Head and Neck Muscle Anatomy – Masticatory, Facial-Expression & Cervical Muscles

Question-and-answer flashcards covering origins, insertions, and actions of muscles of mastication, facial expression, and neck (suprahyoid, infrahyoid, lateral, posterior).

Which muscle originates from the temporal fossa and inserts on the coronoid process of the mandible?

The temporalis muscle.

What is the primary action of the temporalis muscle?

Elevation of the mandible.

From which bony structures does the superficial masseter arise?

The zygomatic bone and zygomatic arch.

Where does the masseter insert?

On the ramus and angle of the mandible.

What is the chief action of the masseter muscle?

Elevation of the mandible.

Which cheek muscle compresses food against the teeth during chewing?

The buccinator.

Name the two pterygoid muscles that assist in mastication but are not visible on the surface models.

The lateral pterygoid and medial pterygoid.

Which muscle of facial expression raises the eyebrows via the epicranial aponeurosis?

Frontal belly of the occipitofrontalis.

What ring-shaped muscle surrounds the eye and enables blinking and squinting?

Orbicularis oculi.

Which facial muscle elevates the upper lip directly beneath the orbicularis oculi?

Levator labii superioris.

Which muscle pulls the upper lip upward and backward, aiding smiling?

Zygomaticus minor.

What is the principal smiling muscle that draws the mouth angle upward and backward?

Zygomaticus major.

Which muscle draws the mouth corners laterally producing a grimace?

Risorius.

Which muscle pulls the angle of the mouth downward (frown)?

Depressor anguli oris (triangularis).

Name the muscle that pulls the lower lip downward.

Depressor labii inferioris.

Which chin muscle protrudes the lower lip (pouting)?

Mentalis.

Which sphincter muscle encircles the mouth and closes the lips?

Orbicularis oris.

Which muscle compresses the nasal cartilages transversely?

Transverse nasalis.

Which small muscle moves the ear and overlying skin forward?

Auricularis anterior.

Which auricular muscle elevates the ear?

Auricularis superior.

Which auricular muscle retracts the ear?

Auricularis posterior.

Which large paired neck muscle originates from the manubrium and clavicle and inserts on the mastoid process?

Sternocleidomastoid (SCM).

Name the three scalene muscles of the lateral neck.

Anterior scalene, middle scalene, and posterior scalene.

What are the two main functions of the scalene group?

Flexing the neck and assisting in inhalation.

Which posterior neck muscle elevates the scapula?

Levator scapulae.

Which two deep posterior neck muscles assist neck extension?

Splenius capitis and semispinalis capitis.

Which broad superficial back muscle helps extend the neck and elevate the scapula?

Trapezius (descending fibers).

Which thin superficial muscle spans the anterior neck and assists in depressing the mandible?

Platysma.

What is the common action of all suprahyoid muscles?

Elevation of the hyoid bone (except the anterior digastric can also depress the mandible if the hyoid is fixed).

Name the two bellies of the digastric muscle.

Anterior belly and posterior belly.

Which suprahyoid muscle forms the floor of the mouth and elevates the hyoid?

Mylohyoid.

Which short suprahyoid muscle lies above the mylohyoid and helps elevate the hyoid?

Geniohyoid.

Which slender muscle passes from the styloid process to the hyoid to elevate it?

Stylohyoid.

What is the shared function of the infrahyoid muscles?

Depressing the hyoid bone.

List the two bellies of the omohyoid muscle.

Superior belly and inferior belly.

Which infrahyoid muscle runs from the manubrium to the hyoid bone?

Sternohyoid.

Which infrahyoid muscle runs from the sternum to the thyroid cartilage?

Sternothyroid.

How do the movements of the hyoid bone contribute to voice production?

Elevation and depression of the hyoid play a role in phonation by adjusting laryngeal position.

What is the primary action of the lateral pterygoid muscle?

Protrusion and depression of the mandible, as well as lateral excursion (moving the jaw side to side).

What is the primary action of the medial pterygoid muscle?

Elevation and protrusion of the mandible, and also assists in lateral excursion.

What action does the sternocleidomastoid muscle perform when contracting unilaterally?

When contracting unilaterally, it causes lateral flexion of the neck to the same side and rotation of the head to the opposite side.

What action does the sternocleidomastoid muscle perform when contracting bilaterally?

Flexion of the neck.

How do the scalene muscles assist in inhalation?

elevates the first two ribs.

Apart from elevating the hyoid, what is another significant action of the anterior belly of the digastric muscle?

Depression of the mandible when the hyoid is fixed.

What nerve innervates the anterior belly of the digastric muscle?

The trigeminal nerve (through the mylohyoid nerve).

What nerve innervates the posterior belly of the digastric muscle?

The facial nerve.