Muscles of the Torso

Scott.lehbauer@lethbridgecollege.ab.ca

Trapezius

Origin• External occipital bone• Spinous process of C7-

T12Insertion• Clavicle• Spine and acromion

process of scapulaFunction• Elevates scapula

Trapezius

Latissimus dorsi

OriginOrigin Spines of the sacral, Spines of the sacral,

lumbar and T7 – T12lumbar and T7 – T12 Iliac crestIliac crestInsertionInsertion Intertubercular Intertubercular

groove of humerusgroove of humerusFunctionFunction Extends, adducts Extends, adducts

and medially rotates and medially rotates armarm

Latissimus Dorsi

Sternocleidomastoid

Origin• Sternum • clavicle

Insertion• Mastoid process

Function• Pulls head to one side

(Lateral flexion) Sternocleidomastoid

Pectoralis Major

Origin• Clavicle • Sternum• Costal cartilage of 2nd – 6th ribs

Insertion• Lateral lip of the

intertubercular groove

Function• Flexes, adducts and medially

rotates armPectoralis Major

Pectoralis minor

Origin• Ribs 3-5

Insertion• Coracoid process of the

scapula

Function• Depresses scapula Pectoralis minor

Serratus anterior

Origin• Outer surface of the

upper ribs

Insertion• Anterior surface of the

scapula

Function• Pulls the scapula forward

and downwardSerratus Anterior

External intercostals

Origin• Inferior border of each

rib

Insertion• Superior border of the rib

below

Function• Elevates for inspiration External Intercostals

Internal Intercostals

Origin• Superior border of each

rib

Insertion• Inferior border of the rib

above

Function• Depresses the ribs for

exhalationInternal Intercostals

Rectus abdominus

Origin• Pubic crest and pubic

symphasis

Insertion• Cartilage of ribs 5-7 • Xiphoid process

Function• Flexes vertebral column

Rectus abdominus

External Obliques

Origin• Lower eight ribs

Insertion• Anterior iliac crest• Abdominal aponeurosis

Function• Tenses abdominal wall • Lateral flexion External Obliques

Internal Obliques

Origin• Crest of ilium• inquinal ligament

Insertion• Costal cartilage of lower• pubis

Function• Tenses abdominal wall and

compresses contentsInternal Obliques

Transverse abdominal

Function• Compresses

abdomen

Transverse Abdominus

Temporalis

Origin• Temporal fossa

Insertion• Coronoid process of the

mandible

Function• Closes jaw

Temporalis

Masseter

Origin• Zygomatic arch

Insertion• Angle and ramus of the

mandible• Coronoid process of the

mandible

Function• Closes jaw and clenches teeth

Masseter

Occipitalis

Function• Tenses and retract

scalp

Occipitalis

Frontalis

Function• Raises eyebrows and

wrinkles forehead

Frontalis

Platysma

Function• Tenses skin of the

neck and depresses mandible

Platysma

Mentalis

Function• Elevates and

protrudes lower lip

Mentalis

Procerus

Function• Wrinkles skin

between the eyes • “serious” look

Procerus

Nasalis

Function• Elevates the corners

of the nostrils

Nasalis

Orbicularis oris

Function• Closes and purses lips

Orbicularis oris

Orbicularis oculi

Function• Closes eye

Orbicularis oculi

Temporoparietalis

Function• Wriggles ears

Temporoparietalis