Gemelli-obturator complex in the deep gluteal space: an anatomic and dynamic study

• Published in: Skeletal radiology Vol. 47; no. 6; pp. 763 - 770
• Main Authors: Balius, Ramon, Susín, Antonio, Morros, Carles, Pujol, Montse, Pérez-Cuenca, Dolores, Sala-Blanch, Xavier
• Format: Journal Article Publication
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2018; Springer; Springer Nature B.V
• Subjects: Adult; Anatomia humana; Anatomy; Buttocks - diagnostic imaging; Buttocks - innervation; Cadaver; Cadavers; Ciències de la salut; Connective tissues; Curvature; Deep gluteal syndrome; Female; Gemelli-obturator internus complex; Healthy Volunteers; Hip; Human anatomy; Human mechanics; Humans; Imaging; Knee; Male; Matemàtiques i estadística; Mecànica humana; Medicine; Medicine & Public Health; Muscle, Skeletal - diagnostic imaging; Muscle, Skeletal - innervation; Nuclear Medicine; Obturator internal gemellus syndrome; Obturator Nerve - diagnostic imaging; Orthopedics; Pathology; Pelvis; Pelvis - diagnostic imaging; Pelvis - innervation; Prone position; Radiology; Rotating matter; Rotation; Sciatic nerve; Sciatic Nerve - diagnostic imaging; Scientific Article; Surgery; Trauma; Ultrasonography - methods; Ultrasound; Àrees temàtiques de la UPC; Deep gluteal syndrome; Obturator internal gemellus syndrome; Gemelli-obturator internus complex; Sciatic nerve
• ISSN: 0364-2348; 1432-2161
• DOI: 10.1007/s00256-017-2831-2

Objective To investigate the behavior of the sciatic nerve during hip rotation at subgluteal space. Materials and methods Sonographic examination (high-resolution ultrasound machine at 5.0–14 MHZ) of the gemelli-obturator internus complex following two approaches: (1) a study on cadavers and (2) a study on healthy volunteers. The cadavers were examined in pronation, pelvis-fixed position by forcing internal and external rotations of the hip with the knee in 90° flexion. Healthy volunteers were examined during passive internal and external hip rotation (prone position; lumbar and pelvic regions fixed). Subjects with a history of major trauma, surgery or pathologies affecting the examined regions were excluded. Results The analysis included eight hemipelvis from six fresh cadavers and 31 healthy volunteers. The anatomical study revealed the presence of connective tissue attaching the sciatic nerve to the structures of the gemellus-obturator system at deep subgluteal space. The amplitude of the nerve curvature during rotating position was significantly greater than during resting position. During passive internal rotation, the sciatic nerve of both cadavers and healthy volunteers transformed from a straight structure to a curved structure tethered at two points as the tendon of the obturator internus contracted downwards. Conversely, external hip rotation caused the nerve to relax. Conclusion Anatomically, the sciatic nerve is closely related to the gemelli-obturator internus complex. This relationship results in a reproducible dynamic behavior of the sciatic nerve during passive hip rotation, which may contribute to explain the pathological mechanisms of the obturator internal gemellus syndrome.