lab practical 3 Flashcards
(86 cards)
Origin DEFINITION
fixed, stationary, immoveable, or
less moveable muscle attachment
Insertion DEFINITION
more moveable muscle
attachment
Body movement occurs when
muscles contract across diarthrotic synovial joints
what happens when a Muscle contracts
muscle fiber shortens,
insertion moves toward the origin
Movements
Flexion:
movement, generally in sagittal plane, decreases the angle of joint and reduces distance between the two bones; typical of hinge joints (bending knee or elbow) but is also
common at ball-and-socket joints (bending forward at the hip)
Movements
Extension:
movement that increases the angle of a joint and the distance between the bones or parts of the body; opposite of flexion; if extension proceeds beyond anatomical position
(bends the trunk backward) it is termed hyperextension
Movements
Abduction:
movement of limb away from the midline of the body, along the frontal plane, or the fanning movement of fingers or toes when spread apart
Movements
Adduction:
movement of limb toward the midline of body or drawing fingers or toes together; opposite of adduction
Movements
Rotation:
movement of body around its longitudinal axis without lateral or medial displacement; common movement of ball-and-socket joints, also describes movement of the
atlas around the dens of the axis
Movements
Circumduction:
combination of flexion, extension, abduction, and adduction; common in ball-and-socket joints like the shoulder; the limb as a whole outlines a cone
Movements
Pronation:
movement of the palm of the hand from an anterior or upward-facing position to a posterior or downward-facing position; distal end of the radius rotates over the ulna so that the bones form and X with pronation of the forearm
Movements
Supination:
movement of the palm of the hand from a posterior position to an anterior
position (the anatomical position); opposite of pronation; radius and ulna are parallel
Movements
Dorsiflexion:
movement of the ankle joint that lifts the foot so that its superior surface
approaches the shin
Movements
Plantar flexion:
movement of the ankle joint in which the foot is flexed downward (as if
standing on one’s toes or pointing the toes)
Movements
Inversion:
movement that turns the sole of the foot medially
Movements
Eversion:
movement that turns the sole of the foot laterally; opposite of inversion
TYPES OF
MUSCLES
* Agonists
- PRIME MOVERS
- muscles most responsible for producing a particular movement
- Contracts to generate the main force of action
TYPES OF
MUSCLES
Antagonists
muscles that oppose or reverse a movement
* Performing the paired action
* When an agonist is active, the fibers of the antagonist are stretched and in a relaxed state
* Antagonists can be agonists in their own right
* Biceps (agonist of flexion at the elbow) are antagonized by the triceps (agonists of extension at the elbow)
TYPES OF
MUSCLES
Synergists:
aid the action of agonists either by assisting with the same movement
or by reducing undesirable or unnecessary movement
* Contraction of a muscle crossing two or more joints would cause movement
at all joints spanned if the synergists were not there to stabilize them
* Ex: muscles that flex the fingers cross both the wrist and finger joints, but you
can make a fist without bending your wrist because synergist muscles
stabilize the wrist joints
TYPES OF
MUSCLES
Fixators
(fixation muscles): specialized synergists that immobilize the origin of an agonist so that all of the tension is exerted at the insertion
* Ex: muscles that help maintain posture
* Ex: muscles of the back that “fix” the scapula during arm movements
fascicle pattern + muscle example:
Parallel
Sartorius
fascicle pattern + muscle example:
Pennate
Rectus femoris
fascicle pattern + muscle example:
Circular
Orbicularis oculi
what are the 3 general functions of muscles
Movement, heat production, posture
