Part 5
Types of Body Movements
 Muscles are attached to no less than two points
 Origin – The attachment to the immovable or less
movable bone
 Insertion – The attachment
to the movable bone
 When the muscle contracts
the insertion moves towards
the origin
Common Types of Body Movements
 Flexion – A movement that decreases the
angle of the joint and brings two bones closer
together
 Example – Bending the knee or
elbow, bending forward at the hip
Common Types of Body Movements
 Extension – Opposite of flexion; Movement
that increases the angle, or the distance,
between two bones or parts of the body
 Example – Straightening the knee or elbow
 If extension is greater than 180
degrees, it is hyperextension
Common Types of Body Movements
 Rotation – The movement of a bone around
its longitudinal axis
 Common movement of ball-and-
socket joints
 Example – Movement of the atlas
around the dens of the axis (as in
shaking your head “no”)
Common Types of Body Movements
 Abduction – The movement of a
limb away from the midline of
the body
 Example – Moving your leg
laterally away from your body;
Also applies to the fanning
movement of the fingers and toes
when they are spread apart
Common Types of Body Movements
 Adduction – Opposite of
abduction; The movement of a
limb towards the midline of the
body
 Example – Moving your leg
medially toward your body
Special Types of Body Movements
 Dorsiflexion and Plantar
Flexion – Up and down
movements of the foot at
the ankle
 Dorsiflexion – Lifting the foot
so that its superior surface
approaches the shin (standing
on your heels)
 Plantar Flexion – Depressing
the foot (pointing the toes)
Special Types of Body Movements
 Inversion and Eversion – Also special
movements of the foot
 Inversion – The turning of the sole medially
 Eversion – The turning of the sole laterally
Special Types of Body Movements
 Supination and Pronation – Refer to
movements of the radius around the ulna
 Supination – Movement that occurs when the forearm
rotates laterally so that the palm faces anteriorly, and the
radius and ulna are parallel
 Pronation – Movement that occurs when the forearm
rotates medially so that the palm faces posteriorly, and
the radius and ulna form an “X”
Special Types of Body Movements
 Opposition – Refers to the action of the
saddle joint between metacarpal 1 and the
carpals; The action by which you move your
thumb to touch the tips of the other fingers on
the same hand
 It is this unique action that
makes the human hand such
a fine tool for grasping and
manipulating things
Types of Muscles
 Muscles can’t push, they can only pull as they
contract.
 Most often body movements are the result of the activity
of two or more muscles acting together or against each
other.
 Muscles are arranged in such a way that whatever one
muscle can do, other muscles can reverse.
Types of Muscles
 Muscles work in pairs:
 Prime Mover (Agonist) – The muscle that has the major
responsibility for causing a particular movement
 Antagonist – Muscles that oppose or reverse a movement


When a prime mover is active, its antagonist is stretched and
relaxed.
Antagonists can be movers in their own right
 For example, the biceps of the arm (prime mover of elbow
flexion) is antagonized by the triceps (a prime mover of elbow
extension).
Types of Muscles
 Synergists – Help prime movers by producing the
same movement or by reducing undesirable
movements
 When a muscle crosses two or more joints, its contraction
will cause movement in all joints crossed unless synergists
are there to stabilize them.
 Example – The finger-flexor muscles cross both the wrist
and the finger joints. You can make a fist without bending
your wrist because synergist muscles stabilize the wrist
joints and allow the prime mover to act on the finger
joints.
Types of Muscles
 Fixators – Specialized synergists; Hold bones still or
stabilize the origin of a prime mover so all the
tension can be used to move the insertion bone
 Examples –


The postural muscles that stabilize the vertebral column
The muscles that anchor the scapula to the thorax
Naming Skeletal Muscles
 Muscles are named on the basis
of several criteria:
1. Direction of muscle fibers


Rectus (straight) – Its fibers run
parallel to that imaginary line
Oblique (slanted) – Its fibers run
slanted to the imaginary line
2. Relative size of the muscle
 Maximus (largest), Minimus (smallest), Longus (long)
 For example, the gluteus maximus is the largest
muscle of the gluteus muscle group
Naming Skeletal Muscles
 Muscles are named on the basis
of several criteria:
3. Location of the skull


Some muscles are named for the
bone with which they are
associated
For example, the temporalis and
the frontalis muscles overlie the
temporal and frontal bones of the
skull
Naming Skeletal Muscles
 Muscles are named on the basis
of several criteria:
4. Number of origins


When the term biceps, triceps, or
quadriceps forms part of a muscle
name, one can assume that the
muscle has 2, 3, or 4 origins,
respectively.
For example, the biceps muscle of the
arm has two heads, or origins, and
the triceps muscle has three.
Naming Skeletal Muscles
 Muscles are named on the basis of several
criteria:
5. Location of the muscle’s origin and insertion


Occasionally, muscles are named for their attachment
sites.
For example, the sternocleidomastoid muscle has its
origin on the sternum (sterno) and inserts on the
mastoid process of the temporal bone
Naming Skeletal Muscles
 Muscles are named on the basis of several
criteria:
6. Shape of the muscle


Some muscles have a distinctive
shape that helps to identify them
For example, the deltoid muscle
is roughly triangular (deltoid
means triangular)
Naming Skeletal Muscles
 Muscles are named on the basis of several
criteria:
7. Action of the muscle


When muscles are named for their actions, terms such
as flexor, extensor, and adductor appear in their
names.
Examples - The adductor muscles of the thigh all
bring about its adduction; The extensor muscles of the
wrist all extend the wrist