2 NAMING MUSCLES: TipsMost skeletal muscles have names that describe some feature of the muscle.Often several criteria are combined into one name.Associating the muscle's characteristics with its name will help you learn and remember them.The following are some terms relating to muscle features that are used in naming muscles.
3 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/cells 5 – Number of Origins 6 – Location of the Attachments 7 – Action of the muscle
5 Shape: deltoid (_______________) rhomboid (like a rhombus with equal and parallel sides)latissimus (____________)teres (__________)trapezius (like a trapezoid, a four-sided figure with two sides parallel).
7 Direction of fibers: ____________ (straight) _____________ (across) ___________(diagonally)______________(circular)
8 Number of origins: biceps (two heads) triceps (three heads) Triceps BrachiiOriginlong head: infraglenoid tubercle of scapulalateral head: upper half of the posterior surface of humerus medial head: distal two thirds of the posterior surface of humerusbiceps (two heads)triceps (three heads)quadriceps (four heads)
9 Origin and insertion:sternocleidomastoid (origin on the sternum and clavicle, insertion on the mastoid process)brachioradialis (origin on the brachium or arm, insertion on the distal end of radius at the styloid process)
10 Action: ____________(to abduct a structure) _____________(to adduct a structure)______________(to flex a structure)_____________ (to extend a structure)_____________ (to lift or elevate a structure)
11 How Muscles Attach to Bone Indirect Attachment – ___________________the _______________________ (sheath of connective tissue that surrounds the exterior of the muscle fibre) extends past the muscle as a ____________________ and then attaches to ____________________________.
12 How Muscles Attach to Bone Direct Attachment – the epimysium adheres to and fuses with the periosteum
14 Try to Remember…The origin usually stays fixed and the insertion moves closer to itOriginInsertion
15 3 Basic Types of Muscle Contractions Concentric________________________________Ex. biceps shorten when lifting an objectEccentric___________________________________Ex. biceps lengthen as the same weight isplaced back on the groundIsometric (static)_________________________________________Ex. trying to lift an immovable object.
16 Push or Pull???Muscles _____________ by contracting and relaxing, muscles _________________They work in pairs to create smooth movement, they are called _________________________(opposing pairs).