Exercise 13 Muscles of the Head and Neck

Exercise 13: Muscles of the Head and Neck

Page 1: Overview

  • Introduction to the muscular structures of the head and neck.

Page 2: Overview of Muscles of Head

  • Outlines major muscular structures focusing on functions and innervation.

Page 3: Muscles of Facial Expression

  • Purpose: Movements that alter facial expressions by moving the skin of head and face.

  • Key Features: Insertion in the skin allows for fine movements; innervated mainly by the Facial Nerve (Cranial Nerve VII).

Page 4: Table 13.1 Muscles of Facial Expression

Scalp

  • Epicranius:

    • Occipitalis: Retracts scalp

      • Origin: Superior nuchal line and temporal bone

      • Insertion: Galea aponeurosis

      • Innervation: Cranial Nerve VII (Facial Nerve)

    • Frontalis: Elevates eyebrows

      • Origin: Galea aponeurosis

      • Insertion: Subcutaneous tissue of eyebrows

      • Innervation: Cranial Nerve VII

Nasal Region

  • Nasalis: Widens nostrils

    • Origin: Maxilla just lateral to nose

    • Insertion: Bridge and alar cartilage of nose

    • Innervation: Cranial Nerve VII

Oral Region (Mouth)

  • Orbicularis Oris: Encircles mouth, closes lips

    • Origin: Maxilla and mandible

    • Insertion: Skin and muscles around the mouth

    • Innervation: Cranial Nerve VII

  • Levator Labii Superioris: Elevates upper lip

    • Origin: Maxilla below infraorbital foramen

    • Insertion: Muscles of upper lip

    • Innervation: Cranial Nerve VII

  • Zygomaticus Major and Minor: Draws angle of mouth upward in smiling

    • Origin: Zygomatic bone

    • Insertion: Upper lip muscles

    • Innervation: Cranial Nerve VII

  • Risorius: Draws angles of the mouth laterally in laughing

    • Origin: Zygomatic arch

    • Insertion: Skin at angle of mouth

    • Innervation: Cranial Nerve VII

  • Depressor Anguli Oris: Draws mouth down

    • Origin: Inferior margin of mandibular body

    • Insertion: Skin at inferior corner of angle of mouth

    • Innervation: Cranial Nerve VII

  • Depressor Labii Inferioris: Draws lower lip downward

    • Origin: Body of mandible lateral to midline

    • Insertion: Skin of inferior lip

    • Innervation: Cranial Nerve VII

Eye

  • Orbicularis Oculi: Closes eye during sleep, blinking, squinting

    • Origin: Median wall of the orbit of the eye

    • Insertion: Skin surrounding eyelids

    • Innervation: Cranial Nerve VII

  • Levator Palpebrae Superioris: Elevates upper eyelid

    • Origin: Lesser wing of sphenoid

    • Innervation: Cranial Nerve III (Oculomotor Nerve)

Neck, Cheek, and Chin

  • Platysma: Draws lip and angle of mouth downward

    • Origin: Fascia of deltoid and pectoralis major

    • Insertion: Skin of cheek and mandible

    • Innervation: Cranial Nerve VII

  • Buccinator: Compresses cheek, holding food between teeth during chewing

    • Origin: Alveolar process of maxilla and mandible

    • Insertion: Orbicularis oris

    • Innervation: Cranial Nerve VII

  • Mentalis: Protrudes lower lip, wrinkles chin

    • Origin: Central mandible

    • Insertion: Skin of chin

    • Innervation: Cranial Nerve VII

Page 5: Muscles of Facial Expression (Illustration)

  • Diagram: Visuals include the Epicranius, Buccinator, and other facial muscles.

Page 6-9: Muscles and Functions

  • Frontalis, Orbicularis Oculi, Zygomaticus Major and Minor: Reiteration of origins, insertions, and main functions.

Page 10: Epicranius Overview

  • Structure: Covers the front, top, and back of the skull featuring Frontalis, Occipitalis, and Galea Aponeurosis.

Page 36: Muscles of Mastication

  • Function: Chewing action facilitated by different muscles.

  • Key Muscles: Temporalis, Masseter, Medial Pterygoid, and Lateral Pterygoid, with specific actions, origins, insertions, and innervations all focused on by the Trigeminal Nerve (Cranial Nerve V).

Page 49: Muscles of the Neck

  • Key Muscle: Sternocleidomastoid and its role in neck movements.

Page 70: Table 13.5 Hyoid Muscle Group

Suprahyoid and Infrahyoid Muscles

  • Suprahyoid: Elevates the hyoid bone and larynx during swallowing and speaking.

  • Infrahyoid: Depresses hyoid bone and thyroid cartilage.

Page 83: Muscles that Move and Support the Head

  • Flexors: Sternocleidomastoid and Scalenes. Key functions include neck flexion and lateral movement.

  • Extensors: Trapezius, Splenius with posterior rami innervation to maintain head posture.

Page 85-101: Illustrations and Practical Exam Preparation

  • Muscles visualized from multiple angles for anatomical understanding.

  • Review of key cranial nerves:

    • Facial Nerve (VII) for facial expression

    • Trigeminal Nerve (V) for mastication.

Practical Exam Practice

  • Identification of specific muscles from diagrams and descriptions.

More detailed notes

Exercise 13: Muscles of the Head and Neck

Page 1: Overview

  • Introduction to the Muscular Structures: The head and neck contain intricate muscular systems that play crucial roles in facial expressions, mastication (chewing), and movements of the neck. Understanding these muscles is vital for recognizing how they contribute to human anatomy and function.

Page 2: Overview of Muscles of the Head

  • Major Muscular Structures: This section outlines the key muscular structures of the head, emphasizing their functions, innervation patterns, and clinical significance. Each muscle's role is examined with insights into how they facilitate movement and expression.

Page 3: Muscles of Facial Expression

  • Purpose: These muscles are primarily responsible for movements that alter facial expressions by maneuvering the skin covering the face and head. They enable diverse expressions that convey emotions such as happiness, sadness, anger, and surprise.

  • Key Features: Unique to these muscles is their insertion in the skin, allowing fine control over facial movements. They are predominantly innervated by the Facial Nerve (Cranial Nerve VII), which can be clinically significant, especially in cases of nerve damage.

Page 4: Table 13.1 Muscles of Facial Expression

Scalp

  • Epicranius (Frontalis and Occipitalis):

    • Occipitalis: Functions to retract the scalp, allowing slight movement of the hair.

      • Origin: Superior nuchal line and temporal bone.

      • Insertion: Galea aponeurosis.

      • Innervation: Cranial Nerve VII (Facial Nerve).

    • Frontalis: Elevates the eyebrows and causes wrinkling of the forehead.

      • Origin: Galea aponeurosis.

      • Insertion: Subcutaneous tissue of the eyebrows.

      • Innervation: Cranial Nerve VII.

Nasal Region

  • Nasalis: A key muscle that functions to widen the nostrils, assisting in respiration and facial expressions.

    • Origin: Maxilla just lateral to the nose.

    • Insertion: Bridge and alar cartilage of the nose.

    • Innervation: Cranial Nerve VII.

Oral Region (Mouth)

  • Orbicularis Oris: Encircles the mouth and is vital for closing the lips during speaking and eating.

    • Origin: Maxilla and mandible.

    • Insertion: Skin and muscles surrounding the mouth.

    • Innervation: Cranial Nerve VII.

  • Levator Labii Superioris: Elevates the upper lip, assisting in expressions of disgust.

    • Origin: Maxilla below the infraorbital foramen.

    • Insertion: Muscles of the upper lip.

    • Innervation: Cranial Nerve VII.

  • Zygomaticus Major and Minor: Responsible for smiling, drawing the angle of the mouth upwards.

    • Origin: Zygomatic bone.

    • Insertion: Muscles of the upper lip.

    • Innervation: Cranial Nerve VII.

  • Risorius: Draws the angles of the mouth laterally, contributing to expressions of laughter.

    • Origin: Zygomatic arch.

    • Insertion: Skin at the angle of the mouth.

    • Innervation: Cranial Nerve VII.

  • Depressor Anguli Oris: Depresses the angle of the mouth, indicative of sadness.

    • Origin: Inferior margin of the body of the mandible.

    • Insertion: Skin at the inferior corner of the angle of the mouth.

    • Innervation: Cranial Nerve VII.

  • Depressor Labii Inferioris: Draws the lower lip downward, adding to negative expressions.

    • Origin: Body of the mandible lateral to the midline.

    • Insertion: Skin of the inferior lip.

    • Innervation: Cranial Nerve VII.

Eye

  • Orbicularis Oculi: Essential for closing the eye during sleep, blinking, and squinting, protecting the eye from debris and excessive light.

    • Origin: Median wall of the orbit.

    • Insertion: Skin surrounding eyelids.

    • Innervation: Cranial Nerve VII.

  • Levator Palpebrae Superioris: Functions to elevate the upper eyelid, crucial for opening the eye.

    • Origin: Lesser wing of the sphenoid.

    • Innervation: Cranial Nerve III (Oculomotor Nerve).

Neck, Cheek, and Chin

  • Platysma: Thin muscle that draws the lip and angle of the mouth downward, indicative of tension or distress.

    • Origin: Fascia of deltoid and pectoralis major.

    • Insertion: Skin of the cheek and mandible.

    • Innervation: Cranial Nerve VII.

  • Buccinator: Important for compressing the cheek, helping to hold food between teeth during chewing.

    • Origin: Alveolar process of maxilla and mandible.

    • Insertion: Orbicularis oris.

    • Innervation: Cranial Nerve VII.

  • Mentalis: Protrudes the lower lip and creates a wrinkle in the chin, often associated with doubt or contempt.

    • Origin: Central mandible.

    • Insertion: Skin of the chin.

    • Innervation: Cranial Nerve VII.

Page 5: Muscles of Facial Expression (Illustration)

  • Diagram: Visual representations include labeled diagrams of the Epicranius, Buccinator, and other key facial muscles to facilitate anatomical understanding.

Page 6-9: Muscles and Functions

  • Detailed Descriptions: This section offers a detailed reiteration of origins, insertions, and primary functions of critical muscles such as Frontalis, Orbicularis Oculi, and the Zygomaticus group, along with relevant clinical implications.

Page 10: Epicranius Overview

  • Structure: Composed of the Frontalis, Occipitalis, and the Galea Aponeurosis, this muscle covers the front, top, and back of the skull, playing a fundamental role in scalp and brow movements.

Page 36: Muscles of Mastication

  • Function: Involved in the process of chewing, allowing for the grinding and tearing of food using various muscle groups.

  • Key Muscles: Primarily the Temporalis, Masseter, Medial Pterygoid, and Lateral Pterygoid, which are all innervated by the Trigeminal Nerve (Cranial Nerve V). Each muscle has a unique action that contributes to the complex movements required for effective mastication.

Page 49: Muscles of the Neck

  • Key Muscle: The Sternocleidomastoid, which plays a pivotal role in rotating and flexing the neck, allowing for a wide range of head movements.

Page 70: Table 13.5 Hyoid Muscle Group

  • Suprahyoid Muscles: Elevate the hyoid bone and larynx during swallowing and speaking, facilitating vocalization and safe swallowing.

  • Infrahyoid Muscles: Depress the hyoid bone and thyroid cartilage, contributing to the stabilization of the larynx during speech and swallowing.

Page 83: Muscles that Move and Support the Head

  • Flexors: Include Sternocleidomastoid and Scalenes, key for neck flexion and lateral movement, enhancing the range of motion and stability of the head.

  • Extensors: Composed of the Trapezius and Splenius; these muscles are responsible for maintaining head posture and extending the neck, vital for posture and balance.

Page 85-101: Illustrations and Practical Exam Preparation

  • Muscle Visualization: Detailed illustrations depict muscles from various angles to enhance anatomical understanding and retention.

  • Review of Key Cranial Nerves:

    • Facial Nerve (VII): Responsible for facial expressions.

    • Trigeminal Nerve (V): Critical for mastication.

  • Practical Exam Practice: Utilizes diagrams and descriptions for the identification of specific muscles, aiding in preparation for practical evaluations in anatomy courses.