Venipuncture Vein Explorer

VisualiserUndergraduate

Pick the median cubital, cephalic or basilic vein on a drawn elbow for its sourced pros and cons, what WHO and EFLM say, and the artery and nerves by it.

Vein Selected vein Artery, deep Nerve, deep Nerve, on the vein Relatively safe stretch (Mikuni; Yamada), kept off the forks (WHO 2010) Veins branch: avoid (WHO 2010)

Tap a vein, or its name, to pick it.

A schematic of the usual layout, not to scale. Real arms vary; feel and look before choosing.

Vein pattern at the elbow

Arms differ. The N shape is the textbook’s, not the most common everywhere (Salem 2026).

Needle for

Show the artery and nerves

Median cubital vein

First in this page’s order for a blood draw. WHO says it is usually the easiest vein to puncture, and EFLM-COLABIOCLI calls ‘the cubital vein’, read here as the median cubital, the most preferable choice. (WHO 2010; EFLM-COLABIOCLI 2018)

Leaves the cephalic vein below the crease and runs up and in across the front of the elbow to the basilic vein. (Gray 1918; Salem 2026; Mikuni 2013)

Visible with a tourniquet 19 of 20 arms, Mukai 2020: 95%
Mean area, tourniquet on: 16.6 mm²
To the median nerve Median, range 1.7 to 21.3 mm (Mukai 2020); 0.81 mm in the one arm whose nerve lay nearer the skin than the artery: 7.6 mm
To the brachial artery Median, range 1.0 to 14.5 mm (Mukai 2020): 3.6 mm

Measured by ultrasound in 20 young adult volunteers (Mukai 2020), so a guide to the usual arm, not to this patient’s.

For it

Lies between the muscles and is usually the easiest vein to puncture. (WHO 2010)
Usually the most prominent, does not roll under the skin, and is in the same place in most patients. (EFLM-COLABIOCLI 2018)
The largest of the three: 16.6 mm² on average with a tourniquet, against 7.6 mm² for the cephalic and 6.0 mm² for the basilic. (Mukai 2020)
Its outer stretch is the one the cadaver studies favor: Yamada found puncture near the cephalic vein the least likely to cause nerve damage, and Mikuni called the stretch from its middle to the cephalic vein relatively safe. (Yamada 2008; Mikuni 2013)

Against it

The brachial artery is close beneath its inner side: a median 3.6 mm away, and as little as 1.0 mm. (Mukai 2020)
The median nerve was a median 7.6 mm away. The paper’s range starts at 1.7 mm, but in the one arm where the nerve lay nearer the skin than the artery it gives 0.81 mm, which the authors say means a high risk of nerve injury if the needle goes through the vein. (Mukai 2020)
A superficial brachial artery, found in 21% of 128 cadaver arms, passed deep under its inner side. (Mikuni 2013)
The medial antebrachial cutaneous nerve passed over it in 27 of 128 cases (21.1%) and lay ‘inferior to’ it, the abstract’s term, in 37 (28.9%). (Yamada 2008)
The lateral antebrachial cutaneous nerve lay deep to it in 56 of the same 128 cases (43.8%), and the vein passed above that nerve in 8 (6.2%). (Yamada 2008)
Not every arm has one: in some patterns the cephalic and basilic veins do not connect at the elbow. (Mikuni 2013; Salem 2026)

Where sources differ. WHO calls the median cubital vein usually the easiest to puncture and warns off the basilic, which has an artery and a nerve under it. EFLM-COLABIOCLI names the cephalic, basilic, median cubital and median antebrachial veins as the first choice, with the median cubital the most preferable. Mukai’s ultrasound study of 20 volunteers puts the cephalic vein first instead, for its distance from the median nerve and the brachial artery, takes the median cubital vein when the cephalic cannot be seen, and judges the basilic not suitable. (WHO 2010; EFLM-COLABIOCLI 2018; Mukai 2020)

What lies near it

Brachial artery. Runs deep to the inner side of the median cubital vein and under the junction with the basilic vein, as Mukai sums up earlier dissections. (Mukai 2020) Where it runs superficially, from birth, in very lean people or in children, a needle through the back wall of the vein can reach it; this happens in fewer than 0.01% of blood donors. (Ialongo 2016)
Median nerve. Lies on the inner side of the brachial artery at the crease, in an earlier study Mukai cites. It was at the artery’s depth in 16 of 20 arms, deeper in 3 and nearer the skin in 1, and in that arm it was 0.81 mm from the median cubital vein, which the authors say means a high risk of nerve injury if the needle goes through the vein. (Mukai 2020)
Lateral antebrachial cutaneous nerve. Runs deep along the cephalic vein in 97% of 128 arms, and lay deep to the median cubital vein in 43.8% of another 128. (Mikuni 2013; Yamada 2008) Sources differ on whether it is the nerve venipuncture injures most often. Ialongo’s review names it; in Horowitz’s 11 causalgia cases the medial nerve was injured in 5 and this one in 2. (Ialongo 2016; Horowitz 1994)
Medial antebrachial cutaneous nerve. Runs over the basilic vein in 73% of 128 arms, and in another 128 cases passed over the median cubital vein in 21.1% and lay ‘inferior to’ it in 28.9%. (Mikuni 2013; Yamada 2008) It was the nerve injured in 5 of the 11 people Horowitz saw with causalgia after a routine venipuncture, against 2 for the lateral nerve. (Horowitz 1994)
Bicipital aponeurosis. A sheet from the biceps tendon that roofs the fossa over the median nerve and the brachial artery, with the median cubital vein usually on top of it. Rarely the vein runs beneath it: Newton and colleagues describe one cadaver arm in which it did. (Newton 2022)

For any site

Do not put the needle in where veins branch, ‘where veins are diverting’ in WHO’s words: it raises the chance of a hematoma. (WHO 2010)
WHO applies a tourniquet 4 to 5 finger widths above the site, and cites guidelines that take it off before 2 minutes. EFLM-COLABIOCLI prefers none where the veins are prominent and uses one only when needed: one hand width, about 3 in (7.5 cm), above the site, for up to 1 minute. Open RN’s US nursing checklist puts it about 2 in (5 cm) above the site, for 2 minutes or less. (WHO 2010; EFLM-COLABIOCLI 2018; Open RN venipuncture checklist)
WHO asks the patient to make a fist; EFLM-COLABIOCLI says not to clench or pump it, because that can raise the measured potassium. (WHO 2010; EFLM-COLABIOCLI 2018)
Use the veins on the back of the hand only when the main elbow veins are unavailable, and avoid the wrist. (EFLM-COLABIOCLI 2018)

Cite this tool

Last updated 25 October 2026. Add the date you accessed it as well, which a citation of a page that can change asks for. If a specific result matters, cite the permalink from the tool’s share row instead of this page: it reproduces the exact parameters.

Reference

ScienceQuest. (2026). Venipuncture Vein Explorer [Interactive tool]. Retrieved [date] from https://sciencequest.in/tools/venipuncture-veins-explorer/

BibTeX

@misc{sciencequest-venipuncture-veins-explorer,
  author       = {{ScienceQuest}},
  title        = {{Venipuncture Vein Explorer}},
  howpublished = {\url{https://sciencequest.in/tools/venipuncture-veins-explorer/}},
  year         = {2026},
  note         = {Interactive tool, last updated 25 October 2026. Add the date you accessed it as urldate.},
}

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A study tool, not a clinical one

This page exists for learning which elbow vein to choose for a blood draw or a cannula, what runs beside each one, and where the guidelines and the studies disagree. It is not clinical decision support and must not be used to treat anybody.

The arm in front of you is not the drawing. Veins, nerves and arteries vary in course and depth from person to person, and the measurements here come from small study samples. Look at and feel the site on the patient before choosing it.
A real needle follows supervised training and local policy. Your course and your institution decide the technique, how many attempts to make, and when to stop and ask for help.

One more caution

Every claim here names its source. If one does not match what you were taught, check the source named beside it, and tell us if we have it wrong. How the tools are checked is set out in the editorial policy.

Which vein is best for venipuncture?

Usually the median cubital vein, in the bend of the elbow. WHO calls it usually the easiest to puncture, and EFLM-COLABIOCLI calls ‘the cubital vein’ the most preferable: usually the most prominent, and it does not roll. This page’s order puts the cephalic vein second and the basilic last, which WHO warns has an artery and a nerve under it.

The order, and where the sources part

Neither guideline ranks all three veins in a list. WHO says the median cubital vein lies between muscles and is usually the easiest to puncture, and warns that an artery and a nerve run under the basilic vein, so a puncture there risks both and usually hurts more; it does not mention the cephalic vein. EFLM-COLABIOCLI names the prominent veins of the fossa, the cephalic, basilic, median cubital and median antebrachial, as the first choice, ahead of the hand, and the median cubital as the most preferable of them.

So the order drawn here is this page’s own. The median cubital vein is first because both guidelines prefer it. The cephalic vein is second because Mukai and colleagues found it the farthest of the three from the median nerve and the brachial artery, a median 24.1 and 21.3 mm away, and neither guideline warns against it. The basilic vein is last because WHO warns about what runs under it and Mukai judged it not suitable.

One study reads the same anatomy the other way. Mukai and colleagues measured 20 young volunteers by ultrasound and put the cephalic vein first, for its distance from the median nerve and the brachial artery, taking the median cubital vein when the cephalic cannot be seen. WHO and Mukai both warn off the basilic vein, while EFLM-COLABIOCLI lists it with the first-choice veins.

The three veins by ultrasound with a tourniquet on: share visible, mean area, and median distance to the median nerve and the brachial artery (Mukai 2020, 20 volunteers)
Vein	Visible	Area, mm²	To nerve, mm	To artery, mm
Median cubital	95%	16.6	7.6	3.6
Cephalic	80%	7.6	24.1	21.3
Basilic	65%	6.0	8.8	12.2

The distances are medians. Mukai’s reported ranges start at 1.5 mm from the median nerve, for the basilic vein, and 1.0 mm from the brachial artery, for the median cubital vein. In the one arm where the median nerve lay nearer the skin than the artery, the paper gives 0.81 mm from the nerve to the median cubital vein, below the 1.7 mm that vein’s reported range starts at.

What a needle can meet

The brachial artery runs deep to the inner side of the median cubital vein (Mukai). In 21% of 128 cadaver arms Mikuni and colleagues found a superficial brachial artery passing under it, and a needle pushed through the vein’s back wall can reach the artery, which happens in fewer than 0.01% of blood donors (Ialongo).
The median nerve lies beside the artery on its inner side (Mukai, citing Ohnishi). Mukai found it at the artery’s depth in 16 of 20 arms, deeper in 3 and nearer the skin in 1, and in that arm it was 0.81 mm from the median cubital vein.
The lateral antebrachial cutaneous nerve runs deep along the cephalic vein in 97% of 128 arms (Mikuni), and lay deep to the median cubital vein in 43.8% of another 128 (Yamada). Sources differ on how often it is hurt: Ialongo’s review names it as the nerve venipuncture injures most often, while in Horowitz’s 11 causalgia cases the medial nerve was injured in 5 and the lateral in 2.
The medial antebrachial cutaneous nerve runs over the basilic vein in 73% of 128 arms (Mikuni), and passes over the median cubital vein in about a fifth of cases (Yamada). Horowitz, a neurologist in Albany, New York, found it injured in 5 of 11 people who developed causalgia after a routine venipuncture.
The bicipital aponeurosis, the sheet from the biceps tendon, roofs the fossa over the median nerve and the artery, with the median cubital vein usually on top of it (Newton). Rarely the vein runs beneath it: Newton and colleagues describe one cadaver arm in which it did.

WHO’s own drawing of the site, figure 2.1, labels an ulnar artery and an ulnar nerve beside the basilic vein in the forearm. The anatomical studies measure the brachial artery and the median nerve at the elbow crease, which is what this drawing shows.

Not every arm has the textbook N

The drawing opens on the N shape, in which the median cubital vein leaves the cephalic below the crease and crosses obliquely up and in to join the basilic. It is the arrangement Gray’s Anatomy (1918) describes, not every population’s commonest. Among 332 elbows of Gulf Arab volunteers, Salem and colleagues found the no-connection pattern most often, in 29.2%, and the M shape next, in 24.09%. Mikuni found no median cubital vein in one of four types in 128 cadaver arms.

The letters are not used the same way everywhere: Mikuni and Salem call a median cubital vein linking the cephalic and basilic veins an N, while StatPearls and Newton call that arrangement M. Switch the pattern to see the veins move, and the places where they branch, which WHO says to avoid (‘where veins are diverting’) because a needle there raises the chance of a hematoma.

A blood draw and a cannula want different sites

The large elbow veins suit a blood draw because their size withstands repeated sampling, while a cannula there can block each time the elbow bends, though it may still go there when access is needed fast or the infusions are short and intermittent (Open RN Nursing Skills; Open RN Advanced Skills). Wallis and colleagues analyzed 5,907 catheters in 3,283 adults at three hospitals in Queensland, Australia, each expected to stay in more than 4 days. One at the elbow was more likely than one in the forearm to block, with a hazard ratio of 1.27, and to come out by accident, 1.65; the hand was worse on both, at 1.47 and 2.45. Two US references still look to the back of the hand first for a cannula (Open RN Advanced Skills; StatPearls, phlebotomy). Set “Needle for” to an IV cannula to shade the forearm.

What this drawing leaves out

Depth and scale. It is a schematic, not a measured arm. The 3D explorers on this site are built from BodyParts3D, whose parts list has none of these veins or nerves, so there is no 3D model to draw them from.
The person in front of you. Every count here comes from a study sample: 20 young Asian volunteers in Japan for the ultrasound figures, two cadaver studies in Japan (Mikuni, 128 arms; Yamada, 128 cases) for the nerve and artery counts, and 11 patients examined by Horowitz, a neurologist at Albany Medical Center, New York, for the nerve injuries. Age, body weight and ancestry can change what a vein looks like and where it runs (Mukai 2020; Salem 2026).
The technique. Needle angle, anchoring and what to do after a missed attempt belong to a supervised course and local policy, not to this page.

Sources

The Clinical and Laboratory Standards Institute’s venipuncture standard, GP41, which EFLM-COLABIOCLI refers to, was replaced in 2025 by PRE02; both are sold rather than free, so this page does not quote them. The drawing is this site’s own.

Common questions

Why is the basilic vein usually the last choice for a blood draw?

Because of what lies under it. WHO’s 2010 guideline says an artery and a nerve run under the basilic vein, so a puncture there risks both and usually hurts more. In Mukai’s ultrasound study of 20 volunteers it was the hardest of the three to see with a tourniquet on and a median 8.8 mm from the median nerve, and the authors judged it not suitable. In Mikuni’s 128 cadaver arms the medial antebrachial cutaneous nerve ran over it in 73%. EFLM-COLABIOCLI still lists it among the first-choice elbow veins, ahead of the hand.

Is the cephalic vein safer than the median cubital vein?

Farther from the median nerve and the brachial artery, yes: a median 24.1 mm from the nerve against 7.6 mm for the median cubital vein (Mukai 2020). But the lateral antebrachial cutaneous nerve runs deep along it in 97% of 128 cadaver arms (Mikuni 2013), and a review names that nerve as the one venipuncture injures most often (Ialongo 2016), though in Horowitz’s 11 causalgia cases the medial antebrachial cutaneous nerve was injured more often. WHO calls the median cubital vein usually the easiest to puncture, and EFLM-COLABIOCLI calls ‘the cubital vein’ the most preferable, as usually the most prominent. Mukai and colleagues put the cephalic first, though even with a tourniquet it was not visible in 4 of 20 arms.

Should an IV cannula go in the antecubital fossa?

Not if it is meant to stay. In Wallis and colleagues’ analysis of 5,907 catheters from a randomized trial, each expected to stay more than 4 days, one at the elbow was more likely to block, with a hazard ratio of 1.27, and to come out by accident, 1.65, than one in the forearm, so the forearm comes first for a cannula. The elbow veins suit a blood draw because their size withstands repeated sampling (Open RN). Open RN and StatPearls, both US references, still look to the back of the hand first.