Muscles of the Head and Neck The Muscular System

General Muscle Terminology Origin: stationary point of attachment Insertion: movable point of attachment Action: Anatomical movement that results from the contraction of the muscle

General Info: Facial muscles Most muscles originate on the surface of the skull and insert into the dermis Create facial movements and expressions

Frontalis Action: raises eyebrow, wrinkles forehead

Occipitalis Action: tenses and retracts the scalp

Masseter Action: closes mandible Ex: closes mouth during chewing

Temporalis Action: elevates mandible Ex: clenching your jaw, crushing food

Orbicularis oculi Action: closes eye Ex: blinking, squinting

Nasalis Action: compresses nostril

Zygomaticus Action: draws corner of mouth upward Ex: smiling

Buccinator Action: compresses cheeks Ex: playing a trumpet, whistling

Orbicularis oris Action: compresses, purses lips Ex: kissing

Depressor anguli oris Action: depresses corner of mouth Ex: frowning

Anatomy - Human frontalis temporalis Orbicularis oculi zygomaticus masseter Orbicularis oris buccinator Depressor anguli platysma sternocleidomastoid

Epicranial aponeurosis frontalis occipitalis temporalis Orbicularis oculi nasalis zygomaticus masseter buccinator sternoclediomastoid Orbicularis oris platysma

General Info: Neck muscles Involved in Swallowing and chewing Moving your head and neck Supporting your head Anterior neck muscles work on the hyoid bone Suprahyoid muscles (above the hyoid) pull hyoid up Infrahyoid muscles (below the hyoid) pull hyoid down

Sternocleidomastoid Extends from the clavicles and the sternum to the mastoid region of the skull Actions: flexion of head, lateral flexion, rotation of head side to side

Platysma Action: tenses skin of neck, depresses mandible (opens mouth)

Digastric (“two bellies”) Action: elevates hyoid bone when swallowing; depresses the mandible (opening mouth)

Mylohyoid Broad/flat muscle provides muscular floor to the mouth and helps press tongue to top of mouth

Sternohyoid Connects the hyoid bone to the sternum Action: depresses hyoid bone and larynx

Sternothyroid Anchors the larynx to the sternum Action: depresses hyoid bone and larynx

Stylohyoid Connects the hyoid bone to the styloid process of the skull Action: elevates hyoid

digastric mylohyoid stylohyoid thyrohyoid omohyoid sternohyoid sternothyroid

Superficial muscles of the neck Sternomastoid Cleidomastoid Sternohyoid Mylohyoid Digastric Masseter Sternomastoid = #18 Cleidomastoid = #6 Sternohyoid = #17 Mylohyoid = #11 Digastric = #7 Masseter = #10 TOO DEEP TO DISSECT Stylohyoid Sternothyroid Thyrohyoid

Digastric Mylohyoid Masseter Sternohyoid sternomastoid cleidomastoid

Name the muscle… Frontalis

Buccinator and orbicularis oris Name the muscle… Buccinator and orbicularis oris

Name the muscle… Orbicularis oculi

Name the muscle… Platysma

Name the muscle… Orbicularis oris

Name the muscle… Depressor Anguli Oris