The equine interspinal ligaments of Ray Wilhite

Our old friend Ray Wilhite sent us this glorious photo of a horse neck that he dissected recently, with permission to post here:

The big yellow sheet at the top is the nuchal ligament, which in many mammals provides axial tension for the cervical vertebrae, and which has been hypothesized (e.g. by Alexander 1985:13) to have existed and provided similar support in at least some sauropods.

But what caught Ray’s eye was the smaller interspinal ligaments running horizontally between the neural spines of the consecutive vertebrae. The literature doesn’t talk about these much because the irresistible glamour of the nuchal ligament grabs everyone’s attention, but they’re there in pretty much everything, being primitive for tetrapods.

Here they are again in absolutely glorious detail. (Seriously, click through for the full-sized version. You can all but make out individual cells.)

Many thanks to Ray for sharing these photos with us!