Muscle Actions

Origin: Galea aponeurotic

Insertion: Skin of the eyebrows

Action: Raises the eyebrows

​ ​ ​ ​ ​ ​ (a)  

• Frontalis
• Occipitalis
• Orbicularis Oculi
• Buccinator
• Zygomaticus major

Origin: Frontal and maxillary bones

Insertion: Skin near the eye

Action: Closes the eye and wrinkles the skin around the eye

​ ​ (a)  

Origin: Maxillary bone and mandible

Insertion: Skin and muscle around the mouth

Action: Closes the lips and wrinkles the skin around the mouth

​ (b)  

• Orbicularis Oculi
• Orbicularis Oris
• Buccinator
• Occipitalis
• Zygomaticus major
• Zygomaticus minor

Origin: Zygomatic arch

Insertion: Mandible

Action: Elevates the jaw, closes the jaw, and grinds food in the molars

​ ​ (a)  

• Masseter
• Occipitalis
• Zygomaticus major
• Zygomaticus minor
• Buccinator

What are the 2 muscles that synergize with one another to perform mastication?

​ ​ 1) Primary mastication muscle​ (a)  

​ 2) Accessory muscle for mastication ​ (b)  

• Masseter
• Temporalis
• Occipitalis
• Zygomaticus major
• Sternocleidomastoid

Smiling muscles

1) Origin: Zygomatic bone

Insertion: Skin near the corner of the mouth

Action: Raises the corners of the mouth and forms a smile

​ ​ ​ ​ (a)  

2) Origin: Zygomatic bone

Insertion: Skin near the corner of the mouth

Action: elevates the upper lip

​ ​ (b)  

• Zygomaticus major
• Zygomaticus minor
• Platysma
• Temporalis
• Sternocleidomastoid
• Trapezius

Origin: Sternum and clavicle

Insertion: Mastoid process of the temporal bone

Action: Flexes the neck and rotates the head to the opposite side.

​ ​ ​ (a)  

• Sternocleidomastoid
• Platysma
• Temporalis
• Trapezius

Origin: Clavicle, sternum, and costal cartilages

Insertion: Humerus

Action: Flexes, adducts, and rotates arm medially

​ ​ (a)  

• Pectoralis Major
• Platysma
• Temporalis
• Trapezius
• Levator Scapulae

Origin: Spinous processes of T6-L5 vertebrae, iliac crest, sacrum, and lower 3 or 4 ribs

Insertion: Intertubercular groove of the humerus

Action: Adducts, extends, and rotates arm medially

​ ​ (a)  

​ ​

• Latissimus Dorsi
• Platysma
• Temporalis
• Trapezius
• Levator Scapulae

Origin: Lateral third of clavicle, acromion process of scapula, and spine of scapula

Insertion: Deltoid tuberosity of humerus

Action: Abducts, flexes, and extends arm at the shoulder.

​ ​ (a)  

​ ​

• Deltoid
• Platysma
• Temporalis
• Trapezius
• Levator Scapulae

Origin: Pubic crest and symphysis

Insertion: Xiphoid process and costal cartilages of ribs 5-7

Action: Flexes vertebral column and compresses the abdomen

​ ​ ​ (a)  

​ ​

• Rectus Abdominis
• Platysma
• Temporalis
• Trapezius
• Levator Scapulae
• Infraspinatus