Characteristics Used to Name Skeletal Muscles ALL MUSCLES

Characteristics Used to Name Skeletal Muscles

ALL MUSCLES l l l Help with posture, movement, or heat Cross at least 1 joint to create movement Shorten to contract ONLY Pull Have an origin that stays still and an insertion point that moves l Most muscles are antagonistic pairs (one muscle does an action, the other reverses it Ex/ Flexors and Extensors)

General Muscle Jobs/Categories l l l Fixators- muscles that help to hold a bone in position, Anchor an origin for another muscle Help with posture l l Prime Mover/agonistmain muscle in a group responsible for a movement Synergists- muscle(s) that are part of a team/group that produce the same movement Cross the same joint Antagonist- reverses the action of the prime mover. l Crosses same joint as prime mover on OPPOSITE side.

Naming Skeletal Muscles 1 – Location of the muscle 2 – Shape of the muscle 3 – Size of the muscle 4 – Direction/Orientation of the muscle fibers 5 – Number of Origins 6 – Location of the Attachments 7 – Action of the muscle

Muscles Named by Location: l frontalis – frontal bone l lateralis – lateral or on the side l tibialis anterior – front of tibia l supra – above l infra – below l sub - underneath

Muscles Named by Shape: l deltoid – triangle l teres – round l serratus –saw-toothe l trapezius – trapezoid l orbicularis – circular

Muscles Named by Size (relative to others in a group or region): l l l l maximus – largest minimis – smallest vastus - huge longus – longest brevis – short major – large minor – small Example: Pectoralis Major

Muscles Named by Direction of Fibers Direction/Orientation: l rectus (straight) - parallel to the muscle’s long axis ex: rectus abdominis l transversus (transverse) – at right angles to the muscle’s long axis l oblique – diagonal

Muscles Named for Number of Origins (fixed attachments): l biceps – two origins ex: biceps brachii l triceps – three origins ex: triceps brachii l quadriceps – four origins

Muscles Named for Origin and Insertion Points Origin and Insertion: sterno = sternum cleiodo = clavicle mastoid = location on the temporal bone sternocleiodomastoid muscle

Muscles Named for Action: l flexor carpi radialis – flexes wrist l abductor magnus – abducts the thigh l extensor digitorum – extends the fingers l Levator scapulae – elevates scapula