Download skeletal muscles part 1

LARGE MUSCLES
FRONTALIS
The frontalis (sometimes also referred to as the "frontal
portion") is a thin quadrilateral muscle that is
intimately adherent to the superficial fascia.
Origin – Galea aponuerotica (a flat tendon attached
to both the frontalis and occipitalis muscles)
Insertion – Integument (skin) above the orbits of the
eyes.
Action – Draws the scalp forward, raises eyebrows,
and wrinkles the skin of the forehead horizontally
TRAPEZIUS
The Trapiezius is a large, superficial muscle at the back
of the neck and the upper part of the thorax, or chest.
The right and left trapezius together form a trapezium,
an irregular four-sided figure.
Origin - the occipital bone at the base of the skull, the
ligaments on either side of the seven cervical (neck)
vertebrae (ligamentum nuchae), and the seventh
cervical and all thoracic vertebrae
Insertion - the posterior of the clavicle (collarbone) and
on the spine of the scapula (shoulder blade)
Action - support of the shoulders and limbs and rotation
of the scapula necessary to raise the arms above
shoulder level.
DELTOID
The Deltoid is a large triangular muscle
covering the shoulder joint and serving to
abduct (take away from) and flex and extend
and rotate the arm
Origin - from the lateral third of the clavicle, the lateral
border of acromion process, and the lower border of
spine of scapula
Insertion - the side of the shaft of the humerus
Action - the abduction, flexion, extension, and
rotation of the arm
PECTORALIS MAJOR
oThe pectoralis major is a large, fan-shaped
muscle. It covers much of the front upper
chest
Origin – The sternum (breastbone) including the
second to sixth ribs
Insertion – The clavicle (collarbone) and converges
on the humerus just below the shoulder
Action – Moves the arm across the body
TRICEPS BRACHII
– The large muscle on the back of the human
upper limb. It is called a three-headed muscle
because there are three bundles of muscle,
each of different origin, joining together at the
elbow.
– Origin of Long Head: Infraglenoid tubercle of
scapula
– Origin of Medial Head: Posterior Humerus
– Origin of Lateral Head: Posterior Humerus
– Insertion – Olecranon process of ULNA
– Action – extends forearm, adducts (brings together)
shoulder
BICEPS
BRACHII
– The biceps brachii is a muscle located on the
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upper arm. It has two heads: The Long Head (outer)
and the Short Head (inner)
ORIGIN: Scapula
Supraglenoid Tuberosity [1 ]
Coracoid Process [2
INSERTION: Radius
Tubercle [1, 2 ]
Fascia of forearm
Bicipital Aponeurosis
ACTION:Rotate the forearm (supination) and Flexion
of the Elbow
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LATISSIMUS
DORSI
It is the widest and most powerful muscle of the back. It
is a large, flat, triangular muscle covering the lower back
• ORIGIN: the lower half of the vertebral column and iliac
crest (hipbone)
• INSERTION: the front of the upper part of the humerus
• ACTION: draws the upper arm downward and
backward and rotates it inward, as exemplified in the
downstroke in swimming the crawl. In climbing it joins
with the abdominal and pectoral muscles to pull the trunk
upward. The two latissimus dorsi muscles also assist in
forced respiration by raising the lower ribs.
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ABDOMINALS
The Abdominals are composed of several muscles: the
Rectus Abdominus, Transverse Abdominus, and the
External and Internal Obliques.
• Rectus Abdominus muscle is commonly known as the
"six-pack" muscle of the abs ACTION: FLEX THE SPINE
as in a crunching motion.
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Transverse Abdominus (also known as the Transversus)
is the deepest muscle of the core (meaning it's
underneath all the other muscles). It wraps laterally
around the abdominal area. ACTION: Acts as a natural
weight belt keeping your insides intact
• External and Internal Obliques run diagonally on the
body, allowing for angled movement. ACTION: Work to
rotate the torso and stabilize the abdomen
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GLUTEUS
MAXIMUS
The gluteus maximus is the uppermost of the three
muscles. It is the largest of the gluteal muscles and one
of the strongest muscles in the human body
• ORIGIN: Outer surface of ilium behind posterior gluteal
line and posterior third of iliac crest lumbar fascia, lateral
mass of sacrum, sacrotuberous ligament and coccyx
• INSERTION: Deepest quarter into gluteal tuberosity of
femur, remaining three quarters into iliotibial tract
(anterior surface of lateral condyle of tibia)
• ACTION: Extends and laterally rotates hip. Maintains
knee extended via iliotibial tract
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SARTORIUS
A narrow muscle of the thigh, the longest in the human
body, that passes obliquely across the front of the thigh
and helps rotate the leg to the cross-legged position
• ORIGIN: superior to the anterior superior iliac spine
• INSERTION: anteromedial surface of the upper tibia in
the pes anserinus
• ACTION: Flexion of knee, Flexion of Leg
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BICEPS
FEMORIS
A muscle of the posterior (the back) thigh. As its name
implies, it has two parts, one of which (the long head)
forms part of the hamstrings muscle group
ORIGIN: Long head: upper inner quadrant of posterior
surface of ischial tuberosity.
Short head: middle third of linea aspera, lateral
supracondylar ridge of femur
INSERTION: Styloid process of head of fibula. lateral
collateral ligament and lateral tibial condyle
ACTION: Flexes and laterally rotates knee. Long head
extends hip
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RECTUS
FEMORIS
Rectus femoris muscle is one of the four quadriceps
muscles of the human body. (The others are the vastus
medialis, the vastus intermedius (deep to the rectus
femoris), and the vastus lateralis. All four combine to
form the quadriceps tendon
• ORIGIN: Straight head: anterior inferior iliac spine.
• Reflected head: ilium above acetabulum
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INSERTION: Quadriceps tendon to patella , via
ligamentum patellae into tubercle of tibia
• ACTION: Extends leg at knee. Flexes thigh at hip
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GASTROCNEMIUS
The gastrocnemius muscle is a very powerful
superficial muscle that is in the back part of the lower leg
and also called the calf.
• ORIGIN: Lower posterior surface of the femur above the
medial condyle and lateral condyle of the femur
• INSERTION: Posterior surface of the calcaneus via the
achilles tendon
• ACTION: Plantar flexion Ex: Jumping
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ACHILLES
TENDON
The Achilles is the tendonous extension of three muscles
in the lower leg: gastrocnemius, soleus, and plantaris
• Begins Mid-Calf
• INSERTION: inserted into the middle part of the
posterior surface of the calcaneus
• ACTION: The primary function of the Achilles tendon is
to transmit the power of the calf to the foot enabling
walking and running. If it has to do with upright, bipedal
motion, the Achilles tendon is a part of that activity.