External intercostal muscles :- By vastralphysiotherapyclinic | September 22, 2018 - 12:26 pm |September 22, 2018 Physiotherapy Clinic External intercostal muscles :- muscle details :- are eleven in number on both sides . origin :- Lower border of ribs . Insertion :- Upper border of rib below . Nerve :- intercostal nerves . Actions :- Inhalation . Tagged external intercostal muscle details. Bookmark the permalink.