Muscles of the Head and Neck A Few

Muscles of the Head and Neck

A Few Facts � The head and facial muscles are unique � The head and face muscles are grouped by ◦ For the most part skeletal muscles originate and insert on the skeleton (bones!) ◦ The head and facial muscles often originate and/or insert on connective tissue or other muscles jobs ◦ Facial expression ◦ Mastication ◦ Some muscles are responsible for both � The neck muscles’ actions affect the head, and also the structures inferior to the neck

Muscles of Facial Expression: Frontalis � O: Cranial aponeurosis � I: Skin of eyebrows and nose � I: Facial nerve � A: Raises eyebrows and wrinkles forehead skin � (Aponeurosis – a broad, flat connective tissue, similar to a tendon, that binds muscles together and connects them to bone)

Muscles of Facial Expression: Orbicularis Oculi O: Frontal bone and maxilla I: Skin of eyelid I: Facial nerve (temporal & zygomatic branches) A: Blinking, squinting, and forceful closing of eyelids

Muscles of Facial Expression: Zygomaticus O: Zygomatic bone I: Skin of superior mouth I: Facial nerve (zygomatic branch) A: Draws angle of mouth upward and laterally (smile!)

Muscles of Facial Expression: Buccinator O: Maxilla & mandible I: Fibers of orbicularis oris I: Facial nerve (buccal branch) A: Compresses cheeks against teeth; synergist in chewing

Muscles of Facial Expression: Triangularis O: Tubercle of mandible I: Mouth I: Facial nerve (mandibular branch) A: Depresses angle of mouth (frown)

Muscles of Facial Expression: Mentalis O: Anterior mandible I: Chin I: Facial nerve (mandibular branch) A: Elevates & wrinkles skin of chin; protrudes lower lip

Muscles of Facial Expression: Occipitalis O: Occipital bone & mastoid process of temporal bone I: Galea aponeurosis I: Facial nerve (posterior auricular branch) A: Wrinkle brow; lift eyebrows

Muscles of Facial Expression: Nasalis O: Maxilla I: Nasal bone I: Facial nerve (buccal branch) A: Compresses bridge of nose; depresses tip; elevates corners of nostrils

Muscles of Facial Expression: Orbicularis Oris O: Fibers of other mouth muscles I: Muscles and skin at angle of mouth I: Facial nerve (buccal branch) A: Closes and protrudes lips

Muscles of Facial Expression: Platysma O: Pectoralis & deltoid I: Mandible & skin of mouth I: Facial nerve (cervical branch) A: Depresses mandible; draws angle of mouth downward; tightens skin of neck

Muscles of Mastication: Masseter O: I: I: A: Zygomatic arch Mandible Mandibular nerve Elevates mandible

Muscles of Mastication: Temporalis O: Temporal fossa I: Coranoid process of mandible I: Mandibular A: Elevates and retracts mandible

Muscles of the Neck: Sternocleidomastoid O: Sternum & medial clavicle I: Mastoid process of temporal bone I: Accessory nerve A: Together – flex cervical column; Alone – rotate and flex neck to side

Muscles of the Neck: Trapezius O: Occipital bone & spinous processes of C 7 – T 12 � I: Lateral clavicle, acromion process, & spine of scapula � I: Accessory nerve � A: Upward rotation, retraction, elevation, & depression of scapulae; extension, rotation, and lateral flexion of neck �

Muscles of the Neck: Levator Scapulae O: Transverse processes of C 1 – C 4 I: Medial border of scapula I: Cervical nerves C 3 – C 5 A: Elevates scapula; rotates scapula downward; extends, rotates, and laterally flexes neck

Muscles of the Neck: Scalenes O: Cervical vertebrae C 2 – C 7 I: 1 st and 2 nd ribs I: Cervical nerves C 3 – C 8 A: Elevates ribs; flexes, laterally flexes, and rotates neck; synergist in inspiration