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Surg Radiol Anat (2015) 37:1118 DOI 10.1007/s00276-014-1300-z
ORIGINAL ARTICLE
Received: 11 February 2014 / Accepted: 11 April 2014 / Published online: 29 April 2014 Springer-Verlag France 2014
to antero-medial as it moves inferiorly. Our ndings are consistent with the hypothesis that the ZO functions as a ring that resists femoral head distraction and contributes to dynamic circulation of synovial uid.
Keywords Zona orbicularis Hip capsule MR arthrography MRI Anatomy
Introduction
The zona orbicularis (ZO) of the hip is a circumferential thickening of the hip joint capsule, at the level of the neck of the femur. Despite descriptions in classic textbooks of anatomy [5, 8, 9, 13], our understanding of the zona orbicularis anatomy and function remains limited. With the advent of hip arthroscopy and increasing interest in the factors that serve to stabilise the hip joint, increasing attention is being paid to the joint capsule and the role of the ZO. Ito [7] has suggested that the ZO contributes to hip stability and is the principal restraint to joint distraction. More recently, it has been proposed that the ZO also has a role in synovial uid circulation within the joint. It has been hypothesised that the ZO functions as a bellow-like mechanism to force synovial uid from the peripheral compartment to the central compartment in a unidirectional ow [4]. When performing hip arthroscopy in the peripheral compartment, the ZO provides a landmark for arthroscope and instrument guidance and orientation [2, 7]. It has been suggested that iatrogenic instability may occur following hip arthroscopy (HA), possibly due to disruption of the iliofemoral ligament [8], and cadaveric work indicates that ZO disruption may also contribute to this phenomenon [7].
The term orbicularis derives from the Latin, orbis, denoting a circular or disk-shaped structure. Traditionally,
Anatomy of the zona orbicularis of the hip: a magnetic resonance study
Francesc Malagelada Rene Tayar Samuel Barke
Giles Stafford Richard E. Field
Abstract
Purpose This study aimed at describing the anatomy of the zona orbicularis (ZO), based on magnetic resonance arthrography (MRA) and magnetic resonance imaging (MRI) scans and to assess the presence of synovial folds in relation to the ZO.
Methods A retrospective review was performed using consecutive hip and pelvic MRA and MRI examinations from our institution. We identied...