Anatomy of Temporalis Muscle

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Questions and Answers

The Temporalis muscle originates from which of the following?

Temporal fossa and infratemporal crest

Superior temporal line and temporal fascia (correct)

Zygomatic arch

Temporal bone

What is the function of the anterior fibers of the Temporalis muscle?

Retraction of the mandible

Protraction of the mandible

Elevation of the mandible (correct)

Lateral movement of the mandible

Which nerve innervates the Temporalis muscle?

Trigeminal nerve

Facial nerve

Deep temporal nerves (correct)

Olfactory nerve

What is the insertion point of the Temporalis muscle?

Coronoid process of the mandible Signup and view all the answers

What is the function of the middle fibers of the Temporalis muscle?

Elevation and retraction of the mandible Signup and view all the answers

What is the blood supply to the Temporalis muscle?

Deep temporal arteries Signup and view all the answers

What is the action of bilateral contraction of the Temporalis muscle?

Elevation and retraction of the mandible Signup and view all the answers

What is the action of unilateral contraction of the Temporalis muscle?

Lateral movement of the mandible Signup and view all the answers

Which of the following muscles of mastication is responsible for moving the mandible?

Masseter muscle Signup and view all the answers

Which muscle fills the temporal fossa?

Temporalis muscle Signup and view all the answers

Which muscle conveys its fibers to the CORONOID PROCESS of the mandible?

Temporalis muscle Signup and view all the answers

Which of the following muscles of mastication is derived from the second branchial arch?

Facial muscle Signup and view all the answers

Which muscle is NOT a muscle of mastication?

Stylohyoid muscle Signup and view all the answers

Which muscle is a derivative of the first branchial arch?

Lateral Pterygoid muscle Signup and view all the answers

Which muscle is responsible for moving the mandible in a lateral direction?

Lateral Pterygoid muscle Signup and view all the answers

Which of the following muscles is a wide, flat, and fan-shaped muscle?

Temporalis muscle Signup and view all the answers

What is the shape of the masseter muscle?

Quadrangular Signup and view all the answers

Which part of the masseter muscle originates from the maxillary process of the zygomatic bone?

Superficial layer Signup and view all the answers

What is the insertion point of the middle layer of the masseter muscle?

Central part of the lateral surface of the ramus of the mandible Signup and view all the answers

What is the function of the masseteric fascia?

It covers the masseter muscle and attaches to the zygomatic arch and mandible Signup and view all the answers

Which muscle is associated with the deep layer of the masseter muscle?

Temporalis Signup and view all the answers

What is the origin of the deep layer of the masseter muscle?

Medial surface of the posterior 1/3 of the zygomatic arch Signup and view all the answers

Which part of the masseter muscle is quadrangular in shape?

The entire masseter muscle Signup and view all the answers

What is the function of the superficial temporal arteries?

Irrigate the temporal fascia Signup and view all the answers

Study Notes

Temporalis Muscle

Strong membranous sheet of fascia: superior temporal line, zygomatic arch (two layers: lateral and medial border)
Origin: • Superficial portion: temporal fascia, superior temporal line • Deep portion: temporal fossa (inferior temporal line and infratemporal crest)
Insertion: • Fibers converge inferior to form a common tendon • Fibers pass between the zygomatic arch and the infratemporal crest (zygomatic canal) • Fibers insert on the coronoid process of the mandible and anterior margin of ramus
Divided into 3 portions based on the direction of the fibers: • Anterior: verticals, from the anterior portion of the temporal fossa (agonists of the masseter muscle) • Middle: from the wide area in the middle of the temporal fossa, oblique direction toward inferior and anterior • Posterior: from the posterior part of the temporal fossa, horizontals
Actions: • Bilateral contraction:
- Anterior fibers: elevation of the mandible
- Posterior fibers: retraction of the mandible
- Middle fibers: elevation and retraction of the mandible • Unilateral contraction: lateral movement (side-to-side grinding movements) towards the same side
Innervation: deep temporal nerves, mandibular nerve, V3 branch of the trigeminal nerve
Vascularization: deep temporal arteries, branches of maxillary artery (pterygoid portion), itself a branch of external carotid artery

Masseter Muscle

Powerful muscle of mastication
Quadrangular in shape
Overlies the lateral surface of the ramus of the mandible until the zygomatic arch
3 portions: superficial, middle, and deep
Superficial layer: • Origin: thick aponeurosis from maxillary process of the zygomatic bone and from the anterior 2/3 of the inferior and lateral border of the zygomatic arch • Insertion: angle and inferior posterior half of the lateral surface of the ramus of the mandible (tendinous septa and bone ridges)
Middle layer: • Origin: medial anterior 2/3 of the zygomatic arch and lower border of the posterior third of this arch • Insertion: central part of the lateral surface of the ramus of the mandible
Deep layer: • Origin: medial surface of the posterior 1/3 of the zygomatic arch • Insertion: superior and lateral part of the mandibular ramus and coronoid process (some of its fibers associate with the superficial part of the temporalis muscle)

Masseteric Fascia

Strong layer of fascia derived from the deep cervical fascia of the neck
Covers the masseter
Attached to the lower border of the zygomatic arch and to the posterior, inferior, and anterior border of the mandible
Invests the parotid gland and Stensen's duct

Branchial Arches

Muscles derived from the first branchial arch: • Mastication muscles (temporalis, masseter, lateral pterygoid, and medial pterygoid) • Mylohyoid muscle • Digastric muscle, anterior belly • Tensor veli palatini muscle • Tensor tympani muscle
Muscles derived from the second branchial arch: • Facial muscles • Stylohyoid muscle • Digastric muscle, posterior belly • Stapedius muscle

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Description

This quiz covers the anatomy of the temporalis muscle, including its origin, insertion, and functional significance. It also explores the surrounding fascia and bones.