😘Trunk and Lower Back Muscles (originate and act on torso structures) movement😘

diaphragm

expand thoratic cavity, inferiorly compress abdominal viscera

external intercostals

elevate and protect ribs

internal intercostals

depress and retract ribs (in forced expiration)

transfersus thoracis

depress ribs

serratus posterior superior

elevate ribs

serratus posterior inferior

depress ribs

longissimus dorsi (of erector spinae)

extend, laterally flex trunk

quadratus lumborum

extend, laterally flex trunk

rectus abdomnins

flex trunk

external oblique

superiorly compress abdominal contents in forced expiration, contralateral rotation of waist

internal oblique

superiorly compress abdominal contents in forced experation, ipsilateral rotation of waist

transverse abdominis

superiorly compress abdominal contents in forced expiration