Muscle Lab Quiz

Anatomy Lab (pt.1)

Action of Temporalis

Elevates the mandible

Origin of Temporalis

Temporal Fossa

Insertion of Temporalis

Mandible

Masseter Action

Elevates the Mandible

Masseter Origin

Zygomatic Arch

Masserter Insertion

Mandible

Platysma action

Elevates / creases skin of neck (face of horror)

Platysma origin

Fascia of upper thorax and lower neck

Platysma insertion

Lower mandible, skin of lower face, muscles of lower mouth

Semispinalis Capitis Action

Unilateral: rotates head to opp. side; Bilateral: extends head and neck

Semispinalis Capitis orgin

Transverse processes of C7-T6 vertebrae

Semispinalis Capitis Insertion

Occipital Bone

Internal Oblique Muscles

Responsible for rotating the trunk; “same side rotators”

External Olique Muscles

Responsible for twisting the trunk “opposite side rotators”

Tendons

More Compact than muscle or bone; durable; provide site of entry for nerves and blood vessels

Aponeuroses

Sheet like tendons

Origin

Immovable attachment

Insertion

Movable attachment

Contraction

Fibers shorten, bringing insertion closer to the origin

Flexion

Bending / decreasing the angle of two bones at a joint

Extension

Straightening / increasing angle between two bones

Rotation

Turning or spinning around a central axis

Adduction

Movment closer to the midline

Abduction

Moving further from the midline

Pronation

Rotation of forearm or foot (turning hand to face down)

Supination

Turning hand or sole of the foot upward

Dorsiflexion

Flexing of the toes

Plantar Flexion

Pointing the toes

Prime Movers

(agonists) Responsible for action

Antagonists

Actions opposing the prime movers

Synergists

Promote actions of prime movers

Fixators

Immobilize point of prime mover origin