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Chapter 7 Part A The Skeleton © Annie Leibovitz/Contact Press Images © 2016 Pearson Education, Inc. PowerPoint® Lecture Slides prepared by Karen Dunbar Kareiva Ivy Tech Community College Why This Matters • Understanding the anatomy of the skeleton enables you to anticipate problems such as pelvic dimensions that may affect labor and delivery © 2016 Pearson Education, Inc. Video: Why This Matters © 2016 Pearson Education, Inc. The Skeleton • The skeletal system, or skeleton, is composed of bones, cartilages, joints, ligaments – Mostly bone – Cartilage occurs in isolated areas – Ligaments connect bones and reinforce joints • The skeleton accounts for 20% of body mass • Two major divisions – Axial skeleton – Appendicular skeleton © 2016 Pearson Education, Inc. Part 1: The Axial Skeleton • Axial skeleton consists of 80 bones divided into three major regions: – Skull – Vertebral column – Thoracic cage • Axial skeleton has three functions: 1. Form longitudinal axis of body 2. Support head, neck, and trunk 3. Protect brain, spinal cord, and thoracic organs © 2016 Pearson Education, Inc. Figure 7.1a The human skeleton. Cranium Skull Facial bones Clavicle Thoracic cage (ribs, sternum and thoracic vertebrae) Scapula Sternum Rib Humerus Vertebra Vertebral column Radius Ulna Sacrum Carpals Phalanges Metacarpals Femur Patella Tibia Fibula Tarsals Metatarsals Phalanges Anterior view © 2016 Pearson Education, Inc. Figure 7.1b The human skeleton. Cranium Clavicle Bones of pectoral girdle Scapula Rib Humerus Upper limb Vertebra Radius Ulna Bones of pelvic girdle Carpals Phalanges Metacarpals Femur Lower limb Tibia Fibula Posterior view © 2016 Pearson Education, Inc. 7.1 The Skull • Skull is most complex bony structure in body • Formed by two sets of bones: 1. Cranial bones (cranium) • Enclose the brain in the cranial cavity • Provide sites of attachment for head and neck muscles © 2016 Pearson Education, Inc. 7.1 The Skull 2. Facial bones • Form framework of face • Contain cavities for special sense organs for sight, taste, and smell • Provide openings for air and food passage • Secure teeth • Anchor facial muscles used for facial expression – Most skull bones are flat and firmly locked together (except for mandible) • Joints are called sutures – Have a serrated, saw-tooth appearance © 2016 Pearson Education, Inc. Figure 7.2a The skull. Bones of cranium Coronal suture Squamous suture Lambdoid suture Facial bones Cranial and facial divisions of the skull © 2016 Pearson Education, Inc. Overview of Skull Geography • Facial bones form anterior aspect, with cranium forming the rest of skull • Cranium is divided into a vault and a base – Cranial vault (calvaria) forms superior, lateral, and posterior portion of skull, as well as forehead – Cranial base forms inferior aspect of skull • Internally base is divided into three “steps,” or fossae: anterior, middle, posterior fossae • Brain sits within these fossae, enclosed by cranium vault – Area referred to as cranial cavity © 2016 Pearson Education, Inc. Figure 7.2b The skull. Anterior cranial fossa Middle cranial fossa Posterior cranial fossa Superior view of the cranial fossae © 2016 Pearson Education, Inc. Figure 7.2c The skull. Temporal lobe of cerebrum Cerebellum Frontal lobe of cerebrum Posterior Cranial Middle fossae Anterior Lateral view of cranial fossae showing the contained brain regions © 2016 Pearson Education, Inc. Overview of Skull Geography (cont.) • Cranium also contains other cavities: – Middle and internal ear cavities – Nasal cavity – Orbits that house eyeballs • Skull has 85 named openings – Foramina, canals, fissures – Provide passageways for spinal cord, major blood vessels, and the 12 cranial nerves © 2016 Pearson Education, Inc. Figure 7.3 Major cavities of the skull, frontal section. Cranial cavity Frontal sinus Ethmoidal air cells Maxillary sinus Nasal cavity Orbit Orbit Frontal bone Zygomatic bone Ethmoid bone Inferior nasal concha Oral cavity Maxilla Vomer Mandible © 2016 Pearson Education, Inc. Cranium • Cranium is comprised of eight cranial bones: – Frontal bone – Parietal bones (two—left and right) – Occipital bone – Temporal bones (two—left and right) – Sphenoid bone – Ethmoid bone © 2016 Pearson Education, Inc. Cranium (cont.) • Frontal bone: shell-shaped bone forms anterior portion of cranium – Vertical part, called squamous region, is also known as the forehead – Inferior portion ends at supraorbital margins • Area underneath eyebrows – Forms superior wall of the orbits and most of anterior cranial fossa – Supraorbital foramen (notch) allows supraorbital artery and nerve to pass to forehead – Glabella is area of frontal bone between orbits • Frontal sinuses located just lateral to glabella © 2016 Pearson Education, Inc. Figure 7.4a Anterior and posterior views of the skull. Parietal bone Frontal bone Squamous part of frontal bone Glabella Frontonasal suture Nasal bone Supraorbital foramen (notch) Sphenoid bone (greater wing) Temporal bone Ethmoid bone Lacrimal bone Supraorbital margin Superior orbital fissure Optic canal Inferior orbital fissure Zygomatic bone Middle nasal concha Perpendicular plate Infraorbital foramen Maxilla Inferior nasal concha Vomer Mandible Mental foramen Anterior view © 2016 Pearson Education, Inc. Ethmoid bone Mandibular symphysis Figure 7.7a The base of the cranial cavity. View Ethmoid Cribriform plate Crista galli bone Anterior cranial fossa Sphenoid Lesser wing Greater wing Hypophyseal fossa of sella turcica Middle cranial fossa Temporal bone (petrous part) Frontal bone Cribriform foramina Optic canal Foramen rotundum Foramen ovale Foramen spinosum Foramen lacerum Internal acoustic meatus Posterior cranial fossa Jugular foramen Parietal bone Hypoglossal canal Occipital bone Foramen magnum Superior view of the skull, calvaria removed © 2016 Pearson Education, Inc. Figure 7.7b The base of the cranial cavity. View Crista galli Ethmoid Cribriform plate bone Anterior cranial fossa Sphenoid Lesser wing Greater wing Hypophyseal fossa of sella turcica Middle cranial fossa Frontal bone Cribriform foramina Optic canal Foramen rotundum Foramen ovale Foramen spinosum Foramen lacerum Temporal bone (petrous part) Posterior cranial fossa Parietal bone Occipital bone Foramen magnum Photo of superior view of the skull, calvaria removed © 2016 Pearson Education, Inc. Jugular foramen Cranium (cont.) • Parietal bones and the major sutures – Two large parietal bones form most of superior and lateral aspects of cranial vault – Four sutures mark articulations of parietal bones with frontal, occipital, and temporal bones: 1. Coronal suture: between parietal bones and frontal bone 2. Sagittal suture: between right and left parietal bones 3. Lambdoid suture: between parietal bones and occipital bone 4. Squamous (squamosal) sutures: between parietal and temporal bones on each side of skull © 2016 Pearson Education, Inc. Figure 7.2a The skull. Bones of cranium Coronal suture Squamous suture Lambdoid suture Facial bones Cranial and facial divisions of the skull © 2016 Pearson Education, Inc. Figure 7.4b Anterior and posterior views of the skull. Sagittal suture Parietal bone Sutural bone Lambdoid suture Occipital bone Superior nuchal line External occipital protuberance Occipitomastoid suture External occipital crest Posterior view © 2016 Pearson Education, Inc. Inferior nuchal line Occipital condyle Mastoid process of temporal bone Figure 7.5a Bones of the lateral aspect of the skull, external and internal views. Frontal bone Sphenoid bone (greater wing) Ethmoid bone Lacrimal bone Coronal suture Parietal bone Squamous suture Lambdoid suture Lacrimal fossa Occipital bone Temporal bone Nasal bone Zygomatic bone Maxilla Zygomatic process Occipitomastoid suture External acoustic meatus Mastoid process Styloid process Alveolar processes Condylar process Mandibular notch Mandibular ramus External anatomy of the right side of the skull © 2016 Pearson Education, Inc. Mandible Mental foramen Mandibular angle Coronoid process Figure 7.5b Bones of the lateral aspect of the skull, external and internal views. Coronal suture Parietal bone Squamous suture Temporal bone Zygomatic process Lambdoid suture Occipital bone Occipitomastoid suture External acoustic meatus Mastoid process Styloid process Condylar process Mandibular angle Photograph of right side of skull © 2016 Pearson Education, Inc. Frontal bone Sphenoid bone (greater wing) Ethmoid bone Lacrimal bone Nasal bone Lacrimal fossa Zygomatic bone Coronoid process Maxilla Alveolar processes Mandible Mental foramen Mandibular notch Mandibular ramus Figure 7.5c Bones of the lateral aspect of the skull, external and internal views. Parietal bone Squamous suture Temporal bone Lambdoid suture Occipital bone Occipitomastoid suture External occipital protuberance Internal acoustic meatus Coronal suture Frontal bone Greater wing Lesser wing Sphenoid bone Frontal sinus Crista galli Nasal bone Sphenoidal sinus Ethmoid bone (perpendicular plate) Vomer Incisive canal Maxilla Pterygoid Alveolar processes process of sphenoid bone Mandible Mandibular foramen Palatine bone Palatine process of maxilla Midsagittal section showing the internal anatomy of the left half of skull Sella turcica of sphenoid bone © 2016 Pearson Education, Inc. Figure 7.5d Bones of the lateral aspect of the skull, external and internal views. Greater wing of sphenoid bone Lesser wing of sphenoid bone Frontal sinus Petrous part of temporal bone External occipital protuberance Internal acoustic meatus Sella turcica and sphenoidal sinus Photo of skull cut through the midline, same view as in (c) © 2016 Pearson Education, Inc. Crista galli Ethmoid bone (perpendicular plate) Palatine bone Cranium (cont.) • Occipital bone – Forms most of skull’s posterior wall and posterior cranial fossa – Articulates with parietal, temporal, and sphenoid bones – Foramen magnum: “large hole” through which brain connects with spinal cord • Flanked by pair of occipital condyles that articulate with 1st vertebra – Hypoglossal canal allows cranial nerve XII to pass through © 2016 Pearson Education, Inc. Cranium (cont.) – External occipital protuberance: protrusion just superior to foramen magnum – External occipital crest: ridges that are site of attachment for ligamentum nuchae – Superior and inferior nuchal lines: site of attachment for many neck and back muscles © 2016 Pearson Education, Inc. Figure 7.4b Anterior and posterior views of the skull. Sagittal suture Parietal bone Sutural bone Lambdoid suture Occipital bone Superior nuchal line External occipital protuberance Occipitomastoid suture External occipital crest Posterior view © 2016 Pearson Education, Inc. Inferior nuchal line Occipital condyle Mastoid process of temporal bone Figure 7.6a Inferior aspect of the skull, mandible removed. Hard palate Maxilla (palatine process) Palatine bone (horizontal plate) Zygomatic bone Temporal bone (zygomatic process) Vomer Mandibular fossa Styloid process Mastoid process Temporal bone (petrous part) Basilar part of the occipital bone Parietal bone External occipital crest External occipital protuberance Inferior view of the skull (mandible removed) © 2016 Pearson Education, Inc. Incisive fossa Intermaxillary suture Median palatine suture Infraorbital foramen Maxilla Sphenoid bone (greater wing) Foramen ovale Foramen spinosum Foramen lacerum Carotid canal External acoustic meatus Stylomastoid foramen Jugular foramen Occipital condyle Inferior nuchal line Superior nuchal line Occipital bone Foramen magnum Figure 7.6b Inferior aspect of the skull, mandible removed. Hard palate Zygomatic arch Mandibular fossa Mastoid process Foramen ovale Foramen lacerum Foramen spinosum Carotid canal Styloid process Jugular foramen Occipital condyle Foramen magnum Photo of inferior view of the skull © 2016 Pearson Education, Inc. Superior nuchal line Cranium (cont.) • Temporal bones: paired bones that make up inferolateral aspects of skull and parts of cranial base – Three major regions: 1. Squamous: zygomatic processes articulate with zygomatic bone to form zygomatic arch and mandibular fossa makes up part of temporomandibular joint 2. Tympanic: surround external acoustic meatus (external ear canal) © 2016 Pearson Education, Inc. Cranium (cont.) 3. Petrous: houses middle and internal ear cavities – Makes up part of the middle cranial fossa – Several foramina penetrate petrous region: » Jugular foramen allows passage of three cranial nerves » Carotid canal: passageway for internal carotid artery » Foramen lacerum: jagged opening covered by cartilage in living human » Internal acoustic meatus and styloidmastoid foramen: cranial nerve passageways – Mastoid and styloid processes: areas for attachment of several neck and tongue muscles © 2016 Pearson Education, Inc. Figure 7.5a Bones of the lateral aspect of the skull, external and internal views. Frontal bone Sphenoid bone (greater wing) Ethmoid bone Lacrimal bone Coronal suture Parietal bone Squamous suture Lambdoid suture Lacrimal fossa Occipital bone Temporal bone Nasal bone Zygomatic bone Maxilla Zygomatic process Occipitomastoid suture External acoustic meatus Mastoid process Styloid process Alveolar processes Condylar process Mandibular notch Mandibular ramus External anatomy of the right side of the skull © 2016 Pearson Education, Inc. Mandible Mental foramen Mandibular angle Coronoid process Figure 7.5b Bones of the lateral aspect of the skull, external and internal views. Coronal suture Parietal bone Squamous suture Temporal bone Zygomatic process Lambdoid suture Occipital bone Occipitomastoid suture External acoustic meatus Mastoid process Styloid process Condylar process Mandibular angle Photograph of right side of skull © 2016 Pearson Education, Inc. Frontal bone Sphenoid bone (greater wing) Ethmoid bone Lacrimal bone Nasal bone Lacrimal fossa Zygomatic bone Coronoid process Maxilla Alveolar processes Mandible Mental foramen Mandibular notch Mandibular ramus Figure 7.8 The temporal bone. External acoustic meatus Petrous part Mastoid process Styloid process © 2016 Pearson Education, Inc. Squamous part Zygomatic process Mandibular fossa Tympanic part Figure 7.6a Inferior aspect of the skull, mandible removed. Hard palate Maxilla (palatine process) Palatine bone (horizontal plate) Zygomatic bone Temporal bone (zygomatic process) Vomer Mandibular fossa Styloid process Mastoid process Temporal bone (petrous part) Basilar part of the occipital bone Parietal bone External occipital crest External occipital protuberance Inferior view of the skull (mandible removed) © 2016 Pearson Education, Inc. Incisive fossa Intermaxillary suture Median palatine suture Infraorbital foramen Maxilla Sphenoid bone (greater wing) Foramen ovale Foramen spinosum Foramen lacerum Carotid canal External acoustic meatus Stylomastoid foramen Jugular foramen Occipital condyle Inferior nuchal line Superior nuchal line Occipital bone Foramen magnum Figure 7.7a The base of the cranial cavity. View Ethmoid Cribriform plate Crista galli bone Anterior cranial fossa Sphenoid Lesser wing Greater wing Hypophyseal fossa of sella turcica Middle cranial fossa Temporal bone (petrous part) Frontal bone Cribriform foramina Optic canal Foramen rotundum Foramen ovale Foramen spinosum Foramen lacerum Internal acoustic meatus Posterior cranial fossa Jugular foramen Parietal bone Hypoglossal canal Occipital bone Foramen magnum Superior view of the skull, calvaria removed © 2016 Pearson Education, Inc. Clinical – Homeostatic Imbalance 7.1 • Mastoid process contains cavities (sinuses) called mastoid air cells • Mastoiditis can develop if a middle ear infection spreads into mastoid process area • Mastoid air cells are separated from brain by a very thin bony plate, increasing chances that the infection could spread to brain © 2016 Pearson Education, Inc. Cranium (cont.) • Sphenoid bone: complex, bat-shaped bone – Keystone bone that articulates with all other cranial bones – Sphenoidal sinuses found within body of sphenoid – Body also includes sella turcica prominence that includes hypophyseal fossa area enclosing the pituitary gland © 2016 Pearson Education, Inc. Cranium (cont.) • Sphenoid contains three pairs of processes: – Greater wings – Lesser wings – Pterygoid processes • Sphenoid contains several foramina: – Optic canals: allow passage of optic nerves – Superior orbital fissure: cranial nerve passage – Foramen rotundum and foramen ovale: also passageways for cranial nerves – Foramen spinosum: opening for arteries © 2016 Pearson Education, Inc. Figure 7.9 The sphenoid bone. Optic canal Lesser wing Body of sphenoid Superior orbital fissure Foramen rotundum Foramen ovale Foramen spinosum Greater wing Hypophyseal fossa of sella turcica Superior view Body of sphenoid Greater wing Lesser wing Superior orbital fissure Pterygoid process Posterior view © 2016 Pearson Education, Inc. Cranium (cont.) • Ethmoid bone: deepest skull bone – Superior part formed by paired cribriform plates that also form roof of nasal cavity and floor of anterior cranial fossa – Crista galli: triangular process that is point of attachment for brain’s dura mater covering – Perpendicular plate: forms superior part of nasal septum and is flanked by lateral masses that contain sinuses called ethmoidal air cells • Lateral masses extend medially to form superior and middle nasal conchae – Orbital plates contribute to medial wall of orbits © 2016 Pearson Education, Inc. Figure 7.10 The ethmoid bone. Crista galli Cribriform plate with cribriform foramina Orbital plate Left lateral mass Ethmoidal air cells Perpendicular plate © 2016 Pearson Education, Inc. Middle nasal concha Figure 7.4a Anterior and posterior views of the skull. Parietal bone Frontal bone Squamous part of frontal bone Glabella Frontonasal suture Nasal bone Supraorbital foramen (notch) Sphenoid bone (greater wing) Temporal bone Ethmoid bone Lacrimal bone Supraorbital margin Superior orbital fissure Optic canal Inferior orbital fissure Zygomatic bone Middle nasal concha Perpendicular plate Infraorbital foramen Maxilla Inferior nasal concha Vomer Mandible Mental foramen Anterior view © 2016 Pearson Education, Inc. Ethmoid bone Mandibular symphysis Figure 7.7a The base of the cranial cavity. View Ethmoid Cribriform plate Crista galli bone Anterior cranial fossa Sphenoid Lesser wing Greater wing Hypophyseal fossa of sella turcica Middle cranial fossa Temporal bone (petrous part) Frontal bone Cribriform foramina Optic canal Foramen rotundum Foramen ovale Foramen spinosum Foramen lacerum Internal acoustic meatus Posterior cranial fossa Jugular foramen Parietal bone Hypoglossal canal Occipital bone Foramen magnum Superior view of the skull, calvaria removed © 2016 Pearson Education, Inc. Cranium (cont.) • Sutural bones – Tiny, irregularly shaped bones that appear within sutures – Significance is unknown, as not everyone has these © 2016 Pearson Education, Inc. Figure 7.4b Anterior and posterior views of the skull. Sagittal suture Parietal bone Sutural bone Lambdoid suture Occipital bone Superior nuchal line External occipital protuberance Occipitomastoid suture External occipital crest Posterior view © 2016 Pearson Education, Inc. Inferior nuchal line Occipital condyle Mastoid process of temporal bone Facial Bones Facial skeleton is made up of 14 bones, 12 of which are paired (mandible and vomer are single) • • • • Mandible Maxillary bones (2) Zygomatic bones (2) Nasal bones (2) © 2016 Pearson Education, Inc. • • • • Lacrimal bones (2) Palatine bones (2) Vomer Inferior nasal conchae (2) Facial Bones (cont.) • Mandible: largest, strongest bone of face – U-shaped lower jawbone made up of body (chin) and two upright rami • Mandibular angle: point where rami and chin meet • Coronoid process: superior end of rami serves as insertion point for large temporalis muscle • Condylar process: posterior to coronoid forms part of temporomandibular joint – Mandibular notch: separates processes • Body consists of alveolar process that contains sockets for teeth and mandibular symphysis ridge • Foramina include mandibular (for nerves) and mental foramina (for nerves and blood vessels) © 2016 Pearson Education, Inc. Figure 7.11a Detailed anatomy of the mandible and the maxilla. Temporomandibular joint Mandibular fossa of temporal bone Mandibular notch Condylar process Coronoid process Mandibular foramen Alveolar process Mental foramen Ramus of mandible Mandibular angle Body of mandible Mandible, right lateral view © 2016 Pearson Education, Inc. Figure 7.4a Anterior and posterior views of the skull. Parietal bone Frontal bone Squamous part of frontal bone Glabella Frontonasal suture Nasal bone Supraorbital foramen (notch) Sphenoid bone (greater wing) Temporal bone Ethmoid bone Lacrimal bone Supraorbital margin Superior orbital fissure Optic canal Inferior orbital fissure Zygomatic bone Middle nasal concha Perpendicular plate Infraorbital foramen Maxilla Inferior nasal concha Vomer Mandible Mental foramen Anterior view © 2016 Pearson Education, Inc. Ethmoid bone Mandibular symphysis Facial Bones (cont.) • Maxillary bones (maxillae): medially fused to form upper jaw and central facial skeleton – Upper teeth held in alveolar processes – Anterior nasal spine forms just below nose – Palatine process forms two-thirds of hard palate – Frontal process: forms lateral bridge of nose – Zygomatic processes articulate with zygomatic bones – Maxillary sinuses: flank nasal cavity laterally © 2016 Pearson Education, Inc. Facial Bones (cont.) – Openings for nerves and blood vessels include: • Inferior orbital fissure • Infraorbital foramen • Incisive fossa and canal © 2016 Pearson Education, Inc. Figure 7.11b Detailed anatomy of the mandible and the maxilla. Orbital surface Zygomatic process (cut) Maxilla, right lateral view © 2016 Pearson Education, Inc. Articulates with frontal bone Frontal process Infraorbital foramen Anterior nasal spine Alveolar process Figure 7.4a Anterior and posterior views of the skull. Parietal bone Frontal bone Squamous part of frontal bone Glabella Frontonasal suture Nasal bone Supraorbital foramen (notch) Sphenoid bone (greater wing) Temporal bone Ethmoid bone Lacrimal bone Supraorbital margin Superior orbital fissure Optic canal Inferior orbital fissure Zygomatic bone Middle nasal concha Perpendicular plate Infraorbital foramen Maxilla Inferior nasal concha Vomer Mandible Mental foramen Anterior view © 2016 Pearson Education, Inc. Ethmoid bone Mandibular symphysis Figure 7.6a Inferior aspect of the skull, mandible removed. Hard palate Maxilla (palatine process) Palatine bone (horizontal plate) Zygomatic bone Temporal bone (zygomatic process) Vomer Mandibular fossa Styloid process Mastoid process Temporal bone (petrous part) Basilar part of the occipital bone Parietal bone External occipital crest External occipital protuberance Inferior view of the skull (mandible removed) © 2016 Pearson Education, Inc. Incisive fossa Intermaxillary suture Median palatine suture Infraorbital foramen Maxilla Sphenoid bone (greater wing) Foramen ovale Foramen spinosum Foramen lacerum Carotid canal External acoustic meatus Stylomastoid foramen Jugular foramen Occipital condyle Inferior nuchal line Superior nuchal line Occipital bone Foramen magnum Facial Bones (cont.) • Zygomatic bones – Form cheekbones and inferolateral margins of orbits – Articulate with zygomatic processes of temporal, frontal, and maxillary bones © 2016 Pearson Education, Inc. Figure 7.4a Anterior and posterior views of the skull. Parietal bone Frontal bone Squamous part of frontal bone Glabella Frontonasal suture Nasal bone Supraorbital foramen (notch) Sphenoid bone (greater wing) Temporal bone Ethmoid bone Lacrimal bone Supraorbital margin Superior orbital fissure Optic canal Inferior orbital fissure Zygomatic bone Middle nasal concha Perpendicular plate Infraorbital foramen Maxilla Inferior nasal concha Vomer Mandible Mental foramen Anterior view © 2016 Pearson Education, Inc. Ethmoid bone Mandibular symphysis Facial Bones (cont.) • Nasal bones – Form bridge of nose – Articulate with frontal, maxillary, and ethmoid bones – Attach to cartilage that forms tip of nose • Lacrimal bones – Form medial walls of orbits – Articulate with frontal, maxillary, and ethmoid bones – Lacrimal fossa that houses lacrimal sac allows passageway for tears to drain © 2016 Pearson Education, Inc. Figure 7.4a Anterior and posterior views of the skull. Parietal bone Frontal bone Squamous part of frontal bone Glabella Frontonasal suture Nasal bone Supraorbital foramen (notch) Sphenoid bone (greater wing) Temporal bone Ethmoid bone Lacrimal bone Supraorbital margin Superior orbital fissure Optic canal Inferior orbital fissure Zygomatic bone Middle nasal concha Perpendicular plate Infraorbital foramen Maxilla Inferior nasal concha Vomer Mandible Mental foramen Anterior view © 2016 Pearson Education, Inc. Ethmoid bone Mandibular symphysis Figure 7.5a Bones of the lateral aspect of the skull, external and internal views. Frontal bone Sphenoid bone (greater wing) Ethmoid bone Lacrimal bone Coronal suture Parietal bone Squamous suture Lambdoid suture Lacrimal fossa Occipital bone Temporal bone Nasal bone Zygomatic bone Maxilla Zygomatic process Occipitomastoid suture External acoustic meatus Mastoid process Styloid process Alveolar processes Condylar process Mandibular notch Mandibular ramus External anatomy of the right side of the skull © 2016 Pearson Education, Inc. Mandible Mental foramen Mandibular angle Coronoid process Facial Bones (cont.) • Palatine bones – L-shaped bones made from two bony plates • Horizontal plate: completes posterior one-third of hard palate • Perpendicular plate: forms part of posterolateral walls of the nasal cavity and a small part of the orbits • Vomer – Plow-shaped bone; forms part of nasal septum © 2016 Pearson Education, Inc. Figure 7.6a Inferior aspect of the skull, mandible removed. Hard palate Maxilla (palatine process) Palatine bone (horizontal plate) Zygomatic bone Temporal bone (zygomatic process) Vomer Mandibular fossa Styloid process Mastoid process Temporal bone (petrous part) Basilar part of the occipital bone Parietal bone External occipital crest External occipital protuberance Inferior view of the skull (mandible removed) © 2016 Pearson Education, Inc. Incisive fossa Intermaxillary suture Median palatine suture Infraorbital foramen Maxilla Sphenoid bone (greater wing) Foramen ovale Foramen spinosum Foramen lacerum Carotid canal External acoustic meatus Stylomastoid foramen Jugular foramen Occipital condyle Inferior nuchal line Superior nuchal line Occipital bone Foramen magnum Figure 7.14a Bones of the nasal cavity. Superior, middle, and inferior meatus Frontal sinus Superior nasal concha Middle nasal concha Ethmoid bone Inferior nasal concha Nasal bone Anterior nasal spine Sphenoid bone Sphenoidal sinus Pterygoid process Palatine bone (perpendicular plate) Maxillary bone (palatine process) Palatine bone (horizontal plate) Bones forming the left lateral wall of the nasal cavity (nasal septum removed) © 2016 Pearson Education, Inc. Figure 7.14b Bones of the nasal cavity. Ethmoid bone Crista galli Cribriform plate Frontal sinus Sella turcica Nasal bone Sphenoidal sinus Palatine bone Perpendicular plate of ethmoid bone Septal cartilage Vomer Alveolar process Palatine process of maxilla of maxilla Nasal cavity with septum in place showing the contributions of the ethmoid bone, the vomer, and septal cartilage Hard palate © 2016 Pearson Education, Inc. Facial Bones (cont.) • Inferior nasal conchae – Paired bones that form part of lateral walls of nasal cavity – Largest of three pairs of conchae • Ethmoid bone forms other two pairs © 2016 Pearson Education, Inc. Figure 7.14a Bones of the nasal cavity. Superior, middle, and inferior meatus Frontal sinus Superior nasal concha Middle nasal concha Ethmoid bone Inferior nasal concha Nasal bone Anterior nasal spine Sphenoid bone Sphenoidal sinus Pterygoid process Palatine bone (perpendicular plate) Maxillary bone (palatine process) Palatine bone (horizontal plate) Bones forming the left lateral wall of the nasal cavity (nasal septum removed) © 2016 Pearson Education, Inc. The Hyoid Bone • Not a bone of skull • Lies in anterior neck inferior to mandible • Only bone in body that does not articulate directly with another bone – Anchored by ligaments • Acts as a movable base for tongue and site of attachment for muscles of swallowing and speech © 2016 Pearson Education, Inc. Figure 7.12 The hyoid bone. Greater horn Lesser horn Body © 2016 Pearson Education, Inc. Special Characteristics of the Orbits and Nasal Cavity • Orbits – Cavities that encase eyes and lacrimal glands – Sites of attachment for eye muscles – Formed by parts of seven bones • Frontal, sphenoid, zygomatic, maxilla, palatine, lacrimal, and ethmoid © 2016 Pearson Education, Inc. Figure 7.13a Bones that form the orbits. Photograph, right orbit © 2016 Pearson Education, Inc. Figure 7.13b Bones that form the orbits. Roof of orbit • Lesser wing of sphenoid bone • Orbital plate of frontal bone Lateral wall of orbit • Zygomatic process of frontal bone • Greater wing of sphenoid bone • Orbital surface of zygomatic bone Inferior orbital fissure Infraorbital groove Zygomatic bone Supraorbital notch Superior orbital fissure Optic canal Medial wall • Sphenoid body • Orbital plate of ethmoid bone • Frontal process of maxilla • Lacrimal bone Nasal bone Floor of orbit • Orbital process of palatine bone • Orbital surface of maxillary bone • Zygomatic bone Infraorbital foramen Contribution of each of the seven bones forming the right orbit © 2016 Pearson Education, Inc. Special Characteristics of the Orbits and Nasal Cavity (cont.) • Nasal cavity: formed by parts of several bones – Roof: cribriform plates of ethmoid – Lateral walls: superior and middle conchae of ethmoid, perpendicular plates of palatine and Inferior nasal conchae • Spaces between conchae called meatuses • Conchae increase turbulence of air flow – Floor: processes of palatine and maxillary bones – Nasal septum • Bony posterior formed by vomer and perpendicular plate of ethmoid • Anterior formed by septal cartilage © 2016 Pearson Education, Inc. Figure 7.14a Bones of the nasal cavity. Superior, middle, and inferior meatus Frontal sinus Superior nasal concha Middle nasal concha Ethmoid bone Inferior nasal concha Nasal bone Anterior nasal spine Sphenoid bone Sphenoidal sinus Pterygoid process Palatine bone (perpendicular plate) Maxillary bone (palatine process) Palatine bone (horizontal plate) Bones forming the left lateral wall of the nasal cavity (nasal septum removed) © 2016 Pearson Education, Inc. Figure 7.14b Bones of the nasal cavity. Ethmoid bone Crista galli Cribriform plate Frontal sinus Sella turcica Nasal bone Sphenoidal sinus Palatine bone Perpendicular plate of ethmoid bone Septal cartilage Vomer Alveolar process Palatine process of maxilla of maxilla Nasal cavity with septum in place showing the contributions of the ethmoid bone, the vomer, and septal cartilage Hard palate © 2016 Pearson Education, Inc. Special Characteristics of the Orbits and Nasal Cavity (cont.) • Paranasal sinuses: formed from five skull bones: frontal, sphenoid, ethmoid, and paired maxillary bones – All contain mucosa-lined, air-filled spaces – Functions: • Warm and humidify air • Help to lighten skull • Enhance resonance of voice © 2016 Pearson Education, Inc. Figure 7.15a Paranasal sinuses. Frontal sinus Ethmoidal air cells (sinus) Sphenoidal sinus Maxillary sinus Anterior aspect © 2016 Pearson Education, Inc. Figure 7.15b Paranasal sinuses. Frontal sinus Ethmoidal air cells Sphenoidal sinus Maxillary sinus Medial aspect © 2016 Pearson Education, Inc.
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