Thecal Sac or Dural Sac
The thecal sac or dural sac is the membranous sheath (theca) or tube of dura mater that surrounds the spinal cord and the cauda equina. The thecal sac contains the cer
Rumplessness, pygostyles and more
Rumpless chickens are characterised by caudal dysplasia, the absence of the pygostyle or caudal appendage – the “parson’s nose”. This is the