By Rob Beatty, MD FACEP
If you’ve ever stood at the bedside with sweat forming under your lead apron, the patient crashing, and your attending breathing down your neck like a hawk in a Patagonia fleece, then you know the existential crisis of choosing your central line site. Do you go neck-first with the internal jugular, dive under the clavicle for the subclavian, or embrace the groin life with the femoral?
For new providers, this decision is often less “choose your fighter” and more “close your eyes and hope the ultrasound likes you.” But fear not, because by the end of this post, you’ll walk away with not just a full understanding of the pros, cons, and technical details of each site—but also a mildly humiliating story that will make you feel better about your own early procedural gaffes.
Internal Jugular: The Neck’s Shining Star
The internal jugular (IJ) vein is the golden retriever of central access—loyal, easy to find with ultrasound, and usually the first line you ever place (or at least try to).
The anatomy is almost poetic: the IJ runs alongside the carotid artery and sits nicely in the apex of the triangle formed by the sternal and clavicular heads of the sternocleidomastoid muscle. When in doubt, go for the right IJ—larger diameter, straighter shot to the SVC, and less thoracic duct risk. Cue ultrasound, linear probe, probe marker to patient’s left, vein compresses, artery pulses (hopefully not after you poke it).
Technique: With the patient in Trendelenburg (assuming they tolerate it), and their head slightly turned away from the side you’re working on, place your ultrasound probe in the transverse orientation just above the clavicle. Look for that delicious target—the anechoic, compressible IJ sitting lateral to the artery. Needle in at a 45-degree angle under real-time visualization, and boom, you’re cooking with gas (or blood, technically).
Pros:
- Easy to visualize with ultrasound
- Low risk of pneumothorax
- Quick access in most patients
Cons:
- Neck mobility and anatomical variance can make things tricky
- Harder to secure in agitated or mobile patients
- Potential carotid artery injury (aka, “oops”)
Humorous aside: During residency, I was attempting my first IJ central line and—I’ll admit it—I was trying to impress my attending. I aspirated to confirm venous blood return (nice!), but somehow got flustered and… I pushed it back in. Yep. Air and all. A gentle puff of air back into the patient’s neck like I was trying to blow up a water balloon. My attending looked at me like I’d just slapped his grandma. “Did… did you just… give the vein its blood back?” he asked. I’ve never apologized so fast—or used such excessive negative pressure ever again.
Subclavian: The Old-School OG
If the IJ is your golden retriever, the subclavian is your grumpy but reliable German shepherd. This site is for when you want long-term access, low infection rates, and you don’t mind a little rib-cage roulette.
The subclavian vein arches under the clavicle and over the first rib, joining the internal jugular to become the brachiocephalic vein. It’s non-collapsible, which is fantastic in hypovolemia and code situations. It’s also pretty deep, meaning ultrasound is technically possible—but trickier.
Technique: Traditionally a landmark-based procedure, you find the junction of the middle and medial thirds of the clavicle, drop your needle under the clavicle, and aim towards the sternal notch. These days, if you’ve got a high-frequency probe and a willing clavicle (i.e., a thin patient), you can sometimes get a long-axis view to guide your stick. But honestly, most people still use the landmark method because clavicles are the natural enemy of high-frequency ultrasound.
Pros:
- Lowest infection rate of the big three
- Comfortable for awake, long-term patients
- Vein doesn’t collapse during hypovolemia
Cons:
- Pneumothorax risk is real
- Harder to compress—bad news if you hit the artery
- Ultrasound visualization is tough
Pro-tip: If your patient is wearing a chest tube like a fashion statement already, subclavian might be the move—you’ve already got a Plan B in place for that potential pneumo.
Femoral: The Groin You Love to Hate
The femoral vein is the no-nonsense, always-there-for-you option. It’s your backup plan, your panic button, your “I don’t have time to get fancy” access site. Is it sexy? No. Is it clean? Absolutely not. But in a crashing patient, it’s sometimes the only answer.
Anatomically, the femoral vein lies medial to the artery, which lies medial to the nerve—hence the old mnemonic: “NAVY” (Nerve, Artery, Vein, Y-fronts). Use the linear probe in transverse orientation at the inguinal crease. Vein compresses; artery does not. Center the vein, needle in at 45°, and don’t forget to wear gloves because… well, you know why.
Pros:
- Fastest and easiest site to access in emergencies
- Great for coagulopathic patients—easy to compress
- Ultrasound-guided cannulation is usually a breeze
Cons:
- Highest infection rate
- Patient mobility = constant dislodgement risk
- You’ll be standing in the danger zone (a.k.a. the splash zone)
If you’ve ever done a femoral line at 3 a.m. on a septic, hypotensive patient and had to MacGyver your gown to avoid being soaked in sweat and C. diff, welcome to the club. Bonus points if the patient has a foley that’s… not ideally situated.
Ultrasound: Your Jedi Weapon
Regardless of your site of choice, ultrasound is the single greatest procedural advancement since someone decided to stop blind-sticking arteries in the 1980s. Use the linear probe for IJ and femoral, and if you’re fancy (or dealing with some fluff), the curvilinear probe for deeper subclavians.
Always identify artery vs vein by compression and pulsatility. Don’t rely on color Doppler alone (trust me, you will be lied to). Use in-plane technique when you can, but in emergency situations, out-of-plane is often faster. Visualize the needle tip—don’t just hope it’s somewhere in there. Real-time needle guidance reduces complications and boosts your confidence. More importantly, it lets you avoid the “I think that was the artery” apology speech.
When to Choose What?
Still unsure which site is best? Here’s a simplified hierarchy:
- Code situation? Femoral—it’s fast and doesn’t require turning the head or moving the patient.
- Need long-term access? Subclavian—less chance of infection, less thrombosis.
- Most common everyday use? IJ—ultrasound-guided, compressible, and straightforward.
Oh, and never, ever give a vein its blood back. I swear I still hear that attending’s shocked gasp in my sleep.
Conclusion: Your Central Line Compass
In emergency medicine, choosing a central line site is less about memorizing anatomy and more about reading the room—patient stability, operator experience, resources available, and anatomical considerations. Each site has its moment to shine (and its moments to destroy your self-confidence). Use your ultrasound like a magic wand, know your anatomy cold, and don’t be afraid to change plans mid-procedure if things aren’t going right.
And if you’ve made central lines feel more like central mysteries, it’s time to level up your game. Check out the 3-Day Combined Ultrasound Clinical Skills and Procedure Workshop from Provider Practice Essentials. It’s hands-on, real-time, and full of the tips and confidence boosts you wish you’d had on day one.
We can’t promise your attending won’t raise an eyebrow again—but at least it won’t be for pushing air back into the IJ.
References
- Bodenham, A. R. (2006). Ultrasound-guided subclavian vein catheterization: Time to bring it in from the cold. British Journal of Anaesthesia, 96(4), 423-426. https://doi.org/10.1093/bja/ael038
- Kumar, A., & Morgan, T. (2018). Central venous catheterization: An update on complications and prevention. Journal of Intensive Care Medicine, 33(12), 655–672. https://doi.org/10.1177/0885066617710036
- Liu, Y., & Wang, H. (2015). Real-time ultrasound-guided central venous catheterization versus landmark technique in critical care patients: A meta-analysis. Critical Care, 19, 64. https://doi.org/10.1186/s13054-015-0798-5
- Merrer, J., et al. (2001). Complications of femoral and subclavian venous catheterization in critically ill patients: A randomized controlled trial. JAMA, 286(6), 700–707. https://doi.org/10.1001/jama.286.6.700
