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Anatomy & Physiology 2e: 11.4 Axial Muscles of the Head Neck and Back

Anatomy & Physiology 2e
11.4 Axial Muscles of the Head Neck and Back
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table of contents
  1. Cover
  2. Title Page
  3. Copyright
  4. Table Of Contents
  5. Chapter 1. An Introduction to the Human Body
    1. 1.0 Introduction
    2. 1.1 How Structure Determines Function
    3. 1.2 Structural Organization of the Human Body
    4. 1.3 Homeostasis
    5. 1.4 Anatomical Terminology
    6. 1.5 Medical Imaging
  6. Chapter 2. The Chemical Level of Organization
    1. 2.0 Introduction
    2. 2.1 Elements and Atoms: The Building Blocks of Matter
    3. 2.2 Chemical Bonds
    4. 2.3 Chemical Reactions
    5. 2.4 Inorganic Compounds Essential to Human Functioning
    6. 2.5 Organic Compounds Essential to Human Functioning
  7. Chapter 3. The Cellular Level of Organization
    1. 3.0 Introduction
    2. 3.1 The Cell Membrane
    3. 3.2 The Cytoplasm and Cellular Organelles
    4. 3.3 The Nucleus and DNA Replication
    5. 3.4 Protein Synthesis
    6. 3.5 Cell Growth and Division
    7. 3.6 Cellular Differentiation
  8. Chapter 4. The Tissue Level of Organization
    1. 4.0 Introduction
    2. 4.1 Types of Tissues
    3. 4.2 Epithelial Tissue
    4. 4.3 Connective Tissue Supports and Protects
    5. 4.4 Muscle Tissue
    6. 4.5 Nervous Tissue
    7. 4.6 Tissue Injury and Aging
  9. Chapter 5. The Integumentary System
    1. 5.0 Introduction
    2. 5.1 Layers of the Skin
    3. 5.2 Accessory Structures of the Skin
    4. 5.3 Functions of the Integumentary System
    5. 5.4 Diseases, Disorders, and Injuries of the Integumentary System
  10. Chapter 6. Bone Tissue and the Skeletal System
    1. 6.0 Introduction
    2. 6.1 The Functions of the Skeletal System
    3. 6.2 Bone Classification
    4. 6.3 Bone Structure
    5. 6.4 Bone Formation and Development
    6. 6.5 Fractures: Bone Repair
    7. 6.6 Exercise, Nutrition, Hormones, and Bone Tissue
    8. 6.7 Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems
  11. Chapter 7. Axial Skeleton
    1. 7.0 Introduction
    2. 7.1 Divisions of the Skeletal System
    3. 7.2 Bone Markings
    4. 7.3 The Skull
    5. 7.4 The Vertebral Column
    6. 7.5 The Thoracic Cage
    7. 7.6 Embryonic Development of the Axial Skeleton
  12. Chapter 8. The Appendicular Skeleton
    1. 8.0 Introduction
    2. 8.1 The Pectoral Girdle
    3. 8.2 Bones of the Upper Limb
    4. 8.3 The Pelvic Girdle and Pelvis
    5. 8.4 Bones of the Lower Limb
    6. 8.5 Development of the Appendicular Skeleton
  13. Chapter 9. Joints
    1. 9.0 Introduction
    2. 9.1 Classification of Joints
    3. 9.2 Fibrous Joints
    4. 9.3 Cartilaginous Joints
    5. 9.4 Synovial Joints
    6. 9.5 Types of Body Movements
    7. 9.6 Anatomy of Selected Synovial Joints
    8. 9.7 Development of Joints
  14. Chapter 10. Muscle Tissue
    1. 10.0 Introduction
    2. 10.1 Overview of Muscle Tissues
    3. 10.2 Skeletal Muscle
    4. 10.3 Muscle Fiber Excitation, Contraction, and Relaxation
    5. 10.4 Nervous System Control of Muscle Tension
    6. 10.5 Types of Muscle Fibers
    7. 10.6 Exercise and Muscle Performance
    8. 10.7 Smooth Muscle Tissue
    9. 10.8 Development and Regeneration of Muscle Tissue
  15. Chapter 11. The Muscular System
    1. 11.0 Introduction
    2. 11.1 Describe the roles of agonists, antagonists and synergists
    3. 11.2 Explain the organization of muscle fascicles and their role in generating force
    4. 11.3 Explain the criteria used to name skeletal muscles
    5. 11.4 Axial Muscles of the Head Neck and Back
    6. 11.5 Axial muscles of the abdominal wall and thorax
    7. 11.6 Muscles of the Pectoral Girdle and Upper Limbs
    8. 11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs
  16. Chapter 12. The Nervous System and Nervous Tissue
    1. 12.0 Introduction
    2. 12.1 Structure and Function of the Nervous System
    3. 12.2 Nervous Tissue
    4. 12.3 The Function of Nervous Tissue
    5. 12.4 Communication Between Neurons
    6. 12.5 The Action Potential
  17. Chapter 13. The Peripheral Nervous System
    1. 13.0 Introduction
    2. 13.1 Sensory Receptors
    3. 13.2 Ganglia and Nerves
    4. 13.3 Spinal and Cranial Nerves
    5. 13.4 Relationship of the PNS to the Spinal Cord of the CNS
    6. 13.5 Ventral Horn Output and Reflexes
    7. 13.6 Testing the Spinal Nerves (Sensory and Motor Exams)
    8. 13.7 The Cranial Nerve Exam
  18. Chapter 14. The Central Nervous System
    1. 14.0 Introduction
    2. 14.1 Embryonic Development
    3. 14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation
    4. 14.3 The Brain and Spinal Cord
    5. 14.4 The Spinal Cord
    6. 14.5 Sensory and Motor Pathways
  19. Chapter 15. The Special Senses
    1. 15.0 Introduction
    2. 15.1 Taste
    3. 15.2 Smell
    4. 15.3 Hearing
    5. 15.4 Equilibrium
    6. 15.5 Vision
  20. Chapter 16. The Autonomic Nervous System
    1. 16.0 Introduction
    2. 16.1 Divisions of the Autonomic Nervous System
    3. 16.2 Autonomic Reflexes and Homeostasis
    4. 16.3 Central Control
    5. 16.4 Drugs that Affect the Autonomic System
  21. Chapter 17. The Endocrine System
    1. 17.0 Introduction
    2. 17.1 An Overview of the Endocrine System
    3. 17.2 Hormones
    4. 17.3 The Pituitary Gland and Hypothalamus
    5. 17.4 The Thyroid Gland
    6. 17.5 The Parathyroid Glands
    7. 17.6 The Adrenal Glands
    8. 17.7 The Pineal Gland
    9. 17.8 Gonadal and Placental Hormones
    10. 17.9 The Pancreas
    11. 17.10 Organs with Secondary Endocrine Functions
    12. 17.11 Development and Aging of the Endocrine System
  22. Chapter 18. The Cardiovascular System: Blood
    1. 18.0 Introduction
    2. 18.1 Functions of Blood
    3. 18.2 Production of the Formed Elements
    4. 18.3 Erythrocytes
    5. 18.4 Leukocytes and Platelets
    6. 18.5 Hemostasis
    7. 18.6 Blood Typing
  23. Chapter 19. The Cardiovascular System: The Heart
    1. 19.0 Introduction
    2. 19.1 Heart Anatomy
    3. 19.2 Cardiac Muscle and Electrical Activity
    4. 19.3 Cardiac Cycle
    5. 19.4 Cardiac Physiology
    6. 19.5 Development of the Heart
  24. Chapter 20. The Cardiovascular System: Blood Vessels and Circulation
    1. 20.0 Introduction
    2. 20.1 Structure and Function of Blood Vessels
    3. 20.2 Blood Flow, Blood Pressure, and Resistance
    4. 20.3 Capillary Exchange
    5. 20.4 Homeostatic Regulation of the Vascular System
    6. 20.5 Circulatory Pathways
    7. 20.6 Development of Blood Vessels and Fetal Circulation
  25. Chapter 21. The Lymphatic and Immune System
    1. 21.0 Introduction
    2. 21.1 Anatomy of the Lymphatic and Immune Systems
    3. 21.2 Barrier Defenses and the Innate Immune Response
    4. 21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types
    5. 21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies
    6. 21.5 The Immune Response against Pathogens
    7. 21.6 Diseases Associated with Depressed or Overactive Immune Responses
    8. 21.7 Transplantation and Cancer Immunology
  26. Chapter 22. The Respiratory System
    1. 22.0 Introduction
    2. 22.1 Organs and Structures of the Respiratory System
    3. 22.2 The Lungs
    4. 22.3 The Process of Breathing
    5. 22.4 Gas Exchange
    6. 22.5 Transport of Gases
    7. 22.6 Modifications in Respiratory Functions
    8. 22.7 Embryonic Development of the Respiratory System
  27. Chapter 23. The Digestive System
    1. 23.0 Introduction
    2. 23.1 Overview of the Digestive System
    3. 23.2 Digestive System Processes and Regulation
    4. 23.3 The Mouth, Pharynx, and Esophagus
    5. 23.4 The Stomach
    6. 23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder
    7. 23.6 The Small and Large Intestines
    8. 23.7 Chemical Digestion and Absorption: A Closer Look
  28. Chapter 24. Metabolism and Nutrition
    1. 24.0 Introduction
    2. 24.1 Overview of Metabolic Reactions
    3. 24.2 Carbohydrate Metabolism
    4. 24.3 Lipid Metabolism
    5. 24.4 Protein Metabolism
    6. 24.5 Metabolic States of the Body
    7. 24.6 Energy and Heat Balance
    8. 24.7 Nutrition and Diet
  29. Chapter 25. The Urinary System
    1. 25.0 Introduction
    2. 25.1 Internal and External Anatomy of the Kidney
    3. 25.2 Microscopic Anatomy of the Kidney: Anatomy of the Nephron
    4. 25.3 Physiology of Urine Formation: Overview
    5. 25.4 Physiology of Urine Formation: Glomerular Filtration
    6. 25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion
    7. 25.6 Physiology of Urine Formation: Medullary Concentration Gradient
    8. 25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition
    9. 25.8 Urine Transport and Elimination
    10. 25.9 The Urinary System and Homeostasis
  30. Chapter 26. Fluid, Electrolyte, and Acid-Base Balance
    1. 26.0 Introduction
    2. 26.1 Body Fluids and Fluid Compartments
    3. 26.2 Water Balance
    4. 26.3 Electrolyte Balance
    5. 26.4 Acid-Base Balance
    6. 26.5 Disorders of Acid-Base Balance
  31. Chapter 27. The Sexual Systems
    1. 27.0 Introduction
    2. 27.1 Anatomy of Sexual Systems
    3. 27.2 Development of Sexual Anatomy
    4. 27.3 Physiology of the Female Sexual System
    5. 27.4 Physiology of the Male Sexual System
    6. 27.5 Physiology of Arousal and Orgasm
  32. Chapter 28. Development and Inheritance
    1. 28.0 Introduction
    2. 28.1 Fertilization
    3. 28.2 Embryonic Development
    4. 28.3 Fetal Development
    5. 28.4 Maternal Changes During Pregnancy, Labor, and Birth
    6. 28.5 Adjustments of the Infant at Birth and Postnatal Stages
    7. 28.6 Lactation
    8. 28.7 Patterns of Inheritance
  33. Creative Commons License
  34. Recommended Citations
  35. Versioning

11.4 Axial Muscles of the Head Neck and Back

Learning Objectives

By the end of this section, you will be able to:

Identify the following muscles and give their origins, insertions, actions and innervations:

  • Axial muscles of the head neck and back

The skeletal muscles are divided into axial (muscles of the trunk and head) and appendicular (muscles of the arms and legs) categories. This system reflects the bones of the skeleton system, which are also arranged in this manner. Some of the axial muscles may seem to blur the boundaries because they cross over to the appendicular skeleton. The first grouping of the axial muscles you will review includes the muscles of the head and neck, then you will review the muscles of the vertebral column, and finally you will review the oblique and rectus muscles.

AXIAL MUSCLES OF THE HEAD NECK AND BACK

Muscles of Facial Expression

The muscles of facial expression originate from the surface of the skull or the fascia (connective tissue) of the face. The insertions of these muscles have fibers intertwined with connective tissue and the dermis of the skin. Because the muscles insert in the skin rather than on bone, when they contract, the skin moves to create facial expression (Figure 11.4.1).

The left panel in this figure shows the anterior view of the facial muscles, and the right panel shows the lateral view.
Figure 11.4.1 – Muscles of Facial Expression: Many of the muscles of facial expression insert into the skin surrounding the eyelids, nose and mouth, producing facial expressions by moving the skin rather than bones.

The orbicularis oris is a circular muscle that moves the lips, and the orbicularis oculi is a circular muscle that closes the eye. The occipitofrontalis muscle elevates the scalp and eyebrows. The muscle has a frontal belly and an occipital belly (near the occipital bone on the posterior part of the skull). In other words, there is a muscle on the forehead (frontalis) and one on the back of the head (occipitals). The two bellies are connected by a broad tendon called the epicranial aponeurosis, or galea aponeurosis (galea = “apple”). The physicians originally studying human anatomy thought the skull looked like an apple.

The buccinator muscle compresses the cheek. This muscle allows you to whistle, blow, and suck; and it contributes to the action of chewing. There are several small facial muscles, one of which is the corrugator supercilii, which is the prime mover of the eyebrows. Place your finger on your eyebrows at the point of the bridge of the nose. Raise your eyebrows as if you were surprised and lower your eyebrows as if you were frowning. With these movements, you can feel the action of the corrugator supercilli. Additional muscles of facial expression are presented in Figure 11.4.2.

This table describes the muscles used in facial expressions. To furrow the brow, the skin of the scalp moves in an anterior direction. The prime mover is the occipitofrontalis frontal belly, which originates from the epicraneal aponeurosis and inserts underneath the skin of the forehead. To unfurrow the brow, the skin of the scalp moves in the posterior direction. The prime mover is the occipitofrontalis occipital belly, which originates from the occipital bone and the mastoid process of the temporal bone and inserts into the epicraneal aponeurosis. To lower the eyebrows, as when scowling or frowning, the skin underneath the eyebrows moves in an inferior direction. The prime mover is the corrugator supercilii, which originates from the frontal bone and inserts into the skin underneath the eyebrow. To flare the nostrils, the nasal cartilage is compressed in an inferior and posterior direction. The prime mover is the nasalis, which originates from the maxilla and inserts into the nasal bone. Raising the upper lip involves elevating the upper lip tissue. The prime mover is the levator labii superioris, which originates from the maxilla and inserts underneath the skin at the corners of the mouth and also into the orbicularis oris. Lowering the lower lip involves depressing the lip and also moving it laterally. The prime mover is the depressor angulus oris, which originates from the mandible and inserts underneath the skin of the lower lip. Opening the mouth and sliding the lower jaw left and right involves depressing the lower jaw and also moving it laterally. The prime mover is thecdepressor angulus oris, which originates from the mandible and inserts underneath the skin at the corners of the mouth. Smiling involves elevating the corners of the mouth and also moving them in a lateral direction. The prime mover is the zygomaticus major, which originates from the zygomatic bone and inserts underneath the skin at the corners of the mouth in the dimple area, and also into the orbicularis oris. Shaping of the lips as during speech involves moving the lips in multiple directions. The prime mover is the orbicularis oris which originates from the tissue surrounding the lips and inserts underneath the skin at the corners of the mouth. Lateral movement of the cheeks such as when sucking on a straw or to compress air in the mouth while blowing involves moving the cheeks in a lateral direction. The prime mover is the buccinator, which originates from the maxilla, the mandible, and the sphenoid bone via the pterygomandibular raphae, and inserts into the orbicularis oris. Pursing of the lips by straightening them laterally involves moving the corners of the mouth in a lateral direction. The prime mover is the risorius, which originates from the fascia of the parotid salivary gland and inserts underneath the skin at the corners of the mouth. Protrusion of the lower lip, as when making a pouting expression, involves protracting the lower lip and the skin of the chin. The prime mover is the mentalis, which originates from the mandible and inserts underneath the skin of the chin.
Figure 11.4.2 Muscles in Facial Expression

Muscles That Move the Eyes

The movement of the eyeball is under the control of the extra ocular (extrinsic) eye muscles, which originate from the bones of the orbit and insert onto the outer surface of the white of the eye. These muscles are located inside the eye socket and cannot be seen on any part of the visible eyeball (Figure 11.4.3 and Table 11.3). If you have ever been to a doctor who held up a finger and asked you to follow it up, down, and to both sides, he or she is checking to make sure your eye muscles are acting in a coordinated pattern.

The left panel shows the lateral view of the muscles for the right eye, and the right panel shows the anterior view of the muscles for the right eye.
Figure 11.4.3 – Muscles of the Eyes: (a) The extraocular eye muscles originate outside of the eye on the skull. (b) Each muscle inserts onto the eyeball.
Muscles of the Eyes (Table 11.3)
MovementTargetTarget motion directionPrime moverOriginInsertion
Moves eyes up and toward nose; rotates eyes from 1 o’clock to 3 o’clockEyeballsSuperior (elevates); medial (adducts)Superior rectusCommon tendinous ring (ring attaches to optic foramen)Superior surface of eyeball
Moves eyes down and toward nose; rotates eyes from 6 o’clock to 3 o’clockEyeballsInferior (depresses); medial (adducts)Inferior rectusCommon tendinous ring (ring attaches to optic foramen)Inferior surface of eyeball
Moves eyes away from noseEyeballsLateral (abducts)Lateral rectusCommon tendinous ring (ring attaches to optic foramen)Lateral surface of eyeball
Moves eyes toward noseEyeballsMedial (adducts)Medial rectusCommon tendinous ring (ring attaches to optic foramen)Medial surface of eyeball
Moves eyes up and away from nose; rotates eyeball from 12 o’clock to 9 o’clockEyeballsSuperior (elevates); lateral (abducts)Inferior obliqueFloor of orbit (maxilla)Surface of eyeball between inferior rectus and lateral rectus
Moves eyes down and away from nose; rotates eyeball from 6 o’clock to 9 o’clockEyeballsSuperior (elevates); lateral (abducts)Superior obliqueSphenoid boneSuface of eyeball between superior rectus and lateral rectus
Opens eyesUpper eyelidSuperior (elevates)Levator palpabrae superiorisRoof of orbit (sphenoid bone)Skin of upper eyelids
Closes eyelidsEyelid skinCompression along superior–inferior axisOrbicularis oculiMedial bones composing the orbitCircumference of orbit

Muscles of the Eyes

Prime moverMovementTargetTarget motion directionOriginInsertion
Superior rectusMoves eyes up and toward nose; rotates eyes from 1 o’clock to 3 o’clockEyeballsSuperior (elevates); medial (adducts)Common tendinous ring (ring attaches to optic foramen)Superior surface of eyeball
Inferior rectusMoves eyes down and toward nose; rotates eyes from 6 o’clock to 3 o’clockEyeballsInferior (depresses); medial (adducts)Common tendinous ring (ring attaches to optic foramen)Inferior surface of eyeball
Lateral rectusMoves eyes away from noseEyeballsLateral (abducts)Common tendinous ring (ring attaches to optic foramen)Lateral surface of eyeball
Medial rectusMoves eyes toward noseEyeballsMedial (adducts)Common tendinous ring (ring attaches to optic foramen)Medial surface of eyeball
Inferior obliqueMoves eyes up and away from nose; rotates eyeball from 12 o’clock to 9 o’clockEyeballsSuperior (elevates); lateral (abducts)Floor of orbit (maxilla)Surface of eyeball between inferior rectus and lateral rectus
Superior obliqueMoves eyes down and away from nose; rotates eyeball from 6 o’clock to 9 o’clockEyeballsSuperior (elevates); lateral (abducts)Sphenoid boneSuface of eyeball between superior rectus and lateral rectus
Levator palpabrae superiorisOpens eyesUpper eyelidSuperior (elevates)Roof of orbit (sphenoid bone)Skin of upper eyelids
Orbicularis oculiCloses eyelidsEyelid skinCompression along superior–inferior axisMedial bones composing the orbitCircumference of orbit

Muscles That Move the Lower Jaw

Figure 11.4.4 – Muscles That Move the Lower Jaw: The muscles that move the lower jaw are typically located within the cheek and originate from processes in the skull. This provides the jaw muscles with the large amount of leverage needed for chewing.

In anatomical terminology, chewing is called mastication. Muscles involved in chewing must be able to exert enough pressure to bite through and then chew food before it is swallowed (Figure 11.4.4 and Table 11.4). The masseter muscle is the prime mover muscle for chewing because it elevates the mandible (lower jaw) to close the mouth, and it is assisted by the temporalis muscle, which retracts the mandible. You can feel the temporalis move by putting your fingers to your temple as you chew. The medial pterygoid and lateral pterygoid muscles provide assistance in chewing and moving food within the mouth by moving the mandible laterally and medially to grind food between the molars.

Muscles of the Lower Jaw (Table 11.4)
MovementTargetTarget motion directionPrime moverOriginInsertion
Closes mouth; aids chewingMandibleSuperior (elevates)MasseterMaxilla arch; zygomatic arch (for masseter)Mandible
Closes mouth; pulls lower jaw in under upper jawMandibleSuperior (elevates); posterior (retracts)TemporalisTemporal boneMandible
Opens mouth; pushes lower jaw out under upper jaw; moves lower jaw side-to-sideMandibleInferior (depresses); posterior (protracts); lateral (abducts); medial (adducts)Lateral pterygoidPterygoid process of sphenoid boneMandible
Closes mouth; pushes lower jaw out under upper jaw; moves lower jaw side-to-sideMandibleSuperior (elevates); posterior (protracts); lateral (abducts); medial (adducts)Medial pterygoidSphenoid bone; maxillaMandible; temporo-mandibular joint

Muscles of the Lower Jaw

Prime moverMovementTargetTarget motion directionOriginInsertion
MasseterCloses mouth; aids chewingMandibleSuperior (elevates)Maxilla arch; zygomatic arch (for masseter)Mandible
TemporalisCloses mouth; pulls lower jaw in under upper jawMandibleSuperior (elevates); posterior (retracts)Temporal boneMandible
Lateral pterygoidOpens mouth; pushes lower jaw out under upper jaw; moves lower jaw side-to-sideMandibleLateral (abducts)Pterygoid process of sphenoid boneMandible
Medial pterygoidCloses mouth; pushes lower jaw out under upper jaw; moves lower jaw side-to-sideMandibleMedial (adducts)Sphenoid bone; maxillaMandible; temporo-mandibular joint

Muscles That Move the Tongue

Although the tongue is obviously important for tasting food, it is also necessary for mastication, deglutition (swallowing), and speech (Figure 11.4.5 and Figure 11.4.6). Because of its mobility, the tongue facilitates complex speech patterns and sounds.

Figure 11.4.5. Muscles that Move the Tongue
This table describes the muscles used in tongue movement, swallowing, and speech. The genioglossus moves the tongue down and sticks the tongue out of the mouth. It originates in the mandible. The styloglossus moves the tongue up and retracts the tongue back into the mouth. It originates in the temporal bone. The hyoglossus flattens the tongue. It originates in the hyoid bone. The palatoglossus bulges the tongue. It originates in the soft palate. The digastric raises the hyoid bone in a way that also raises the larynx, allowing the epiglottis to cover the glottis during deglutition; it also assists in opening the mouth by depressing the mandible. It originates in the mandible and temporal bone. The stylohyoid raises and retracts the hyoid bone in a way that elongates the oral cavity during deglutition. It originates in the temporal bone. The mylohyoid raises the hyoid bone in a way that presses the tongue against the roof of the mouth, pushing food back into the pharynx during deglutition. It originates in the mandible. The geniohyoid raises and moves the hyoid bone forward, widening the pharynx during deglutition. It originates in the mandible. The ornohyoid retracts the hyoid bone and moves it down during later phases of deglutition. It originates in the scapula. The sternohyoid depresses the hyoid bone during swallowing and speaking. It originates in the clavicle. The thyrohyoid shrinks the distance between thyroid cartilage and the hyoid bone, allowing production of high-pitch vocalizations. It originates in the hyroid cartilage. The sternothyroid depresses the larynx, thyroid cartilage, and hyoid bone to create different vocal tones. It originates in the sternum. The sternocleidomastoid and semispinalis capitis rotate and tilt the head to the side and forward. They originate in the sternum and clavicle. The splenius capitis and longissimus capitis rotate and tilt the head to the side and backwards.
Figure 11.4.6a. Muscles for Tongue Movement, Swallowing, and Speech

Muscles for Tongue Movement, Swallowing, and Speech

MuscleOriginInsertionMovementInnervation
Tongue
GenioglossusMandibleTongue undersurface; hyoid boneDraws tongue to one side; depresses midline of tongue or protrudes tongueHypoglossal nerve
StyloglossusTemporal bone (styloid process)Tongue undersurface and sidesDraws tongue upward and posteriorlyHypoglossal nerve
HyoglossusTemporal bone (styloid bone)Sides of tongueDepresses tongueHypoglossal nerve
PalatoglossusSoft palateSide of tongueElevates root of tongue; closes oral cavity from pharynxAccessory and vagus nerves
This table describes the muscles used in tongue movement, swallowing, and speech. The genioglossus moves the tongue down and sticks the tongue out of the mouth. It originates in the mandible. The styloglossus moves the tongue up and retracts the tongue back into the mouth. It originates in the temporal bone. The hyoglossus flattens the tongue. It originates in the hyoid bone. The palatoglossus bulges the tongue. It originates in the soft palate. The digastric raises the hyoid bone in a way that also raises the larynx, allowing the epiglottis to cover the glottis during deglutition; it also assists in opening the mouth by depressing the mandible. It originates in the mandible and temporal bone. The stylohyoid raises and retracts the hyoid bone in a way that elongates the oral cavity during deglutition. It originates in the temporal bone. The mylohyoid raises the hyoid bone in a way that presses the tongue against the roof of the mouth, pushing food back into the pharynx during deglutition. It originates in the mandible. The geniohyoid raises and moves the hyoid bone forward, widening the pharynx during deglutition. It originates in the mandible. The ornohyoid retracts the hyoid bone and moves it down during later phases of deglutition. It originates in the scapula. The sternohyoid depresses the hyoid bone during swallowing and speaking. It originates in the clavicle. The thyrohyoid shrinks the distance between thyroid cartilage and the hyoid bone, allowing production of high-pitch vocalizations. It originates in the hyroid cartilage. The sternothyroid depresses the larynx, thyroid cartilage, and hyoid bone to create different vocal tones. It originates in the sternum. The sternocleidomastoid and semispinalis capitis rotate and tilt the head to the side and forward. They originate in the sternum and clavicle. The splenius capitis and longissimus capitis rotate and tilt the head to the side and backwards.
Figure 11.4.6b. Muscles for Tongue Movement, Swallowing, and Speech

Muscles for Tongue Movement, Swallowing, and Speech

MuscleOriginInsertionMovementInnervation
Swallowing and speaking
DigastricMandible; temporal boneHyoid boneDepresses mandible when hyoid is fixed; elevates hyoid when mandible is fixed;Posterior belly; facial nerve Anterior belly mylohyoid nerve
StylohyoidTemporal bone (styloid process)Hyoid boneElevates and retracts hyoid; elongates floor of mouthFacial nerve
MylohyoidMandibleHyoid bone; median rapheElevates floor of mouth in initial stage of swallowingMylohyoid nerve
GeniohyoidMandibleHyoid boneDepresses mandible when hyoid; elevates and protracts hyoid when mandible is fixedSpinal nerve C1 via hypoglossal nerve
OmohyoidScapulaHyoid boneDepresses hyoid after it has been elevatedAnsa cervicalis
SternohyoidClavicleHyoid boneDepresses the hyoid during swallowing and speakingAnsa cervicalis
ThyrohyoidThyroid cartilageHyoid boneDepresses hyoid; Elevates larynx when hyoid is fixedSpinal nerve C1 via hypoglossal nerve
SternothyroidSternumThyroid cartilageDepresses larynx after it has been elevated in swallowing and vocalizationAnsa cervicalis
Sternocleid- omastoid;Sternum; clavicleTemporal bone (mastoid process); occipital boneUnilaterally tilts head up and to the opposite side; Bilaterally draws head forward and downAccessory nerve and spinal nerves C2-C3
Semispinalis capitisC5-C8; T1-T6Occiput between the superior and inferior nuchal lineExtends and rotates the head to the opposite sidePosterior rami of middle cervical and thoracic nerves
Splenius capitis;Nuchal line; spinous process of C7-T3Superior nuchal line, Mastoid processUnilaterally and ipsilaterally flexes and rotates the head; Bilaterally extends head Posterior rami of middle cervical nerves
Longissimus capitisT1-T5; C4-C7Posterior margin of mastoid process and temporal boneExtends and hyperextends head; flexes and rotates the head ipsilaterallyDorsal rami of cervical and thoracic nerves (C6 to T4)

Tongue muscles can be extrinsic or intrinsic. Extrinsic tongue muscles insert into the tongue from outside origins, and the intrinsic tongue muscles insert into the tongue from origins within it. The extrinsic muscles move the whole tongue in different directions, whereas the intrinsic muscles allow the tongue to change its shape (such as, curling the tongue in a loop or flattening it).

The extrinsic muscles all include the word root glossus (glossus = “tongue”), and the muscle names are derived from where the muscle originates. The genioglossus (genio = “chin”) originates on the mandible and allows the tongue to move downward and forward. The styloglossus originates on the styloid process of the temporal bone, and allows upward and backward motion. The palatoglossus originates on the soft palate to elevate the back of the tongue, and the hyoglossus originates on the hyoid bone to move the tongue downward and flatten it.

Muscles of the Anterior Neck

The muscles of the anterior neck assist in deglutition (swallowing) and speech by controlling the positions of the larynx (voice box), and the hyoid bone, a horseshoe-shaped bone that functions as a foundation on which the tongue can move. The muscles of the neck are categorized according to their position relative to the hyoid bone (Figure 11.4.7). Suprahyoid muscles are superior to it, and the infrahyoid muscles are located inferiorly.

This figure shows the front view of a person’s neck with the major muscle groups labeled.
Figure 11.4.7 – Muscles of the Anterior Neck: The anterior muscles of the neck facilitate swallowing and speech. The suprahyoid muscles originate from above the hyoid bone in the chin region. The infrahyoid muscles originate below the hyoid bone in the lower neck.

The suprahyoid muscles raise the hyoid bone, the floor of the mouth, and the larynx during deglutition. These include the digastric muscle, which has anterior and posterior bellies that work to elevate the hyoid bone and larynx when one swallows; it also depresses the mandible. The stylohyoid muscle moves the hyoid bone posteriorly, elevating the larynx, and the mylohyoid muscle lifts it and helps press the tongue to the top of the mouth. The geniohyoid depresses the mandible in addition to raising and pulling the hyoid bone anteriorly.

The strap-like infrahyoid muscles generally depress the hyoid bone and control the position of the larynx. The omohyoid muscle, which has superior and inferior bellies, depresses the hyoid bone in conjunction with the sternohyoid and thyrohyoid muscles. The thyrohyoid muscle also elevates the larynx’s thyroid cartilage, whereas the sternothyroid depresses it.

Muscles That Move the Head

The head is balanced, moved and rotated by the neck muscles (Table 11.5). When these muscles act unilaterally, the head rotates. When they contract bilaterally, the head flexes or extends. The major muscle that laterally flexes and rotates the head is the sternocleidomastoid. In addition, both muscles working together are the flexors of the head. Place your fingers on both sides of the neck and turn your head to the left and to the right. You will feel the movement originate there. This muscle divides the neck into anterior and posterior triangles when viewed from the side (Figure 11.4.8).

Muscles That Move the Head (Table 11.5)
MovementTargetTarget motion directionPrime moverOriginInsertion
Rotates and tilts head to the side; tilts head forwardSkull; vertebraeIndividually: rotates head to opposite side; bilaterally: flexionSternocleidomastoidSternum; clavicleTemporal bone (mastoid process); occipital bone
Rotates and tilts head backwardSkull; vertebraeIndividually: laterally flexes and rotates head to same side; bilaterally: extensionSemispinalis capitisTransverse and articular processes of cervical and thoracic vertebraOccipital bone
Rotates and tilts head to the side; tilts head backwardSkull; vertebraeIndividually: laterally flexes and rotates head to same side; bilaterally: extensionSplenius capitisSpinous processes of cervical and thoracic vertebraTemporal bone (mastoid process); occipital bone
Rotates and tilts head to the side; tilts head backwardSkull; vertebraeIndividually: laterally flexes and rotates head to same side; bilaterally: extensionLongissimus capitisTransverse and articular processes of cervical and thoracic vertebraTemporal bone (mastoid process)

Muscles That Move the Head

Prime moverMovementTargetTarget motion directionOriginInsertion
SternocleidomastoidRotates and tilts head to the side; tilts head forwardSkull; vertebraeIndividually: rotates head to opposite side; bilaterally: flexionSternum; clavicleTemporal bone (mastoid process); occipital bone
Semispinalis capitisRotates and tilts head backwardSkull; vertebraeIndividually: laterally flexes and rotates head to same side; bilaterally: extensionTransverse and articular processes of cervical and thoracic vertebraOccipital bone
Splenius capitisRotates and tilts head to the side; tilts head backwardSkull; vertebraeIndividually: laterally flexes and rotates head to same side; bilaterally: extensionSpinous processes of cervical and thoracic vertebraTemporal bone (mastoid process); occipital bone
Longissimus capitisRotates and tilts head to the side; tilts head backwardSkull; vertebraeIndividually: laterally flexes and rotates head to same side; bilaterally: extensionTransverse and articular processes of cervical and thoracic vertebraTemporal bone (mastoid process)

Muscles of the Posterior Neck and the Back

The posterior muscles of the neck are primarily concerned with head movements, like extension. The back muscles stabilize and move the vertebral column, and are grouped according to the lengths and direction of the fascicles.

The splenius muscles originate at the midline and run laterally and superiorly to their insertions. From the sides and the back of the neck, the splenius capitis inserts onto the head region, and the splenius cervicis extends onto the cervical region. These muscles can extend the head, laterally flex it, and rotate it (Figure 11.4.8).

The top left panel shows a lateral view of the muscles of the neck, and the bottom left panel shows the posterior view of the superficial and deep muscles of the neck. The center panel shows the deep muscles of the back, and the right panel shows the deep spinal muscles.
Figure 11.4.8 – Muscles of the Neck and Back: The large, complex muscles of the neck and back move the head, shoulders, and vertebral column.

The erector spinae group forms the majority of the muscle mass of the back and it is the primary extensor of the vertebral column. It controls extension, lateral flexion, and rotation of the vertebral column, and maintains the lumbar curve. The erector spinae comprises the iliocostalis (laterally placed) group, the longissimus (intermediately placed) group, and the spinalis (medially placed) group.

The iliocostalis group includes the iliocostalis cervicis, associated with the cervical region; the iliocostalis thoracis, associated with the thoracic region; and the iliocostalis lumborum, associated with the lumbar region. The three muscles of the longissimus group are the longissimus capitis, associated with the head region; the longissimus cervicis, associated with the cervical region; and the longissimus thoracis, associated with the thoracic region. The third group, the spinalis group, comprises the spinalis capitis (head region), the spinalis cervicis (cervical region), and the spinalis thoracis (thoracic region).

The transversospinales muscles run from the transverse processes to the spinous processes of the vertebrae. Similar to the erector spinae muscles, the semispinalis muscles in this group are named for the areas of the body with which they are associated. The semispinalis muscles include the semispinalis capitis, the semispinalis cervicis, and the semispinalis thoracis. The multifidus muscle of the lumbar region helps extend and laterally flex the vertebral column.

Important in the stabilization of the vertebral column is the segmental muscle group, which includes the interspinales and intertransversarii muscles. These muscles bring together the spinous and transverse processes of each consecutive vertebra. Finally, the scalene muscles work together to flex, laterally flex, and rotate the head. They also contribute to deep inhalation. The scalene muscles include the anterior scalene muscle (anterior to the middle scalene), the middle scalene muscle (the longest, intermediate between the anterior and posterior scalenes), and the posterior scalene muscle (the smallest, posterior to the middle scalene).

Chapter Review

Muscles are either axial muscles or appendicular. The axial muscles are grouped based on location, function, or both. Some axial muscles cross over to the appendicular skeleton. The muscles of the head and neck are all axial. The muscles in the face create facial expression by inserting into the skin rather than onto bone. Muscles that move the eyeballs are extrinsic, meaning they originate outside of the eye and insert onto it. Tongue muscles are both extrinsic and intrinsic. The genioglossus depresses the tongue and moves it anteriorly; the styloglossus lifts the tongue and retracts it; the palatoglossus elevates the back of the tongue; and the hyoglossus depresses and flattens it. The muscles of the anterior neck facilitate swallowing and speech, stabilize the hyoid bone and position the larynx. The muscles of the neck stabilize and move the head. The sternocleidomastoid divides the neck into anterior and posterior triangles.

The muscles of the back and neck that move the vertebral column are complex, overlapping, and can be divided into five groups. The splenius group includes the splenius capitis and the splenius cervicis. The erector spinae has three subgroups. The iliocostalis group includes the iliocostalis cervicis, the iliocostalis thoracis, and the iliocostalis lumborum. The longissimus group includes the longissimus capitis, the longissimus cervicis, and the longissimus thoracis. The spinalis group includes the spinalis capitis, the spinalis cervicis, and the spinalis thoracis. The transversospinales include the semispinalis capitis, semispinalis cervicis, semispinalis thoracis, multifidus, and rotatores. The segmental muscles include the interspinales and intertransversarii. Finally, the scalenes include the anterior scalene, middle scalene, and posterior scalene.

Review Questions

An interactive H5P element has been excluded from this version of the text. You can view it online here:
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An interactive H5P element has been excluded from this version of the text. You can view it online here:
https://open.oregonstate.education/aandp/?p=1540#h5p-258

An interactive H5P element has been excluded from this version of the text. You can view it online here:
https://open.oregonstate.education/aandp/?p=1540#h5p-259

An interactive H5P element has been excluded from this version of the text. You can view it online here:
https://open.oregonstate.education/aandp/?p=1540#h5p-260

An interactive H5P element has been excluded from this version of the text. You can view it online here:
https://open.oregonstate.education/aandp/?p=1540#h5p-261

Critical Thinking Questions

1. Explain the difference between axial and appendicular muscles.

2. Describe the muscles of the anterior neck.

3. Why are the muscles of the face different from typical skeletal muscle?

Glossary

anterior scalene
a muscle anterior to the middle scalene
appendicular
of the arms and legs
axial
of the trunk and head
buccinator
muscle that compresses the cheek
corrugator supercilii
prime mover of the eyebrows
deglutition
swallowing
digastric
muscle that has anterior and posterior bellies and elevates the hyoid bone and larynx when one swallows; it also depresses the mandible
epicranial aponeurosis
(also, galea aponeurosis) flat broad tendon that connects the frontalis and occipitalis
erector spinae group
large muscle mass of the back; primary extensor of the vertebral column
extrinsic eye muscles
originate outside the eye and insert onto the outer surface of the white of the eye, and create eyeball movement
frontalis
front part of the occipitofrontalis muscle
genioglossus
muscle that originates on the mandible and allows the tongue to move downward and forward
geniohyoid
muscle that depresses the mandible, and raises and pulls the hyoid bone anteriorly
hyoglossus
muscle that originates on the hyoid bone to move the tongue downward and flatten it
iliocostalis cervicis
muscle of the iliocostalis group associated with the cervical region
iliocostalis group
laterally placed muscles of the erector spinae
iliocostalis lumborum
muscle of the iliocostalis group associated with the lumbar region
iliocostalis thoracis
muscle of the iliocostalis group associated with the thoracic region
infrahyoid muscles
anterior neck muscles that are attached to, and inferior to the hyoid bone
lateral pterygoid
muscle that moves the mandible from side to side
longissimus capitis
muscle of the longissimus group associated with the head region
longissimus cervicis
muscle of the longissimus group associated with the cervical region
longissimus group
intermediately placed muscles of the erector spinae
longissimus thoracis
muscle of the longissimus group associated with the thoracic region
masseter
main muscle for chewing that elevates the mandible to close the mouth
mastication
chewing
medial pterygoid
muscle that moves the mandible from side to side
middle scalene
longest scalene muscle, located between the anterior and posterior scalenes
multifidus
muscle of the lumbar region that helps extend and laterally flex the vertebral column
mylohyoid
muscle that lifts the hyoid bone and helps press the tongue to the top of the mouth
occipitalis
posterior part of the occipitofrontalis muscle
occipitofrontalis
muscle that makes up the scalp with a frontal belly and an occipital belly
omohyoid
muscle that has superior and inferior bellies and depresses the hyoid bone
orbicularis oculi
circular muscle that closes the eye
orbicularis oris
circular muscle that moves the lips
palatoglossus
muscle that originates on the soft palate to elevate the back of the tongue
posterior scalene
smallest scalene muscle, located posterior to the middle scalene
scalene muscles
flex, laterally flex, and rotate the head; contribute to deep inhalation
segmental muscle group
interspinales and intertransversarii muscles that bring together the spinous and transverse processes of each consecutive vertebra
semispinalis capitis
transversospinales muscle associated with the head region
semispinalis cervicis
transversospinales muscle associated with the cervical region
semispinalis thoracis
transversospinales muscle associated with the thoracic region
spinalis capitis
muscle of the spinalis group associated with the head region
spinalis cervicis
muscle of the spinalis group associated with the cervical region
spinalis group
medially placed muscles of the erector spinae
spinalis thoracis
muscle of the spinalis group associated with the thoracic region
splenius
posterior neck muscles; includes the splenius capitis and splenius cervicis
splenius capitis
neck muscle that inserts into the head region
splenius cervicis
neck muscle that inserts into the cervical region
sternocleidomastoid
major muscle that laterally flexes and rotates the head
sternohyoid
muscle that depresses the hyoid bone
sternothyroid
muscle that depresses the larynx’s thyroid cartilage
styloglossus
muscle that originates on the styloid bone, and allows upward and backward motion of the tongue
stylohyoid
muscle that elevates the hyoid bone posteriorly
suprahyoid muscles
neck muscles that are superior to the hyoid bone
temporalis
muscle that retracts the mandible
thyrohyoid
muscle that depresses the hyoid bone and elevates the larynx’s thyroid cartilage
transversospinales
muscles that originate at the transverse processes and insert at the spinous processes of the vertebrae
trapezius
muscle that stabilizes the upper part of the back

Solutions

Answers for Critical Thinking Questions

  1. Axial muscles originate on the axial skeleton (the bones in the head, neck, and core of the body), whereas appendicular muscles originate on the bones that make up the body’s limbs.
  2. The muscles of the anterior neck are arranged to facilitate swallowing and speech. They work on the hyoid bone, with the suprahyoid muscles pulling up and the infrahyoid muscles pulling down.
  3. Most skeletal muscles create movement by actions on the skeleton. Facial muscles are different in that they create facial movements and expressions by pulling on the skin—no bone movements are involved.

Annotate

Next chapter
11.5 Axial muscles of the abdominal wall and thorax
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Anatomy and Physiology
Copyright © 2019 by Lindsay M. Biga, Sierra Dawson, Amy Harwell, Robin Hopkins, Joel Kaufmann, Mike LeMaster, Philip Matern, Katie Morrison-Graham, Devon Quick & Jon Runyeon

Anatomy & Physiology by Lindsay M. Biga, Sierra Dawson, Amy Harwell, Robin Hopkins, Joel Kaufmann, Mike LeMaster, Philip Matern, Katie Morrison-Graham, Devon Quick & Jon Runyeon is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License, except where otherwise noted.

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