Facial Muscles Quiz to Learn Anatomy

The Epicranius Frontalis covers the frontal bone and plays a major role in facial expressions. It elevates the eyebrows and wrinkles the forehead by contracting upward. Anatomically, it is part of the broader epicranial group. Its location on the frontal bone makes it the correct choice, unlike the Zygomaticus Major, Sternocleidomastoid, or Trapezius, which perform completely different actions in other regions of the body.

The term Epicranius refers to the two-part system of the Frontalis and Occipitalis muscles connected by the galea aponeurotica. The Frontalis is frequently labeled as Epicranius because it forms the anterior portion. Occipitalis forms the posterior portion, but the common reference for movement and facial expression centers on the Frontalis. Temporalis and Masseter relate to jaw movement, making them incorrect.

The Orbicularis Oculi muscle encircles the eye and allows eyelid closure through circular contraction. This action is essential for blinking, protection, and tear distribution. Other listed muscles serve unrelated roles: Rectus Abdominis flexes the spine, Deltoid controls shoulder abduction, and Trapezius stabilizes the upper back. Only Orbicularis Oculi performs eyelid closure, making it the correct response for this question.

Orbicularis Oris surrounds the mouth opening and creates controlled movements of the lips such as puckering, closing, and shaping speech. Its circular structure allows precise lip control. Masseter and Temporalis produce jaw movement while Buccinator compresses the cheeks. Because none of them control true lip movement, Orbicularis Oris is the most accurate and anatomically correct choice.

The Mentalis muscle elevates and protrudes the lower lip while creating a chin-wrinkling effect. It is located centrally at the tip of the chin and contributes significantly to expressions of doubt or pouting. Zygomaticus moves the mouth upward, Sternocleidomastoid rotates the head, and Masseter closes the jaw. Only the Mentalis has the specific action of wrinkling the chin and moving the lower lip.

The Buccinator muscle compresses the cheeks inward toward the teeth. This action prevents food from collecting in the cheek area during chewing and assists in blowing, whistling, or sucking. It does not directly generate chewing force like the Masseter. It also has no involvement in breathing or tongue control, making “compresses cheeks inward” the only correct and anatomically accurate choice.

The Masseter originates from the zygomatic arch and maxilla, inserting into the mandible’s angle and ramus. Its contraction elevates the mandible, producing jaw closure—one of the strongest actions in the body. The other options describe unrelated muscle groups with different origins and insertions. The anatomical precision of origin, insertion, and function clearly identifies the Masseter as the correct answer.

The Platysma is a thin, superficial neck muscle that depresses the mandible and tenses the skin of the lower face and neck. It contributes to expressions of fear or tension. It has no role in breathing, elbow flexion, or ocular control. Its anatomical placement in the superficial neck region and its connection to jaw and lip movement confirm that it is the only correct choice.

The Zygomaticus muscles elevate the corners of the mouth, producing a smile. They pull upward and outward from the zygomatic bone to the mouth’s corners. Trapezius controls upper back movement, Pectoralis Major controls arm movement, and Gluteus Maximus extends the hip. None influence smiling. Thus, Zygomaticus is the correct anatomical determinant of smiling expression.

The Risorius retracts the corners of the mouth laterally, creating expressions such as grinning or controlled smiling. It does not elevate the mouth like Zygomaticus, nor does it influence vision, breathing, or digestion. Its specific action on horizontal mouth movement makes it the correct option. Anatomically, it attaches from fascia over the masseter to the mouth’s corner, enabling sideways pulling.

The Sternocleidomastoid originates from the sternum and clavicle and inserts into the mastoid process and the superior nuchal line of the occipital bone. When contracted, it flexes the neck and rotates the head to the opposite side. This complex action distinguishes it clearly from the other options, which either contain incorrect origins or actions not associated with this key cervical muscle.

The Pectoralis Major originates from the clavicle, sternum, and first six costal cartilages. Its fibers converge into the intertubercular sulcus of the humerus. This gives it leverage for arm flexion, medial rotation, and adduction. The alternative options present incorrect or anatomically impossible muscle attachments. Only the correct origin-insertion-action trio matches known anatomical structure.

Serratus Anterior originates on ribs 1–8 and inserts on the medial border of the anterior scapula. It protracts the scapula and stabilizes it against the thoracic wall. This action allows overhead movements and prevents winging. The other choices describe incorrect or unrelated muscle actions or attachments, making Serratus Anterior the only correct answer based on functional anatomy.

The Deltoid arises from the lateral clavicle, acromion, and scapular spine. It inserts into the deltoid tuberosity of the humerus. Acting as a whole, it abducts the arm— lifting it away from the body’s midline. Other options list incorrect origins, insertions, or unrelated joint actions. This precise anatomical combination makes the deltoid the correct choice.

The Pectoralis Minor begins at ribs 3–5 and inserts into the coracoid process of the scapula. It pulls the scapula forward and downward when the ribs are fixed. This stabilizing and protraction-based action differentiates it clearly from the incorrect choices, which either misstate origins or actions. Its anatomical orientation confirms its role in scapular positioning.

Rectus Abdominis runs vertically along the abdomen and flexes the spine, pulling the rib cage toward the pelvis. It is essential for bending forward and maintaining posture. Other options relate to rib expansion, arm movement, or knee movement, none of which involve the rectus abdominis. Thus, spinal flexion and trunk stability identify it as the correct answer.

External Oblique lies on the lateral trunk and supports pelvic stability and rotation. It is responsible for trunk rotation to the opposite side and lateral bending. It works synergistically with other abdominal muscles to stabilize the pelvis during movement. The distractor muscles control unrelated actions: Gluteus Maximus extends the hip, Deltoid moves the shoulder, and Rectus Abdominis flexes the spine with limited rotational capacity.

Internal Oblique lies beneath the External Oblique and assists spine flexion and same-side trunk rotation. Its fiber direction allows twisting toward the contracting muscle. It stabilizes the lumbar region alongside Rectus Abdominis. Transversus Abdominis provides core bracing, Psoas Major flexes the hip, and Rectus Abdominis flexes the torso without significant rotation. Thus, Internal Oblique is the most accurate choice.

The Transverse Abdominis wraps horizontally around the abdomen and acts like a natural weight belt. It compresses abdominal contents and stabilizes the lumbar spine, providing core support. Unlike Rectus Abdominis (spinal flexion) or Obliques (rotation and flexion), the Transverse Abdominis focuses on stabilization. Psoas Major contributes to hip flexion rather than core stabilization, making Transverse Abdominis the only correct response.