Post on 17-Dec-2015
NAMING MUSCLES: TipsNAMING MUSCLES: Tips
• Most 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.
Naming Skeletal Muscles
1 – LocationLocation of the muscle2 – ShapeShape of the muscle3 – SizeSize of the muscle4 – Direction/OrientationDirection/Orientation of the muscle fibers/cells5 – Number of OriginsNumber of Origins 6 – LocationLocation of the Attachments7 – ActionAction of the muscle
Location:
• ____________________ (chest)• ____________________ (buttock)• ____________________ (arm) • ______________________(above)• ______________________ (below)• _____________________(under or beneath)• _______________________ (lateral).
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).
Size:
• ____________ (huge)• _______________ (large)• __________________(long)• ____________ (small)• __________________(short)
Direction of fibers:
• ____________ (straight)• _____________ (across)• ___________(diagonally)• ______________(circular)
Number of origins:
• biceps (two heads)• triceps (three heads)• quadriceps (four heads)
Triceps Brachii
Origin long head: infraglenoid tubercle of scapulalateral head: upper half of the posterior surface of humerusmedial head: distal two thirds of the posterior surface of humerus
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)
Action:
• ____________(to abduct a structure)• _____________(to adduct a structure)• ______________(to flex a structure)• _____________ (to extend a structure)• _____________ (to lift or elevate a structure)
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 ____________________________.
How Muscles Attach to Bone
• Direct Attachment – the epimysium adheres to and fuses with the periosteum
Review:
• What is origin?• What is Insertion?
Try to Remember…
• The origin usually stays fixed and the insertion moves closer to it
Origin
Insertion
3 Basic Types of Muscle Contractions Concentric
– ________________________________– Ex. biceps shorten when lifting an object
Eccentric– ___________________________________– Ex. biceps lengthen as the same weight is
placed back on the ground
Isometric (static)– _________________________________________– Ex. trying to lift an immovable object.
Push or Pull???
• Muscles _____________ by contracting and relaxing, muscles _________________
• They work in pairs to create smooth movement, they are called _________________________(opposing pairs).
Agonist vs Antagonist?
• Agonist–
• Antagonist -
Example:
• In elbow flexion, the biceps brachii will concentrically contract while the triceps brachii will eccentrically contract.
Fixators/Stabilizer
• Muscles that are active isometrically (muscle does not shorten or lengthen) in order to fixate an area when the agonist contracts
• Fixators/ Stabilizers -
Fixators/Stablizer
• Example: When performing a push-up, the serratus anterior stabilizes the shoulder girdle during the downward stage in order to prevent adduction
Examples of opposing muscles and muscle groups
AGONIST (Prime Mover)
ANTAGONIST
Elbow flexion Biceps brachiiBiceps brachii Triceps brachiiTriceps brachiiShoulder abduction
Medial shoulder rotation
Knee extension
Wrist flexion
Dorsi flexion
Trunk flexion
Hip flexion