Trunk OIA Muscles

Sternocleidomastoid

O: Manubrium & Medial clavicle

I: Mastoid process & lateral occiput

A: Cervical: ipsilateral bending & contralateral rotation

Anterior scalenes

O: Transverse processes C3-C6

I: 1st Rib

A: Cervical: ipsilateral lateral bending

Middle scalenes

O: Transverse processes of cervical vertebrae (C2-C7)

I: 1st Rib

A: Cervical: ipsilateral lateral bending

Posterior scalenes

O: Transverse processes C6-C7

I: 2nd Rib

A: Cervical: ipsilateral lateral bending

Splenius capitis

O: Ligamentum nuchae & spinous processes of C4-T4

I: Mastoid process & occipital bone

A: Cervical: extension & ipsilateral rotation

Splenius cervicis

O: Upper thoracic spinous processes

I: Upper cervical transverse processes

A: Cervical: extension & ipsilateral rotation

Suboccipitals

O: C1-C2

I: Occipital bone & C1

A: Head: extension, ipsilateral lateral bending , ipsilateral rotation

Rectus abdominis

O: Pubic symphysis & pubic crest

I: Xiphoid process & costal cartilages of ribs 5-7

A: Trunk flexion

External oblique

O: Lateral lower ribs

I: Abdominal aponeurosis & anterior iliac crest

A: Trunk: flexion, contralateral rotation, ipsilateral lateral bending

Internal oblique

O: Iliac crest & thoracolumbar fascia

I: Anterior lower ribs & abdominal aponeurosis

A: Trunk: flexion, ipsilateral rotation, ipsilateral lateral bending

Transverse abdominis

O: Lower ribs, iliac crest, thoracolumbar fascia

I: Abdominal aponeurosis

A: Compresses abdomen

Erector spinae group

O: Vertebrae: spinous processes and transverse processes, Posterior ribs, Posterior pelvis

I: Mastoid process, Posterior ribs, Vertebrae superior to origin: spinous processes and transverse processes

A: Vertebrae: extension & ipsilateral lateral bending

Semispinalis capitis

O: Lower cervical and upper thoracic vertebrae: Transverse processes

I: Occiput

A: Head and Cervical spine extension

Multifidi group

O: Sacrum & transverse processes of thoracic vertebrae

I: Spinous precess of vertebrae 2-4 vertebrae above origin

A: Vertebrae: extension & contralateral rotation

Rotatores group

O: Cervical through lumbar vertebrae: transverse processes

I: spinous process of vertebrae 1-2 vertebrae above origin

A: Vertebrae: extension & contralateral rotation

Serratus posterior superior

O: Upper thoracic vertebrae: spinous processes

I: Posterior upper ribs

A: Elevates ribs during inhalation

Serratus posterior inferior

O: Lumbar vertebrae: spinous processes

I: Posterior lower ribs

A: Depresses ribs during exhalation

Masseter, Temporalis, Medial pterygoid

Closes mouth

Lateral pterygoid

Opens mouth

External intercostals

O: Rib

I: Rib below origin

A: Elevates ribs

Internal intercostals

O: Rib

I: Rib below origin

A: Depresses ribs

Diaphragm

O: Inner surface of lower ribs, Lumbar vertebrae, Sternum

I:

A: Increases size of thoracic cage during inhalation

Quadratus lumborum

O: Posterior iliac crest

I: Lumbar transverse processes

A: Lumbar: ipsilateral lateral bending (trunk lateral bending)