Contrasts between Cervical and Lumbar Motion Segments

Anatomy and clinical significance of the uncinate process and uncovertebral joint: A comprehensive review

“…The surface area of the articular surface of the uncinate process is on average 23.4 mm 2 which is nearly half the area of the articular surface on the vertebrae above which averages 44.2 mm 2 (Panjabi et al, ). The articulation is enclosed laterally by unorganized connective tissue creating a pseudocapsule (Prescher, ; Mercer and Bogduk, ; Taylor et al, ). Mercer and Bogduk () termed this connective tissue structure “periosteofascial tissue.” It was described as arising from deep to the lateral edge of the posterior longitudinal ligament and passing anteriorly to enclose the lateral uncovertebral articulation.…”

“…This is in contrast to other joints which show synovial tissue formation around 10–11 weeks and by the time the fetus is full term they exhibit well formed joints with a clear synovial lining (Orofino et al, ). The uncinate process grows upward from the age of 4 and continues to enlarge from age 9 to 14 years (Bland and Boushey, ; Taylor et al, ). As the uncinate processes enlarge, fissures begin to form in the lateral and posterolateral intervertebral discs between the age of 8 or 10 years (Pesch et al, ; Bland and Boushey, ; Taylor et al, ).…”

“…Uncovertebral osteophytes that arise from the anterior aspect of the uncinate process curl laterally and, combined with overlying fibroligamentous thickening, may compress the anteromedial wall of the second portion of the vertebral artery (Lyon, ; Virtama and Kivalo, ; Dvorak, ; Citow and Macdonald, ; Yilmazlar et al, ). The uncovertebral osteophytes that project into the path of the vertebral artery cause it to meander around the obstruction to continue on its path to enter the superior foramen transversarium (Taylor et al, ; Cagnie et al, ). As opposed to nerve root compression which occurs at the lower cervical spine, vertebral artery compression due to uncovertebral osteophytes tends to occur at the level of the mid‐cervical spine (Ebraheim et al, ).…”

“…surface on the vertebrae above which averages 44.2 mm 2 (Panjabi et al, 1991). The articulation is enclosed laterally by unorganized connective tissue creating a pseudocapsule (Prescher, 1998;Mercer and Bogduk, 1999;Taylor et al, 2000). Mercer and Bog-duk (1999) termed this connective tissue structure "periosteofascial tissue."…”

“…The uncinate process grows upward from the age of 4 and continues to enlarge from age 9 to 14 years (Bland and Boushey, 1990;Taylor et al, 2000). As the uncinate processes enlarge, fissures begin to form in the lateral and posterolateral intervertebral discs between the age of 8 or 10 years (Pesch et al, 1984;Bland and Boushey, 1990;Taylor et al, 2000). These fissures give rise to the joint space of the uncovertebral articulation.…”