spondyloptosis) Etiologic (Wiltse (3)) classification * Type 1: Dysplastic Congenital defect of the neural arch
* Type 2: Isthmic Pars interarticularis defect (3 subtypes) a) Stress (fatigue) fracture (most common type, present in this case) b) Elongated pars c) Acute pars fracture * Type 3: Degenerative Facet joint osteoarthrosis * Type 4: Traumatic Acute fracture of the vertebral arch other than the pars * Type 5: Pathological Insufficiency fracture as a result of bone weakening diseases * Type 6: Iatrogenic Fracture secondary to spinal surgery such as laminectomy Table 2.
Description: Middle or posterior caudal vertebra lacking the neural arch
INTRODUCTION: Pedicle is highly loaded with elements of neural arch
along with facets and laminae.
Ivanov and coworkers (22) conducted a finite element analysis of L3-S1 vertebrae and discovered that unilateral removal of the lateral one-half of the pars resulted in significantly higher stresses in the neural arch
, much more so than the removal of the lateral one-fourth of the pars.
Next, rectangular rosette pattern strain gauges are attached to the neural arch
to calculate the direction and magnitude of principal strain under various loads and motions.
The cartilaginous neural arch
and spine of PU2 (NPU2) is present opposite the parhypural.
murivorus in being larger with a more strongly depressed neural arch
(see discussion in 1 and figures in Gilmore, 7).
The three landmarks that define the neural arch
(LM3, 4, 5) describe three main tips that characterise the seahorse vertebrae.
The hangman's fracture (traumatic spondylolisthesis of the axis) represents fractures of the neural arch
of C2 that are produced by a hyper-extension force.
The pars interarticularis is defined as the parts of the neural arch
that lie between the superior and inferior articular facets.
Chapter 10, entitled "Functional Pathology", discusses posture and its effects on, for example, disc nutrition, the neural arch
, and muscle action, then discusses creep in spinal tissues, and finally muscle function and dysfunction.
Remarks--The vertebrae of Texasophis are distinguished by their small size, elongate vertebral form, moderately vaulted neural arch
, low neural spine, and especially by the distinct hemal keel that is separated from strong subcentral ridges by very deep grooves.