On the frozen preparations, the sagittal sections along the axis of the iliopectineal eminence allowed
us to measure the change in direction of the iliopsoas muscular fibers at this level. The pelvic and
femoral portions of the iliopsoas m. made a 40-45˚ angle on the ventral edge of the pelvis.
Discussion
The iliopsoas tendon, as we have described it, is in fact a musculotendinous complex made up of a
main tendon arising from the psoas major m., an accessory tendon arising from the iliacus m. and
proper muscular fibers belonging to the iliacus m. Our observations about the main tendon of the
iliopsoas m. are in agreement with the classic data from the literature about its course and its rotation
[3, 12]. Insertion into the posterior aspect of the lesser trochanter, sometimes with interposition of a
gliding bursa, has been reported previously [14, 19]. On the contrary, we always observed direct
insertion of the tendon into the tip of the lesser trochanter. As far as we know, partial or complete
splitting of the tendon, as we found in 4 cases in our series, has been reported rarely [16]. The proper
muscular fibers of the iliacus m. inserting onto the anterior aspect of the lesser trochanter and in the
infratrochanteric area were already described in the former and recent descriptions of the tendon.
However, a lower iliac muscular bundle running around the main tendon on its anteromedial aspect,
as we found in all our preparations, has been described rarely [3].
The ilio-infratrochanteric muscular bundle, also found in all our preparations, has been described, as
an isolated tendon named Winslow's iliacus minor m. inserted under the lesser trochanter [9, 18].
Nevertheless, it seems more logical to consider this bundle as a constant bundle of the iliacus m. [4].
The iliopsoas m. can glide over the iliopectineal eminence thanks to the presence of the iliopectineal
bursa. In our study, the appearance of this bursa was the same as in the classical descriptions which
describe it as a triangle with the inferior summit between the iliopectineal eminence and the lesser
trochanter. [3]. Its upper portion is divided into two compartments for the two parts of the iliopsoas
tendon. We did not notice the existence of any communication between the bursa and the articular
cavity of the hip joint. This communication may be present between the pubofemoral lig. and the
vertical part of the ilio-femoral lig. in about 15% of cases [2, 4]. This communication is the basis of
the technique which allows bursography through a hip arthrogram [17]. The macroscopic findings in
our work on the fissure between the main and accessory tendons and the gliding fold, identified by
its gray aspect on the gliding surface, are in agreement with the existing data concerning the
iliopsoas tendon [16].
There are multiple physiopathological hypotheses to explain the snapping hip syndrome. Schaberg et
al have, for example, hypothesized a conflict between the iliopsoas tendon and the lesser trochanter
[15]. However, the most reasonable explanation has been given by Lyons et al [10], who consider the
iliopectineal eminence and the anterior edge of the pelvis as a true reflecting pulley for the iliopsoas
m. The variations in size and in location of the iliopectineal eminence must be taken into
consideration in the global pathophysiology of the snapping hip syndrome, but in this work we did
not do a morphometrical study of this zone. However, on a personal study of four patients with
snapping hip syndrome, painful for two of them, magnetic resonance imaging (MRI) of the region
was normal. When the thigh is actively extended, the sudden increase in muscle tension caused
displacement over the iliopectineal eminence and provoked the snapping hip and its characteristic
audible sound. This pathophysiological mechanism is the basis for surgical treatment proposed for
painful forms found in athletes [5, 7]. Surgery consists in a posterior partial section of the tendon
facing the iliopectineal bursa respecting the muscular fibers, which would seem to relax the part of
the muscle located in front of the iliopectineal eminence [6, 7]. The development of such techniques
confirms the necessity of deep anatomical knowledge of the musculotendinous complex of the
femoral portion of the iliopsoas m. Nevertheless, comprehension of the precise pathophysiology of
anterior hip snapping needs a morphometric study of iliopectineal eminence and a better knowledge
of the bursa conjunctiva.