Wednesday, February 16, 2011

Muscles of head and neck


Facial muscles:

Epicranius (occipitofrontalis)

Frontal belly

Occipital belly

Galea aponeurotica

Orbicularis oculi

Buccinator

Orbicularis oris

Nasalis




Masticatory muscles

Masseter :
Origin-inferior border and medial surface of zygomatic arch

Insertion-lateral surface of ramus of mandible and angle of mandible

Temporalis :
Origin-temporal fossa
Insertion-coronoid process of mandible

Action : masseter, temporalis --- elevates mandible
—close the mouth






medial pterygoid

lateral pterygoid

Action :

Medial pterygoid—elevates mandible—close the mouth

Lateral pterygoid—pull the head of mandible forwards--- open the mouth



Muscles of neck

Superficial group :

Platysma

Sternocleidomastoid
Origins: manubrium and medial1/3 of clavicle

Insertion: mastoid process of temporal bone;

Actions: acting alone, the head is inclined ipsilateral and the face is rotated to opposite side; acting together, they extend the head.




Suprahyoid muscles :

Mylohyoid
Stylohyoid
Geniohyoid
Action: Elevate (raise) hyoid bone and depress mandible.


Infrahyoid muscles :

sternohyoid
omohyoid
sternothyroid
thyrohyoid

Action: depress hyoid or larynx



The deep cervical muscles:

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