Chest muscles

Mm. intercostales, Mm. scaleni und M. transversus thoracis

The muscles Mm. intercostales and M. transversus thoracis belong to the autochthonous chest muscles, which are an important part of the respiratory muscles. The Mm. scaleni belong to the deep neck muscles. As they function as auxiliary breathing muscles, they are also explained here.

A schematic drawing of the muscles (Mm. intercostales, Mm. scaleni and M. transversus thoracis) can be displayed by clicking on the respective name in the "WebViewer".

autochthonous chest muscles - Mm. intercostales und M. transversus thoracis

	Mm. intercostales externi	Mm. intercostales interni	M. transversus thoracis
origin	Lower margin of a rib (Tuberculum costae up to Cartilage-bone junction)	upper margin of a rib (Angulus costae to Sternum)	inside rib cartilage of 2nd-6th rib
insertion	upper margin of next deeper rib progression: from posterior top to posterior bottom (Tuberculum costae to cartilage-bone junction)	lower edge of next highest rib progression: from back bottom to front top (Angulus costae to sternum)	Inside of Corpus sterni and Processus xiphoideus sterni
function	rib lifter (inspiration), tighten the interrib spaces; stabilization of the thoracic wall	rib countersink (expiration); tighten the interrib spaces; stabilization of the thoracic wall	Rib countersink (expiration)
innervation	Nervi intercostales 1-11	Nervi intercostales 1-11	Nervi intercostales 2-6

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Mm. scaleni

	M. scalenus anterior	M. scalenus medius	M. scalenus posterior
origin	Tubercula anteriora of the transverse processes of the 3rd-6th cervical vertebra	Tubercula posteriora of the transverse processes of the 3rd - 7th cervical vertebra	Tubercula posteriora of the transverse processes of the 5th-7th cervical vertebra
insertion	Tuberculum musculi scaleni anterioris of the 1st rib	1st rib (dorsal of Sulcus arteriae subclaviae)	Outside surface of the 2nd rib
function	Punctum mobile on the ribs: Inspiration (lifting of the upper ribs) Fixed point on the ribs: one-sided contraction results in lateral flexion of the cervical spine to the ipsilateral side Both-sided contraction results in ventral flexion of the neck
innervation	direct branches from the spinal nerves cervical plexus and brachial plexus (C3-6)

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Further links

Exercises

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