Muscle colloquium 7, musculi thoracis

M. pectorales superficialis

O: paramedially on cranial end of sternum

In: crista tuberculi major on humeri

F: adductor / draws limb forward and backward / draws trunk sideward

M. pectorales profundus

O: corpus sterni, towards cartilago xiphoideus

In: tuberculum minor on humerus

F: moves the trunk cranially during movement / extensor of shoulder joint / draws the limb backward

Mm. levators costarum

O: processus transversus of thoracic vertebrae

In: cranial edge of following rib

F: inspiratory (breathing in)

Mm. intercostales externi

O: caudal border of ribs

In: cranial border of following rib

F: inspiratory (breathing in)

Mm. intercostalis interni

O: cranial border of ribs

In: caudal border of preceding rib

F: expiratory (breathing out, exhaling)

M. transversus thoracis

O: lig. sterni / medial sternum

In: internal surface of cartilago costalis 2 - 6

F: expiratory (breathing out, exhaling)

M. rectus thoracis

O: first costae

In: cartilago costae of rib 2 - 4

F: inspiratory (breathing in)

M. serratus dorsalis caudalis

O: fascia thoracolumbalis

In: caudal border of rib 11, 12 & 13

F: expiratory (breathing out, exhaling) by dragging the last three ribs caudally

M. serratus dorsalis cranialis

O: fascia thoracolumbalis / prcessus spinosus of vertebrae 1 - 8

In: cranial border and lateral border of ribs 2 - 10

F: inspiratory (breathing in) extends the thorax by moving the ribs foreward

M. scalenus medius

O: processus transversus of C3 - C6

In: middle portion of the first rib

F: supports inspiratory / lateral flexor

M. scalenus dorsalis

O: processus transversus of C3 - C6

In:

• car: 8 - 9 rib

• ru: 4 - 5 rib

F: supports inspiratory / lateral flexor