1. THORACIC AND HEAD/NECK MUSCLES
Origin and Insertion
Ms. Treto

2. HEAD AND NECK MUSCLES

3. TEMPORALIS
ORIGIN: Temporal fossa and temporal fascia. The fibers blend together to pass between the zygomatic arch and the side of the skull.
INSERTION: The upper anterior border and inner surface of the coronoid process and the ramus of the mandible.
ACTION: elevates the mandible,
retracts the mandible

4. MASSETER test you on this ORIGIN:Superficial portion: from the
maxillary process of the zygomatic bone,
and the anterior two-thirds of the
inferior border of the zygomatic arch
Deep portion: I will not
test you on this
INSERTION:Superficial portion: the angle and ramus of the mandible.
ACTION: Elevation and protraction of the mandible. Clenching of the teeth

5. LEVATOR SCAPULAE ORIGIN: Posterior tubercles of
the transverse processes of C1-C4
INSERTION: Superior part of the
medial border of the scapula
ACTION:Elevation of the scapula,
downward rotation of the scapula

6. Thoracic Muscles

7. Trapezius Origin – occipital bone/spinous processes of c7 – T12.
Insertion – acromion/spine of
scapula; lateral 1/3 of scapula.
Action – stabilizes/elevates/
retracts/ rotates scapula

8. Latissimus Dorsi Origin –spinous processes of T7 – L5,
iliac crest, ribs, and inferior angle
of scapula
Insertion – intertubercle groove of
humerus
Action – adducts, extends and
internally rotates the arm. Also, a
very powerful rotator of the trunk.

9. Infraspinatus Origin – infraspinous fossa of the scapula
Insertion – greater tubercle of the
humerus
Action – lateral rotation of the arm
and stabilizes the humerus

10. Rhomboid Major and Minor
Major action – retracts the scapula
and rotates it to depress the glenoid
cavity.
Minor action – retracts and rotates
scapula

11. Sternocleidomastoid Origin – manubrium and medial
portion of the clavicle
Insertion – mastoid process
of the temporal bone
Action – 1. Unilaterally –
cervical rotation and lateral
flexion. 2. Bilaterally – cervical
flexion and raises the sternum

12. Pectoralis Major Origin –Clavicle, sternum and upper ribs
Insertion – greater tubercle
on humerus
Action – 1. adduction of
humerus. 2. flexion and
extension of humerus.

13. Rectus Abdominis Origin – crest of pubis
Insertion – costal cartilage of
ribs 5 – 7, xiphoid process
of sternum
Action – flexion of the
lumbar spine

14. External Obliques Origin – Ribs 5 - 12 Insertion – Iliac crest
Action – Contralateral rotation
of torso