Muscles

What are the major muscles of the body?

•Muscle names are based on Latin and are given according to the following criteria:
•Muscle size

•Muscle shape

•Location of muscle

•Orientation of muscle

•Muscle origin and insertion

•Number of origins (head) on the muscle

•Muscle function

•Examples:

•Biceps brachii (two origins on upper arm)

•Deltoid (triangular like the Greek letter delta ∆)

deltoid

pectoralis major

biceps brachii

adductor

gastrocnemius

quadriceps
group

external obliques

rectus abdominis

frontalis

trapezius

triceps brachii

gluteus maximus

gastrocnemius

latissimus dorsi

trapezius

gluteus medius

hamstring group

soleus

How do muscles attach to the
skeleton?

•Muscles are attached to bones by tendons.

•The attachment of the tendon to the more stationary bone is called the origin. The attachment to the more movable bone is called the insertion.

•The middle of the muscle is called
the belly.

•Muscles work in pairs.

• Prime Mover= muscle doing the action

(contracting)

• Synergists are muscles that help in that same direction

• Antagonist= opposing muscle relaxing

during motion

• Example of antagonistic pair: biceps brachii

& triceps brachii

Summary

•Muscles can be identified by their shape, location, size or function. They are attached to bones by tendons and extend from the origin to the insertion site. Muscles work in pairs with the prime
mover contracting while the antagonist
extends.