CLINICAL ANATOMY OF THE PELVIS Kaan Ycel M

CLINICAL ANATOMY OF THE PELVIS Kaan Yücel M. D. , Ph. D. 14. January. 2014 Tuesday

Sexual differences are related mainly 1. Heavier build and larger muscles of most men 2. Adaptation of the pelvis (particularly the lesser pelvis) in women for parturition (childbearing). The difference between the male and female pelvis Difference Between Male & Female Pelvis

male or funnel-shaped pelvis with a contracted outlet 41% of women long, narrow, and oval shaped wide pelvis 2% of women

Ø 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. Ø A prime focus of attention is the pelvic girdle because sexual differences usually are clearly visible. Ø Even fragments of the pelvic girdle are useful in determining sex.

Feature General Structure Male pelvis Female pelvis Thick & Heavy Thin & Light Greater pelvis Deep Shallow Lesser pelvis Narrow and deep, tapering Wide and shallow, cylindirical Heart-shaped, narrow Oval and rounded, wide Comparatively small Comparatively large Pelvic inlet Pelvic outlet Ischial spines Project further medially into the pelvic cavity Do not project as far medially into the pelvic cavity & smooth

Feature Male pelvis Female pelvis Obturator foramen Round Oval Acetabulum Large Small Narrow, inverted V (approximately 70 degrees) Almost 90 degrees Smaller (50 -60 degrees) Larger (80 -85 degrees) Prominent Not prominent Greater schiatic notch Subpubic angle Sacral promontory

PELVIC DIAMETERS (CONJUGATES) Size of the lesser pelvis 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, diameters of the lesser pelvis are noted radiographically or manually during a pelvic examination.

PELVIC DIAMETERS (CONJUGATES)

Diameters of pelvic outlet Antero - posterior diameters Anatomical antero-posterior diameter 11 cm from tip of the coccyx to lower border of symphysis pubis Obstetric antero-posterior diameter 13 cm from tip of the sacrum to lower border of symphysis pubis as the coccyx moves backwards during the second stage of labour.

Diameters of pelvic outlet Bituberous diameter 11 cm between inner aspects of ischial tuberosities Bispinous diameter 10. 5 cm between tips of ischial spines Transverse diameters

Diameters of pelvic inlet Antero - posterior diameters Anatomical antero-posterior diameter True conjugate 11 cm from tip of sacral promontory to upper border of symphysis pubis

Diameters of pelvic inlet Antero - posterior diameters Obstetric conjugate 10. 5 cm from tip of sacral promontory to the most bulging point on back of symphysis pubis , about 1 cm below its upper border. shortest antero-posterior diameter

Diameters of pelvic inlet Antero - posterior diameters Diagonal conjugate 12. 5 cm 1. 5 cm longer than the true conjugate From tip of sacral promontory to lower border of symphysis pubis

Minimum anteroposterior (AP) diameter of the lesser pelvis True (obstetrical) conjugate Narrowest 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.

Diagonal conjugate (from inferior pubic lig. to promontory) Measured by palpating 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.

Transverse diameter is the greatest distance between the linea terminalis on either side of the pelvis.

Pelvic Fractures Ø Anteroposterior compression of the pelvis occurs during crush accidents (as when a heavy object falls on the pelvis). Ø This type of trauma commonly produces fractures of the pubic rami. Ø 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: Pubic rami Acetabula Region of the sacroiliac joints Alae of the ilium 25 Year Old Male with displaced fracture of the sacrum and symphysis pubis. The most severe pelvic fractures separate the two sides of the pelvis from each other.

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.

Sacroiliac joint dysfunction Degenerative arthritis (osteoarthritis) Pregnancy Gout Rheumatoid arthritis Psoriasis Ankylosing spondylitis X-ray of the sacroiliac joints showing joint space narrowing, erosive change and