The Hip Bone - Ilium - Ischium - Pubis - TeachMeAnatomy
These bones are the ilium, ischium, and pubis. These hip Other minor arteries supply blood to the pelvis and do not originate from the iliac. The ilium, ischium, pubis, acetabulum,. I were to do something that causes a fracture to my pelvis, the structure that does things like protecting. Answer to When do the ilium, ischium, and pubis fuse to form the os coxae? What features do each of these bones contribute to the.
The hip joint, or acetabulum, is at the central location on each side of the pelvis. The girdle provides origin points for various muscles of the legs that allow for movement of the femoral head in the acetabulum.
The distance from the acetabulum to the crest of the iliac allows for greater leverage of the muscles attached than if those muscles originated more closely to the joint. This would give an evolutionary advantage that allows for more rapid movement than other forms of locomotion at a lower energy cost.
The pelvis is also connected by muscles to the axial skeleton to allow orientation and stabilization.
The pelvis has a "floor" that has several functions. The first function is to contain the visceral organs. This provides structural integrity to the floor caudal region of the pelvis and prevents prolapse through the pelvic outlet.
The second function is to control the opening of the anus, vagina in females, and the urinary outlet. This is accomplished through several layers of musculature and ligaments. This floor of the pelvis will be described in a later section. Embryology The earliest appendicular skeletal elements appear at approximately 28 days, which coincides with the appearance of limb buds. Condensation of mesenchymal tissue in the fifth week form in the limb buds to form bone models.
These models undergo chondrification to form hyaline cartilage bone models beginning in the sixth week. At this point, radiologic studies can discern a basic skeletal system. The following week the first ossification center is present in the iliac crest. At the same time, fusion if the sacrum and ilium occur. After the tenth week of gestation, the fusion of all the bones of the girdle and pelvis has occurred. Primary ossification centers are present.
Secondary ossification continues post-birth. Complete ossification is not effected until adulthood. At the pelvic brim, the iliac arteries bifurcate into the internal and external iliac arteries.
The external iliac exits the pelvis through the inguinal ligament and supplies the ipsilateral lower extremity with blood. The internal iliac artery supplies the pelvic organs, perineal floor, and gluteal muscles with blood. It has 2 major divisions, known as the anterior and posterior.
The anterior division supplies the upper part of the bladder via the umbilical and superior vesicular arteries. The pelvic floor, head of the femur, and ilium are supplied via the obturator artery. The trigone of the bladder, prostate, and seminal glands are supplied by the inferior vesical artery.
The middle rectal artery supplied the rectum with blood. The internal pudendal artery supplies the perineal muscles and skin as well as the as the penis and clitoris. In women, the uterine artery supplies blood to the uterus, fallopian tube, ovary, cervix, and vagina. The posterior division includes several branches. The iliolumbar artery supplies blood to the psoas major, iliacus, and quadratus lumborum muscles. It also supplies the cauda equina. The lateral sacral arteries supply blood to the sacral plexus and vertebral canal.
Other minor arteries supply blood to the pelvis and do not originate from the iliac. The superior rectal artery supplies blood to the rectum and anus. The median sacral artery anastomoses with the with the lateral sacral arteries. It is a vestigial, direct continuation of the aorta. Finally, the ovarian artery supplies blood to the ovaries and anastomoses with the uterine artery.
There are several groups of lymph nodes in the pelvis.
Hip Bone Anatomy or Pelvic Bone[Ilium-Pubis-Ischium] | Bone and Spine
They include the external, internal, and common iliac nodes. They also include the sacral, pararectal, lumber, and inguinal nodes. There is extensive communication for these node groups, and it facilitates spreading of cancer to other pelvic or abdominal organs.
Nerves There are two plexuses of nerves that provide motor and sensory innervation to the pelvis. They are the sacral plexus and the coccygeal plexus. It includes the sciatic nerve L4 through S3. This is the longest nerve in the body. It innervates almost the entire skin of the leg as well the muscles of the leg and foot. The S2-S4 pudendal nerve innervates both the skin and muscles of the perineum.
The superior gluteal nerve L4 through S1 and the inferior gluteal nerve L5 through S2 innervate the gluteal muscles. The nerve to the quadratus femoris L4 through S1 innervates the quadratus femoris and gemellus inferior muscles of the hip. The nerve to the obturator internus muscle L5 through S2 innervates said muscle.
The nerve to the S1-S2 piriformis muscle innervates said muscle. The S2-S3 perforating cutaneous nerve innervates the medial and lower part of the buttock. The coccygeal plexus S4 through S5 and coccygeal nerves innervate the coccygeus and levator ani muscles, and well as the skin immediately dorsal to the anal vent. The obturator nerve arises from the lumbar plexus L2 through L4 and innervates the skin of the medial aspect of the thigh.
Parasympathetic and sympathetic innervation is also present. The superior hypogastric plexus provides sympathetic innervation to the pelvis. The inferior hypogastric plexuses contain both parasympathetic and sympathetic fibers. In general, parasympathetic and sympathetic innervation works as expected in the "fight or flight" response.
Parasympathetic output causes gastrointestinal GI peristalsis, and contracts muscles for defecation and urination. It is also involved in engorgement of erectile tissue. Sympathetic output acts antagonistically to the parasympathetic output and is also involved in muscle contraction during orgasm. Remember the medical school phrase that compares the male sexual function to firing a pistol: Some muscles attach to the trunk and provide movent and stabilization.
Finally, the muscles of the pelvic floor and perineum are located wholly within the pelvis. From caudal superficial to cephalad deepthey are the urogenital triangle, the urogenital diaphragm, and the pelvic diaphragm. The urogenital triangle consists of several muscles. The superficial transverse perineal muscle originates at the ischial tuberosity and extends to the central, tendinous perineal body, which lies immediately ventral to the anus.
It is involved primarily with the support of the pelvic floor. The second muscle is the ischiocavernosus. It extends from the ischial tuberosity to the ischiopubic rami and is involved in supporting the erect male penis, the female vagina, as well as flexing the anus. The third muscle is the bulbocavernosus bulbospongiosus in men. It is located in the midline of the pelvis and describes a dorsal to a ventral path starting from the tendinous body and coursing to the ischiocavernosus.
In both males and females, it contributes to erection. In the female, the fibers are divided and course laterally around the vaginal introitus.
The final muscle in the urogenital triangle is the anal sphincter. This is attached to the dorsal end of the perineal body or central tendinous portion, and some fibers spread to the levator ani posteriorly. The function of this muscle is defecatory regulation. Deeper more cephalad into the pelvis is the urogenital diaphragm. It is a triangular ligament with a string muscular component that stretches from the pubic symphysis to the to the ischial tuberosities.
It occupies the ventral portion of the pelvic outlet. It is composed of several muscles. In males, the external sphincter is located just caudal to the prostate, and in females, it is located just caudal to the internal sphincter. The external sphincter is skeletal muscle and is under voluntary control. Both the internal and external sphincter are involved in regulating urination.
The deep transverse perineal muscle extends from the inferior rami of the ischium and inserts into the tendinous median plane. It aids in support of the pelvis. The caudal and cephalad borders of this muscular-tendinous plane are embedded in a layer of fascia.
The ischium forms the posteroinferior region of each hip bone. It supports the body when sitting. The pubis forms the anterior portion of the hip bone. The pubis curves medially, where it joins to the pubis of the opposite hip bone at a specialized joint called the pubic symphysis. Ilium When you place your hands on your waist, you can feel the arching, superior margin of the ilium along your waistline see Figure 8.
This curved, superior margin of the ilium is the iliac crest. The rounded, anterior termination of the iliac crest is the anterior superior iliac spine. This important bony landmark can be felt at your anterolateral hip. Inferior to the anterior superior iliac spine is a rounded protuberance called the anterior inferior iliac spine. Both of these iliac spines serve as attachment points for muscles of the thigh. Posteriorly, the iliac crest curves downward to terminate as the posterior superior iliac spine.
More inferiorly is the posterior inferior iliac spine. This is located at the inferior end of a large, roughened area called the auricular surface of the ilium. The auricular surface articulates with the auricular surface of the sacrum to form the sacroiliac joint. Both the posterior superior and posterior inferior iliac spines serve as attachment points for the muscles and very strong ligaments that support the sacroiliac joint.
The shallow depression located on the anteromedial internal surface of the upper ilium is called the iliac fossa. The inferior margin of this space is formed by the arcuate line of the ilium, the ridge formed by the pronounced change in curvature between the upper and lower portions of the ilium. The large, inverted U-shaped indentation located on the posterior margin of the lower ilium is called the greater sciatic notch.
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.
The Hip Bone
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 Pelvic Girdle and Pelvis | Anatomy & Physiology
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.
Hip Bone Anatomy or Pelvic Bone[Ilium-Pubis-Ischium]
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.