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

Buccinator Location

Buccinator Action

Compresses Cheek

Occipitofrontalis (Frontal Belly) Location

Occipitofrontalis (Frontal Belly) Action

Draws Scalp Anteriorly

Occipitofrontalis (Occipital Belly) Location

Occipitofrontalis (Occipital Belly) Action

Retracts Scalp

Masseter Location

Masseter Origin

Zygomatic Arch

Masseter Insertion

Angle or Ramus of Mandible

Masseter Action

Elevates or Closes Mandible

Mentalis Location

Mentalis Action

Protrudes Lower Lip

Orbicularis Oculi Location

Orbicularis Oculi Action

Closes Eyelids in Blinking and Aids in Flow of Tears Across Eye

Orbicularis Oris Location

Orbicularis Oris Action

Closes Lips and Protrudes Lips in Kissing

Sternocleidomastoid Location

Sternocleidomastoid Origin

Manubrium of Sternum and Clavicle

Sternocleidomastoid Insertion

Mastoid Process of Temporal Bone

Sternocleidomastoid Action

Abducts, Rotates, and Flexes Head; Aids in Forceful Inhalation by Elevating the Sternum and First Ribs

Temporalis Location

Temporalis Origin

Temporal Fossa

Temporalis Insertion

Coronoid Process or Ramus of Mandible

Temporalis Action

Elevates or Closes Mandible

Zygomaticus Major Location

Zygomaticus Major Origin

Zygomatic Bone

Zygomaticus Major Insertion

Superolateral Angle of Mouth or Muscles of Upper Lip

Zygomaticus Major Action

Elevates Corners of Mouth in Smiling and Laughing

Zygomaticus Minor Location

Zygomaticus Minor Action

Elevates Corners of Mouth in Smiling and Laughing

Diaphragm Location

Diaphragm Action

Inspiration and Contraction for Sneezing, Coughing, Laughing, and Crying

External Oblique Location

External Oblique Action

Compresses Abdominal Wall, Laterally Rotates Waist, and Flexes/Rotates Vertebral Column

Internal Oblique Location

Internal Oblique Action

Compresses Abdominal Wall, Laterally Rotates Waist, and Flexes/Rotates Vertebral Column

External Intercostals Location

External Intercostals Action

Elevates Ribs and Increases Volume in Thorax

Internal Intercostals Location

Internal Intercostals Action

Elevates Ribs and Depresses Ribs during Forced Expiration

Rectus Abdominis Location

Rectus Abdominis Origin

Pubic Crest and Pubic Symphysis

Rectus Abdominis Insertion

Costal Cartilages 5-7 and Xiphoid Process of Sternum

Rectus Abdominis Action

Flexes Spine and Compresses Abdominal Wall

Serratus Anterior Location

Serratus Anterior Action

Abducts/Rotates Scapula and Draws Scapula Laterally/Forward

Transverse Abdominis Location

Transverse Abdominis Action

Compresses Abdominal Wall, Laterally Rotates Waist, and Flexes/Rotates Vertebral Column

Trapezius Location

Trapezius Origin

Posterior Occipital Bone or Nuchal Ligament and Spinous Process of Cervical Vertebrae 7 - Thoracic Vertebrae 4

Trapezius Insertion

Clavicle and Acromion or Spine of Scapula

Trapezius Action

Extends/Abducts Head, Rotates/Adducts Scapula, and Fixes Scapula

Latissimus Dorsi Location

Latissimus Dorsi Origin

Spinous Process of Thoracic Vertebrae 7-12, Lumbar Vertebrae 1-5, Iliac Crest, and Ribs 10-12

Latissimus Dorsi Insertion

Intertubercular Sulcus of Humerus

Latissimus Dorsi Action

Extends, Adducts, and Medially Rotates Humerus and Draws Shoulder Inferiorly

Pectoralis Major Location

Pectoralis Major Origin

Clavicle, Sternum, Costal Cartilages of Ribs 1-7, and Aponeurosis of External Oblique

Pectoralis Major Insertion

Intertubercular Sulcus 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 Glenoid Cavity, Draws Scapula Laterally/Forward; Depresses Apex of Shoulder and Elevates Ribs during Forceful Inhalation

Deltoid Location

Deltoid Origin

Clavicle, Acromion, and Spine of Scapula

Deltoid Insertion

Deltoid Tuberosity of Humerus

Deltoid Action

Flexes, Medially Rotates and Abducts Arm and Extends/Laterally Rotates Humerus.

Supraspinatus Location

Supraspinatus Origin

Supraspinous Fossa of Scapula

Supraspinatus Insertion

Greater Tubercle of Humerus

Supraspinatus Action

Abducts Arm/Should and Helps Stabilize Shoulder Joint

Infraspinatus Location

Infraspinatus Origin

Infraspinous Fossa of Scapula

Infraspinatus Insertion

Greater Tubercle of Humerus

Infraspinatus Action

Laterally Rotates Arm/Humerus and Stabilizes Shoulder Joint

Subscapularis Location

Subscapularis Origin

Subscapular Fossa of Scapula

Subscapularis Insertion

Lesser Tubercle of Humerus and Anterior Surface of Shoulder Joint Capsule

Subscapularis Action

Medially Rotates Arm/Humerus and Stabilizes Shoulder Joint

Teres Major Location

Teres Major Origin

Inferior Angle of Scapula

Teres Major Insertion

Intertubercular Sulcus of Humerus and Lesser Tubercle of Humerus

Teres Major Action

Extends/Medially Rotates Humerus, Adducts Arm, and Extends, Adducts, and Medially Rotates Shoulder

Teres Minor Location

Teres Minor Origin

Lateral Border of Scapula

Teres Minor Insertion

Posterior Greater Tubercle of Humerus

Teres Minor Action

Laterally Rotates Arm/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

Brachioradialis Location

Brachioradialis Origin

Lateral Supracondylar Ridge of Humerus