Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

Overview

The obturator artery is a key pelvic vessel supplying:

The medial thigh
Structures around the hip joint

Clinical Importance

Understanding its anatomy is essential in:

Pelvic trauma
Acetabular fracture surgery
Total hip arthroplasty

Anatomical variations can lead to significant hemorrhage if injured

Origin of the Obturator Artery

Typically arises from the anterior division of the internal iliac artery
Originates within the pelvis and courses toward the obturator canal

Course

Runs along the lateral pelvic wall
Enters the obturator canal
Passes from the pelvis into the medial compartment of the thigh

Division of the Obturator Artery

Within the obturator canal, it divides into:

Anterior branch
Posterior branch

Arrangement

These branches form a vascular ring around the obturator membrane

Branches of the Obturator Artery

1. Acetabular Branch

Passes through the ligament of the head of the femur
Supplies a small portion of the femoral head

2. Muscular Branches

Supply the adductor muscles of the medial thigh

Important Anatomical & Clinical Considerations

Corona Mortis (“Crown of Death”)

Definition

A vascular connection between:

Obturator vessels (internal iliac system)
External iliac system (commonly via inferior epigastric vessels)

Characteristics

Often venous, but arterial variants exist
Incidence varies widely

Location

Approximately 3–7 cm from the pubic symphysis
Lies posterior and superior to the superior pubic ramus

Clinical Significance

At Risk During

Pelvic trauma
Pelvic fracture surgery
Ilioinguinal approach

Complication

Can cause severe, difficult-to-control hemorrhage

Hence the term “crown of death”

Acetabular Screw Placement in Total Hip Arthroplasty

Importance

Safe screw placement requires awareness of neurovascular structures around the acetabulum

Quadrant System

Method

Draw a line from ASIS to the center of the acetabulum
A perpendicular line divides it into four quadrants

Danger Zones

Anterior Inferior Quadrant

Contains obturator vessels

Anterior Superior Quadrant

Contains external iliac vessels

These quadrants should be avoided for screw placement

Surgical Risks Involving the Obturator Artery

1. Retractor Placement

Risk

Injury if placed beneath the transverse acetabular ligament
Risk increases when positioned too anteriorly

2. Transverse Acetabular Ligament

Anatomy

Bridges the acetabular notch, forming a tunnel
Allows passage of vessels into the joint

Surgical Tip

If division is required:
- Release from the posterior half
  Reduces risk of vascular injury

3. Pelvic Fracture Reduction

Technique Consideration

Reduction clamps are commonly used

Safer Approach

Apply clamps from the medial side of the pelvic ring

Avoids lateral neurovascular structures

Summary Points

The obturator artery arises from the internal iliac artery (anterior division)
Travels through the obturator canal and divides into anterior and posterior branches
Provides an acetabular branch to the femoral head
Corona mortis is a critical vascular variation with high bleeding risk
Knowledge of acetabular quadrants is essential for safe screw placement
Careful surgical technique is required to avoid vascular injury during pelvic procedures

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