Transcript Where they are

Muscles
&
Muscle Groups
•Where They Are
•What They Do
•Joint Action
Erector Spinae
Where they are: They are positioned on each
side of the spinal column, from neck to
tailbone.
What they do: They help the trunk to move
smoothly in many planes and maintain or
move the spine into an upright position. They
help maintain neutral spine.
Joint action:
• Low back extension
• Lateral flexion
• Trunk rotation
Hip Adductors
Where they are: They are on the inside of
the thighs.
What they do: They pull the legs inward.
Joint action:
• Knee flexion
• Hip extension
Hamstrings
Where they are: They are at the back of the
thighs.
What they do: They bend the knees and help
turn the lower legs inward. They extend the
legs backward and help turn the legs inward.
Joint action:
• Knee flexion
• Hip extension
Rectus Abdominis
Where they are: These muscles extend
down the centre of the anterior trunk to the
pubic bone.
What they do: They bend the trunk forward
and help maintain neutral position.
Joint action:
• Thoracic flexion
Obliques
Where they are: They are on both sides of
the front of the trunk.
What they do: They help maintain a neutral
position.
Joint action:
• Low back lateral flexion
• Spinal rotation
Gluteus Medius
(Hip Abductors)
Where they are: These muscles sit on the
upper side and side of the hips.
What they do: They move the legs outward,
away from the centre line of the body.
Joint action:
• Hip flexion
• Hip abduction
• Internal rotation
• Hip extension
Tensor Fasciae Latae
(T.F.L.)
Where they are: These muscles are on the
lateral side of the thighs.
What they do: They bring the knees toward
the chest, turn the knees inward, and move
the legs away from the centre of the body.
Joint action:
• Hip abduction from a flexed position
• Internal hip rotation
Gluteus Minimus
Where they are: These muscles are inside
the hip area, connecting the pelvis to the
femurs.
What they do: They raise the legs outward to
the sides and turn the legs inward. They may
help lift the knees toward the chest.
Joint action:
• Hip internal rotation
Pectorals
Clavicular & Sternal
Where they are: These muscles are located
in the upper chest.
What they do: They draw the arms across
the body and rotate the arms inward. They
also help with lifting the arms above the head
and lowering them back don to the sides.
Joint action:
• Shoulder horizontal adduction
• Shoulder adduction
Wrist Extensors
Where they are: These muscles are in the
back of the forearms.
What they do: They pull the palms of the
hands away from you.
Joint action:
• Wrist extension
Triceps
Where they are: These muscles are in the
back of the upper arms.
What they do: They straighten the elbows.
Joint action:
• Elbow extension
Wrist Flexors
Where they are: These muscles are located
on the front of the forearms.
What they do: They help bend the palms of
the hands toward you.
Joint action:
• Wrist flexion
Latissimus Dorsi
Where they are: This is the broad muscle
that stretches across the back into the back of
the arms.
What they do: It helps draw the arms down
and back and internally rotates them. It also
pulls the trunk up toward static arms (as in
rope climbing).
Joint action:
• Shoulder extension
• Shoulder adduction
Biceps
Where they are: These muscles are in the
front of the upper arms.
What they do: They bend the elbows.
Joint action:
• Elbow flexion
Deltoids
(Anterior, Lateral, Posterior)
Where they are: These muscles are over the
tops of the shoulders. covering the shoulder
joints like shoulder pads.
What they do: They raise the arms up to
shoulder level sideways and, in conjunction
with other muscles, help rotate the arms and
raise them to the front and back.
Joint action:
• Shoulder flexion
• Shoulder abduction
• Shoulder horizontal abduction
Trapezius
(Lower, Middle, Upper)
Where they are: This is a triangular shaped muscle
that runs from the spine to the shoulder blades.
What they do: It draws the shoulders together and
downward and generally acts as a brace for the
shoulders. Weak trapezius muscles can aggravate
dowager's hump and round shoulders. The trapezius
takes a lot of strain if you sit hunched at a terminal or
over a desk for long hours.
Sternocleidomastoid
Where they are: Each side of the neck.
What they do: Each side acts independently to
bend the head sideways and turn the head. They
both act together to bend the head to the chest.
Joint action:
• Neck rotation
• Neck lateral flexion (side bending) and rotation
Tibialis Anterior
Where they are: These muscles are in the
front of the lower legs.
What they do: They raise the feet up and
turn the feet inward.
Joint action:
• Ankle dorsiflexion
• Ankle inversion
Gluteus Maximus
Where they are: These muscles cover the buttocks.
What they do: They pull the legs backward and turn
the legs outward. They assist in standing up from a
seated position.
Joint action:
• Hip extension
Hip Iliopsoas
(Flexors)
Where they are: These muscles attach the lower
spine to the femurs.
What they do: They bring the knees to the chest.
Joint action:
• Hip flexion
Quadriceps
Where they are: These muscles are in front of the
thighs.
What they do: They straighten the knee.
Joint action:
• Knee extension
Soleus
Where they are: These muscles are in the back of
the lower legs.
What they do: They point the toes.
Joint action:
• Plantar flexion of the ankle joint
Gastrocnemius
Where they are: These muscles are in the back of
the lower legs.
What they do: They raise the heels and point the
toes downward.
Joint action:
• Plantar flexion of the ankle joint
• Assist with flexion of the knee
Maximum Number of Points
(100%)