What it is
The iliac crest is the curved rim of the hip bone you rest your hands on. It sits just under the skin, with little padding. A direct blow, such as a tackle, a knee or a fall onto your side, crushes the tissue against it: there's bleeding under the bone's thin outer layer and into the muscles that attach there (the side tummy muscles above, the hip muscles below), and the bone itself is bruised. The bruise can be anywhere from the bony point at the front of the hip to the back of the crest.
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Who gets it
Players of collision sports: American football, rugby, ice hockey and Australian football, and cricket fielders landing on the ball. In the National Football League (NFL), hip injuries were 3.1% of all injuries over 10 years; contact injuries were most often bruises, and most players were back within 2 weeks. A fall onto your side can do the same at any age.
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How it's recognised, and when an X-ray is needed
Pain at the moment of impact, marked tenderness along the crest, swelling and later bruising; twisting or bending the trunk, and lifting the leg out to the side, hurt. A typical hip pointer doesn't need a scan. An X-ray is needed when:
- You can't walk or put weight on the leg, the pain is severe after a fall, or there's tingling or numbness (NHS advice).
- You're older and fell: in later life a fall onto the hip can break it, which our broken hip guide covers.
- A teenager's pain came with a pop during a sprint, kick or jump rather than a blow, or sits at the bony point at the front of the hip.
- An athlete can't play on after a painkilling injection, which suggests a fracture.
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The severe variant: a tummy muscle torn off the bone
Sometimes the blow tears the internal oblique, a side tummy muscle, off the crest. Pain is worst at the moment of injury and spreads into the side of the tummy, the player can't sit up, injections barely help, and a dent may be felt above the bone. In two Australian footballers, MRI (magnetic resonance imaging) showed tears of 65 to 80 mm with collections of blood; one returned in 6 weeks, and both recovered fully over the off-season. Three professional footballers had the muscle reattached and returned at 55, 60 and 122 days.
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After a hard blow: the organs inside
A hard blow to the tummy or side can injure the organs inside, including the spleen, liver and kidney, and team doctors check for spleen, kidney and bowel injury after a hip pointer. The NHS says the spleen can be damaged by a blow or a sporting accident and can burst straight away or weeks later, causing pain behind the left ribs that is tender to touch, dizziness and a fast heartbeat.
The warning signs about a blow combine NHS pages: the spleen page, the stomach ache page for severe tummy pain or a tummy that hurts to touch, the broken ribs page for tummy or shoulder pain with a rib injury, and the blood in urine page for an urgent check of any blood in your pee. Putting them together is ours.
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Teenagers: the fractures that mimic it
Until it stops growing, the pelvis has growth plates where big muscles pull: the bony point at the front of the hip (the anterior superior iliac spine, or ASIS, for the sartorius), the point just below it (the anterior inferior iliac spine, or AIIS, for the rectus femoris), the crest (for the tummy muscles), and the sitting bone (for the hamstrings). In a sudden sprint, kick or jump, the muscle can pull off a piece of growth plate: an avulsion fracture. The crest of the hip bone is one of the last growth plates to close, in the late teens.
These fractures happen in teenagers, at an average age of about 14.5, and 75% to 80% are in boys, mostly from running, kicking and jumping in football, American football, baseball and gymnastics. Where they happen varies by series: the front of the hip (the ASIS and AIIS) and the sitting bone come first, and the crest made up 1.5% to 11%. In one series of 242, girls were more likely than boys to have a crest avulsion.
An avulsion usually comes from the athlete's own effort, not a blow, often with a pop or crack, and pain at a bony point at the front of the hip or along the crest. Walking may still be possible, but lifting the leg against resistance hurts sharply. A standard X-ray of the pelvis usually shows it.
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A gap on the X-ray isn't always a fracture
A gap in the crest's growth plate on X-ray was found in 9 of 13 teenagers with a hip pointer, on both sides in all 9, although only 2 had pain on both sides; it disappeared once they stopped growing, so it is probably a normal variant. When the X-ray is unclear, MRI or CT (computed tomography) scans help, and in one study ultrasound identified avulsions correctly 84% of the time, including some that X-rays missed.
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