Chapter 28 Flashcards
Origin
End of the muscle that is attached to the least moveable structure
Insertion
Other end of the muscle that is attached to the moveable structure
Action
Work that is accomplished when muscle fibers contract
Muscles of mastication are responsible for
Elevating
Protruding
Retruding
Lateral movements
Muscles of mastication
Masseter
Temporal
Medial pterygoid
Lateral pterygoid
Masseter muscle
Most powerful (elevates muscles)
Temporal muscle
Inserts into coronoid process and elevates mandible
Medial pterygoid muscle
Elevate mandible and close mouth
Lateral pterygoid muscle
Superior head- fibers penetrate TMJ capsule into disc
Inferior head- fibers insert into neck of condole
Protrudes and depresses mandible
Hyoid muscles
Open the mouth (strong depression of mandible)
Hyoid bone
Horse shoe shaped bone suspended beneath the mandible
2 groups of hyoid muscles
Suprahyoid and infrahyoid
What are the suprahyoids
Digastrics
Mylohoid
Geniohyoid
Stylohyoid
Digastrics
Contracting - backward pull on mandible (retrudes)
2 nerves supplying the digastrics
Anterior - V3
Posterior - VII
Mylohoid
Floor of the mouth
From mylohoid line of the mandible to hyoid bone
V3 innervation
Inferior alveolar artery- blood supply
Geniohyoid
From genial tubercle to hyoid
Depresses mandible and elevates hyoid
1st. Cranial nerve
Lingual artery - blood supply
Stylohoid
Styloid process to hyoid
Hyoid bone backward/upward
CN VII
Facial/occupital arteries
What are the infrahyoids
Omohyoid
Sternohyoid
Sternothyroid
Thyrohyoid
Omohyoid
2 bellies separated by an intermediate tendon
From scapula and hyoid
Crosses under sternocleidomastoid (SCM)
Sternohyoid
Upper border of the sternum
Sternothyroid
Upper part of sternum to thyroid cartilage
Thyrohyoid
From thyroid cartilage to hyoid bone
Movements
Protrusion Retrusion Lateral excursion Elevation Depression
Protrusion
Lateral pterygoid muscles
Retrusion
Temporal and digastrics
Lateral excursions
Lateral pterygoid
(L) pterygoid contracts - mandible goes to the (R)
(R) pterygoid contracts - mandible goes to the (L)
Elevation
Medial pterygoid, masseter, and temporal
Depression
Lateral pterygoid and hyoids
Deglutition
Mastication/swallowing
Sternocleidomastoid muscle
Area for referred pain
Palpate to check for enlarged lymph nodes
From mastoid process to sternum and clavicle
Tilting and rotating of head
Innervated by CN XI (spinal accessory nerve)
Trapezius muscle
From external occipital protuberance and spinous process of cervical and thoracic vertebrae - scapula and clavicle
Addicted/elevates scapula (adducts- moves towards the midline)
Triangular in shape
Muscles of mastication can
Refer pain to the TMJ
