Expiratory Muscles

Question 1

What are the three anterior thoracic muscles used in forced exhalation?

Answer 1

1. internal intercostal muscles
2. innermost intercostals
3. tranversus thoracis

Question 2

What are the two posterior thoracic muscles used in forced exhalation?

Answer 2

1. Serratus Posterior Inferior
2. Subcostals

Question 3

Origin: superior margin of each rib
Course: superior and medially to…
Insertion: inferior surface of rib above

Answer 3

Internal intercostal (interosseous portion)

Question 4

Origin: superior margin of ribs 1-11
Course: parallel to internal intercostal muscles
Insertion: inferior surface of the rib above

Answer 4

Innermost intercostal

Question 5

Origin: posterior surface of the body of the sternum and the xiphoid process
Course: laterally/some also superiorly
Insertion: inner chondral surface of ribs 2-6

Answer 5

Transversus Thoracis

Question 6

Origin: inner posterior surface thorax
Course: parallel to the internal intercostals
Insertion: multiple ribs?

Answer 6

Subcostals

Question 7

Origin: spinous processes of vertebrae T11-T12, L1-L3
Insertion: the inferior borders of ribs 7-12

Answer 7

Serratus posterior inferior

Question 8

Origin: pubis (a part of the pelvic girdle)
Insertion: xiphoid process and costal cartilage of ribs 5-7
Contraction: depress the rib cage

Answer 8

Rectus abdominis

Question 9

Origin: ribs 6-12
Insertion: iliac crest
Course: fan inferiorly and medially
Contraction: depress the lateral rib cage

Answer 9

External Oblique Abdominis

Question 10

Origin: iliac crest
Insertion: cartilaginous portion of lower ribs
Contraction: pulls down the rib cage

Answer 10

Internal oblique abdominis

Question 11

Origin: posterior abdominal wall at the vertebral column
Course: runs laterally
Insertion: Inner surface of ribs 6-12
Contraction: compresses the abdomen

Answer 11

Transverse Abdominis