Exercise Science
PSE 4U
Muscle Groups of the:
1.
2.
3.
4.
5.
Axilla
Scapular Region
Rotator Cuff
Arm
Forearm Flexors
6.
7.
8.
9.
10.
11.
Forearm Extensors
Gluteal Region
Thigh
Leg
Abdomen
Back
Group 1
Muscles of the Axilla
Pectoralis Major
Description: A large fan
shaped muscle –
covers upper portion of
chest, forms anterior of
axillary fold
Origin: Clavicle, sternum,
and ribs 1-7
Insertion: Crest of greater
tubercle of humerus
Action: Flexes, adducts
and medially rotates
arm
Group 1
Muscles of the Axilla
Pectoralis Minor
Description: A flat thin
muscle directly beneath
and obscured by the
pectoralis major. Forms
anterior wall of Axilla
Origin: Anterior surface of
ribs 3-5
Insertion: Coracoid process
of the scapula
Action: Depresses the
scapula and elevates
ribs 3-5
Group 1
Muscles of the Axilla
Serratus Anterior
Description: Forms medial wall
of axilla. Serrated or
sawtooth appearance. Lies
deep to scapula and
beneath & inferior to
pectoral muscles on lateral
rib C1
Origin: Outer surface of ribs1-9
Insertion: Entire length of
vertebral border of the
scapula
Action: Stabilizes, abducts and
rotate the scapula upward
Group 1
Muscles of the Axilla
Subscapularis
Description: Forms part of
posterior wall of axilla; a
“rotator cuff” muscle
Origin: Subscapular fossa
Insertion: Lesser tubercle
of the humerus
Action: Extends and
medially rotates the arm,
stabilizes shoulder joint.
Group 1
Muscles of the Axilla
Teres Major
Description: A thick rounded
muscle found inferior to
the teres minor. Helps
form posterior wall of
axilla
Origin: Axillary border of
scapula
Insertion: Lesser tubercle of
the humerus
Action: Adducts, extends
and medially rotates the
arm
Group 1
Muscles of the Axilla
Latissimus Dorsi
Description: A broad flat,
triangular muscle of the
lower back (lumbar region).
Forms part of posterior wall
of axilla
Origin: Spinous processes of
T7-T12 and L1-L5, the
sacrum, iliac crest, and ribs
10-12
Insertion: Intertubercular
groove of the humerus
Action: Extends, adducts and
medially rotates the arm;
pulls shoulder inferiorly
Group 2
Muscles of the Scapular Region
Trapezius
Description: A flat triangular
muscle, upper fibers run
downward to scapula, middle
fibers run horizontally to
scapula, lower fibers run
superiorly to scapula
Origin: Occipital bone, the
ligamentum nuchae, and the
spinous processes of C7-T12
Insertion: Lateral 1/3 of clavicle
and the spine of the scapula
Action: Abducts and extends
head, rotates and adducts
scapula
Group 2
Muscles of the Scapular Region
Levator Scapulae
Description: Thick strap like
muscle located at back &
side of the neck, deep to
trapezius;
Origin: Transverse
processes of C1-C4
Insertion: Superior angle of
scapula
Action: Elevates scapula,
and rotates and abducts
neck
Group 2
Muscles of the Scapular Region
Rhomboid Major
Description: A rectangular
shaped muscle lying deep
to trapezius and inferior to
levator scapulae. Inferior
to rhomboideus minor.
Origin: Spinous processes of
T1-T4
Insertion: Inferior, vertebral
border of the scapula
Action: Adducts, stabilizes
and rotates the scapula
Group 2
Muscles of the Scapular Region
Rhomboid Minor
Description: A rectangular
shaped muscle lying deep
to trapezius and inferior to
levator scapulae
Origin: Spinous processes of
C6-C7
Insertion: Superior, vertebral
border of the scapula
Action: Adducts, stabilizes and
rotates the scapula
Group 2
Muscles of the Scapular Region
Deltoid
Description: Responsible for
roundness of shoulder
Origin: Clavicle, acromion
process, and spine of the
scapula.
Insertion: Deltoid tuberosity of
the humerus
Action: Abducts, flexes,
extends medially, and
laterally rotates the arm
Group 3
Muscles of the Rotator Cuff
Consists of 4 muscles
a) Supraspinatus
b) Infraspinatus
c) Teres Minor
d) Subscapularis (mnemonic S.I.T.S.
- they sit on the shoulder)
*If any of the rotator cuff muscles is damaged due to strain or bad
mechanics, the consequences are serious for arm/shoulder actions
Group 3
Muscles of the Rotator Cuff
Supraspinatus
Description: Named for its
location on posterior aspect
of scapula
Origin: Supraspinous fossa of
the scapula
Insertion: Greater tubercle of
the humerus by a common
tendon with Infraspinatus
and Teres Minor
Action: Abducts arm and
stabilizes the shoulder
Group 3
Muscles of the Rotator Cuff
Infraspinatus
Description: Partially covered
by deltoid & trapezius
Origin: Infraspinous fossa of
the scapula
Insertion: Greater tubercle of
the humerus by common
tendon with Supraspinatus
& Teres Minor.
Action: Extends, laterally
rotates arm and stabilizes
the shoulder
Group 3
Muscles of the Rotator Cuff
Teres Minor
Description: Small, elongated
muscle that lies inferior to
infraspinatus
Origin: Axillary border of the
scapula.
Insertion: Greater tubercle of the
humerus by common tendon
with supraspinatus &
infraspinatus
Action: Same action as
infraspinatus muscle
(Extends, laterally rotates arm
and stabilizes the shoulder)
Group 3
Muscles of the Rotator Cuff
Subscapularis
Description: A large
triangular muscle, and the
only muscle in the group
located on the anterior
surface of the scapula
Origin: Subscapular fossa of
the scapula
Insertion: Lesser tubercle of
the humerus
Action: Medially rotates
humerus and stabilizes
the shoulder.
Group 4
Muscles of the Arm
Triceps Brachii
Description: Large fleshy muscle
and the only muscle of
posterior compartment of the
arm
Origin: Long head= Infraglenoid
tuberosity of the scapula
Lateral and medial heads=
posterior surface of humerus
Insertion: Olecranon process of
the ulna
Action: Extends the forearm and
arm, and adducts the arm
Group 4
Muscles of the Arm
Coracobrachialis
Description: A small
cylindrical muscle.
Origin: Coracoid process of
the scapula
Insertion: Medial shaft
of the humerus
Action: Flexion & adduction
of the humerus
Group 4
Muscles of the Arm
Brachialis
Description: Strong muscle
that is immediately deep
to the biceps brachii
Origin: Anterior, distal
humerus
Insertion: Coronoid Process
of the ulna
Action: Flexion of the
forearm
Group 4
Muscles of the Arm
Anconeus
Description: A short triangular
muscle closely associated
with distal end of triceps
Origin: Lateral epicondyle of
the humerus
Insertion: Olecranon process
of the ulna
Action: Extends the forearm
Group 5
Forearm Flexors
Pronator Teres
Description: A two headed
muscle
Origin: Medial epicondyle of
the humerus and the
coronoid process of the
ulna
Insertion: Middle shaft of the
radius
Action: Pronates and weakly
flexes the forearm
Group 5
Forearm Flexors
Flexor Carpi Radialis
Description: Runs diagonally
across the forearm; midway,
its fleshy belly is replaced by
a flat tendon that becomes
cordlike at wrist
Origin: Medial epicondyle of the
humerus
Insertion: 2nd and third meta
carpals
Action: Flexes & abducts the
hand; aids in flexion and
pronation of forearm.
Powerful flexor of wrist
Group 5
Forearm Flexors
Flexor Carpi Ulnaris
Description: Most medial
muscle of this group; two
headed
Origin: Medial epicondyle of
humerus; olecranon
process; posterior surface
of ulna
Insertion: Pisiform, hamate &
5th metacarpal
Action: Flexes & adducts the
hand; powerful flexor of
wrist
Group 7
Muscles of the Gluteal Region
Gluteus Maximus
Description: Largest and
strongest, most superficial of
gluteal muscles; forms bulk of
buttock mass; fibers are thick
& coarse.
Origin: Lateral surface of ilium,
sacrum and coccyx
Insertion: Lateral condyle of tibia
by lateral fascia and gluteal
tuberosity of the femur
Action: Extends, abducts, and
laterally rotates the thigh
Group 7
Muscles of the Gluteal Region
Gluteus Medius
Description: Thick muscle
largely covered by gluteus
maximus and sits on top of
gluteus minimus
Origin: Outer ilium, between
the posterior & the anterior
gluteal lines
Insertion: Greater trochanter of
the femur
Action: Abducts & medially
(internal) rotates the thigh
Group 7
Muscles of the Gluteal Region
Gluteus Minimus
Description: Smallest and
deepest of the gluteus
muscles
Origin: Outer (external) ilium,
between the anterior and
the inferior gluteal lines
Insertion: Greater trochanter of
the femur
Action: Abducts and medially
(internally) rotates the thigh;
same action as the gluteus
medius
Group 7
Muscles of the Gluteal Region
Sartorius
Description: A superficial
anterior muscle of the thigh.
It derives its name from the
latin word sartor meaning
“to mend”.
Origin: Anterior superior iliac
spine
Insertion: Medial surface of the
tibia
Action: The sartorius acts
across two joints: Flexes
and laterally rotates the hip
and flexes the knee
Group 7
Muscles of the Gluteal Region
Quadratus Femoris:
Description: Short thick
muscle; most inferior of
lateral rotator muscles,
extends laterally from
pelvis
Origin: Ischial Tuberosity
Insertion: Shaft of the femur
just below the greater
trochanter
Action: Laterally rotates the
thigh and stabilizes hip
joint
Sartorius
Group 8
Muscles of the Thigh
Anterior Compartment
Description: A superficial
anterior muscle of the thigh.
It derives its name from the
latin word sartor meaning
“to mend”.
Origin: Anterior superior iliac
spine
Insertion: Medial surface of the
tibia
Action: The sartorius acts
across two joints: Flexes
and laterally rotates the hip
and flexes the knee
IIiopsoas
Group 8
Muscles of the Thigh
Anterior Compartment
Description: A composite of
two closely related muscles:
iIiacus and psoas major
Origin: Psoas major – the
transverse processes and
bodies of T12 and L1-L5
IIiacus – iliac fossa and
sacrum
Insertion: Lesser trochanter of
femur
Action: Flex the thigh; flex the
trunk on the femur
Group 8
Muscles of the Thigh
Rectus Femoris
Description: Superficial,
straight muscle of the
anterior thigh; longest head
and only muscle of the
group to cross the hip joint
Origin: Anterior inferior iliac
spine
Insertion: Tibial tuberosity, via
the patella and the patellar
ligament
Action: Extends the leg (knee)
and flexes the thigh
Group 8
Muscles of the Thigh
Vastus Lateralis
Description: Forms lateral
aspect of thigh
Origin: Greater trochanter and
the lateral lip of the linea
aspera of the femur
Insertion: Tibial tuberosity, via
the patella and the patellar
ligament
Action: Extend the leg (knee)
Group 8
Muscles of the Thigh
Vastus Medialis
Description: Forms
inferomedial aspect of
thigh
Origin: Medial lip of the linea
aspera of the femur
Insertion: Tibial tuberosity,
via the patella and the
patellar ligament
Action: Extends the leg
(knee)
Group 8
Muscles of the Thigh
Vastus Intermedius
Description: Lies between
vastus lateralis and
vastus medialis on
anterior thigh
Origin: Anterior, lateral shaft
of the femur
Insertion: Tibial tuberosity,
via the patella and the
patellar ligament
Action: Extend the leg
(knee)
Group 8
Muscles of the Thigh
Pectineus
Description: Short flat
muscle; overlies adductor
brevis on proximal thigh
Origin: Superior ramus of
the pubis
Insertion: Posterior femur
just below the lesser
trochanter
Action: Adducts and laterally
rotates the thigh
Group 8
Muscles of the Thigh
Adductor Longus
Description: Most anterior of
adductor muscles
Origin: Crest and the
symphysis of the pubis
Insertion: Middle 1/3 of the
linea aspera of the femur
Action: Adducts and laterally
rotates the thigh
Group 8
Muscles of the Thigh
Adductor Brevis
Description: Largely
concealed by adductor
longus and pectineus
Origin: Inferior ramus of the
pubis
Insertion: Upper part of the
linea aspera of the femur
Action: Adducts and laterally
rotates the thigh (femur)
Group 8
Muscles of the Thigh
Adductor Magnus
Description: A triangular
muscle with a broad
insertion; a composite
muscle that is part adductor
and part hamstring in action
Origin: Inferior ramus of the
pubis and the ischium
Insertion: Most of the length of
the linea aspera, and the
adductor tubercle of the
femur
Action: Adducts, flexes,
extends and laterally rotates
the thigh
Group 8
Muscles of the Thigh
Gracilis
Description: Long, thin,
superficial muscle of the
medial thigh
Origin: Symphysis pubis
and the pubic arch
Insertion: Proximal portion
medial tibia just below the
condyle
Action: Adducts the thigh
and flexes the leg
Group 8
Muscles of the Thigh
Biceps Femoris
L.H.
S.H.
Description: Most lateral
muscle of the group; arises
from two heads
Origin: Long head-ischial
tuberosity
Short head-distal linea
aspera
Insertion: Head of fibula, and
the lateral condyle of the
tibia
Action: Flexes and laterally
rotates the leg (knee), long
head extends thigh
Group 8
Muscles of the Thigh
Semitendinosus
Description: Lies medial to
biceps femoris, quite fleshy;
its slendedr tendon begins
about 2/3 way down the
thigh
Origin: Ischial Tuberosity
Insertion: Medial, proximal end
of the tibia
Action: Extends thigh, flexes
and medially rotates leg
Group 8
Muscles of the Thigh
Semimembranosus
Description: Deep to
semitendinosus
Origin: Ischial tuberosity
Insertion: Medial, proximal
end of the tibia
Action: Extends thigh, flexes
and medially rotates leg
Group 9
Muscles of the Leg
Anterior Compartment
Tibialis Anterior
Description: Superficial muscle
of anterior leg; laterally
parallels sharp anterior
margin of tibia
Origin: Lateral tibia
Insertion: Medial cuneiform &
first metatarsal
Action: Dorsiflexes & inverts
the foot
Group 9
Muscles of the Leg
Anterior Compartment
Extensor Digitorum Longus
Description: On anterolateral
surface of leg; lateral to
tibialis anterior
Origin: Lateral condyle of the
tibia, proximal shaft of the
fibula
Insertion: Dorsal surface of the
phalanges of digits 2-5
Action: Dorsiflexes & everts
the foot; extends digits 2-5
Group 9
Muscles of the Leg
Anterior Compartment
Extensor Hallucis Longus
Description: Deep to
extensor digitorum longus
& tibialis anterior; narrow
origin
Origin: Medial shaft of
fibula, and interosseous
membrane
Insertion: Distal phalanx of
the hallux (1st digit)
Action: Dorsiflexes & inverts
foot; extends the hallux
Group 9
Muscles of the Leg
Superior Compartment
Gastrocnemius:
Description: Superficial
muscle of pair; two
prominent bellies that
form proximal curve of
calf
Origin: Medial & lateral
condyles of the femur
Insertion: Calcaneus
Action: Flexes the leg and
plantar flexes the foot
Group 9
Muscles of the Leg
Posterior Compartment
Soleus
Description: Deep to
gastronemius on posterior
surface of calf
Origin: Posterior fibula and
tibia
Insertion: Calcaneus
Action: Plantar flexes the foot
and important during
walking, running & dancing
Group 9: Muscles of the Leg
Posterior Compartment – Deep
Muscles
Popliteus:
Description: Thin, triangular
muscle at posterior knee;
passes downward &
medially to tibial surface
Origin: Lateral condyle of
the femur
Insertion: Proximal portion
of the tibia
Action: Flexes the leg &
rotates it medially to
unlock knee from full
extension when flexion
begins
Group 10
Muscles of the Abdominal Wall
External Abdominal
Oblique:
Description: Largest & most
external of the abdominal
oblique muscles; fibers run
downward & medially;
aponeurosis turns under
inferiorly forming inguinal
ligament
Origin: External surface of ribs 512 (fleshy strips)
Insertion: Linea alba, iliac crest
and inguinal ligament
Action: Compresses the
abdomino pelvis cavity and
laterally rotates; aids in lateral
flexion
Group 10
Muscles of the Abdominal wall
Internal Abdominal Oblique:
Description: Fibers fan
upward & forward and run
at right angles to those of
external oblique (which it
underlies)
Origin: Inguinal ligament
and iliac crest
Insertion: Linea alba and
inferior 4 ribs
Action: same as external
abdominal oblique
Group 10
Muscles of the Abdominal Wall
Transversus Abdominis:
Description: Deepest
(innermost) muscle of
abdominal wall; fibers run
horizontally
Origin: Inguinal ligament,
iliac crest, lumbodorsal
fascia and ribs 7-12
Insertion: Linea alba, and
pubic crest
Action: Compresses the
abdomen and laterally
rotates trunk
Group 10
Muscles of the Abdominal Wall
Rectus Abdominis:
Description: Medial superficial muscle
pair; is located on each side of a
tendinous line (linea alba)
extending from xiphoid process of
sternum to the pubis; segmented
by three reinforcing tendinous
intersections horizontally which
give the abs the classic
washboard appearance
Origin: Pubic Crest and symphysis
pubis
Insertion: Xiphoid process &
cartlidges of ribs 5-7
Action: Compresses the abdomen
and flexes lumbar vertebrae
Spinalis:
Group 11
Muscles of the Back
Erector Spinae Muscle
Description: Most medial muscle
column of erector spinae
Origin: Spinous process of the
upper lumbar, lower thoracic,
and 7th cervical vertebrae
Insertion: Spinous processes of
the upper thoracic & the
cervical vertebrae
Action: Extends the vertebral
column
Group 11
Muscles of the Back
Erector
Spinae
Muscle
Description:
Intermediate tripartite
Longissimus:
muscle group of erector spinae;
mainly pass between transverse
processes of the vertebrae
Origin: Transverse processes of the
lumbar, thoracic & lower cervical
vertebrae
Insertion: Transverse processes of
the vertebrae above the vertebra
of origin, and the mastoid process
of temporal bone (capitis)
Action: Extend the vertebral column &
head; acting on oneside bend it
laterally; capitis extends the head
& turns face towards same side
(bend laterally)
Group 11
Muscles of the Back
Erector
Spinae
Muscle
Ilio Costalis:
Description: Most lateral muscle
group of erector spinae
muscles; extend from pelvis to
neck
Origin: Crest of the sacrum;
spinous processes of the
lumbar & lower thoracic
vertebrae; iliac crests; angles
of the ribs
Insertion: Angles of the ribs;
transverse processes of the
cervical vertebrae
Action: Extend the vertebral
column & acting on one side,
bend it laterally maintain erect
posture