Set 5 Muscles
Superficial Power Muscles
of the Torso
Lumbodorsal Fascia
Lumbodorsal fascia
 Origin: coccyx up past T10
 Insertion: point of half diamond ends up
around L3-L4 area
 Action: increases surface area for
attachment of large muscles
Latissimus dorsi
“power-stroke” muscle
Latissimus dorsi

Origin: Spinous processes of sacral, lumbar
and lower thoracic vertebrae (T7L5); iliac crest (pelvis); lower ribs
(9-12)

Insertion: Intertubercular grove of humerus
(twist around teres major)

Action: Powerfully extends and adducts arm
and rotates humerus inwardly or pulls
shoulder downward and posteriorly
Intertubercular groove
Pectoralis major
“pledge of allegiance” muscle
Pectoralis major: pars abdominalis
Pectoralis major: pars abdominalis
 Origin: aponeurosis of external obliques
over medial part of ribs 5-7
 Insertion: lateral ridge of intertubercular groove
of humerus
 Action: adducts shoulder, rotates medially and
extends (last part of tennis or
volleyball serve)
Pectoralis major: pars sternocostalis
Pectoralis major: pars sternocostalis
 Origin: anterior surface of sternum
and costal cartilage of ribs 1-7
 Insertion: lateral ridge of intertubercular groove
of humerus
 Action: adducts the arm across chest and
pulls shoulder forward (tennis
forehand)
Pectoralis major: pars clavicularis
Pectoralis major: pars clavicularis
 Origin: sternal half of clavicle
 Insertion: lateral ridge of intertubercular groove
of humerus
 Action: adducts the arm upward toward the
face (last part of bowling or uppercut in
boxing)
Trapezius: pars spinalis
(lower division)
“sexy shoulder” muscle
Trapezius pars spinalis (lower division)
 Origin:
Spinous process of T4-T12 vertebrae
 Insertion:
posterior portion of the spine of scapula
 Action: Power muscle that pulls scapula
back and medially rotates
Trapezius: pars acromialis
(middle division)
“sexy shoulder” muscle
Trapezius: pars acromialis (middle division)
 Origin: lower end of the nuchal ligament,
spinous processes of C6-T3 vertebrae
 Insertion:
medial margin of the acromial process and
the distal end of the scapular spine
 Action: Power muscle that lifts the shoulder upward
and back
Trapezius: pars clavicularis
(upper division)
“sexy shoulder” muscle
Trapezius: pars clavicularis (upper division)
 Origin:
begins at the superior part of nuchal ligament
from the occipital bone and continues along the
nuchal ligament to C6 vertebrae
 Insertion:
 Action:
superior border of the last lateral third of
the clavicle
elevates scapula and helps rotate arm
upward (supports weight of arm)
Trapezius
“sexy shoulder” muscle
Nuchal Ligament