Muscles of trunk, neck, and face

Splenius group

Capitis, cervicis

Splenius group bilateral action

Extend head and neck

Splenius group unilateral action

Sidebend and rotate head and neck to same side

Erector spinae

Spinalis, Longissimus, Iliocostalis

Spinalis

Longissimus

Iliocostalis

Erector spinae bilateral action

Extend vertebral column

Erector spinae unilateral action

Sidebend vertebral column to same side

Transversopinal muscles

Semispinalis group, Multifidis group, Rotatores group

Transversospinal muscle origin

Transverse processes of vertebrae

Transversospinal muscles insertion

Spinous processes of vertebrae

Transversospinal muscle bilateral action

Extension of vertebral column

Transversospinal muscle unilateral action

Sidebending to same side, rotating to opposite side

Semispinalis group

Muscle slips span 4-6 vertebral layers

Multifidis group

Muscle slips span 2-4 vertebral layers

Rotatores group

Muscle slips span 1-2 vertebral layers

Sternocleidomastoid

Sternocleidomastoid origin

Manubrium and clavicle

Sternocleidomastoid insertion

Mastoid process of temporal bone

Sternocleidomastoid bilateral action

Head extension

Sternocleidomastoid unilateral action

Rotation to opposite side

Scalenes

Anterior, middle, and posterior

Scalenes bilateral action

Elevate 1st and 2nd rib

Scalenes unilateral action

Sidebends neck

Frontalis

Frontalis action

Raises eyebrows

Orbicularis oculi

Orbicularis oculi action

Closes eye tightly

Zygomaticus major

Zygomaticus major action

Elevates corner of mouth

Depressor anguli oris

Depressor anguli oris action

Depresses corners of mouth

Orbicularis oris

Orbicularis oris action

Closes mouth, purses lips

Temporalis

Masseter

Temporalis and masseter action

Elevate mandible (close mouth)

Medial and lateral pterygoid

Medial and lateral pterygoid bilateral action

Protrude mandible

Medial and lateral pterygoid unilateral action

Side-to-side movement

External oblique

External oblique bilateral action

Flexes trunk

External oblique unilateral action

Sidebend trunk to same side, rotate to opposite side

Internal oblique

Internal oblique bilateral action

Flexes trunk

Internal oblique unilateral action

Sidebend and rotate trunk to same side

Rectus abdominis

Rectus abdominis bilateral action

Flexes trunk

Rectus abdominis unilateral action

Sidebends trunk

Tranversus abdominis

Transversus abdominis action

Maintains abdominal wall tension and increase intra-abdominal pressure

Diaphragm

Diaphragm origin

Lower ribs, sternum, and lumbar vertebrae

Diaphragm insertion

Central tendon

Diaphragm action

Moves inferiorly when contracted (increase thoracic volume, drawing air into lungs); moves superiorly when relaxed (decreases thoracic volume, pushes air out of lungs)

Intercostals

External, Internal, and Innermost intercostals

External intercostals

External intercostals action

Elevates ribs during inhalation

Internal intercostals and innermost intercostals

Internal intercostals and innermost intercostals action

Depress ribs during exhalation