What are the anatomical landmarks for subclavian central line placement?

Anatomical Landmarks for Subclavian Central Line Placement

While ultrasound guidance is strongly recommended for subclavian central line placement, knowledge of anatomical landmarks remains essential for optimal patient safety and procedural success. 1, 2

Key Anatomical Landmarks

• The subclavian vein runs beneath the clavicle, entering the thorax at the junction of the medial and middle thirds of the clavicle - this junction serves as a primary landmark for needle insertion 3
• The deltoid tuberosity, located on the lateral aspect of the clavicle, can serve as an alternative anatomical landmark that simplifies subclavian vein cannulation by minimizing patient manipulation and anatomic measurements 4
• The subclavian vein lies anterior and inferior to the subclavian artery, with the pleural space in close proximity posteriorly - understanding this anatomical relationship is critical to avoid arterial puncture and pneumothorax 5

Patient Positioning

• Position the patient in Trendelenburg position (head down) to increase venous filling and distend the subclavian vein, improving the likelihood of successful cannulation 1, 6
• A small rolled towel placed between the scapulae can help extend the shoulders and make the landmarks more prominent 6
• The patient's head should be turned slightly away from the side of insertion to improve access to the area 6

Infraclavicular Approach Landmarks

• The needle insertion site is approximately 1 cm below the junction of the middle and medial thirds of the clavicle 3
• The needle should be directed toward the suprasternal notch, maintaining a path parallel to the frontal plane 4
• The infraclavicular area facilitates easier dressing changes compared to neck area exit sites 6

Supraclavicular Approach Landmarks

• The supraclavicular approach uses the junction of the lateral edge of the clavicular head of the sternocleidomastoid muscle with the clavicle 7
• The needle is inserted at the lateral border of the clavicular head of the sternocleidomastoid muscle, just above the clavicle 7
• This approach provides a more direct path to the superior vena cava with potentially fewer complications than the infraclavicular approach 7

Ultrasound Integration with Landmarks

• Even when using ultrasound guidance, understanding anatomical landmarks is crucial for proper probe positioning and interpretation of ultrasound images 5
• Ultrasound allows visualization of anatomical variations, which occur in a significant proportion of patients and may not be detectable using landmark techniques alone 5
• For subclavian access, a thin-wall needle (Seldinger) technique is preferred over a catheter-over-the-needle technique 6

Common Pitfalls and Safety Considerations

• Relying solely on anatomical landmarks without ultrasound guidance increases complication risk, especially with anatomic variations 1
• The subclavian approach carries higher risks of pneumothorax, catheter fatigue, "pinch-off syndrome," and potential catheter fracture compared to other sites 2, 6
• The close proximity of the subclavian artery, brachial plexus, and pleura increases the risk of complications when using a landmark-only technique 8
• The Centers for Disease Control and Prevention (CDC) recommends the subclavian site over jugular or femoral sites for non-tunneled CVCs to reduce infection risk, but this must be balanced against other mechanical complications 2

Evidence-Based Recommendations

• Ultrasound-guided venepuncture is strongly recommended for all CVC insertions as it is associated with lower incidence of complications and higher success rates than 'blind' landmark-based venepuncture 2, 6
• Two-dimensional ultrasound reduces the risk of inadvertent arterial puncture and hematoma formation during subclavian vein cannulation 8
• To achieve the best skill level for CVC placement, knowledge from anatomic landmark techniques should be combined and integrated with ultrasound-guided techniques 5