Muscles of the Head

Points of the Muscle

  • Origin: Immovable end of the muscle.

  • Insertion: Moveable end.

  • During a contraction: Insertion is pulled toward the origin.

Muscle Function in Groups:

  • Prime Mover: Muscle that is responsible for most of the movement.

  • Synergist: Helps the prime mover.

  • Antagonist: Muscles that resist the primer mover and are moving the muscle in the opposite direction.

Muscles of Facial Expressions:

  1. Epicranus: Covers the upper cranium. Contains two parts: frontalis and occipitalis.

  • Contraction: Wrinkles the forehead.

  1. Orbicularis Oculi: Ringlike muscle that surrounds the eye.

  • Contraction: Closes the eyes, blinking.

  1. Orbicularis Oris: Sphincter muscle that encircles the mouth.

  • Contraction: Kissing

  1. Buccinator: Located in the cheek wall under the masseter and obicularis oris.

  • Contraction: Blowing out air.

  1. Zygomaticus: Extends from the zygomatic arch to the corner of the mouth.

  • Contraction: Smiling, laughing

  1. Platysma: Extends from the chest up over the neck to the face.

  • Contraction: Propulsion

Muscles of Mastication (Chewing)

  1. Masseter: Extends from the zygomatic arch to the mandible.

Contraction: Raised jaw.

  1. Temporalis: Fan shaped muscle located on the side of the skull above the ear.

Contraction: Raises jaw.

  1. Medial Pterygoid: Extends from the sphenoid, palantine, and maxillary to the sphenoid bone.

Contraction: Raises jaw.

  1. Lateral Pterygoid: Extends from below the mandibular condyle to the sphenoid.

Contraction: Opens mouth, moves jaw side to side.

Muscles that Move the Head

  • Located in the neck.

  1. Sternocteidomastoid: Long muscle in the side of the neck extends from chorax to the skull behind the ear.

Contraction: Pulls head to one side and chest.

  1. Splenius Capitis: Connects the base of the skull to the vertebrae in the neck and upper thorax.

Contract: Rotates head, bends, rotates.

  1. Semispinalis Capitis: Extends from the vertebrae in the neck to the occipital.

Contraction: Extends head, rotation, bends neck to one side.

  1. Longissimus Capitis: Extends from vertebrae of the neck and thorax to the temporal bone.

Contraction: Extends head, rotation, bends neck to one side.