Muscles: Actions, Origins & Insertions

Study Notes

Facial Muscles

Frontalis: Raises eyebrows; originates from the galea aponeurotica and inserts into skin of the eyebrows and bridge of the nose.
Occipitalis: Pulls scalp posteriorly; starts and ends at the galea aponeurotica.
Orbicularis Oculi: Closes, blinks, and squints eyes; originates from the medial margin of the orbit and inserts into skin around the eyelids.
Orbicularis Oris: Closes mouth, known as the 'kissing muscle'; originates from the maxilla and mandible, inserting into the lips.
Zygomaticus: Retracts and elevates the upper lip; originates from the zygomatic bone and inserts into the skin on the lateral sides of the mouth.

Jaw and Neck Muscles

Masseter: Closes jaw and elevates mandible; originates from the zygomatic arch and inserts into the mandibular ramus.
Sternocleidomastoid: Rotates head and flexes neck; originates from the clavicle and manubrium of the sternum, inserting at the mastoid process of the temporal bone.
Sternohyoid: Depresses the larynx and hyoid bone; originates from the clavicle and manubrium of sternum, inserting into the hyoid bone.

Thoracic and Upper Back Muscles

Pectoralis Major: Responsible for flexion, adduction, and medial rotation at the shoulder; originates from ribs 2-6, sternum, and clavicle, inserting into the greater tubercle of the humerus.
Pectoralis Minor: Protracts scapula; originates from ribs 3-5 and inserts into the coracoid process of the scapula.
Rhomboid Major: Adducts scapula; originates from the spinous processes of vertebrae, inserting into the vertebral border of scapula.
Serratus Anterior: Protracts scapula; originates from ribs 1-8, inserting into the vertebral border of the scapula.
Trapezius: Extends neck and elevates or retracts scapula; originates from the occipital bone and spinous processes of cervical and thoracic vertebrae, inserting into the clavicle and scapula.

Breathing Muscles

External Intercostals: Elevates ribs; originates from the inferior border of each rib, inserting into the superior border of each rib.
Internal Intercostals: Depresses ribs; originates from the superior border of each rib, inserting into the inferior border of each rib.

Arm and Shoulder Muscles

Deltoid: Abducts shoulder; originates from the clavicle and scapula, inserting into the deltoid tuberosity of the humerus.
Latissimus Dorsi: Responsible for extension, adduction, and medial rotation at the shoulder; originates from spinous processes of inferior thoracic and lumbar vertebrae, inserting into the intertubercular groove of the humerus.
Infraspinatus: Facilitates lateral rotation at the shoulder; originates from the infraspinous fossa of scapula, inserting into the greater tubercle of the humerus.
Supraspinatus: Assists in shoulder abduction; originates from the supraspinous fossa of the scapula, inserting into the greater tubercle of the humerus.
Teres Major: Aids in extension, adduction, and medial rotation at the shoulder; originates from the scapula, inserting into the intertubercular groove of the humerus.
Subscapularis: Medial rotation at the shoulder; originates from the subscapular fossa of the scapula, inserting into the lesser tubercle of the humerus.

Forearm Muscles

Biceps Brachii: Flexes at elbow and shoulder, facilitates supination; originates from the coracoid process and tubercle above the glenoid cavity of the scapula, inserting into the tuberosity of the radius.
Triceps Brachii: Extends at elbow; has three heads originating from the scapula and posterior humerus, inserts at the olecranon of the ulna.
Brachialis: Flexes at elbow; originates from the anterior distal humerus, inserting into the tuberosity of the ulna.
Brachioradialis: Flexes at elbow; originates from the ridge above the lateral epicondyle of the humerus, inserting at the styloid process of the radius.
Pronator Teres: Responsible for pronation; originates from the medial condyle of the humerus and coronoid process of the ulna, inserting into the radius.
Flexor Carpi Radialis: Flexes and abducts at wrist; originates from the medial epicondyle of the humerus, inserting into the bases of the 2nd and 3rd metacarpals.

Description

This quiz covers the key muscles including their actions, origins, and insertions. Ideal for students studying human anatomy, it provides essential information for understanding muscle functions. Use these flashcards as a quick reference to master muscle anatomy.