<prompt> Which of the following is a remnant of ductus aeriosus?Ligamentum aeriosumLigamentum teresBoth of the aboveNone of the above  <response>: On the right, when the distal pa of the sixth aoic arch and the fifth aoic arch disappear, the recurrent laryngeal nerve moves up and hooks around the right subclan aery. On the left, the nerve does not move up, since the distal pa of the sixth aoic arch persists as the ductus aeriosus, which later forms the ligamentum aeriosum Ref: Langmans embryology 11th edition Chapter 12. 