Functional anatomy of the extraocular muscles during vergence.

Magnetic resonance imaging (MRI) now enables precise visualisation of the mechanical state of the living human orbit, enabling inferences about the effects of mechanical factors on ocular kinematics. We used 3-dimensional (3D) magnetic search coil recordings and MRI to investigate the mechanical state of the orbit during vergence in humans. Horizontal convergence of 23 degrees from a remote to a near target aligned on one eye was geometrically ideal, and was associated with lens thickening and extorsion of the rectus pulley array of the aligned eye with superior oblique muscle relaxation and inferior oblique muscle contraction.

Spectrum of infantile esotropia in primates: Behavior, brains, and orbits.

Introduction: Recent studies of human infants have described a spectrum of early-onset esotropia, from small angle to large heterotropias. We report here a similar spectrum of early-onset esotropia in infant monkeys, with emphasis on the relationship between visuomotor deficits, central nervous system circuitry, and orbital anatomy.

Methods: Eye movements were recorded in macaque monkeys with natural, infantile-onset esotropia (n = 7) and in control monkeys (n = 2) to assess alignment, latent nystagmus, dissociated vertical deviation (DVD), and pursuit/optokinetic nystagmus (OKN) asymmetries.

Horizontal rectus muscle anatomy in naturally and artificially strabismic monkeys.

Purpose: Structural abnormalities of extraocular muscles (EOMs) or their pulleys are associated with some forms of human strabismus. This experiment was conducted to investigate whether such abnormalities are associated with artificial or naturally occurring strabismus in monkeys.

Methods: Binocular alignment and grating visual acuities were determined in 10 monkeys representing various species using search coil recording and direct observations.

Trabecular bone microarchitecture is deteriorated in men with spinal cord injury.

Unlabelled: Using magnetic resonance imaging, men with spinal cord injury (n = 10) were found to have fewer trabeculae that were spaced further apart in the knee than able-bodied controls of similar age, height, and weight (n = 8). The deteriorated trabecular bone microarchitecture may contribute to the increased fracture incidence after injury.

Introduction: Spinal cord injury results in a dramatic decline in areal bone mineral density (aBMD) and a marked increase in lower extremity fracture; however, its effect on trabecular bone microarchitecture is unknown.