Muscles Continued

Pages: 192-197Muscles ContinuedSkeletal Muscle ActionDependent mostly on the kind of joint it is associated with and the way the muscles attaches on either side of that joint.Origin:Immovable end of a muscleInsertion:Movable end of a muscleDuring contraction, insertion is pulled towards origin

Some muscles have more than one origin or insertionEx. Biceps brachiiInteraction of Skeletal MusclesAlmost always function in groupsPrime Mover:Provides most movementSynergists:Muscles that contract and assist the prime moverAntagonists:Resist a prime movers action and causes movement in the opposite direction.Major Skeletal Muscles Name of muscle is often describes the muscles:Relative sizeShapeLocationActionNumber of attachmentsDirection of its fibersExamples: Pectoralis Major-of large size located in the pectoral region, Deltoid: shaped like a delta or triangle, Extensor digitorum: extends the digits

Muscles of Facial ExpressionResponsible for expressions of surprise, sadness, anger, fear, disgust, and painInclude:EpicraniusComposed of two parts: Frontalis and OccipitalisOrbicularis oculiOrbicularis orisBuccinatorZygomaticusPlatysma

Muscles of MasticationAttached to mandible and produce chewing movementsInclude:MasseterTemporalisMuscles That Move the HeadFlex, extend and rotateInclude:SternocleidomastoidSplenius capitisSemispinalis capitis

Action Origin InsertionPlease use table 8.4, 8.5 and 8.6 to fill out your AOI word document.

Frontalis Occipitalis Orbicularis oculiOrbicularis orisBuccinatorZygomaticusPlatysmaMasseterTemporalisSternocleidomastoidSplenius capitisSemispinalis capitis