Unit 1 Exam Thoracic Wall Muscles

Question 1

External intercostal muscles

Answer 1

Attachment 1: inferior border of upper rib

Attachment 2: superior border of lower rib

primary actions: elevates ribs (inspiration)

innervation intercostal nerves T1-T11

Question 2

Internal intercostal muscles

Answer 2

attachment 1: inferior border of upper rib

attachment 2: superior border of lower rib

primary actions: depress ribs (expiration)

innervations: intercostal nerves T1-T11

Question 3

Innermost intercostal muscles

Answer 3

attachment 1: inferior border of upper rib

attachment 2: superior border of lower rib

primary action: acts with internal intercostals, depress ribs

innervations: intercostal nerves T1-T11

Question 4

Subcostal muscles

Answer 4

attachments: attach rib to rib but cross over 1-2 ribs

primary actions: act with innermost/internal intercostals

Question 5

transversus thoracis muscles