Thoracic Anatomy: Musculature Flashcards
What are the 5 “True Muscles” of the thoracic wall?
serratus posterior levatores costarum transversus thoracis subcostals intercostals
Name the 2 serratus posterior muscles.
Serratus posterior superior (C7-T3)
Serratus posterior inferior (T11-L2)
Action of serratus posterior superior muscle.
elevate superior 4 ribs
Action of serratus posterior inferior.
depress inferior ribs (prevents diaphragm from pulling ribs upward)
Which triangular muscles have a proximal attachment of the transverse processes of C7-T11
Levatores Costarum
Main action of levatores costarum muscles…
elevate ribs (C7-T11)
Name the three layers of intercostal muscles from superficial to deep…
External intercostal
Internal intercostal
Innermost intercostal
the intercostal nerves and vessels run between fibers of which muscles?
internal and innermost intercostal muscles
Fiber orientation of external intercostal muscles…
inferoanteriorly (“hands in pockets” orientation)
Fiber orientation of internal and innermost intercostal muscles…
inferposteriorly
The innermost intercostal muscle is a group of fibers from the _______ muscle
internal intercostal
The external intercostals extend to the abdomen to make up which muscles?
External Oblique (“hands in pockets” orientation)
Action of external intercostal muscles
elevate ribs during FORCED inspiration
This group of muscles originates at the INTERNAL surface of ribs and attaches distally to the superior border of the ribs 2-3 inferior from origin…
Subcostal muscles
Fiber orientation of subcostal muscles
same as internal intercostals (inferoposteriorly)
origin of this muscle is the posterior surface of the lower sternum, sitting on the interior of thoracic cage…
transversus thoracis (analogous to transversus abdominus)
Attachment site of transversus thoracis…
Internal costal cartilage surface of ribs 2-6
This nerve provides innervation to:
- Intercostals
- Transversus Thoracis
- Subcostals
intercostal nerves
What band of fibrous tissue sits between the thoracic cage and the lining of pulmonary cavities?
endothoracic fascia
This structure attaches the costal parietal pleura to the thoracic wall…
endothoracic fascia
at the apices of the lungs, the endothoracic fascia becomes more dense, and is called…
suprapleural membrane
Name the three large muscles which overly the anteiror thoracic cage, but do not directly exert an action on it…
pectoralis major
pectoralis minor
serratus anterior
small muscle that runs vertically in some people along the sternum…
sternalis muscle
Which nerves innervate the levator costorum?
posterior rami of C8-T11
Which fascia invests the pectoralis minor?
clavipectoral fascia
