AOI Facial and abdominal muscles

Internal oblique

• A: Supports abdominal wall
• O: Iliac crest
• I: Xiphoid

External oblique

• A: Supports abdominal wall
• O: 5-12 ribs
• I: Xiphoid

Transverse abdominis

• A: Aids in twisting and supporting abdominal wall
• O: Iliac crest
• I: Xiphoid

Rectus abdominis

• A: Flexes waist as in sit-ups
• O: Pubis
• I: Xiphoid process, costal cartilages 5-7

Orbicularis oris

• A: Closes lips; purses and protrudes lips
• O: Maxilla and mandible
• I: Skin and muscles at angles of mouth

Orbicularis oculi

• A: Closes eye; produces blinking and squinting; draws eyebrows inferior
• O:Frontal and maxillary bones
• I: Tissue of eyelid

Buccinator

• A: Compresses cheek; draws corner of mouth laterally; also a muscle of mastication
• O: Molar region of maxilla and mandible
• I: Orbicularis oris

Masseter

• A: Prime mover of jaw closure; elevates mandible
• O: Zygomatic bone
• I: Mandible

Nasalis

• A: Compress/ expand nares
• O: Maxilla
• I: Nasal cartilage

AOI Facial and abdominal muscles