Muscles of Inspiration - Origin, Insertion, and Action
Internal Intercostal Muscles (chondral portion) : Origin
Ribs 1-11
Levatores Costarum, Brevis Portion : Origin
Transverse process of C7-T11
External Intercostal Muscles : Insertion
Upper surface of rib immediately below
levatores costarum, longus portion : insertion
bypass the rib below the point of origin and inserts onto the next rib
Diaphragm : Insertion
central tendon
subclavius : origin
clavicle
pectoralis minor : insertion
coracoid process of scapula
subclavius : action
elevates rib
pectoralis major : insertion
greater tubercle of humerus
Diaphragm : Origin
inferior boundary of rib cage, xiphoid process, posterior vertebral column
External Intercostal Muscles : Origin
lower surface of each rib (except 12)
sternocleidomastoid : origin
mastoid process of the temporal bone (on skull)
Diaphragm : Action
pulls central tendon down and forward during inspiration
scalenus (anterior, middle, and posterior) : insertion
ribs 1-2
serratus anterior : origin
ribs 1-9
pectoralis minor : origin
ribs 2-5
serratus posterior superior : insertion
ribs 2-5
levator scapulae : insertion
scapula
rhomboids : insertion
scapula
serratus anterior : insertion
scapula
trapezius : insertion
scapula + superior surface of clavicle
rhomboids : actions
stabilizes shoulder girdle
pectoralis major : origin
sternal head + clavicular head
sternocleidomastoid : insertion
sternal head and clavicle
levatores costarum, longus portion : origin
transverse process of T7-T11
levatores costarum, brevis portion : insertion
tubercle of rib below
subclavius : insertion
1st rib
scalenus (anterior, middle, and posterior) : origin
C2-C6 vertebrae
External Intercostal Muscles : Action
elevates rib cage
Internal Intercostal Muscles (chondral portion) : Action
elevates ribs
levatores costarum, brevis and longus portions : action
elevates ribs
scalenus (anterior, middle, and posterior) : action
elevates ribs 1-2
serratus anterior : action
elevates ribs 1-9
serratus posterior superior : action
elevates ribs 2-5
pectoralis minor : action
elevates ribs 2-5 with shoulder fixed
levator scapulae : action
elevates scapula
pectoralis major : action
elevates sternum + rib cage
sternocleidomastoid : action
elevates sternum + rib cage
* trapezius : action
elongates neck, stabilizes head
trapezius : origin
spinous process C2-T12
rhomboidus minor : origin
spinous process of C7-T11
serratus posterior superior : origin
spinous process of C7-T3
rhomboidus major : origin
spinous process of T2-T5
Internal Intercostal Muscles (chondral portion) : Insertion
superior surface of the rib below
levator scapulae : origin
transverse process C1-C4
