Aponeuroses
Broad sheet-like CT that attaches muscle to bone.
A muscle that produces most of the force during a particular joint action
Agonist (Prime Mover)
Agonist (prime mover)
A muscle that produces most of the force during a particular joint action.
Classes of muscles based upon the arrangement of the fasciculi
1. Fusiform
2. Circular
3. Convergent
4. Parallel
5. Pennate
These muscles have fascicles that arrive at one common tendon from a wide area & create muscles that are triangular in shape
Convergent Muscles
Convergent Muscles
These muscles have fascicles that arrive at one common tendon from a wide area & create muscles that are triangular in shape
Fusiform
Muscle fibers that run the length of the muscle & tapers at each end.
Muscle fibers that run the length of the muscle & tapers at each end.
Fusiform
Bones=Levers
Joints=Fulcrums
...
Class I Lever
Weight-fulcrum-pull
Bipennate
A muscle that has fascicles that originate on both sides of a tendon that runs the length of the muscle.
A muscle that has fascicles that originate on both sides of a tendon that runs the length of the muscle.
Bipennate
Multipennate
Shaped like a bunch of feathers with their quills converging on a single point.
Shaped like a bunch of feathers with their quills converging on a single point.
Multipennate
A muscle that has fascicles that originate on one side on a tendon that run the length of the muscle.
Unipennate
Unipennate
A muscle that has fascicles that originate on one side on a tendon that run the length of the muscle.
Skeletal muscles extend from one bone to another and from one bone to skin on the other.
True or False
True
Action
Movement accomplished by a muscle when it contracts
Origin (of a muscle)
Usually the most stationary and most proximal end of the muscle.
Two types: fixed end and head
Insertion
(Mobile end) Usually the most distal end attached to the bone undergoing the most movement.
Belly
Region between the origin and insertion.
Tendon
Long cable-like structures that are responsible for attaching muscle to bone.
Agonist
The muscles accomplishing a movement.
Antagonist
Muscles opposing the movement of the agonist.
Synergists
Members of a group of muscles working together to produce a movement.
Ex: Biceps brachii & brachialis function in elbow flexion
Prime mover
The muscle responsible for the major role accomplishing the desired movement.
Ex: Brachialis
Fixator
Muscles that hold one bone in place relative to the body while a more distal bone is moved.
Ex: Muscles in the scapula to keep the shoulder stationary while humerus is moving.
What influences the degree to which a muscle can contract and the amount of force generated?
The shape and size of a muscle.
3 Major classes based on fasciculi orientation
1. Pennate
2. Straight
3. Orbicular
Types of pennate muscles
1. Unipennate (semipennate)
2. Bipennate
3. Multipennate
Unipennate/semipennate
All fasciculi are on one side of the tendon.
Bipennate
Fasciculi arranged like the barbs of a feather on two sides of a tendon.
Multipennate
Fasciculi arranged at many places around the central tendon.
(Muscle extending from knee)
Straight muscle
Fasciculi are arranged parallel to the long axis of the muscle.
Orbicular muscle
Fasiculi are arranged in a circle around an opening and act as sphincters to close and open.
How are muscles named?
1. Location
2. Size
3. Shape
4. Orientation of fasciculi
5. Origin and Insertion
6. Number of heads
7. Function
Shapes of muscles
1. Quadrate
2. Rhomboidal
3. Fusiform
4.Trapezium
5. Triangular
6. Digastric
7. Bicipital
What is a lever?
Ridged structure that can move around a fixed point.
What is a fulcrum?
The fixed point.
Effort (Pull)
Causes the movement or the contraction of the bicep.
Resistance (Weight)
Opposes the movement.
Class I Lever
L(oad) - F(ulcrum) - E(ffort or Pull)
Class II Lever
F(ulcrum) - L(oad) - E(ffort or Pull)
Class III Lever
F(ulcrum) - E(ffort or Pull) - L(oad)