The vascular variability of the iliac system and clinical diagnosis in radiology and neurology

Abstract

The sciatic nerve is the largest nerve in the human body giving both
motor and sensory innervations to the lower limb. It can be affected in chronic
diseases, such as diabetes, or compressed anatomically by structures such as
piriformis and aneurysms leading to sciatica or paralysis of the lower limb. The
current study therefore focuses on the arterial supply of the sciatic nerve as well
as its course. Embryologically, the sciatic nerve is supplied via the axial artery
during the first trimester. As the axial artery regresses, the iliac system
develops. A failure of sciatic artery regression leads to several variations of
pelvic and femoral arteries, with a risk of iatrogenic injury/trauma for those
patients undergoing pelvic, gluteal and thigh surgical procedures. An
understanding of the variability of the pelvic arteries in relation to a coexistent
sciatic artery will provide an appropriate background for clinicians. The present
study proposes a new theory of sciatic artery development and persistence, as
well as new theories for the superior and inferior gluteal, internal pudendal and
obturator arteries. The thesis is in two parts: first an anatomical study on the
dissection of 171 cadavers including the pelvic, gluteal and thigh regions to
observe (i) the patterns of the arteries these regions, and (ii) the course of the
sciatic nerve. With variable course of sciatic nerve, there is a variability of its
blood supply. Moreover, it includes a new classification of sciatic nerve with
respect to clinical implications. The thesis clarifies the origins of the sciatic
artery and its course. The second part is a literature review of sciatic artery
aneurysm cases in 171 patients, which clarifies the risk of aneurysm, together
with its incidence with respect to pathologic finding and associated disorders.
Radiologists have to be aware of the internal iliac artery classifications to
be able to alert general surgeons, orthopaedic surgeons, obstetricians,
gynecologists, and urologists so that they can improve patient management.

Date of Award	2013
Original language	English
Supervisor	Roger Soames (Supervisor)