Practical 3 - Muscle Locations, Origins, Insertions, and Actions

Buccinator Location

Buccinator Action

Compresses the cheek for sucking and whistling

Occipitofrontalis (Frontal Belly) Location

Occipitofrontalis (Frontal Belly) Action

Raises eyebrows and draws the scalp anteriorly (wrinkles the forehead)

Occipitofrontalis (Occipital Belly) Location

Occipitofrontalis (Occipital Belly) Action

Retracts the scalp

Masseter Location

Masseter Origin

Zygomatic Arch

Masseter Insertion

- Angle of the Mandible

- Ramus of the Mandible

Masseter Action

Elevates (closes) the mandible (jaw)

Mentalis Location

Mentalis Action

Protrudes the lower lip and wrinkles the chin

Orbicularis Oculi Location

Orbicularis Oculi Action

Closes the eyelids

Orbicularis Oris Location

Orbicularis Oris Action

Closes and purses the lips

Sternocleidomastoid Location

Sternocleidomastoid Origin

- Manubrium of Sternum

- Medial Clavicle

Sternocleidomastoid Insertion

Mastoid Process of the Temporal Bone

Sternocleidomastoid Action

Abducts, rotates, and flexes the head

Temporalis Location

Temporalis Origin

Temporal Fossa

Temporalis Insertion

- Coronoid Process

- Ramus of Mandible

Temporalis Action

Elevates (closes) the mandible (jaw).

Trapezius Location

Trapezius Origin

- Posterior Occipital Bone

- Nuchal Ligament

- Cervical Vertebrae 7 - Thoracic Vertebrae 4

Trapezius Insertion

- Clavicle

- Acromion

- Spine of Scapula

Trapezius Action

Extends and abducts the head; and rotates, adducts, and fixes the scapula

Zygomaticus Major Location

Zygomaticus Major Origin

Zygomatic Bone

Zygomaticus Major Insertion

- Superolateral Angle of the Mouth

- Muscles of the Upper Lip

Zygomaticus Major Action

Elevates the corners of the mouth for smiling and laughing

Zygomaticus Minor Location

Zygomaticus Minor Origin

Lateral Surface of Zygomatic Bone

Zygomaticus Minor Insertion

Skin of Upper Lip

Zygomaticus Minor Action

Elevates the upper lip

Diaphragm Location

Diaphragm Action

Inspiration

External Oblique Location

External Oblique Action

Compresses abdominal wall and laterally rotates waist

Internal Oblique Location

Internal Oblique Action

Compresses abdominal wall and laterally rotates waist

External Intercostals Location

External Intercostals Action

Elevates ribs during inspiration

Internal Intercostals Location

Internal Intercostals Action

Elevates and depresses ribs

Latissimus Dorsi Location

Latissimus Dorsi Origin

- Thoracic Vertebrae 7-12

- Lumbar Vertebrae 1-5

- Crest of Ilium

- Ribs 10-12

Latissimus Dorsi Insertion

Intertubercular Sulcus of Humerus

Latissimus Dorsi Action

Extends, adducts, and medially rotates the humerus; and draws shoulder inferiorly

Pectoralis Major Location

Pectoralis Major Origin

- Clavicle

- Sternum

- Cartilages of Ribs 1-7

Pectoralis Major Insertion

Crest of Greater Tubercle of Humerus

Pectoralis Major Action

Flexes, adducts, and medially rotates humerus

Pectoralis Minor Location

Pectoralis Minor Origin

Ribs 3-5

Pectoralis Minor Insertion

Coracoid Process of Scapula

Pectoralis Minor Action

Depresses the glenoid cavity

Rectus Abdominis Location

Rectus Abdominis Origin

- Crest of Pubis

- Pubic Symphysis

Rectus Abdominis Insertion

- Costal Cartilages 5-7

- Xiphoid Process of Sternum

Rectus Abdominis Action

Flexes the spine and compresses the abdominal wall

Serratus Anterior Location

Serratus Anterior Action

Abducts scapula superiorly

Transverse Abdominis Location

Transverse Abdominis Action

Compresses abdominal wall and laterally rotates waist

Deltoid Location

Deltoid Origin

- Clavicle

- Acromion

- Spine of Scapula

Deltoid Insertion

Deltoid Tuberosity of Humerus

Deltoid Action

Abducts, flexes, extends, and medially/laterally rotates humerus

Supraspinatus Location

Supraspinatus Origin

Supraspinous Fossa

Supraspinatus Insertion

Greater Tubercle of Humerus

Supraspinatus Action

Abducts arm and helps stabilize the shoulder joint

Infraspinatus Location

Infraspinatus Origin

Infraspinous Fossa

Infraspinatus Insertion

Greater Tubercle of Humerus

Infraspinatus Action

Laterally rotates the arm and stabilizes the shoulder joint

Subscapularis Location

Subscapularis Origin

Subscapular Region

Subscapularis Insertion

Lesser Tubercle of Humerus

Subscapularis Action

Medially rotates the arm and stabilizes the shoulder joint

Teres Major Location

Teres Major Origin

Inferior Angle of Scapula

Teres Major Insertion

Crest of Lesser Tubercle of Humerus

Teres Major Action

Extends and medially rotates the humerus

Teres Minor Location

Teres Minor Origin

Lateral Border of Scapula

Teres Minor Insertion

Greater Tubercle of Humerus

Teres Minor Action

Laterally rotates and adducts humerus; and stabilizes shoulder joint

Biceps Brachii Location

Biceps Brachii Origin

- Long Head: Superior Margin of Glenoid Cavity

- Short Head: Coracoid Process of Scapula

Biceps Brachii Insertion

Radial Tuberosity

Biceps Brachii Action

Flexes the forearm, flexes the arm, and supinates the forearm

Triceps Brachii Location

Triceps Brachii Origin

- Infraglenoid Tubercle of Scapula

- Lateral and Posterior Surface of Humerus

Triceps Brachii Insertion

- Olecranon

- Tuberosity of Ulna

Triceps Brachii Action

Extends/adducts the arm and extends the forearm

Brachialis Location

Brachialis Action

Flexes the forearm