He's in the lead, just metres away from grabbing gold, then suddenly the athlete crumples, any hope of finishing the event dashed. With an awkward step an agonising tendon sprain has sealed the fate of a number of the world’s fittest competitors, including a horse, during the London Olympics. Tendons are pale, glistening cables lashing muscle to bone. Acting like elastic springs they protect muscles from overstretching, by preventing joints from bending too far, but in so doing can themselves be injured. Pictured is a damaged ox tail tendon, its parallel strands of collagen protein viewed using electron microscopy. The tight ball of recoiled broken fibres highlights the energy-absorbing nature of this tissue. Scientists find that when injured, damage signals spread along the tendon’s strands. They believe this increases the likelihood of specialised cells detecting and repairing the injury. And perhaps explains why sprains, while immediately excruciating, recover relatively quickly.
Written by Lindsey Goff
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.