T/S, Superficial And Intermediate Back Muscles Flashcards
2 functions of thoracic region
Stable basis for muscles
Protection for intrathoracic organs
Mechanical bellows for breathing
What is the primary characteristic of thoracic vertebrae?
Costal facets
Typic thoracic vertebrae characteristics
-Pedicles are directed posteriorly from body
-large TP projected posterior-laterally
-long SP and projected down
-facet joints are nearly vertical
Which segments are typical? Atypical?
Typical vs atypical
Typical: T2-T10
Atypical: T1, T11, T12
Atypical are “selfish” b/c they have a whole rib for themselves
T1 atypical vertebrae characteristics
-full costal facet superiorly (accommodates entire 1st rib head)
-partial costal facet inferiorly (part of 2nd rib head)
-SP is prominent
T11 and T12 atypical vertebrae characteristics
-bodies have single full costal facets
Serrated posterior inferior OIIA
Origin: SP of T11 to L3 and supraspinous ligaments
Insertion: lower borders of ribs 9 to 12
Innervation: intercostal nerves T9-T12
Action: depresses ribs 9-12, exhalation (respiratory function)
Serrated posterior superior OIIA
Origin: ligamentum nuchae, SP of C7 to T2 and supraspinous ligaments
Insertion: upper border of ribs 2 to 5
Innervation: intercostal nerves T1-T5
Action: elevates ribs 2 to 5
Serratus posterior superior and inferior (fiber orientation and location)
-serratus posterior superior (descending fibers, deep to rhomboids)
-serratus posterior inferior (ascending fibers, deep to Lats)
Superficial/appendicular group of muscles
Trap, lat, rhomboids, Levator
What do the costovertebral joints allow the ribs to do?
Rotate around their longitudinal axis (mainly upper ribs)
Ascend and descend relative to vertebral column (mainly in lower ribs)
What does a typical rib articulate with? Forms what?
Bodies of adjacent vertebrae (form joint of head of rib)
TP of its related vertebra (form costotransverse joint)
