Vascular access: IJ, femoral, radial, cubital fossa
Stem
At the ultrasound station, the scenario card describes a 63-year-old man, 88 kg, scheduled for a Whipple procedure who needs a right internal jugular central line after induction. The standardized patient lies supine with his head near neutral. The examiner at the machine asks for the vascular access task. A linear 6–15 MHz probe is in your hand.
Question
Show me the internal jugular: how do you prove which vessel is the vein, and where does your needle go?
Ideal answer
HeadlineThe large oval vein lateral and superficial to the round carotid, proven by compression; my needle tip is tracked into it.
- Linear probe, 7 MHz or more, depth to target.1 High frequency, short axis, marker to his right, apex of the sternocleidomastoid triangle near the cricoid.
- Prove the vein three ways. It flattens under gentle pressure, the thick-walled artery does not; the artery is round and pulsatile; color Doppler if needed.1
- Head near neutral, then trace, because rotation stacks the vein on the carotid; a few centimeters: patent, no thrombus, not overlying the artery.
- Show the optimal needle position, which is scored:2 out-of-plane, tip tracked into the vein, or in-plane in long axis for a deeper target.
- Wire in the vein before I dilate, not the adjacent artery; manometry through a catheter if short axis is ambiguous.1
Breaking down the answer
- Four sites, four hazards — the outline names IJ, femoral, radial and cubital fossa;3 the station tests telling artery from vein with certainty and a path that avoids the structure next door.
| Site | Probe position | Identifying features | Hazard |
|---|---|---|---|
| Internal jugular | Transverse at the apex of the sternocleidomastoid triangle, ~cricoid level | Large oval compressible vein lateral and superficial to the round carotid; enlarges with Trendelenburg or Valsalva | Carotid puncture, pneumothorax low in the neck |
| Femoral | Transverse just below the inguinal ligament | Nerve, artery, vein lateral to medial; vein medial to artery; saphenous joins anteromedially | Arterial puncture, retroperitoneal bleeding above the ligament |
| Radial artery | Transverse at the wrist, proximal to the styloid | Small round pulsatile artery 2–5 mm deep with two venae comitantes | Posterior wall puncture, hematoma |
| Cubital fossa | Transverse at the antecubital crease | Basilic vein medial, cephalic lateral, brachial artery with paired veins and median nerve medially | Brachial artery puncture, median nerve injury |
- Head rotation — contralateral rotation increases IJ-carotid overlap, and older patients overlap more;1 near neutral, a through-and-through puncture of the vein misses the artery.
- Femoral level — common femoral vein below the inguinal ligament, above the saphenous junction and the deep femoral branch: bleeding stays compressible and the artery is not split into branches under the vein.
- Radial dynamic tip tracking — out-of-plane, I slide the probe ahead of the needle and keep the tip a bright dot inside the artery, avoiding double-wall puncture of a vessel only 2–3 mm wide.
- Cubital fossa vein choice — the basilic is larger and straight, but the brachial artery and median nerve lie deep and medial to it; I stay superficial and lateral, or choose the cephalic.
- Why the wire check — in long axis I see the wire in the vein lumen and absent from the artery;1 dilating a wire that passed through the vein into the carotid causes stroke and hemorrhage.
Follow-up question
After a difficult IJ cannulation, the pressure tracing from the catheter you just placed is pulsatile and the blood is bright. What do you do?
Follow-up answer
HeadlineProbable carotid cannulation: I stop and tell the surgeon and the team.
I do not remove a large-bore catheter or dilator from the carotid: I leave it, transduce it to confirm arterial pressure and call vascular surgery, because removal and compression of a large hole risks hemorrhage, a hematoma compressing the airway and stroke. A small-gauge needle only: withdraw and compress for 10 minutes. I reassess neck, airway and neurologic status and choose another site. An IJ that does not compress and holds echogenic material is thrombus; I abandon that side, because a wire through clot risks pulmonary embolism.
Pitfalls that cost points
- Using the inguinal crease as the level: it often lies below the bifurcation, where the superficial femoral artery overlies the vein.
- Losing the needle tip out-of-plane and calling the shaft the tip.
Rapid-fire
Q: Why does the IJ enlarge with Trendelenburg? A: Head-down tilt raises venous pressure in the neck, distending the vein and lowering air embolism risk.1
Q: Why is out-of-plane prone to error? A: The beam crosses the needle at one point, so the dot may be the shaft rather than the tip unless I track it.
Q: What confirms an arterial puncture before I dilate? A: Transducing the catheter or a small cannula for a pulsatile waveform; color of the blood is unreliable in a hypoxemic patient.
Q: Why is the femoral vein medial? A: The sheath holds artery and vein, vein medial, nerve lateral outside it; overlap occurs (especially in children), and the inguinal crease is an unreliable landmark for the ligament.1
Numbers to know
| Item | Value |
|---|---|
| Probe | Linear, ≥7 MHz (typically 6–15 MHz)1 |
| IJ depth | ~1–2 cm |
| Femoral vein depth | ~2–4 cm |
| Radial artery depth and size | 2–5 mm deep, 2–3 mm wide |
| Head rotation | Near neutral; overlap rises with rotation |
| Small-needle arterial puncture | Compress ~10 min |
Links
- Central venous access and its complications, The ultrasound application station: format and tasks, Pneumothorax and tension pneumothorax, Massive hemorrhage and transfusion
- ASA Practice Guidelines for Central Venous Access (2020); ASE/SCA Guidelines for Performing Ultrasound-Guided Vascular Cannulation (2011)
Sources
- 1.Guidelines for Performing Ultrasound Guided Vascular Cannulation: Recommendations of the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists · ASE/SCA, 2011 · asecho.org
- 2.OSCE Example Scenarios (all stations) · ABA, 2023 · theaba.orgVascular task template: probe orientation, optimal needle positioning, two structures.
- 3.APPLIED Exam Objective Structured Clinical Examination (OSCE) Content Outline · ABA · theaba.org
Facts on this page were checked against these sources on Oct 14, 2026. Guidelines change; confirm doses against current institutional protocols.