The Skeletal System Focus on the Skull

Review Anatomical Terms Anterior/Posterior Dorsal/Ventral Medial/Lateral Superior/Inferior

Axial Skeleton Includes bones of the skull, vertebral column and thoracic cage Creates a framework of support and protection for internal organs Provides sites of attachment of muscles

The Skull Protects the brain and supports delicate sense organs 8 cranial bones 14 facial bones 6 auditory ossicles (tiny bones in the ears) Hyoid bone

Bones of the Cranium Frontal bone (1)- forms the forehead and roof of the ocular orbits Parietal Bone (2) – posterior to the frontal bone; forms the sides and roof of skull Occiptal Bone (1) – posterior and inferior portions of the skull; foramen magnum Temporal Bone (2) – form the sides and base of the skull; a number of distinct anatomical landmarks

Bones of the Cranium – Lateral View Frontal Bone Parietal Bone Temporal Bone Occipital Bone

Bones of the Cranium - Frontal Frontal Bone Parietal Bone Temporal Bone

Bones of the Cranium – Inferior View Temporal Bone Parietal Bone Occipital Bone

Bones of the Cranium – Horizontal View Frontal Bone Temporal Bone Parietal Bone Occipital Bone

Sutures of the Cranium Sagittal Suture – extends along the midline of the cranium; between parietal bones Coronal Suture – between frontal bone and parietal bones Lambdoid Suture – between occipital and parietal bones Squamous Suture– between the temporal bones and the parietal bones

Sutures of the Cranium – Lateral View Coronal Suture Frontal Bone Parietal Bone Temporal Bone Lambdoid Suture Squamous Suture Occipital Bone

Sutures of the Cranium - Frontal Coronal Suture Frontal Bone Parietal Bone Temporal Bone REVIEW

The skull at birth

The skull at birth

Bones of the Cranium continued Sphenoid Bone–forms the floor of the skull and braces side of skull; acts like a bridge between cranial and facial bones Ethmoid Bone – anterior to the sphenoid; stabilizes the brain; forms the roof and sides of the nasal cavity Vomer – forms the inferior portion of the nasal septum Palatine Bone – forms the posterior hard palate (“roof of mouth”); contributes to the walls of the nasal cavity and the floor of each orbit

Bones of the Cranium – Lateral View Coronal Suture Frontal Bone Parietal Bone Sphenoid Bone Temporal Bone Ethmoid Bone Lambdoid Suture Squamous Suture Occipital Bone

Bones of the Cranium - Frontal Coronal Suture Frontal Bone Parietal Bone Sphenoid Bone Ethmoid Bone Temporal Bone Vomer

Bones of the Cranium – Inferior View Palatine Bone Sphenoid Bone Vomer Temporal Bone Parietal Bone Occipital Bone

Bones of the Cranium–Horizontal View Frontal Bone Ethmoid Bone Sphenoid Bone Temporal Bone Parietal Bone Occipital Bone

Bones of the Face Maxilla (2) – articulates with all other facial bones except the mandible; forms part of the orbit, walls of nasal cavity and anterior roof of mouth Zygomatic Bones (2) – articulates with the frontal bone and the maxilla; completes lateral orbit of eye Nasal Bones– bridge of nose; articulate with frontal bone and maxilla Lacrimal Bones– with the orbit; medial surface Mandible – lower jaw

Bones of the Face – Lateral View Coronal Suture Frontal Bone Parietal Bone Sphenoid Bone Temporal Bone Ethmoid Bone Lambdoid Suture Lacrimal Bone Squamous Suture Nasal Bone Occipital Bone Zygomatic Bone Maxilla Mandible

Bones of the Face - Frontal Coronal Suture Frontal Bone Parietal Bone Nasal Bone Sphenoid Bone Ethmoid Bone Temporal Bone Lacrimal Bone Zygomatic Bone Maxilla Vomer Mandible

Bones of the Face – Inferior View Maxilla Palatine Bone Maxilla Zygomatic Bone Sphenoid Bone Vomer Temporal Bone Parietal Bone Occipital Bone

Teeth (32) Incisors - 8 Canines - 4 Pre-molars - 8 Molars - 12

Processes any elevation or projection Can be part of a joint or a site of attachment for muscles, ligaments and tendons

Processes of the cranium Styloid process (temporal) Mastoid process (temporal) Coronoid process (mandible) Condylar process (mandible) Mandibular process (mandible) Occipital condyle (occipital) Zygomatic process (zygomatic) External occipital protuberance (occipital) Pterygoid process (sphenoid) Hamulus of the pterygoid process (sphenoid)

Styloid Process Pointed piece of bone that extends down from the temporal bone just below the ear Attachment for ligaments that support the hyoid bone and muscles that control the tongue and pharynx

Mastoid Process Built up area of the lower temporal bone where important neck muscles attach Site of attachment for muscle that rotates and elevates the head and clavicle

Coronoid Process “like a crown” Attachment point for muscle that closes the jaw

Condylar Process Forms a hinge with the temporal bone

Mandibular Process Smooth surface of the condylar process

Occipital Condyle Articulates with the atlas vertebrae (the first vertebrae in the spinal column

Zygomatic Process Three extensions of the zygomatic bone that connect with the frontal bone, maxilla, and temporal bone

External Occipital Protuberance Bony protrusion of the occipital bone Muscles that keep the head upright and allow the head to tilt backward attach here

The Sphenoid Bone Pterygoid Process and the hamulus of the pterygoid process

Process of the Skull – Lateral View Coronal Suture Frontal Bone Parietal Bone Sphenoid Bone Temporal Bone Ethmoid Bone Lambdoid Suture Lacrimal Bone Squamous Suture Nasal Bone Occipital Bone Zygomatic Bone Zygomatic Process Maxilla Mastoid Process Styloid Process Mandible

Process of the Skull - Frontal Coronal Suture Frontal Bone Parietal Bone Nasal Bone Sphenoid Bone Ethmoid Bone Temporal Bone Lacrimal Bone Zygomatic Bone Ethmoid Bone Maxilla Vomer Mandible

Process of the Skull– Inferior View Maxilla Palatine Bone Maxilla Zygomatic Bone Sphenoid Bone Zygomatic Process Vomer Styloid Process Mastoid Process Temporal Bone Occipital Condyle Parietal Bone Occipital Bone

Processes of the Skull – Horizontal View Frontal Bone Ethmoid Bone Sphenoid Bone Temporal Bone Parietal Bone Occipital Bone

Name the Process

Name the Process

Foramina and Other Structures General terms to describe openings include Foramen, canal, meatus, fissure sinus

Foramina and Other Structures Supraorbital foramen (frontal) Infraorbital foramen (maxilla) Mental foramen (mandible) Mandibular foramen (mandible) External acoustic meatus (temporal) Palatine foramen (palatine) Foramen ovale (sphenoid) Foramen lacerum (temporal) Foramen spinosum (sphenoid) Foramen rotundum (sphenoid) Jugular foramen (temporal) Foramen magnum (occipital) Stylomastoid foramen (temporal) Carotid canal (temporal)

Supraorbital foramen** “above” the orbit Opening for blood vessels and nerves passing from the eyebrows and eyelids

Infraorbital foramen** “below the orbit” Opening for facial nerves

Mental foramen** Distal/lateral opening for the mental nerve and vessels that innervate the lip

Mandibular foramen Proximal/medial opening for the mental nerve and vessels that innervate the lip and teeth

External Auditory meatus** Opening that leads to the eardrum (tympanum)

Palatine foramen Nerves that innervate the palate

Foramen ovale** Trigeminal nerve – mandibular branch

Foramen lacerum Filled with cartilage

Foramen spinosum Nerves that innervate the meninges enter the brain

Foramen rotundum Trigeminal nerve: maxillary branch

Jugular foramen** Jugular vein

Foramen magnum** Spinal cord

Stylomastoid foramen Facial nerves exit skull

Carotid Canal** Carotid artery

Process of the Skull – Lateral View Coronal Suture Frontal Bone Parietal Bone Sphenoid Bone Temporal Bone Ethmoid Bone Lambdoid Suture Lacrimal Bone Squamous Suture Nasal Bone Occipital Bone Zygomatic Bone Zygomatic Process Maxilla External Auditory Meatus Mastoid Process Styloid Process Mandible Mental Foramen Mandible

Process of the Skull - Frontal Coronal Suture Frontal Bone Parietal Bone Supraorbital Foramen Nasal Bone Superior Orbital Fissure Sphenoid Bone Optic Canal Ethmoid Bone Temporal Bone Lacrimal Bone Infraaorbital Foramen Zygomatic Bone Ethmoid Bone Maxilla Vomer Mandible

Process of the Skull– Inferior View Maxilla Palatine Bone Maxilla Zygomatic Bone Sphenoid Bone Zygomatic Process Foramen Ovale Vomer Carotid Canal Styloid Process Jugular Foramen Mastoid Process Temporal Bone Occipital Condyle Parietal Bone Foramen Magnum Occipital Bone

Processes of the Skull – Horizontal View Frontal Bone Ethmoid Bone Sphenoid Bone Optic Canal Foramen Ovale Temporal Bone Jugular Foramen Carotid Canal Parietal Bone Occipital Bone Foramen Magnum