Generality
The ilium is a part of the ilium. To be precise, it is the part located higher - it overlooks both the ischium and the pubis - and of greater amplitude.
The iliac bone is the hip bone; it is an equal element, which develops laterally to the sacrum and participates, with this and the coccyx, in the formation of the pelvic girdle.
The ilium has two anatomically interesting sections: the so-called ilium body and the so-called ilium wing.
The body borders on the ischium and pubis and contributes to the formation of the acetabulum.
The wing, on the other hand, borders the sacrum and gives rise to a bone structure known as the iliac crest.
The ilium is the site of insertion of various muscles, including the external oblique abdominal, the buttocks (large, medium and small), the iliac muscle, the sartorius muscle and so on.
Together with the other bones of the pelvis, the ilium supports the upper part of the human body.
What is ilium?
The ilium is one of the three bony portions that make up the ilium.
To be precise, of the three portions that make up the iliac bone, it is the one located higher and of greater amplitude.
The iliac bone, also known as the hip bone, is the even and symmetrical bone which, together with the sacrum and the coccyx, constitutes that anatomical structure identified with the name of pelvic girdle.
THE OTHER PORTIONS OF THE ILIAC BONE
The other two portions of the iliac bone are the ischium and the pubis.
Ischium and pubis both develop inferiorly to the ilium, but, while the first projects backwards, the second moves forward, joining the contralateral iliac bone pubis and forming the so-called pubic symphysis.
ILIUM IS PART OF THE BONES OF THE PELVIS
The iliac bone - with its three portions ilium, ischium and pubis - and the combination of sacro-coccyx represent the so-called pelvic bones.
Anatomists call the pelvis, or pelvis, or pelvic region, the lower torso of the human body.
Located between the abdomen and the thighs, the pelvis comprises, in addition to the pelvic bones: the so-called pelvic cavity, the so-called pelvic floor and the so-called perineum.
Anatomy
Anatomically, the ilium has two relevant sections, known as the ilium body and ilium wing.
BODY
The body of the ilium is the section of the ilium that borders the ischium and the pubis: compared to the body, the ischium and pubis both reside below, but, while the first develops backwards, the second develops forward.
The body of the ilium includes part of the acetabulum; the acetabulum is the hollow in which the head of the femur takes place, in what is the so-called hip joint.
WING
The wing of the ilium is the section that:
- It resides above the body;
- It connects to the "sacrum, forming a" major joint known as the sacro iliac joint;
- It gives life to a bone structure, certainly known to most people, called the iliac crest.
On the wing, two surfaces are recognizable: the internal surface (or iliac fossa) and the external surface (or gluteal surface). The iliac fossa is concave and represents the point of origin of the iliac muscle; the gluteal surface, on the other hand, is convex, has semicircular lines called gluteal lines (anterior gluteal line, posterior gluteal line and inferior gluteal line) and represents the attachment point of the buttocks (NB: for more information on the ilium muscles, see the part dedicated to the "functions of" ilio ").
Furthermore, on the lateral edges, with both anterior and posterior orientation, the wing has bony prominences that take the name of spines: oriented forward, the so-called anterior superior iliac spine and anterior inferior iliac spine develop; oriented backwards, instead, the so-called posterior superior iliac spine and posterior inferior iliac spine come to life.
Development
The three sections of the iliac bone - ilium, ischium and pubis - are fused together.
The fusion of the aforesaid sections is a process that, in the human being, takes place around the 14th / 15th year of life.
Function
The bones of the pelvis, of which the ilium is in fact one of the various components, have at least three noteworthy tasks:
- Support the upper body;
- Connect the axial skeleton (which includes the skull, the vertebral column, the rib cage, etc.) to the lower limbs;
- Giving insertion to muscles, ligaments and tendons, essential for walking and more.
ILIUS AND HIP JOINT
As stated, the ilium takes part in the hip joint, as it participates in the formation of the acetabulum.
The "hip" is that equal joint element that allows the human being to assume an upright position, walk, run, jump, etc.
ILIUM AND MUSCLES
The muscles that have relations with the ilium are:
- The external oblique abdominal muscle. It is a muscle of the abdomen, which originates at the level of the ribs and has several insertions: in the iliac crest, in the pubic tubercle and in the linea alba.
- The multifidus muscle. It has several points of origin, including the superior posterior iliac spine. It is a back muscle.
- The gluteus maximus muscle. It is a muscle of the butt, which has multiple points of origin, including the posterior gluteal line and the rough portion of the iliac crest.
It ends at the gluteal tuberosity of the femur and in the so-called iliotibial tract. - The gluteus medius muscle. It is a muscle of the buttocks, which originates on the external surface of the ilium, in thearea between the iliac crest and the posterior gluteal line (N.B: it's just below the gluteus maximus muscle).
It ends in the greater trochanter of the femur. - The gluteus minimus muscle. It is a muscle of the butt, which originates on the external surface, in the "area between the anterior gluteal line and the inferior gluteal line. It arises just below the gluteus medius muscle.
It ends in the greater trochanter of the femur. - The iliac muscle. It originates in the iliac fossa and ends at the base of the lesser trochanter of the femur. It serves for flexion and lateral rotation of the thigh.
- The sartorius muscle. It is an anterior thigh muscle. It originates from superior anterior iliac spine and ends at the level of the goose leg of the tibia.
- The great dorsal muscle. It is the largest muscle in the human body. It originates in several points: in the section of the vertebral column between the seventh thoracic vertebrae and the fifth lumbar vertebrae, in the iliac crest, in the lower corner of the scapula, in the thoraco-lumbar fascia and in the last 3-4 ribs.
It ends in the intertubercular sulcus of the humerus.
Associated pathologies
Among the pathologies that can affect the ilium, bone fractures and hip pathologies certainly deserve a mention, with specific involvement of the acetabulum.
HIP PATHOLOGIES
The two most important pathologies of the hip, which can derive from an anomaly of the acetabulum, are: coxarthrosis (or osteoarthritis of the hip) and congenital dysplasia of the hip.
Please note: all three portions of the ilium participate in the formation of the acetabulum, therefore not only the ilium but also the ischium and pubis.
BONE FRACTURES
The fractures of the ilium are injuries of a traumatic nature, which usually occur after accidental falls, car accidents or impacts during the practice of sports in which physical contact is required (eg: rugby, American football, etc.) .
The areas of the ilium most prone to fracture are the wings.
Ilium fractures can be divided into two categories: stable fractures and unstable fractures. All fractures characterized by a single breaking point are stable, while all fractures characterized by two or more breaking points are unstable.
A severe ilium fracture can result in damage to the bladder or urethra.
