Ch 11, origin, insertion and action of muscles

Masseter

Origin- Zygomatic arch

Insertion- Lateral surface of the mandibular ramus, Or just mandible

Action- Elevates mandible and closes the jaws

Temporalis

Origin- Along temporal lines of skull

insertion- Coronoid process of mandible

Action- Elevates mandible

Pterygoids Medial and lateral

Origan- Lateral pterygoid plate

Insertion- Medial surface of mandibular ramus

Action-

• Medial- elevates the mandible and closes the jaws, slides the mandible from side to side (lateral excursion),

• Lateral- opens jaws, protrudes mandible or performs lateral excursions

Sternocleidomastoid

Origin- Sternum, clavicle,

Insertion- Mastoid process,

Action- Head rotation= no

Masseter

Origin- Zygomatic arch,

Insertion- Mandible,

Action- Chewing or mastication

Rectus abdominis

Origin- Pubis,

Insertion- Sternum,

Action- Sit ups

Intercostals

Origin- Ribs,

Insertion- Ribs,

Actions- Inhale/exhale

Diaphragm

Origin- Sternum, ribs, vertebrate,

nsertion- Central tendon,

Action- Inhaling

Pectoralis major

Origin- Clavicle, sternum,

Insertion- Humerus,

Action- Humerus across chest

Latissimus dorsi

Origin- Lumbar vertebrate, iliac crest,

Insertion- Humerus,

Action- Adduction of the humerus, think Lat pulldowns

Deltoid

Origin- Clavicle, scapula (spine),

Insertion- Humerus,

Action- Abduction of humerus think Overhead press/ shoulder press

Trapezius

Origin- Occipital bone, vertebra,

Insertion- Scapula (acromion, spine),

Action- Elevates skull, scapula

Biceps brachii

Origin- Coracoid (scapula),

Insertion- Radius,

Action- Forearm flexion

Triceps brachii

Origin- Humerus (posterior surface), scapula,

Insertion- Ulna,

Action- Forearm extension

Quadriceps

Origin- Femur,

Insertion- Patella/tibia,

Action-

• Rectus femoris,

• Vastus lateralis,

• Vastus medialis,

• Vastus intermedius,

  • (leg extension)

Hamstring

Origin- Ischium,

Insertion- Tibia (posterior),

Action-

• Biceps femoris,

• Semitendinosus,

• Semimembranosus,

  • (Leg flexion, ex- hamstring curl)

Gastrocnemius

Origin- Femur,

Insertion- Achilles tendon/calcaneus,

Action- Plantar flexion