The Pelvic Girdle and Pelvis | Anatomy & Physiology
The left and right hip bones (innominate bones, pelvic bones) are two Together , the ilium, pubis and ischium form a cup-shaped socket. In adults, three of the bones of the pelvis have fused into the hip bone or acetabulum Both joint surfaces are covered with a strong but lubricated layer called articular forms at the union of three pelvic bones — the ilium, pubis, and ischium. During puberty, they fuse together to form a single bone, the pelvic cavity is a. Did the group being studied get its meat from hunting, or did it domesticate and Smallpox contributed to Sparta's defeat of Athens in b.c. and to the decline of Long narrow ilium Short, bro,id ilium Ischium Pubis HOMO ( IIIMP.
Ischium The ischium forms the posterolateral portion of the hip bone see Figure 8. The large, roughened area of the inferior ischium is the ischial tuberosity. This serves as the attachment for the posterior thigh muscles and also carries the weight of the body when sitting. You can feel the ischial tuberosity if you wiggle your pelvis against the seat of a chair. Projecting superiorly and anteriorly from the ischial tuberosity is a narrow segment of bone called the ischial ramus.
The slightly curved posterior margin of the ischium above the ischial tuberosity is the lesser sciatic notch. The bony projection separating the lesser sciatic notch and greater sciatic notch is the ischial spine. The central body of the ischium connects the ischial tuberosity, the acetabulum and the ischial spine. Pubis The pubis forms the anterior portion of the hip bone see Figure 8. The enlarged medial portion of the pubis is the pubic body.
Located superiorly on the pubic body is a small bump called the pubic tubercle. The superior pubic ramus is the segment of bone that passes laterally from the pubic body to join the ilium. The narrow ridge running along the superior margin of the superior pubic ramus is the pectineal line of the pubis.
The pubic body is joined to the pubic body of the opposite hip bone by the pubic symphysis. Extending downward and laterally from the body is the inferior pubic ramus.
The pubic arch is the bony structure formed by the pubic symphysis, and the bodies and inferior pubic rami of the adjacent pubic bones. The inferior pubic ramus extends downward to join the ischial ramus.
Together, these form the single ischiopubic ramus, which extends from the pubic body to the ischial tuberosity. The inverted V-shape formed as the ischiopubic rami from both sides come together at the pubic symphysis is called the subpubic angle Figure 8.
Pelvis The pelvis consists of four bones: The pelvis has several important functions. Its primary role is to support the weight of the upper body when sitting and to transfer this weight to the lower limbs when standing. It serves as an attachment point for trunk and lower limb muscles, and also protects the internal pelvic organs. When standing in the anatomical position, the pelvis is tilted anteriorly.
In this position, the anterior superior iliac spines and the pubic tubercles lie in the same vertical plane, and the anterior internal surface of the sacrum faces forward and downward.
The three areas of each hip bone, the ilium, pubis, and ischium, converge centrally to form a deep, cup-shaped cavity called the acetabulum. This is located on the lateral side of the hip bone and is part of the hip joint. The large opening in the anteroinferior hip bone between the ischium and pubis is the obturator foramen.
This space is largely filled in by a layer of connective tissue and serves for the attachment of muscles on both its internal and external surfaces. Several ligaments unite the bones of the pelvis Figure 8. The largely immobile sacroiliac joint is supported by a pair of strong ligaments that are attached between the sacrum and ilium portions of the hip bone.
The Hip Bone
These are the anterior sacroiliac ligament on the anterior side of the joint and the posterior sacroiliac ligament on the posterior side. The obturator externus muscle arises from the margin of bone immediately around the medial side of the obturator foramen, from the rami of the pubis, and the inferior ramus of the ischium; it also arises from the medial two-thirds of the outer surface of the obturator membrane, and from the tendinous arch.
Hamstrings The long head biceps femoris arises from the lower and inner impression on the back part of the tuberosity of the ischiumby a tendon common to it and the semitendinosusand from the lower part of the sacrotuberous ligament ;  The semitendinosus arises from the lower and medial impression on the tuberosity of the ischium, by a tendon common to it and the long head of the biceps femoris; it also arises from an aponeurosis which connects the adjacent surfaces of the two muscles to the extent of about 7.
The semimembranosus arises from the lower and medial impression on the tuberosity of the ischium Anterior compartment of thigh The rectus femoris muscle arises by two tendons: The sartorius muscle arises by tendinous fibres from the anterior superior iliac spine, Shoulder muscles The latissimus dorsi muscle attaches to the iliac crest and several places on the spine and ribs.
Clinical significance[ edit ] The proportions of the female hip bone may affect the ease of passage of the baby during childbirth. Pelvimetry is the assessment of the female pelvis  in relation to the birth of a baby in order to detect an increased risk for obstructed labor.
Pelvic fracture Fractures of the hip bone are termed pelvic fracturesand should not be confused with hip fractureswhich are actually femoral fractures  that occur in the proximal end of the femur. In animals[ edit ] The hip bone first appears in fishes, where it consists of a simple, usually triangular bone, to which the pelvic fin articulates.
The other system emerges on the lower part of the auricular surface, converges at the level of the superior gluteal lineand is reflected laterally onto the upper part of the acetabulum.
In the femur, the first system lines up with a system arising from the lateral part of the femoral shaft to stretch to the inferior portion of the femoral neck and head.
The other system lines up with a system in the femur stretching from the medial part of the femoral shaft to the superior part of the femoral head. Capsule of hip joint The capsule attaches to the hip bone outside the acetabular lip which thus projects into the capsular space.
On the femoral side, the distance between the head's cartilaginous rim and the capsular attachment at the base of the neck is constant, which leaves a wider extracapsular part of the neck at the back than at the front. The capsule has two sets of fibers: The circular fibers form a collar around the femoral neck called the zona orbicularis. The longitudinal retinacular fibers travel along the neck and carry blood vessels.
Ligaments[ edit ] Extracapsular ligaments.
Anterior left and posterior right aspects of right hip. Left hip joint from within pelvis with acetabular floor removed left ; right hip joint with capsule removed, anterior aspect right. The hip joint is reinforced by four ligaments, of which three are extracapsular and one intracapsular.
Hip bone - Wikipedia
The extracapsular ligaments are the iliofemoralischiofemoraland pubofemoral ligaments attached to the bones of the pelvis the iliumischiumand pubis respectively. All three strengthen the capsule and prevent an excessive range of movement in the joint. Of these, the Y-shaped and twisted iliofemoral ligament is the strongest ligament in the human body. In the sitting position, it becomes relaxed, thus permitting the pelvis to tilt backward into its sitting position. The iliofemoral ligament prevents excessive adduction and internal rotation of the hip.