middle rectal plexus middle rectal plexus the middle rectal plexus is a nerve plexus which supplies the middle part of the rectum. middle rectal plexusdetailsfrominferior hypogastric plexusidentifierslatinplexus rectalis mediusta98a14.3.03.049ta26716fma6645anatomical terms of neuroanatomy it is a branch of the inferior hypogastric plexus. the middle rectal plexus used to be referred to by anatomists as copeland's web, due to its identification by biologist charles copeland and the design of his anatomical drawings in the early 20th century.