A&P Lab Practical 2

muscle functions

Occipitofrontalis

Raises eyebrows/wrinkles forehead

Corrugator supercilli

Pull eyebrows down medially

Orbicularis oculi

Closes eyelids

Zygomaticus major

Pulls corner of mouth up & laterally (smiling)

Zygomaticus minor

Pulls upper lip up & outward (snarling)

Buccinator

Compresses cheeks against teeth/lips (whistling

Orbicularis oris

Puckers lips (kissing)

Mentalis

Pulls lower lip up & outward (pouting)

Platysma

Pulls lower lip/neck skin down & laterally (frown)

Temporalis

Elevates mandible

Masseter

Elevates mandible

Digastric (anterior belly)

Depresses mandible

Sternocleidomastoid

Rotation head/flex neck

Splenius Capitis

Extend head/extension/flexion

Scalenes

Elevates first rib

Diaphragm

Increases & decreases volume of thoracic cavity

External Intercostals

Expands ribcage

Internal Intercostals

Pulls ribs together

Rectus Abdominis

Flexes vertebral column

External Oblique

Compresses abdomen/rotates trunk

Internal Oblique

Compresses abdomen/rotates trunk

Transverse Abdominis

Compresses abdomen/rotates trunk

Splenius Cervicis

Extend neck/laterally flex and rotate head to same side

Semispinalis

Head and neck extension & lateral flexion

Spinalis(medial) longissimus (middle) and Iliocostalis (lateral)

extend & laterally flex spine

Rotatores Extend spine/rotate spine to opposite side

Quadratus lumborum

lateral flexion of back