Buying guide · Seat cushions

Coccyx wedge, Diffuser or ring cushion?

Name: Connect Mobility
Address: T27/9 Margaret Street, Picton, NSW, 2571, AU
Telephone: 1300 216 888
Price range: $$

Written by Nadim Assaf, registered pharmacist, Connect Mobility in Picton

A sore tailbone makes sitting hard work. Let's look at how each cushion shape takes the pressure off, and which one to skip.

The short version

For tailbone pain, get a cushion with a cut-out at the back. That's what Healthdirect recommends, and it's what most people with tailbone pain end up preferring.

Tailbone pain, and you want the simplest fixCoccyx Wedge$89

Tailbone pain, and you sit for hours or you're a larger buildCoccyx Diffuserfrom $139

After childbirth, surgery or with haemorrhoidsKeyhole Wedge$115

Low back ache but no tailbone painPosture Wedge$79

How a cut-out helps

Your tailbone, or coccyx, is the little bone at the very bottom of your spine. On a flat seat, especially when you slump, it takes some of your weight. If it's bruised or inflamed, that hurts.

A coccyx cushion has a gap cut out of the back. Your tailbone sits over the gap, so your weight goes through your sit bones instead. Most of these cushions are also wedge shaped. That tips your pelvis forward a little, which lifts the tailbone further off the seat.

Woman sitting on the TheraMed Coccyx Tailbone Wedge, side view — Sitting on the Coccyx Wedge. The cut-out is at the back of the seat. Photo: TheraMed.

The shapes compared

Here's what each shape does, and who it suits.

Coccyx Tailbone Wedge

This is the one most people start with. It's a 40.5 cm square of firm foam, sloping at about 9 degrees, with a cut-out for the tailbone. It suits office chairs, car seats and dining chairs.

At $89 it's the cheapest way to get a proper cut-out. One owner said the gap at the back was great for their sciatica too.

Close-up of the cut-out on the TheraMed Coccyx Tailbone Wedge — The tailbone cut-out on the Coccyx Wedge. Photo: TheraMed.

TheraMed diagram of the ways the Coccyx Tailbone Wedge can be used — The ways you can use it. Image: TheraMed.

Coccyx Diffuser

The Coccyx Diffuser has the same kind of cut-out, but it's built for longer sitting. TheraMed calls the design a "diffuser". It's a firm inner core of foam, sandwiched between two layers of memory foam.

The memory foam moulds to you, and the firm core stops you sinking through to the chair. That spreads your weight more evenly than plain foam. It's the one to look at if you sit for hours, drive a lot, or use a wheelchair.

It also comes in bariatric sizes. The XL is 50 x 45 cm and the XXL is 56 x 45 cm, both 9.5 cm deep. If you're a larger build, a standard cushion can bottom out quickly. The bariatric sizes have the depth to cope.

TheraMed Coccyx Diffuser with half its cover off, showing the foam layers — Half the cover off, so you can see the layers. Photo: TheraMed.

Man sitting on the TheraMed Coccyx Diffuser in a wheelchair at a desk — In a wheelchair at a desk. Photo: TheraMed.

Diffuser (no cut-out)

The plain Diffuser uses the same layered foam without the gap. It's for general comfort and spreading pressure when your tailbone isn't the problem. It comes in five sizes, from 40 x 40 cm up to the bariatric XXL.

The plain TheraMed Diffuser cushion with half its cover off — The plain Diffuser, with no cut-out. Photo: TheraMed.

TheraMed image showing each size and cover option for the Diffuser cushion — The sizes and covers. Image: TheraMed.

Keyhole Wedge

The Keyhole is a wedge with a keyhole-shaped opening instead of a simple notch. It takes pressure off the tailbone and the tender area around it.

TheraMed makes it for after childbirth, after bottom surgery, and for haemorrhoids. It has a green Steri-Plus cover that wipes clean, which matters in the weeks after birth.

Close-up of the keyhole opening on the TheraMed Keyhole Wedge — The keyhole opening. Photo: TheraMed.

Posture Wedge

The Posture Wedge is a plain 9 degree foam wedge with no opening. It lifts your hips slightly higher than your knees, which many people with a sore lower back find easier. It won't help a sore tailbone.

About ring cushions

We sell the TheraMed latex Ring, and some people like it. But we want to be straight with you about where it fits.

The TheraMed latex Ring cushion without its cover — The Ring without its cover. The hole is in the middle. Photo: TheraMed.

For tailbone pain, a ring isn't the best shape. Your tailbone sits at the back, not in the middle, so a hole in the centre doesn't take much weight off it. People with tailbone pain nearly always prefer a cut-out.

For pressure sores, don't use a ring at all. The international pressure injury guideline says not to use ring or donut cushions. The edges press in a circle, which can cut off blood flow and damage the skin.

A ring can help for short spells after childbirth or with haemorrhoids. One NHS maternity guide says to use it with caution, because sitting on one for over 30 minutes can restrict circulation. The Keyhole Wedge is a better choice for longer sitting.

When to see a doctor

Healthdirect says tailbone pain usually settles within weeks to months. See your GP if it isn't improving after a few weeks.

See a doctor sooner if you have numbness or tingling, a fever, weight loss you can't explain, or trouble with your bladder or bowels. Do the same after a bad fall.

If you use a wheelchair or you're at risk of pressure sores, talk to your OT. You may need a pressure care cushion, like the Jay range. Our pressure care cushion guide explains the options.

Looking after them

From TheraMed's care instructions

Never soak the foam. Spot clean it only.

The grey Dura-Fab covers are hand wash in lukewarm water, then drip dry. The green Steri-Plus covers resist moisture and wipe clean with mild detergent or a diluted, non-phenolic disinfectant.

Side by side

Tailbone painTheraMed Coccyx Tailbone Wedge$89Firm foam wedge with a tailbone cut-out. The simple fix.View cushion

Long sittingTheraMed Coccyx Diffuserfrom $139Layered memory foam with a cut-out. Bariatric sizes to $225.View cushion

After birth or surgeryTheraMed Keyhole Wedge$115Keyhole opening and a wipe-clean cover.View cushion

	Coccyx Wedge	Coccyx Diffuser	Keyhole	Ring	Posture Wedge
Our price	$89	$139 to $225	$115	$96.95	$79
Opening	Tailbone cut-out	Tailbone cut-out	Keyhole	Centre hole	None
Foam	Firm foam	Memory foam around a firm core	Foam	Natural latex	Firm foam
Size	40.5 x 40.5 cm	44 x 42 cm to 56 x 45 cm	40.5 x 40.5 cm	41 x 41 cm	40.5 x 40.5 cm
Shape	9° wedge	7.5 or 9.5 cm deep	9° wedge	Ring, 8 cm deep	9° wedge
Covers	Dura-Fab or Steri-Plus	Dura-Fab or Steri-Plus	Steri-Plus	Steri-Plus	Dura-Fab or Steri-Plus

Specs are from TheraMed. All are made in Australia and carry TheraMed's 12-month warranty against faults.

Questions we get

Which way round does the wedge go?

The thick end and the cut-out go at the back of the chair, under your tailbone.

Can I use it in the car?

Yes. The Coccyx Wedge suits most car seats. Check your head still clears the roof, as it lifts you a few centimetres.

My lower back aches too.

A lumbar support behind your back helps. Healthdirect suggests a cushion or lumbar roll. The TheraMed Back Huggar pairs well with any of these cushions.

Not sure which shape?

Tell Nadim where it hurts and how long you sit each day. He'll point you to the right cushion, or tell you it's time to see your GP. Call 1300 216 888.

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