Table of ContentsView AllTable of ContentsAnatomyFunctionAssociated ConditionsTreatment
Table of ContentsView All
View All
Table of Contents
Anatomy
Function
Associated Conditions
Treatment
Theilium, also known as the iliac bone, is the largest and uppermost bone on both sides of the pelvis. It is an essential part of the pelvic girdle.
In adults, this fan-shaped bone is fused with two other bones (the ischium and pubis) to make the hip bone (often referred to as the coxal bone).As such, the ilium serves a weight-bearing function and is part of the structure that ensures the spine is supported when the body is upright.
The ilium is an essential part of the apparatus that allows for locomotion. Conditions associated with the ilium include fractures, genetic deformities, and arthritis.
As part of the hip bone, the ilium, alongside theischiumandpubis, are fused to one another, and, via the sacroiliac ligaments, are attached to thesacrum(the tailbone).This juncture, which is largely immobile, is thesacroiliacjoint.
Anatomically speaking, the ilium is broken down into two parts: the body and the wing.
The body of the ilium is the more central portion, and it forms a part of theacetabulum—the socket joint where the head of thefemur(upper leg bone) rests—as well as the acetabular fossa, a deeper depression just above the joint.
The wing of the ilium, as the name implies, is the larger, expanded portion of the bone. On each side, it represents the outer, side edge of the pelvis.
The ilium also has a number of important landmarks:
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Anatomical Variations
As indicated above, the primary purpose of the ilium is to serve as part of the pelvis and assist in both supporting the upper body and facilitating locomotion and walking. Numerous muscles and nerves connect to the ilium, helping determine this bone’s function. Relevant muscles include:
Many ligaments also connect to the ilium, and these are often associated with the stabilizing functions of this bone. From the anterior superior iliac spine arise theinguinalandiliofemoralligaments, which connect to the pubic bone and the femur, respectively.Thesacrotuberousligament supports the sacrum and prevents it from moving; it attaches to the iliac tuberosity.
Finally, several other supportive ligaments—the dorsal,interosseous, ventral sacroiliac, and iliolumbar—also connect to the iliac tuberosity.
The ilium can become fractured due to falls or other trauma. Symptoms of this include sharp pain, swelling and bruising, as well as an inability to put weight on the hip.
Genetic deformities can also arise in the shape of the ilium and pelvis, which can cause a range of problems.
Finally, inflammation of thesacroiliac joint—a condition called sacroiliitis—can cause low back pain, fever, and stiffness.This often arises due to arthritis in the hip or spine. Sacroiliitis can also be associated with:
pregnancy, and infection may put stress or wear and tear on this area, causing sacroiliitis.
Pain associated with the ilium can be due to:
You may also have referred pain, which originates somewhere else in the body but is felt in the hip. Injuries to the joint or lower back can cause referred pain.
Treatment for issues surrounding the ilium and pelvis varies depending on the cause and severity of the condition. With genetic deformities, for example, treatment will focus on the specific complications that are present.
Treatment for a fractured ilium depends on the extent of the injury. For minor fractures, treatment may include:
For more severe fractures, surgery may be required to repair the area.
For hip strain, physical therapy and ahome exercise programmay strengthen the muscles that support the hip and help to improve muscle flexibility.
Summary
The ilium is the largest and uppermost bone on both sides of the pelvis. It is important for weight-bearing and ensures the spine is supported when the body is upright and moving. Several conditions can cause pain in the ilium, and treatment will depend on the specific cause.
7 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Rice University.The pelvic girdle and pelvis. InAnatomy and Physiology. Houston, TX. Pressbooks.Wobser AM, Adkins Z, Wobser RW.Anatomy, Abdomen and Pelvis: Bones (Ilium, Ischium, and Pubis). StatPearls Publishing. [Updated 2023 Jul 24].Figueroa C, Jozsa F, Le PH.Anatomy, Bony Pelvis and Lower Limb: Pelvis Bones. StatPearls Publishing.[Updated 2023 Jul 30].Jarvis M, Batta N.Ilium: Radiology Reference Article. Radiopaedia.org.Baronio M, Sadia H, Paolacci S, et al.Etiopathogenesis of sacroiliitis: implications for assessment and management. Korean J Pain. 2020 Oct 1;33(4):294-304. doi: 10.3344/kjp.2020.33.4.294Vitale K, Smitaman E, Huang BK.Medial iliac stress fractures in athletes: report of two rare cases: review of literature and clinical recommendations.Skeletal Radiol. 2019;48(7):1119-1123. doi:10.1007/s00256-018-3117-zAmerican Academy of Orthopaedic Surgeons.Hip strains.
7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Rice University.The pelvic girdle and pelvis. InAnatomy and Physiology. Houston, TX. Pressbooks.Wobser AM, Adkins Z, Wobser RW.Anatomy, Abdomen and Pelvis: Bones (Ilium, Ischium, and Pubis). StatPearls Publishing. [Updated 2023 Jul 24].Figueroa C, Jozsa F, Le PH.Anatomy, Bony Pelvis and Lower Limb: Pelvis Bones. StatPearls Publishing.[Updated 2023 Jul 30].Jarvis M, Batta N.Ilium: Radiology Reference Article. Radiopaedia.org.Baronio M, Sadia H, Paolacci S, et al.Etiopathogenesis of sacroiliitis: implications for assessment and management. Korean J Pain. 2020 Oct 1;33(4):294-304. doi: 10.3344/kjp.2020.33.4.294Vitale K, Smitaman E, Huang BK.Medial iliac stress fractures in athletes: report of two rare cases: review of literature and clinical recommendations.Skeletal Radiol. 2019;48(7):1119-1123. doi:10.1007/s00256-018-3117-zAmerican Academy of Orthopaedic Surgeons.Hip strains.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Rice University.The pelvic girdle and pelvis. InAnatomy and Physiology. Houston, TX. Pressbooks.Wobser AM, Adkins Z, Wobser RW.Anatomy, Abdomen and Pelvis: Bones (Ilium, Ischium, and Pubis). StatPearls Publishing. [Updated 2023 Jul 24].Figueroa C, Jozsa F, Le PH.Anatomy, Bony Pelvis and Lower Limb: Pelvis Bones. StatPearls Publishing.[Updated 2023 Jul 30].Jarvis M, Batta N.Ilium: Radiology Reference Article. Radiopaedia.org.Baronio M, Sadia H, Paolacci S, et al.Etiopathogenesis of sacroiliitis: implications for assessment and management. Korean J Pain. 2020 Oct 1;33(4):294-304. doi: 10.3344/kjp.2020.33.4.294Vitale K, Smitaman E, Huang BK.Medial iliac stress fractures in athletes: report of two rare cases: review of literature and clinical recommendations.Skeletal Radiol. 2019;48(7):1119-1123. doi:10.1007/s00256-018-3117-zAmerican Academy of Orthopaedic Surgeons.Hip strains.
Rice University.The pelvic girdle and pelvis. InAnatomy and Physiology. Houston, TX. Pressbooks.
Wobser AM, Adkins Z, Wobser RW.Anatomy, Abdomen and Pelvis: Bones (Ilium, Ischium, and Pubis). StatPearls Publishing. [Updated 2023 Jul 24].
Figueroa C, Jozsa F, Le PH.Anatomy, Bony Pelvis and Lower Limb: Pelvis Bones. StatPearls Publishing.[Updated 2023 Jul 30].
Jarvis M, Batta N.Ilium: Radiology Reference Article. Radiopaedia.org.
Baronio M, Sadia H, Paolacci S, et al.Etiopathogenesis of sacroiliitis: implications for assessment and management. Korean J Pain. 2020 Oct 1;33(4):294-304. doi: 10.3344/kjp.2020.33.4.294
Vitale K, Smitaman E, Huang BK.Medial iliac stress fractures in athletes: report of two rare cases: review of literature and clinical recommendations.Skeletal Radiol. 2019;48(7):1119-1123. doi:10.1007/s00256-018-3117-z
American Academy of Orthopaedic Surgeons.Hip strains.
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