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PELVIS

10.01.2014

Kaan YücelM.D., Ph.D.

http://yeditepeanatomy1.org

Kaan Yücel http://yeditepeanatomy1.org Pelvis

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In common usage, the pelvis (L. basin) is the part of the trunk inferoposterior to the abdomen and is the area of transition between the trunk and the lower limbs. The bones of the pelvis consist of the right and left pelvic (hip) bones, the sacrum, and the coccyx.

The pelvic girdle is a basin-shaped ring of bones that connects the vertebral column to the two femora. The pelvic girdle is strong and rigid, especially compared to the pectoral (shoulder) girdle.In the mature individual, the pelvic girdle is formed by three bones: Right and left hip bones (coxal bones; pelvic bones): large, irregularly shaped bones, each of which develops from the fusion of three bones, the ilium, ischium, and pubis. Sacrum: formed by the fusion of five, originally separate, sacral vertebrae.

The ilium is the superior, fan-shaped part of the hip bone. The ala iliaca, wing of the ilium represents the spread of the fan, and the body of the ilium, the handle of the fan. On its external aspect, the body participates in formation of the acetabulum. The entire superior margin of the ilium is thickened to form a prominent crest (iliac crest), which is the site of attachment for muscles and fascia of the abdomen, back, and lower limb and terminates anteriorly as the anterior superior iliac spine and posteriorly as the posterior superior iliac spine.

The ischium has a body and ramus. The body of the ischium helps form the acetabulum and the ramus of the ischium forms part of the obturator foramen. The large posteroinferior protuberance of the ischium is the ischial tuberosity. The small pointed posteromedial projection near the junction of the ramus and body is the ischial spine.

The pubis is an angulated bone with a superior ramus, which helps form the acetabulum, and an inferior ramus, which helps form the obturator foramen.

The pelvis is divided into greater (false) and lesser (true) pelves by the oblique plane of the pelvic inlet (superior pelvic aperture). The bony edge (rim) surrounding and defining the pelvic inlet is the pelvic brim.

The pelvic inlet is the circular opening between the abdominal cavity and the pelvic cavity. Through the pelvic inlet structures traverse between the abdomen and pelvic cavity. It is completely surrounded by bones and joints. The pelvic outlet is diamond shaped, with the anterior part of the diamond defined predominantly by bone and the posterior part mainly by ligaments.

The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains reproductive organs, the urinary bladder, the pelvic colon, and the rectum.The linea terminalis consists of the the arcuate line, the pecten pubis or pectineal line, and the pubic crest. It is part of the pelvic brim, which is the edge of the pelvic inlet.

The primary joints of the pelvic girdle are the sacroiliac joints and the pubic symphysis. The sacroiliac joints link the axial skeleton (skeleton of the trunk, composed of the vertebral column at this level) and the inferior appendicular skeleton (skeleton of the lower limb). The lumbosacral and sacrococcygeal joints, although joints of the axial skeleton, are directly related to the pelvic girdle. Strong ligaments support and strengthen these joints.

The sacroiliac joints are strong, weight-bearing compound joints, consisting of an anterior synovial joint (between the earshaped auricular surfaces of the sacrum and ilium, covered with articular cartilage) and a posterior syndesmosis (between the tuberosities of the same bones). Weight is transferred from the axial skeleton to the ilia via the sacroiliac ligaments, and then to the femurs during standing, and to the ischial tuberosities during sitting. The sacrum is actually suspended between the iliac bones and is firmly attached to them by posterior and interosseous sacroiliac ligaments.

The pubic symphysis is a secondary cartilaginous joint which consists of a fibrocartilaginous interpubic disc and surrounding ligaments uniting the bodies of the pubic bones in the median plane. The ligaments joining the bones are thickened at the superior and inferior margins of the symphysis, forming superior and inferior pubic ligaments.

L5 and S1 vertebrae articulate at the anterior intervertebral (IV) joint formed by the L5/S1 IV disc between their bodies and at two posterior zygapophysial joints (facet joints) between the articular processes of these vertebrae as lumbosacral joints.

The sacrococcygeal joint is a secondary cartilaginous joint with an intervertebral disc.

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Dr.Kaan Yücel http://yeditepeanatomy1.org Pelvis

In common usage, the pelvis (L. basin) is the part of the trunk inferoposterior to the abdomen and is

the area of transition between the trunk and the lower limbs. The pelvic cavity is the inferiormost part of the

abdominopelvic cavity. The bones of the pelvis consist of the right and left pelvic (hip) bones, the sacrum, and

the coccyx.

The pelvic girdle is a basin-shaped ring of bones that connects the vertebral column to the two femora.

In the mature individual, the pelvic girdle is formed by three bones:

Right and left hip bones (coxal bones; pelvic bones): large, irregularly shaped bones, each of which

develops from the fusion of three bones, the ilium, ischium, and pubis.

Sacrum: formed by the fusion of five, originally separate, sacral vertebrae.

The internal (medial or pelvic) aspects of the hip bones bound the pelvis, forming its lateral walls.

In infants and children, the hip bones consist of three separate bones that are united by a triradiate

cartilage at the acetabulum, the cup-like depression in the lateral surface of the hip bone, which articulates

with the head of the femur. After puberty, the ilium, ischium, and pubis fuse to form the hip bone. The two

hip bones are joined anteriorly at the pubic symphysis (L. symphysis pubis) and articulate posteriorly with the

sacrum at the sacroiliac joints to form the pelvic girdle.

The primary functions of the pelvic girdle are to:

bear the weight of the upper body when sitting and standing.

transfer that weight from the axial to the lower appendicular skeleton for standing and walking.

provide attachment for the powerful muscles of locomotion and posture and those of the abdominal wall,

withstanding the forces generated by their actions.

Consequently, the pelvic girdle is strong and rigid, especially compared to the pectoral (shoulder)

girdle. Other functions of the pelvic girdle are to:

Contain and protect the pelvic viscera (inferior parts of the urinary tracts and the internal reproductive

organs) and the inferior abdominal viscera (intestines), while permitting passage of their terminal parts (and,

in females, a full-term fetus) via the perineum.

Provide support for the abdominopelvic viscera and gravid (pregnant) uterus.

Provide attachment for the erectile bodies of the external genitalia.

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1. PELVIS

2 PELVIC GIRDLE


Provide attachment for the muscles and membranes that assist the functions listed above by forming the

pelvic floor and filling gaps that exist in or around it.

Figure 1. Pelvic girdle- hip bones (os coxae) & sacrum

Pelvic girdle –anterior viewhttp://forensicanth-nu.wikispaces.com/Pelvis+Group

Each pelvic bone is formed by three elements: the ilium, pubis, and ischium. At birth, these bones are

connected by cartilage in the area of the acetabulum; later, at between 16 and 18 years of age, they fuse into

a single bone.

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3. HIP (PELVIC) BONES

Pelvic bone (Hip bone) separated by an oblique line on the medial surface

FALSE PELVIS (PELVIS MAJOR, GREATER PELVIS)pelvic bone above this line lateral wall of the false pelvis.

part of the abdominal cavityPart of the abdominal cavity

Occupied by abdominal visceraTRUE PELVIS (PELVIS MINOR, LESSER PELVIS)

contains the pelvic cavity.major obstetrical and gynecological significance

pelvic bone above this line lateral wall of the true pelvis

http://forensicanth-nu.wikispaces.com/Pelvis+Group


ILIUMLatin (ile, ilis), meaning "groin-kasık" or "flank-böğür"

Figure 2. Iliumhttp://faithanatomyg3.wikispaces.com/Hips

Of the three components of the pelvic bone, the ilium is the most superior in position. The upper fan-

shaped part of the ilium is associated on its inner side with the abdomen and on its outer side with the lower

limb.

The ilium is separated into upper and lower parts by a ridge on the medial surface. Anteriorly, the

ridge separating the upper and lower parts of the ilium is rounded and termed the arcuate line (The arcuate

line forms part of the linea terminalis and the pelvic brim).


AcetabulumAla iliaca (Wing of the ilium)Anterior inferior iliac spine Anterior superior iliac spineAuricular surfaceBody of the iliumGreater sciatic notchIiopubic eminence (or iliopectineal eminence) Iliac crestIliac fossaIliac tuberosityIliopectineal lineInferior/anterior/posterior gluteal lines

http://faithanatomyg3.wikispaces.com/Hips


The portion of the ilium lying inferiorly to the arcuate line is the pelvic part of the ilium and contributes

to the wall of the lesser or true pelvis.

The ala iliaca, wing of the ilium represents the spread of the fan, and the body of the ilium, the handle

of the fan. On its external aspect, the body participates in formation of the acetabulum.

The upper part of the ilium expands to form a flat, fan-shaped "wing," “ala iliaca” provides bony

support for the lower abdomen, or false pelvis. This part of the ilium provides attachment for muscles

functionally associated with the lower limb. The anteromedial surface of the wing is concave and forms the

iliac fossa.

The entire superior margin of the ilium is thickened to form a prominent crest (iliac crest), which is the

site of attachment for muscles and fascia of the abdomen, back, and lower limb. The iliac crest terminates

anteriorly as the anterior superior iliac spine and posteriorly as the posterior superior iliac spine.

A less prominent posterior inferior iliac spine occurs along the posterior border of the sacral surface of

the ilium, where the bone angles forward to form the superior margin of the greater sciatic notch.

A prominent lateral expansion of the crest just posterior to the anterior superior iliac spine is the

tuberculum of iliac crest. The posterior end of the iliac crest thickens to form the iliac tuberosity.

The anteromedial concave surface of the ala forms the iliac fossa. Posteriorly, the sacropelvic surface

of the ilium features an auricular surface and an iliac tuberosity, for synovial and syndesmotic articulation

with the sacrum, respectively. The anterior inferior iliac spine is on the anterior margin of the ilium, and

below this, where the ilium fuses with the pubis, is a raised area of bone; iliopubic eminence (or iliopectineal

eminence). The iliopubic eminence marks the point of union of the ilium and pubis. It constitutes a lateral

border of the pelvic inlet.The iliopectineal line is the border of the eminence.

The gluteal surface of the ilium faces lies below the iliac crest posterolaterally. It is marked by three

curved lines (inferior, anterior, and posterior gluteal lines), which divide the surface into four regions:

inferior gluteal line originates just superior to the anterior inferior iliac spine and curves inferiorly across the

bone. It ends near the posterior margin of the acetabulum.

anterior gluteal line originates from the lateral margin of the iliac crest between the anterior superior iliac

spine and the tuberculum of iliac crest, and arches inferiorly across the ilium.

posterior gluteal line descends almost vertically from the iliac crest to a position near the posterior inferior

iliac spine.



ISCHIUMFrom the Greek ἰσχίον ischion, meaning “hip”

Figure 3. Ischiumhttp://www.lollylegs.com/injuries/ischial_tuberosity.aspx

The ischium is the posterior and inferior part of the pelvic bone. It has:

a large body that projects superiorly to join with the ilium and the superior ramus of the pubis; and

a ramus (L. branch) that projects anteriorly to join with the inferior ramus of the pubis.

The body of the ischium helps form the acetabulum and the ramus of the ischium forms part of the

obturator foramen.

The most prominent feature of the ischium is a large tuberosity; ischial tuberosity on the

posteroinferior aspect of the bone. This tuberosity is an important site for the attachment of lower limb

muscles and for supporting the body when sitting. The small pointed posteromedial projection near the

junction of the ramus and body is the ischial spine. The concavity between the ischial spine and the ischial


AcetabulumBody of ischiumGreater sciatic notchIschial spineIschial tuberosityLesser sciatic notchObturator foramenRamus ossis ischii (ramus of ischium)

http://www.lollylegs.com/injuries/ischial_tuberosity.aspx


tuberosity is the lesser sciatic notch. The larger concavity, the greater sciatic notch, is superior to the ischial

spine and is formed in part by the ilium.

PUBISfrom Latin pubes "genital area,

groin," related to pubes "full-grown" Figure 4. Pubis

http://home.comcast.net/~wnor/pelvis.htm

The anterior and inferior part of the pelvic bone is the pubis. It has a body and two arms (rami).

The pubis is an angulated bone with a superior ramus, which helps form the acetabulum, and an

inferior ramus, which helps form the obturator foramen. A thickening on the anterior part of the body of the

pubis is the pubic crest, which ends laterally as a prominent swelling; pubic tubercle. The lateral part of the

superior pubic ramus has an oblique ridge; pecten pubis (pectineal line of pubis). The superior pubic ramus is

marked on its inferior surface by the obturator groove, which forms the upper margin of the obturator canal.

Distinct features of the pelvic boneAcetabulumThe lateral surface of the pelvic bone has a large articular socket, the acetabulum, which, together

with the head of the femur, forms the hip joint. The acetabulum is formed by the three hip bones. The margin


AcetabulumInferior ramus of pubisObturator foramen/groovePecten pubis (pectineal line of pubis)Pubic crestPubic tubercle

http://home.comcast.net/~wnor/pelvis.htm


of the acetabulum is marked inferiorly by a prominent notch (acetabular notch). The wall of the acetabulum

consists of nonarticular and articular parts:

nonarticular part is rough and forms a shallow circular depression (acetabular fossa) in central and inferior

parts of the acetabular floor-the acetabular notch is continuous with the acetabular fossa

articular surface is broad and surrounds the anterior, superior, and posterior margins of the acetabular fossa.

The smooth crescent-shaped articular surface (lunate surface) is broadest superiorly where most of

the body's weight is transmitted through the pelvis to the femur. The lunate surface is deficient inferiorly at

the acetabular notch. The acetabular fossa provides attachment for the ligament of the head of the femur,

whereas blood vessels and nerves pass through the acetabular notch.

Inferior to the acetabulum is the large obturator foramen, most of which is closed by a flat connective

tissue membrane, the obturator membrane. A small obturator canal remains open superiorly between the

membrane and adjacent bone, providing a route of communication between the lower limb and the pelvic

cavity.

The posterior margin of the pelvic bone is marked by two notches separated by the ischial spine:

greater sciatic notch

lesser sciatic notch

The posterior margin terminates inferiorly as the large ischial tuberosity.

The irregular anterior margin of the pelvic bone is marked by the anterior superior iliac spine, anterior

inferior iliac spine, and the pubic tubercle.

Figure 4. Hip boneshttp://anatomytopics.wordpress.com/tag/primitive-streak


http://anatomytopics.wordpress.com/tag/primitive-streak/


The pelvis is divided into greater (false) and lesser (true) pelves by the oblique plane of the pelvic inlet

(superior pelvic aperture). The bony edge (rim) surrounding and defining the pelvic inlet is the pelvic brim,

formed by the:

Promontory and ala of the sacrum (superior surface of its lateral part, adjacent to the body of the

sacrum).

A right and left linea terminalis (terminal line)

The pubic arch is formed by the ischiopubic rami (conjoined inferior rami of the pubis and ischium) of

the two sides. These rami meet at the pubic symphysis, their inferior borders defining the subpubic angle. The

width of the subpubic angle is determined by the distance between the right and the left ischial tuberosities,

which can be measured with the gloved fingers in the vagina during a pelvic examination.

PELVIC INLET (SUPERIOR PELVIC APERTURE)The pelvic inlet is the circular opening between the abdominal cavity and the pelvic cavity. Through

the pelvic inlet structures traverse between the abdomen and pelvic cavity. It is completely surrounded by

bones and joints.

The pelvic inlet is formed:

anteriorly by the pubic symphysis

posteriorly by the sacrum

laterally by the iliopectineal line

The promontory of the sacrum protrudes into the inlet, forming its posterior margin in the midline.


4. PELVIC INLET & PELVIC OUTLET


PELVIC OUTLET (INFERIOR PELVIC APERTURE)The pelvic outlet is diamond shaped, with the anterior part of the diamond defined predominantly by

bone and the posterior part mainly by ligaments.

Anatomical outlet is bounded by;

pubic arch,anteriorly

ischial tuberosities, laterally

sacrotuberous and sacrospinous ligaments, posterolaterally

tip of the coccyx, posteriorly

Obstetric outlet is bounded by:

the roof is the plane of least pelvic dimension,

the floor is the anatomical outlet,

anteriorly the lower border of symphysis pubis,

posteriorly the coccyx.

laterally the ischial spines.

The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the

pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity

primarily contains reproductive organs, the urinary bladder, the pelvic colon, and the rectum.

The greater pelvis (false pelvis) is the part of the pelvis:

Superior to the pelvic inlet.

Bounded by the iliac alae posterolaterally and the anterosuperior aspect of the S1 vertebra posteriorly.

Occupied by abdominal viscera (e.g., the ileum and sigmoid colon).

The lesser pelvis (true pelvis) is the part of the pelvis:

Between the pelvic inlet and the pelvic outlet.

Has an inlet, an outlet, and a cavity.

The pelvic inlet is bounded posteriorly by the sacral promontory, laterally by the iliopectineal lines, and

anteriorly by the symphysis pubis.

Bounded by the pelvic surfaces of the hip bones, sacrum, and coccyx.

That is of major obstetrical and gynecological significance.

PELVIC CAVITYIt is a segment, the boundaries of which are:

the roof is the plane of pelvic brim,



the floor is the plane of least pelvic dimension,

anteriorly the shorter symphysis pubis,

posteriorly the longer sacrum.

The terms pelvis, lesser pelvis, and pelvic cavity are commonly used incorrectly, as if they were

synonymous terms.

The linea terminalis consists of the the arcuate line, the pecten pubis or pectineal line, and the pubic

crest. It is part of the pelvic brim, which is the edge of the pelvic inlet. The pecten pubis forms part of the

pelvic brim and the continuation on the superior ramus pubis of the linea terminalis, forming a sharp ridge.

The arcuate line of the ilium is a smooth rounded border on the internal surface of the ilium. It is immediately

inferior to the iliac fossa. It forms part of the border of the pelvic inlet. The pecten pubis forms part of the

pelvic brim.

Figure 5. Pelvic inlet & outlet Figure 6. Pelvic cavity, lesser (true) pelvis and greater (false) pelvishttp://kullamilowski.files.wordpress.com/2012/08/pelvic-cavity.jpeg

http://128.134.207.23/maternity/component2.htm


5. JOINTS OF THE PELVIC GIRDLE

http://128.134.207.23/maternity/component2.htm

http://kullamilowski.files.wordpress.com/2012/08/pelvic-cavity.jpeg


The primary joints of the pelvic girdle are the sacroiliac joints and the pubic symphysis. The sacroiliac

joints link the axial skeleton (skeleton of the trunk, composed of the vertebral column at this level) and the

inferior appendicular skeleton (skeleton of the lower limb). The lumbosacral and sacrococcygeal joints,

although joints of the axial skeleton, are directly related to the pelvic girdle. Strong ligaments support and

strengthen these joints.

The sacroiliac joints are strong, weight-bearing compound joints, consisting of an anterior synovial

joint (between the ear-shaped auricular surfaces of the sacrum and ilium, covered with articular cartilage) and

a posterior syndesmosis (between the tuberosities of the same bones). The sacroiliac joints differ from most

synovial joints in that limited mobility is allowed, a consequence of their role in transmitting the weight of

most of the body to the hip bones.

Weight is transferred from the axial skeleton to the ilia via the sacroiliac ligaments, and then to the

femora during standing, and to the ischial tuberosities during sitting. The sacrum is actually suspended

between the iliac bones and is firmly attached to them by posterior and interosseous sacroiliac ligaments.

Each sacro-iliac joint is stabilized by three ligaments:

anterior sacro-iliac ligament, which is a thickening of the fibrous membrane of the joint capsule and

runs anteriorly and inferiorly to the joint;

interosseous sacro-iliac ligament, which is the largest, strongest ligament of the three, is positioned

immediately posterosuperior to the joint and attaches to adjacent expansive roughened areas on the

ilium and sacrum, thereby filling the gap between the two bones; and

posterior sacro-iliac ligament, which covers the interosseous sacro-iliac ligament.

The abundant interosseous sacroiliac ligaments (lying deep between the tuberosities of the sacrum

and ilium) are the primary structures involved in transferring the weight of the upper body from the axial

skeleton to the two ilia of the appendicular skeleton.

The posterior sacroiliac ligaments are the posterior external continuation of the same mass of fibrous

tissue. Inferiorly, the posterior sacroiliac ligaments are joined by fibers extending from the posterior margin of

the ilium (between the posterior superior and posterior inferior iliac spines) and the base of the coccyx to

form the massive sacrotuberous ligament. This ligament passes from the posterior ilium and lateral sacrum

and coccyx to the ischial tuberosity, transforming the sciatic notch of the hip bone into a large sciatic

foramen. The sacrospinous ligament, passing from lateral sacrum and coccyx to the ischial spine, subdivides

the sciatic foramen into greater and lesser sciatic foramina.


6. SACROILIAC JOINTS


The sacrospinous and sacrotuberous ligaments are major components of the lateral pelvic walls that

help define the apertures between the pelvic cavity and adjacent regions through which structures pass.

Most of the time, movement at the sacroiliac joint is limited by interlocking of the articulating bones

and the sacroiliac ligaments to slight gliding and rotary movements. By allowing only slight upward movement

of the inferior end of the sacrum relative to the hip bones, resilience is provided to the sacroiliac region when

the vertebral column sustains sudden increases in force or weight.

Figure 7. Sacroiliac joint Figure 8. Sacroiliac joint and ligamenthttp://www.zygatech.com/sacroiliac-joint.php http://en.wikipedia.org/wiki/File:Gray319.png

This secondary cartilaginous joint consists of a fibrocartilaginous interpubic disc and surrounding

ligaments uniting the bodies of the pubic bones in the median plane. The interpubic disc is generally wider in


7. PUBIC SYMPHYSIS

http://en.wikipedia.org/wiki/File:Gray319.png

http://www.zygatech.com/sacroiliac-joint.php


women. The ligaments joining the bones are thickened at the superior and inferior margins of the symphysis,

forming superior and inferior pubic ligaments. The superior pubic ligament connects the superior aspects of

the pubic bodies and interpubic disc, extending as far laterally as the pubic tubercles. The inferior (arcuate)

pubic ligament is a thick arch of fibers that connects the inferior aspects of the joint components, rounding off

the subpubic angle as it forms the apex of the pubic arch. (See Figure 3).

Orientation

In the anatomical position, the pelvis is oriented so that the front edge of the top of the pubic

symphysis and the anterior superior iliac spines lie in the same vertical plane. As a consequence, the pelvic

inlet, which marks the entrance to the pelvic cavity, is tilted to face anteriorly, and the bodies of the pubic

bones and the pubic arch are positioned in a nearly horizontal plane facing the ground.

L5 and S1 vertebrae articulate at the anterior intervertebral (IV) joint formed by the L5/S1 IV disc

between their bodies and at two posterior zygapophysial joints (facet joints) between the articular processes

of these vertebrae. The facets on the S1 vertebra face posteromedially, interlocking with the anterolaterally

facing inferior articular facets of the L5 vertebra, preventing the lumbar vertebra from sliding anteriorly down

the incline of the sacrum. These joints are further strengthened by fan-like iliolumbar ligaments radiating from

the transverse processes of the L5 vertebra to the ilia.

Figure 9. Iliolumbar ligament Figure 10. Iliolumbar ligament and ligaments of the sacroiliac jointshttp://thepainsource.com/iliolumbar-syndrome http://www.msdlatinamerica.com/ebooks/RockwoodGreensFracturesinAdults/sid1100603.html


8. LUMBOSACRAL JOINTS

9. SACROCOCCYGEAL JOINT

http://www.msdlatinamerica.com/ebooks/RockwoodGreensFracturesinAdults/sid1100603.html

http://thepainsource.com/iliolumbar-syndrome/


The sacrococcygeal joint is a secondary cartilaginous joint with an intervertebral disc. Fibrocartilage

and ligaments join the apex of the sacrum to the base of the coccyx. The anterior and posterior

sacrococcygeal ligaments are long strands that reinforce the joint.

VARIATIONS IN MALE AND FEMALE PELVESThe pelvic girdles of males and females differ in several respects. These sexual differences are related

mainly to the heavier build and larger muscles of most men and to the adaptation of the pelvis (particularly

the lesser pelvis) in women for parturition (childbearing).

Although anatomical differences between male and female pelves are usually clear cut, the pelvis of

any person may have some features of the opposite sex. The gynecoid pelvis is the normal female type; its

pelvic inlet typically has a rounded oval shape and a wide transverse diameter. An android (masculine or

funnel-shaped) pelvis in a woman may present hazards to successful vaginal delivery of a fetus.

In forensic medicine (the application of medical and anatomical knowledge for the purposes of law),

identification of human skeletal remains usually involves the diagnosis of sex. A prime focus of attention is the

pelvic girdle because sexual differences usually are clearly visible. Even fragments of the pelvic girdle are

useful in determining sex.

1) The pelvic inlet in women is circular in shape compared with the heart-shaped pelvic inlet in men. The

more circular shape is partly caused by the less distinct promontory and broader alae in women.

2) The angle formed by the two arms of the pubic arch is larger in women (80-85°) than it is in men (50-60°).

3) The ischial spines generally do not project as far medially into the pelvic cavity in women as they do in

men.

In 1933, Caldwell and Moloy classified pelves into four groups: gynecoid, android, anthropoid, and

platypelloid.

a. Gynecoid type is present in about 41% of women, the typical female pelvis

b. Android type is the male or funnel-shaped pelvis with a contracted outlet.

c. Anthropoid type is long, narrow, and oval shaped.

d. Platypelloid type is present in only about 2% of women, is a wide pelvis flattened at the brim, with the

promontory of the sacrum pushed forward.

Figure 11. Male and female pelveshttp://district.bluegrass.kctcs.edu/rmccane0001/shared_files/bio137website/BIO137/137Lab7/Lab7Pelvis.html


CLINICAL ANATOMY

http://district.bluegrass.kctcs.edu/rmccane0001/shared_files/bio137website/BIO137/137Lab7/Lab7Pelvis.html


PELVIC DIAMETERS (CONJUGATES)The size of the lesser pelvis is particularly important in obstetrics because it is the bony canal through

which the fetus passes during a vaginal birth. To determine the capacity of the female pelvis for childbearing,

the diameters of the lesser pelvis are noted radiographically or manually during a pelvic examination.

Diameters of pelvic outletAntero - posterior diameters Anatomical antero-posterior diameter =11cm

from the tip of the coccyx to the lower border of symphysis pubis Obstetric antero-posterior diameter = 13 cm

from the tip of the sacrum to the lower border of symphysis pubis as the coccyx moves backwards during the second stage of labour.

Transverse diameters Bituberous diameter = 11 cm

between the inner aspects of the ischial tuberosities Bispinous diameter = 10.5 cm

between the tips of ischial spines Diameters of pelvic inlet

Antero -posterior diametersAnatomical antero-posterior diameter (true conjugate) = 11cm

from the tip of the sacral promontory to the upper border of the symphysis pubis Obstetric conjugate = 10.5 cm


Department of Gynecology & Obstetrics


from the tip of the sacral promontory to the most bulging point on the back of symphysis pubis which is about 1 cm below its upper border. It is the shortest antero-posterior diameter Diagonal conjugate = 12.5 cm

i.e. 1.5 cm longer than the true conjugate. From the tip of sacral promontory to the lower border of symphysis pubis (or inferior pubic ligament)Transverse diametersAnatomical transverse diameter =13cm

largest diameter in the pelvis, between the farthest two points on the iliopectineal linesObstetric transverse diameter

It bisects the true conjugate and is slightly shorter than the anatomical transverse diameterOblique diametersRight oblique diameter =12 cm

from the right sacroiliac joint to the left iliopectineal eminenceLeft oblique diameter = 12 cm

from the left sacroiliac joint to the right iliopectineal eminenceThe minimum anteroposterior (AP) diameter of the lesser pelvis, the true (obstetrical) conjugate –

conjugata vera-, is the narrowest fixed distance through which the baby's head must pass in a vaginal delivery.

This distance, however, cannot be measured directly during a pelvic examination because of the presence of

the bladder. Consequently, the diagonal conjugate (from inferior pubic lig. to promontory) is measured by

palpating the sacral promontory with the tip of the middle finger, using the other hand to mark the level of

the inferior margin of the pubic symphysis on the examining hand. After the examining hand is withdrawn, the

distance between the tip of the index finger (1.5 cm shorter than the middle finger) and the marked level of

the pubic symphysis is measured to estimate the true conjugate, which should be 11.0 cm or greater.

During a pelvic examination, if the ischial tuberosities are far enough apart to permit three fingers to

enter the vagina side by side, the subpubic angle is considered sufficiently wide to permit passage of an

average fetal head at full term.

Anatomy for Forceps http://emedicine.medscape.com/article/263603-overview#a04

http://www.gfmer.ch/Obstetrics_simplified/anatomy_of_the_female_pelvis.htm

Figure 12. Pelvic conjugateshttp://www.ufrgs.br/imunovet/molecular_immunology/muscles.html


http://www.ufrgs.br/imunovet/molecular_immunology/muscles.html

http://www.gfmer.ch/Obstetrics_simplified/anatomy_of_the_female_pelvis.htm

http://emedicine.medscape.com/article/263603-overview#a04


PELVIC FRACTURESAnteroposterior compression of the pelvis occurs during crush accidents (as when a heavy object falls

on the pelvis). This type of trauma commonly produces fractures of the pubic rami. When the pelvis is

compressed laterally, the acetabula and ilia are squeezed toward each other and may be broken.

Fractures of the bony pelvic ring are almost always multiple fractures or a fracture combined with a

joint dislocation. Pelvic fractures can result from direct trauma to the pelvic bones, such as occurs during an

automobile accident, or be caused by forces transmitted to these bones from the lower limbs during falls on

the feet. Weak areas of the pelvis, where fractures often occur, are the pubic rami, the acetabula (or the area

immediately surrounding them), the region of the sacroiliac joints, and the alae of the ilium.

Pelvic fractures may cause injury to pelvic soft tissues, blood vessels, nerves, and organs. Fractures in

the pubo-obturator area are relatively common and are often complicated because of their relationship to the

urinary bladder and urethra, which may be ruptured or torn. Falls on the feet or buttocks from a high ladder

may drive the head of the femur through the acetabulum into the pelvic cavity, injuring pelvic viscera, nerves,

and vessels.

Pelvic Fractures in Emergency Medicine @ http://emedicine.medscape.com/article/825869-overview

Sacroiliac joint dysfunctionSacroiliac joint dysfunction is a cause of lower back pain. As with most other joints in the body, the

sacroiliac joint joints have a cartilage layer covering the bone. The cartilage allows for some movement and

acts as a shock absorber between the bones. When this cartilage is damaged or worn away, the bones begin

to rub on each other, and degenerative arthritis (osteoarthritis) occurs. This is the most common cause of


Department of Physiotherapy & Rehabilition

Department of

http://emedicine.medscape.com/article/825869-overview


sacroiliac joint joint dysfunction. Degenerative arthritis occurs commonly in the sacroiliac joint joints, just like

other weight-bearing joints of the body.

Another common cause of sacroiliac joint dysfunction is pregnancy. During pregnancy, hormones are

released in the woman's body that allows ligaments to relax. This prepares the body for childbirth. Relaxation

of the ligaments holding the sacroiliac joint together allows for increased motion in the joints and can lead to

increased stresses and abnormal wear.

There are many disorders that affect the joints of the body that can also cause inflammation in the

sacroiliac joints. These include gout, rheumatoid arthritis, psoriasis, and ankylosing spondylitis. These are all

various forms of arthritis that can affect all joints. Ankylosing spondylitis is an inflammatory arthritis that

always affects the sacroiliac joints. It can lead to stiffness and severe pain in the sacroiliac joints. As the

disease process continues, the sacroiliac joints fuse together and have no further motion. Once this occurs,

there is no further pain associated with the SI joints.

Walker JM. The sacroiliac joint: a critical review. Phys Ther. 1992;72:903-916.

http://physther.org/content/72/12/903.full.pdf

Forst SL, Wheeler MT, Fortin JD, Vilensky JA. The sacroiliac joint: anatomy, physiology and clinical significance. Pain

Physician. 2006;9:61-67.

http://www.painphysicianjournal.com/2006/january/2006;9;61-68.pdf


http://www.painphysicianjournal.com/2006/january/2006;9;61-68.pdf

http://physther.org/content/72/12/903.full.pdf

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