The knowledge of the lumbar spine biomechanics is essential for clinical applications. Due to the difficulties to experiment on living people and the irregular results published, simulation based on finite elements (FE) has been developed, making it possible to adequately reproduce the biomechanics of the lumbar spine. A 3D FE model of the complete lumbar spine (vertebrae, discs, and ligaments)...

OBJECTIVE To compare the biomechanical properties of a 10-hole 3.5 mm locking compression plate (LCP) with 2 proximal and 2 distal bicortical locked screws reinforced with either a Steinmann pin of 30-40% the medullary diameter or a poly-ether-ether-ketone (PEEK) rod of ∼75% the medullary diameter in a cadaveric tibia gap model. STUDY DESIGN Ex vivo study. SAMPLE POPULATION Cadaveric canine...

Larval fish use the 'fast start' escape response to rapidly evade the strike of a predator with a three-dimensional (3D) maneuver. Although this behavior is essential for the survival of fishes, it is not clear how its motion is controlled by the motor system of a larval fish. As a basis for understanding this control, we measured the high-speed kinematics of the body of zebrafish (Danio rerio)...

Brown Pelicans (Pelecanus occidentalis) plunge dive into water to capture fish with highly distensible pouches. During prey capture, the pouch may expand to hold 11 L of water and the mandibular rami may bow from a resting position of 5 cm to over 15 cm. We compared mineralization of two bending regions of the mandible with a nonbending region, and examined cross-sectional morphology to determi...

BACKGROUND The factors associated with lateral curve flexibility in degenerative scoliosis have not been well documented. Disc degeneration could result in significant change in stiffness and range of motion in lateral bending films. The osteophytes could be commonly observed in degenerative spine but the relationship between osteophyte formation and curve flexibility remains controversial. The...

The in vitro lamprey spinal cord contains a "central pattern generator" (CPG) that can generate locomotor activity with excitatory amino acids added to the bath. The motor pattern can be entrained by imposed rhythmic bending of either the caudal or rostral end of the notochord/spinal cord. In the present study, the quantitative and mechanistic features of entrainment were investigated. Increasi...

Given the importance of thoraco-lumbar spine movements in the locomotion of mammals, it is surprising that in vivo three-dimensional (3-D) data on the intervertebral movement of the mammalian thoraco-lumbar vertebral column during symmetrical gaits is limited to horses and dogs. To test whether kinematic patterns similar to those published for these cursorial species are also present during a c...

Background–The purpose of this investigation is to measure the normal neck and trunk motion of daily living and to compare this to annualized movements as defined by the ASTM F2423-11 and ISO 18192-1:2011 standards. Methods–Ten volunteers wore a custom sensor system that monitored their upper and lower spine motion. The system allows continuous measurement of the frequency and magnitude of spin...

STUDY DESIGN Biomechanical evaluation using porcine spines. OBJECTIVE Compare the fixation strength of two currently used fusionless adolescent idiopathic scoliosis correction techniques following cyclic loading using porcine spines. SUMMARY OF BACKGROUND DATA The ability of fusionless implants to control or correct scoliosis in a growing patient requires such implants to maintain spinal fi...

BACKGROUND Rhinoplasty techniques to affect nasal tip rotation are well described. Cephalic alar trim is a powerful method for achieving tip elevation. Previous studies and texts provide aesthetic guidelines for nasolabial angles. Often, surgeon experience determines the degree of lower lateral cartilage resection to achieve optimal results. This study analyzes the change in tip elevation with ...