Facial and Jaw Muscles Anatomy Quiz

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Questions and Answers

What is the primary action of the Supraspinatus muscle?

Retracts the scapula

Adducts the arm at the shoulder

Laterally rotates the humerus

Abducts the arm at the shoulder (correct)

Which muscle is responsible for protracting the scapula?

Levator scapulae

Serratus anterior (correct)

Rhomboideus major

Trapezius (middle)

Which muscle acts to flex the elbow and supinate the forearm?

Pronator teres

Triceps brachii

Brachialis

Biceps brachii (correct)

What is the insertion point of the Rectus femoris muscle?

Patella and tibial tuberosity Signup and view all the answers

What action does the Trapezius (upper) muscle perform?

Elevates the scapula Signup and view all the answers

What is the origin of the Soleus muscle?

Proximal third of tibia and fibula Signup and view all the answers

Which of the following muscles extends the knee?

Vastus intermedius Signup and view all the answers

Which muscle is involved in dorsiflexion and inversion at the ankle?

Tibialis anterior Signup and view all the answers

What action is performed by the Infraspinatus muscle?

Laterally rotates the humerus Signup and view all the answers

Which muscle primarily flexes the knee?

Biceps femoris Signup and view all the answers

Which muscle stabilizes the scapula during shoulder movements?

Rhomboideus major Signup and view all the answers

Which of the following muscles has its origin from T12 to L5 vertebral bodies?

Psoas major Signup and view all the answers

What is the primary action of the Diaphragm during breathing?

Lowers the thoracic cavity Signup and view all the answers

What is the action of the Orbicularis oculi muscle?

Closes eye and lowers eyebrows Signup and view all the answers

Where does the Zygomaticus major muscle originate?

Zygomatic bone Signup and view all the answers

Which muscle is responsible for elevating the mandible during chewing?

Temporalis Signup and view all the answers

What is the primary action of the Deltoid (anterior) muscle?

Flexes and medially rotates humerus at shoulder Signup and view all the answers

What is the insertion point of the Masseter muscle?

Mandible ramus and angle Signup and view all the answers

The Pectoralis major muscle primarily performs which action?

Flexion, adduction, and medial rotation of humerus Signup and view all the answers

What muscle is responsible for pulling the lower lip down?

Platysma Signup and view all the answers

Which muscle flexes the neck when both sides contract?

Sternocleidomastoid Signup and view all the answers

What action is performed by the Subscapularis muscle?

Medially rotates humerus at shoulder Signup and view all the answers

Where does the Frontalis muscle insert?

Skin of eyebrows Signup and view all the answers

Which muscle is primarily involved in compressing the cheeks?

Buccinator Signup and view all the answers

What is the origin of the Temporalis muscle?

Zygomatic arch and bone Signup and view all the answers

Which muscle extends and laterally rotates the humerus?

Deltoid (posterior) Signup and view all the answers

What action does the Sternocleidomastoid muscle perform when one side contracts?

Cocks the head Signup and view all the answers

Study Notes

Facial Expression Muscles

Orbicularis oculi: Closes the eye (squinting) and lowers the eyebrows. It originates from the frontal bone and maxilla and inserts on the eyelid.
Orbicularis oris: Closes the lips (pursing, protruding). It originates from the maxilla and mandible and inserts on the skin and muscle around the mouth.
Zygomaticus major: Raises the corners of the mouth (smiling). It originates from the zygomatic bone and inserts on the skin and muscle at the corner of the mouth.
Buccinator: Compresses the cheeks (whistling, sucking). It originates from the mandible and maxilla molar regions and inserts on the orbicularis oris.
Frontalis: Raises the eyebrows. It originates from the epicranial aponeurosis and inserts on the skin of the eyebrows.

Jaw Muscles

Masseter: Elevates the mandible (closing the mouth while chewing). It originates from the zygomatic arch and bone and inserts on the mandible ramus and angle.
Temporalis: Elevates the mandible, originating from the temporal, frontal, and parietal bones, and inserts on the coronoid process of the mandible.
Platysma: Pulls the lower lip down (frowning), and depresses the mandible (opening the mouth as when chewing or surprised). It originates from the pectoralis muscle and inserts on the mandible and skin of the lower face.

Neck Muscles

Sternocleidomastoid: When both sides are contracted, it flexes the neck (looking down). When one side is contracted, it cocks the head. It originates from the manubrium and clavicle and inserts on the mastoid process of the temporal bone.
Splenius capitis: When both sides are contracted, it extends the neck (looking up). When one side is contracted, it cocks the head. It originates from C7 to T3 (variable) and inserts on the nuchal line and mastoid process.

Shoulder Muscles

Deltoid (anterior): Flexes and medially rotates the humerus at the shoulder. It originates from the clavicle and inserts on the deltoid tuberosity of the humerus.
Deltoid (middle): Abducts the humerus at the shoulder (upward flap). It originates from the acromion and inserts on the deltoid tuberosity of the humerus.
Deltoid (posterior): Extends and laterally rotates the humerus at the shoulder. It originates from the scapular spine and inserts on the deltoid tuberosity of the humerus.
Pectoralis major: Flexes, adducts, and medially rotates the humerus at the shoulder (overhead fist raise, bench press motion). It originates from the sternum to rib 7 and the medial half of the clavicle and inserts on the intertubercular groove of the humerus.
Latissimus dorsi: Extends, adducts, and medially rotates the humerus at the shoulder (gym lat pull-downs). It originates from T7 to L5, ribs 10 to 12, and the iliac crest and inserts on the intertubercular groove of the humerus (the muscle travels under the axillary region).

Rotator Cuff Muscles

Subscapularis: Medially rotates the humerus at the shoulder. It originates from the subscapular fossa of the scapula and inserts on the lesser tubercle of the humerus.

Muscles Acting on the Shoulder

Supraspinatus: Originates from the supraspinous fossa of the scapula and inserts on the greater tubercle of the humerus. This muscle helps abduct (raise) the arm at the shoulder and stabilize the shoulder joint.
Infraspinatus: Originates from the infraspinous fossa of the scapula and inserts on the middle part of the greater tubercle of the humerus. It laterally rotates the humerus at the shoulder and contributes to shoulder joint stabilization.
Teres Minor: Originates from the lateral border of the scapula and inserts on the inferior part of the greater tubercle of the humerus. This muscle aids in laterally rotating the humerus at the shoulder and stabilizes the shoulder joint.
Levator Scapulae: Originates from the C1 to C4 vertebrae and inserts on the medial border of the scapula. This muscle elevates and retracts the scapula (shoulder blade), contributing to actions such as bringing the shoulder up towards the ear.
Rhomboideus Major: Originates from the T2 to T5 vertebrae and inserts on the medial border of the scapula. This muscle retracts (pulls back) the scapula, essential for pulling the shoulders together.
Serratus Anterior: Originates from ribs 1 to 9 and inserts on the anterior surface of the vertebral border of the scapula. It protracts (pushes forward) the scapula, used in actions like punching or hugging.
Trapezius:
- Upper Trapezius: Originates from the occipital bone and C1-C7 vertebrae and inserts on the lateral 1/3 of the clavicle and acromion process. It elevates the scapula, like during a shoulder shrug.
- Middle Trapezius: Originates from T1 to T5 vertebrae and inserts on the spine of the scapula. This part retracts the scapula, pulling the shoulders back.
- Lower Trapezius: Originates from T6 to T12 vertebrae and inserts on the medial 1/3 of the scapula spine. It retracts and depresses the scapula, aiding in pulling the shoulders back and down.

Muscles Acting on the Elbow

Brachialis: Originates from the anterior distal shaft of the humerus and inserts on the coronoid process of the ulna. This muscle flexes the elbow, bringing the forearm towards the upper arm, similar to bringing a spoon to the mouth.
Pronator Teres: Originates from the medial epicondyle of the humerus and the coronoid process of the ulna and inserts on the lateral midshaft of the radius. It pronates the forearm (rotates palm down), essential for turning a doorknob laterally.
Biceps Brachii:
- Long Head: Originates from the supraglenoid tubercle of the scapula and inserts on the radial tuberosity.
- Short Head: Originates from the coracoid process of the scapula and inserts on the radial tuberosity. This muscle is essential for flexing the elbow and supinating (rotating palm up) the forearm. It plays a role in scooping up water in the hand to drink.
Triceps Brachii:
- Long Head: Originates from the infraglenoid tubercle of the scapula.
- Lateral Head: Originates from the posterior proximal shaft of the humerus.
- Medial Head: Originates from the posterior distal shaft of the humerus. All heads insert on the olecranon of the ulna. This muscle extends the forearm at the elbow (straightening the arm), for example, lowering a spoon back to the table.

Muscles Acting on the Wrist

Extensor Carpi Radialis Brevis: Originates from the lateral epicondyle of the humerus and inserts on metacarpal III (base). This muscle extends the wrist and radially deviates (moves hand toward the thumb) the wrist.
Flexor Carpi Radialis: Originates from the medial epicondyle of the humerus and inserts on metacarpals II and III (base). This muscle flexes the wrist and radially deviates it.
Extensor Carpi Ulnaris: Originates from the lateral epicondyle of the humerus and the posterior shaft of the ulna and inserts on metacarpal V (base). This muscle extends the wrist and ulnarly deviates (moves hand toward the little finger) the wrist.
Flexor Carpi Ulnaris: Originates from the medial epicondyle of the humerus and inserts on the pisiform bone, hamate bone, and metacarpal V (base). This muscle flexes the wrist and ulnarly deviates it.
Extensor Digitorum: Originates from the lateral epicondyle of the humerus and inserts on the dorsal side of digits 2 to 5. This muscle extends the digits of the hand and the wrist.
Flexor Digitorum: Originates from the medial epicondyle of the humerus and inserts on the anterior side of digits 2 to 5. This muscle flexes the digits of the hand and the wrist.

Muscles Acting on the Vertebral Column

Spinalis Thoracis: Originates from T11 to L2 vertebrae and inserts on T3 to T7 vertebrae. This muscle causes lateral flexion (bending to the side) of the vertebral column when contracted on one side. When contracted bilaterally, it extends and hyperextends (extends beyond normal) the vertebral column.
Rectus Abdominis: Originates from the pubis crest and pubic symphysis (joint in the front of the pelvis) and inserts on the xiphoid process (projection at the bottom of the sternum) and costal cartilage 5 to 7. This muscle compresses the abdomen and flexes the vertebral column.

Muscles of Breathing

External Intercostals: Originate from the inferior border of the rib above and insert on the superior borders of the rib below. When they contract, they pull the ribs up towards their origin, elevating the ribcage and causing inspiration (inhaling).
Diaphragm: Shaped like a dome, it originates from the xiphoid process, ribs 10 to 12, costal cartilage 5 to 9, and lumbar vertebrae 1 to 5 and inserts on a central tendon. It contracts and drops down, enlarging the thoracic cavity and causing inspiration.

Muscles Acting at the Hip

Pectineus: Originates from the pubis and pubic ramus and inserts from the lesser trochanter to the superior part of the linea aspera of the femur. This muscle flexes the hip and adducts (brings towards the midline) the leg.
Adductor Longus: Originates from the superior ramus of the pubis and inserts on the linea aspera of the femur (shorter insertion than adductor magnus). It flexes the hip and adducts the leg.
Adductor Magnus: Originates from the inferior ischial ramus and inserts on the linea aspera of the femur. This muscle extends the hip, and adducts the leg.
Gluteus Maximus: Originates from the ilium, sacrum, and coccyx and inserts on the gluteal tuberosity of the femur. This muscle extends the hip (as in pushing down while climbing stairs), laterally rotates the leg and helps stabilize the hip joint.
Gracilis: Originates from the pubis and inserts on the medial aspect of the proximal tibia. This muscle adducts the leg at the hip and flexes the knee.
Tensor Fasciae Latae: Originates from the iliac crest near the anterior superior iliac spine and inserts on the lateral condyle of the tibia. It tenses and stabilizes the hip and knee joints, abducts the leg at the hip, and assists in rotating the thigh medially.
Psoas Major: Originates from vertebral bodies T12 to L5 and inserts on the lesser trochanter of the femur. This muscle flexes the hip (like lifting the leg to place on a stair).
Sartorius: Originates from the anterior superior iliac spine of the coxal bone and inserts on the medial aspect of the tibial tuberosity. This muscle flexes the hip, flexes the knee, and laterally rotates the thigh (into a cross-legged position).

Muscles that Flex the Knee

Biceps Femoris:
- Long Head: Originates from the ischial tuberosity.
- Short Head: Originates from the posterior mid-shaft of the femur. Both heads insert on the head of the fibula. This muscle extends the hip, flexes the knee, and laterally rotates the leg.
Semimembranosus: Originates from the ischial tuberosity and inserts on the posterior medial condyle of the tibia. This muscle extends the hip and flexes the knee.
Semitendinosus: Originates from the ischial tuberosity and inserts on the medial surface of the proximal tibia. This muscle extends the hip and flexes the knee.

Muscles that Extend the Knee

Vastus Lateralis: Originates from the greater trochanter, the lateral lip of the linea aspera, and wraps around to the anterior surface and inserts on the tibial tuberosity and patella. This muscle extends the knee.
Vastus Medialis: Originates from the intertrochanteric line, the medial lip of the linea aspera, and wraps around to the anterior surface and inserts on the tibial tuberosity and patella. This muscle extends the knee.
Vastus Intermedius: Originates from the anterior shaft of the femur and inserts on the tibial tuberosity and patella. This muscle extends the knee.
Rectus Femoris: Originates from the anterior inferior iliac spine of the coxal bone and inserts on the tibial tuberosity and patella. This muscle extends the knee and flexes the hip (such as when kicking a ball).

Muscles Acting on the Ankle

Soleus: Originates from the proximal third of the tibia and fibula and inserts on the calcaneus (heel bone). This muscle plantar flexes (points toes down) the ankle.
Gastrocnemius: Originates from the medial and lateral epicondyles of the femur and inserts on the calcaneus. This muscle plantar flexes the ankle and flexes the knee.
Tibialis Anterior: Originates from the lateral condyle and antero-lateral surface of the tibia and inserts on the medial cuneiform bone, under metatarsal 1. This muscle dorsiflexes (flexes foot upwards) and inverts (turns sole inward) the ankle.

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Description

Test your knowledge about the key facial and jaw muscles, including their functions, origins, and insertions. This quiz dives into the anatomy of muscles responsible for expressions and chewing. See how well you understand the role of these muscles in human anatomy.