Skull & Face Anatomy

SKULL AND FACE ANATOMY

Frontal View of Skull

  • Frontal Bone

  • Sphenoid Bone

  • Lacrimal Bone

  • Maxilla

  • Temporal Bone

  • Nasal Bone

  • Parietal Bone

  • Zygomatic Bone

  • Mandible

Course Reference

  • KINE 3600

  • MUSCULOSKELETAL ANATOMY

  • Crump Institute for Biological Imaging

THE SKULL

Structure of the Skull

  • Two Parts of the Skull:

    • Cranial Skeleton (Neurocranium)

    • Facial Skeleton (Viscerocranium)

Cranial Skeleton (Neurocranium) Components

  • Contains:

    • The Brain

    • Cranial Meninges

    • Cranial Nerves

    • Blood Vessels

  • Made up of:

    • Frontal Bone (1)

    • Parietal Bones (2)

    • Temporal Bones (2)

    • Occipital Bone (1)

    • Sphenoid Bone (1)

    • Ethmoid Bone (1)

Facial Skeleton (Viscerocranium) Components

  • Also known as facial skeleton includes the following bones:

    • Maxillae (2)

    • Palatine Bones (2)

    • Nasal Bones (2)

    • Inferior Nasal Conchae (2)

    • Zygomatic Bones (2)

    • Lacrimal Bones (2)

    • Vomer (1)

    • Mandible (1)

Associated Bones of the Skull

  • Cranium Bones:

    • Occipital Bone (1)

    • Parietal Bones (2)

    • Frontal Bone (1)

    • Temporal Bones (2)

    • Sphenoid Bone (1)

    • Ethmoid Bone (1)

  • Face Bones:

    • Maxillae (2)

    • Palatine Bones (2)

    • Nasal Bones (2)

    • Inferior Nasal Conchae (2)

    • Zygomatic Bones (2)

    • Lacrimal Bones (2)

    • Vomer (1)

    • Mandible (1)

SPECIFIC BONES IN DETAIL

Frontal Bone

  • Components:

    • Frontal Eminence

    • Frontal Process

    • Superciliary Arch

    • Supraorbital Margin

    • Zygomatic Process

    • Infraorbital Margin

    • Alveolar Process

  • Foramina:

    • Supraorbital Foramen

    • Zygomaticofacial Foramen

    • Infraorbital Foramen

  • Associated Cavity:

    • Orbital Cavity

    • Nasal Cavity

  • Notable Features:

    • Canine Fossa

    • Incisive Fossa

    • Mental Foramen

Parietal Bones

  • Features:

    • Parietal Eminence

    • Squamous Part of Temporal Bone

    • Superior and Inferior Temporal Lines

    • Mastoid Part of Temporal Bone

  • Associated Suture:

    • Lambdoid Suture

Temporal Bones

  • Features:

    • Squamous Part

    • Mastoid Part

    • Tympanic Part

    • Zygomatic Process

    • External Acoustic Meatus

    • Mandibular Fossa

Occipital Bone

  • Features:

    • External Occipital Protuberance

    • Nuchal Lines (Superior and Inferior)

    • Occipital Condyles

    • Foramen Magnum

Foramen Magnum

  • Function:

    • Passageway from the skull to the spinal column

  • Contents:

    • Spinal Cord and Meninges

    • Vertebral Arteries

    • Anterior and Posterior Spinal Arteries

    • Spinal Accessory Nerve (XI)

Sphenoid Bone

  • Description:

    • Known as the “Bat Bone”

    • Unpaired bone in neurocranium

    • Forms the base of the cranium, behind the eye and below the front part of the brain

  • Contains:

    • Two air-filled sinuses

Ethmoid Bone

  • Location:

    • Sits in front of the sphenoid at the roof of the nose, between the two orbits

  • Function:

    • Separates the nasal cavity from the brain

FACIAL SKELETON (VISCERCRANIUM)

Defined Structure

  • Comprises:

    • Lacrimal Bones (2)

    • Nasal Bones (2)

    • Maxillae (2)

    • Zygomatic Bones (2)

    • Palatine (2)

    • Nasal Conchae (2)

    • Mandible (1)

    • Vomer (1)

Specific Compositions

  • Lacrimal Bones:

    • Smallest bones in the face

    • Located on the medial side of the orbit, articulates with the inferior nasal concha, ethmoid, frontal, and maxillary bones.

  • Nasal Bone:

    • Forms the bridge of the nose

    • Articulates with the frontal bone superiorly, ethmoid and the frontal process of the maxilla posteriorly.

  • Maxilla:

    • Contains Alveolar Processes (maxillary sinus)

    • Forms the floor of the orbits, sides and lower walls of the nasal cavities, and the hard palate

    • Infraorbital Foramen is a neurovascular passageway

  • Zygomatic Bones:

    • Also known as the cheek bones

    • Make up part of the eye orbit, articulating with the maxilla, the temporal bone, the sphenoid bone, and the frontal bone.

  • Palatine Bones:

    • Pair of bones contributing to the upper palate

    • Articulate with maxillae to form the hard palate.

  • Nasal Conchae:

    • Also called Turbinate or Turbinal

    • Scroll-shaped bony elements forming the upper chambers of the nasal cavities.

  • Vomer:

    • Forms the inferior part of the nasal septum

    • Articulates with the ethmoid superiorly and palatine inferiorly.

  • Mandible:

    • Features:

    • Mandibular fossa

    • Temporomandibular joint with temporal bone

    • Mandibular notch and condyle

    • Ramus and angle of mandible

    • Alveolar margin for lower teeth

ORBIT OF THE EYE

Bones Making Up the Orbit

  • Bones:

    • Frontal

    • Zygomatic

    • Maxilla

    • Lacrimal

    • Ethmoid

    • Sphenoid

    • Palatine

BONES OF THE INNER EAR

  • Three Small Bones:

    • Malleus (Hammer)

    • Incus (Anvil)

    • Stapes (Stirrup)

  • Additional Structures in Inner Ear:

    • Tympanic Membrane

    • Semicircular Canal

JOINTS OF THE SKULL

Principal Sutures

  • Coronal Suture: between Frontal Bone and Parietal Bones

  • Sagittal Suture: along the center between both Parietal Bones

  • Lambdoid Suture: between Occipital Bone and Parietal Bones

  • Temporal Suture: connecting Temporal Bone to Parietal Bone

Temporomandibular Joints (TMJ)

  • Characteristics:

    • Only voluntarily movable joints of the skull

    • Hinge joints with articular discs

  • Movements:

    • Elevation/Depression

    • Protrusion/Retrusion

    • Lateral Excursion

MUSCLES OF MASTICATION

Main Muscles

  1. Temporalis:

    • Origin: Temporal line

    • Insertion: Coronoid process of mandible

    • Action: Elevation/Retrusion

    • Innervation: Trigeminal Nerve

  2. Masseter:

    • Origin: Zygomatic Arch

    • Insertion: Lateral Angle/Ramus of mandible

    • Action: Elevation/Protrusion

    • Innervation: Trigeminal Nerve

  3. Lateral Pterygoid:

    • Origin: Sphenoid (Greater wing/Lateral Pterygoid plate)

    • Insertion: Condyle of mandible/TMJ

    • Action: Protrusion/Depression

    • Innervation: Trigeminal Nerve

  4. Medial Pterygoid:

    • Origin: Maxilla / Lateral Pterygoid plate

    • Insertion: Medial Angle/Ramus of mandible

    • Action: Elevation/Protrusion

    • Innervation: Trigeminal Nerve

FACIAL MUSCLES

  • Role in:

    • Facial expression

    • Chewing & moving food in the mouth

    • Closing eyelids

    • Neck movement

SCALP ANATOMY

Layers of the Scalp

  • Skin

  • Connective Tissue

  • Aponeurosis

  • Loose Connective Tissue

  • Bone

  • Periosteum

    • Tables of Bone: Outer Table & Inner Table

MENINGES

Layers of the Meninges

  1. Dura Mater:

    • Contains Periosteal layer and Meningeal layer

  2. Arachnoid Mater:

    • Includes Subdural Space

    • Subarachnoid space containing cerebrospinal fluid

  3. Pia Mater:

    • Contains blood vessels and adheres to the surface of the brain

Meningeal Spaces

  • Epidural Space:

    • Contains Middle Meningeal Artery

  • Subdural Space:

    • Contains Veins

  • Subarachnoid Space:

    • Contains Cerebrospinal Fluid

ORGANIZATION OF THE BRAIN

  • Major Parts:

    • Cerebral Hemisphere

    • Diencephalon

    • Cerebellum

    • Brain Stem

    • Midbrain

    • Pons

    • Medulla Oblongata

CEREBRUM

  • Largest part of the brain

  • Divided into hemispheres

CEREBRAL CORTEX

  • Controls:

    • Highest mental & behavioral activities

    • Conscious & unconscious skeletal muscle contractions

CEREBRAL LOBES FUNCTIONS

  1. Frontal Lobe:

    • Primary motor cortex for conscious control of skeletal muscles, planning behavior, and language production.

  2. Parietal Lobe:

    • Primary sensory cortex responsible for conscious perception of touch, pain, temperature, and language comprehension.

  3. Temporal Lobe:

    • Auditory cortex for hearing and olfactory stimulus perception.

  4. Occipital Lobe:

    • Visual cortex for conscious perception of visual stimuli.

CEREBELLUM

  • Function:

    • Coordinates movements

    • Regulates posture and reflexes

DIENCEPHALON

  • Contains:

    • Thalamus: Relay and processing of sensory information

    • Hypothalamus: Controls autonomic functions and hormone regulation

BRAINSTEM FUNCTIONS

  • Autonomic control of respiration, heart rate, etc.

  • Major components:

    • Midbrain

    • Pons

    • Medulla Oblongata

CRANIAL NERVES

  • 12 Pairs of Cranial Nerves:

    • Types: Motor nerves, Sensory nerves, Mixed nerves (both motor and sensory)

FUNCTIONAL OVERVIEW OF CRANIAL NERVES

  1. Olfactory (CN I): Sensory - Smell

  2. Optic (CN II): Sensory - Vision

  3. Oculomotor (CN III): Motor - Eye movement

  4. Trochlear (CN IV): Motor - Eye movement

  5. Trigeminal (CN V): Mixed - Face movement and sensation

  6. Abducens (CN VI): Motor - Eye movement

  7. Facial (CN VII): Mixed - Face movement and sensation

  8. Vestibulocochlear (CN VIII): Sensory - Hearing, balance

  9. Glossopharyngeal (CN IX): Mixed - Taste, speech

  10. Vagus (CN X): Mixed - Taste, speech, visceral function

  11. Accessory (CN XI): Motor - Shoulder elevation

  12. Hypoglossal (CN XII): Motor - Tongue movement

  • SO-4, LR-6: Superior Oblique inervated by CN #4, innervated by CN #6

SUMMARY OF CRANIAL NERVES
  • Sensory Function Examples:

    • Taste (VII, IX, X)

    • Hearing and balance (VIII)

  • Motor Functions Examples:

    • Eye muscles (III, IV, VI)

    • Tongue (XII)

    • Muscles of mastication (V)

    • Muscles of facial expression (VII)

    • Muscles involved in speech and swallowing (IX, X)

MNEMONIC DEVICES FOR CRANIAL NERVES
  • To remember the cranial nerves:

    • "On Old Olympus Towering Tops A Fine Vested German Viewed Some Hops."

  • To remember the types of nerves (Sensory or Motor):

    • "Some Say Mary May But Mary’s Brother Says Best Beware Mary’s Mother.