A markedly non-compliant middle ear system with a normal external ear canal volume is demonstrated as a Type _________ tympanogram.

In this context, a markedly non-compliant middle ear system with a normal external ear canal volume indicates a specific type of tympanogram known as Type B. This type of tympanogram is characterized by a flat line on the graph, which suggests that there is little to no movement of the tympanic membrane in response to changes in air pressure.

A Type B tympanogram typically represents fluid in the middle ear, a perforation of the tympanic membrane, or some form of serious pathology affecting compliance but normal ear canal volume indicates that there is no obstruction or abnormality in the external ear canal, which aligns with the description of the scenario.

Types A and C indicate normal and negative pressure systems respectively, while Type Ad would suggest a hypercompliant system often seen in cases like ossicular disarticulation, which does not fit the scenario of a non-compliant system. Therefore, the characteristics you have described are best represented by a Type B tympanogram.