The Pelvic Girdle and Hip Joint 177This is because bony landmarks are more reflective of
the underlying bony structure and generally will pro-
vide a more accurate appraisal than body contours.
Neutral Position
During standing in an upright position, an oblique
plane through the PSIS of the ilia and the symphysis
pubis forms an angle of about 60° relative to the hori-
zontal plane. This angle is termed the angle of pelvic
inclination (Smith, Weiss, and Lehmkuhl, 1996). This
is the neutral position of the pelvis and roughly cor-
responds to a position in which both of the ASIS and
the pubic symphysis are in the same frontal plane
as seen in figure 4.15A. Since the angle of inclina-
tion cannot be determined in a class setting, the
vertical alignment of the landmarks is used as an
easy method to evaluate pelvic position. A neutral
position of the pelvis also takes into account other
planes, such that one ASIS would not be higher or
lower or rotated forward or backward relative to the
other ASIS.Anterior and Posterior Pelvic Tilt
Anterior and posterior pelvic tilts are opposite
movements of the whole pelvis in the sagittal
plane about a mediolateral axis. In an anterior tilt
(increased inclination), the top of the pelvis rotates
forward such that the ASIS are forward relative to
the pubic symphysis as seen in figure 4.15B. From
a side view, a vertical plane extending from the
ASIS would fall in front of the pubic symphysis. In
dance this is sometimes referred to as a “released”
position of the pelvis.
In a posterior tilt or backward tilt (decreased inclina-
tion), the top of the pelvis rotates backward such that
the ASIS are back relative to the pubic symphysis asFIGURE 4.14 Posterior view of primary muscles acting on the hip joint (right hip). (A) Muscles, (B) attachments,
(C) lines of pull and actions.
Gluteus
minimus