Pelvic fractures and associated injuries are a cause of significant
morbidity and mortality. Most pelvic fractures are secondary to
automobile passenger or pedestrian accidents but are also the result
of minor falls in older persons and from major falls or crush injuries.
The mortality rate from all pelvic fractures is approximately 5%.
However, with complex pelvic fractures, the mortality rate is 22%.1
The major functions of the pelvis are protection, support, and
hematopoiesis. The pelvis consists of the two innominate bones,
which are made up of the ilium, ischium, and pubis; the sacrum;
and the coccyx. The two innominate bones and sacrum form a ring
structure, which is the basis of pelvic stability. This stability
is largely dependent on the strong posterior sacroiliac (SI), sacrotuberous,
and sacrospinous ligaments (Figure 269-1).
A small amount of pelvic stability is also provided by the pubic symphysis. Any
single break in the ring will yield a stable injury without significant
risk of displacement. An injury with two breaks in the ring is unstable
with the risk of displacement.
The major posterior stabilizing structures of the pelvic ring—that
is, the posterior tension band of the pelvis—include the
iliolumbar ligament and the posterior sacroiliac, sacrospinous,
and sacrotuberous ligaments.
The iliopectineal, or arcuate, line divides the pelvis into the
upper, or false, pelvis, which is part of the abdomen, and the lower,
true pelvis (Figure 269-2). In addition,
this line constitutes the major portion of the femorosacral arch,
which, along with the subsidiary tie arch (bodies of pubic bones
and superior rami), supports the body in the erect position. In
the sitting position, the weightbearing forces are transmitted by
the ischiosacral arch augmented by its tie arch, the pubic bones,
inferior pubic rami, and ischial rami. The tie arches fracture first,
especially at the symphysis pubis, pubic rami, and just lateral
to the SI joints. Incorporated in the pelvic structure are five
joints that allow some movement in the bony ring. The lumbosacral,
SI, and sacrococcygeal joints, and the symphysis pubis allow little
movement. The acetabulum is a ball-and-socket joint that is divided
into three portions: the iliac portion, or superior dome, is the
chief weightbearing surface; the inner wall consists of the pubis
and is thin and easily fractured; and the posterior acetabulum is
derived from the thick ischium.
Roentgenographic anatomy of the pelvis and acetabulum.
The pelvis is extremely vascular. The iliac artery and venous
trunks pass near the SI joints bilaterally. The nerve
supply through the pelvis is derived from the lumbar and sacral
plexuses. Injury to the pelvis may produce deficits at any level
from the nerve root to small peripheral branches (Figure
269-3). The lower urinary tract is contained in the pelvis
(Figure 269-4). In the adult, the bladder
lies behind the symphysis and pubic bones, and the peritoneum covers
the dome and base posteriorly. The location of the bladder and the
degree of peritoneal reflection are determined by urine content.
The lower GI tract housed in the pelvis includes a small portion
of the descending colon, the sigmoid colon, the rectum, and the
anus. In women, the uterus and vagina are also housed in the bony
Arterial and nerve supply of the pelvis. a = artery;
aa = arteries; Ext. = exterior; Inf. = inferior;
Int. = interior; Lat. = lateral; sup. = superior.
(Reproduced with permission from Pansky B: Review of Gross
Anatomy, 6th ed. © 1995, McGraw-Hill, New York.)
Sagittal section of the male pelvis showing the relation of
the full bladder.
The possibility of pelvic fracture should be considered in every
patient with serious blunt trauma. Determine the mechanism of injury
and the prehospital evaluation and treatment. Ask the patient about
areas of pain, last urination or defecation, present bladder sensation,
and the last solid and fluid intake. In addition, the time of the
last menses or the presence of pregnancy, brief past medical history,
current medications, and allergies should be ascertained.
In trauma patients who are awake and alert, the physical examination
is very sensitive for the diagnosis of a pelvic fracture.2 Symptoms
and signs of pelvic injuries vary from local pain and tenderness
to pelvic instability and severe shock. On inspection, examine for
perineal and pelvic edema, ecchymoses, lacerations, and deformities.
Inspect for hematomas above the inguinal ligament or over the scrotum
(Destot sign). Examine the patient by palpating for tenderness or
movement at the iliac crests, pubic rami, ischial rami, sacrum,
and coccyx. Compress the pelvis lateral to medial through the iliac
crests, anterior to posterior through the symphysis pubis, and anterior
to posterior through the iliac crests. Compress the greater trochanters
and determine the range of motion of the hips.2 During
the physical examination, avoid excessive movement of unstable fractures
as this could produce further injury and additional blood loss.
Rectal examination may detect superior or posterior displacement
of the prostate, rectal injury, or an abnormal bony prominence or
large hematoma or tenderness along the fracture line (Earle sign).
Proctoscopic examination may be required to fully assess for the
presence of rectal tears. Decrease in anal sphincter tone may suggest
neurologic injury, and blood at the urethral meatus may suggest
urologic injury. Pelvic examination should be carefully performed
in women to detect the presence of blood or lacerations that suggest
the possibility of open fracture. Carefully evaluate neurovascular
function. If a ...