OIA (Seperated) Axial Muscles

Orbicularis oris (OI)

Origin: Maxilla and mandible; Insertion: Lips

Orbicularis oris (A)

Action: Closes and purses lips ("kissing muscle")

Zygomaticus major (OI)

Origin: Zygomatic bone; Insertion: Angle of mouth

Zygomaticus major (A)

Action: Elevates corners of mouth (smiling)

Zygomaticus minor (OI)

Origin: Zygomatic bone; Insertion: Upper lip

Zygomaticus minor (A)

Action: Elevates upper lip (smiling)

Buccinator (OI)

Origin: Alveolar processes of maxilla and mandible; Insertion: Fibers of orbicularis oris

Buccinator (A)

Action: Compresses cheek ("trumpeter's muscle")

Platysma (OI)

Origin: Superior thorax; Insertion: Mandible and skin of cheek

Platysma (A)

Action: Tenses skin of neck and depresses mandible

Risorius (OI)

Origin: Fascia around parotid salivary gland; Insertion: Angle of mouth

Risorius (A)

Action: Draws corners of mouth laterally

Corrugator supercilii (OI)

Origin: Frontal bone; Insertion: Skin of eyebrow

Corrugator supercilii (A)

Action: Wrinkles eyebrows

Orbicularis oculi (OI)

Origin: Medial margin of orbit; Insertion: Skin around eyelids

Orbicularis oculi (A)

Action: Closes eye

Masseter (OI)

Origin: Zygomatic arch; Insertion: Mandibular ramus

Masseter (A)

Action: Elevates mandible

Temporalis (OI)

Origin: Temporal bone; Insertion: Coronoid process of mandible

Temporalis (A)

Action: Elevates mandible

Sternocleidomastoid (OI)

Origin: Sternum and clavicle; Insertion: Mastoid process

Sternocleidomastoid (A)

Action: Together flex neck; alone rotates head to opposite side

Semispinalis capitis (OI)

Origin: Transverse processes of lower cervical and upper thoracic vertebrae; Insertion: Occipital bone

Semispinalis capitis (A)

Action: Extends head; laterally flexes neck

Semispinalis cervicis (OI)

Origin: Transverse processes T1-T5; Insertion: Spinous processes C2-C5

Semispinalis cervicis (A)

Action: Extends vertebral column; rotates opposite side

Semispinalis thoracis (OI)

Origin: Transverse processes T6-T10; Insertion: Spinous processes C5-T4

Semispinalis thoracis (A)

Action: Extends vertebral column; rotates opposite side

External intercostals (OI)

Origin: Inferior border of rib; Insertion: Superior border of next rib

External intercostals (A)

Action: Elevates ribs

Internal intercostals (OI)

Origin: Superior border of rib; Insertion: Inferior border of next rib

Internal intercostals (A)

Action: Depresses ribs

Rectus abdominis (OI)

Origin: Superior surface of pubis; Insertion: Xiphoid process & costal cartilages of ribs 5-7

Rectus abdominis (A)

Action: Flexes vertebral column; depresses ribs