surgical repair (high embolic risk)
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