Muscle O/I/A Flashcards
transversus thoracis
O - sternal body
I - ribs 2-6
A - depress and pull medially ribs 3-6
levatores costarum
O - transverse processes of C7 - T11
I - rib below
A - elevates the ribs
serrates posterior superior
O - ligamentum niche
I - ribs 2-5
A - elevates the upper ribs
serrates posterior inferior
O - supraspinous ligament of T11 - L3
I - ribs 9-12
A - pulls down lower rib cage to help enlarge thorax
anterior scalenes
O - transverse process of C3-6
I - first rib
A - elevates and fixes the upper ribs
middle scalenes
O - transverse process of C2-7
I - first rib
A - elevates and fixes the upper ribs
posterior scalenes
O - transverse process of C6-7
I - second rib
A - elevates and fixes the upper ribs
SCM
O - manubrium and sternal end of clavicle
I - mastoid process
A - elevates the sternum
Action of the abdominals
active expiration by depressing the lower ribs and compressing the abdominal contents, thus pushing up the diaphragm
rectus abdominis
O - pubic crest and symphysis
I - xiphoid process and cartilages of ribs 5-7 (via tendinous intersections into the rectus sheath)
external abdominal oblique
O - ribs 5 - 12
I - lower 2 ribs, iliac crest, abdominal aponeurosis
internal abdominal oblique
O - inguinal ligament, iliac crest, thoracolumbar fascia
I - lower 3-4 ribs, abdominal aponeurosis
transversus abdominis
O - lower 6 ribs, thoracolumbar fascia, iliac crest, inguinal ligament
I - abdominal aponeurosis
