Chapter 07 Axial Skeleton Human Anatomy PDF

Because learning changes everything. ® Chapter 07 Axial Skeleton Human Anatomy SIXTH EDITION McKinley O’Loughlin Pennefather-O’Brien © 2021 McGraw Hill. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or fu...

Because learning changes everything. ® Chapter 07 Axial Skeleton Human Anatomy SIXTH EDITION McKinley O’Loughlin Pennefather-O’Brien © 2021 McGraw Hill. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill.  Outline Skull Sex Differences in the Skull Aging of the Skull Vertebral Column Thoracic Cage Aging of the Axial Skeleton Development of the Axial Skeleton © McGraw Hill 2  Introduction Typically 206 bones in the adult skeleton Skeletal system is divided into two parts: Axial skeleton: skull, vertebral column, and thoracic cage Appendicular skeleton: shoulder and hip bones and those of the upper and lower extremities © McGraw Hill 3  Axial Skeleton Figure 7.1 © McGraw Hill 4  Skull The skull is composed of cranial and facial bones Cranial bones: eight bones that surround and enclose the brain Unpaired: ethmoid, frontal, occipital, and sphenoid Paired: parietal and temporal Facial bones: 14 bones that form the face and have no brain contact Unpaired: vomer and mandible Paired: maxillae, nasal, lacrimal, zygomatic, palatine, and inferior nasal conchae Contains many cavities, the largest being the cranial cavity which houses the brain © McGraw Hill 5  Cranial and Facial Divisions of the Skull Figure 7.2 © McGraw Hill 6  Major Cavities of the Skull Figure 7.3 Access the text alternative for slide images. © McGraw Hill 7  Anterior View of the Skull Figure 7.4 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 8  Superior and Posterior Views of the Skull Figure 7.5 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 9  Lateral View of the Skull Figure 7.6 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 10  Sagittal Section of the Skull Figure 7.7 Access the text alternative for slide images. © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 11  Inferior View of the Skull Figure 7.8 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 12  Superior View of the Endocranial Cavity of the Skull Figure 7.9 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 13  Sutures Immovable joints between skull bones Four major sutures: Coronal suture: junction between frontal and parietal bones Lambdoid suture: junction between occipital and parietal bones Sagittal suture: junction between parietal bones Squamous suture: junction between temporal and parietal bones May contain sutural bones variable in size, number, and location During adulthood, sutures start to disappear as bones fuse © McGraw Hill 14  Bones of the Cranium The eight bones of the cranium protect the brain Calvaria: Skullcap; roof of cranium Made of parietal bones and parts of frontal and occipital bones Base of cranium: floor Made of parts of ethmoid, sphenoid, occipital and temporal bones © McGraw Hill 15  Cranial Bones and Features 1 Table 7.2 Cranial Bones and Selected Features Bone(s) and Associated Bone Boundaries Within the Selected Features and Their Functions Passageways Skull Frontal bone Forms superior and anterior parts Frontal crest: Attachment site for meninges to help Supraorbital foramen of skull, part of anterior cranial stabilize brain within skull fossa and orbit Frontal sinuses: Lighten bone, moisten inhaled air, and give resonance to voice Orbital part: Forms roof of orbit Squamous part: Attachment of scalp muscles Supraorbital margin: Forms protective superior border of orbit Parietal bones Each forms most of lateral and Inferior and superior temporal lines: Attachment site Parietal foramina superior walls of skull for temporalis muscle Parietal eminence: Forms rounded prominence on each side of skull Temporal bones Each forms inferolateral wall of Mandibular fossa: Articulates with mandible Mastoid Carotid canal the skull; forms part of middle air cells: Lighten mastoid process External acoustic meatus cranial fossa; has three parts— Mastoid process: Attachment site of some neck Internal acoustic meatus petrous, squamous, and tympanic muscles to extend or rotate head Mastoid foramen Petrous part: Protects sensory structures in inner ear Stylomastoid foramen Styloid process: Attachment site for hyoid bone Jugular foramen (with occipital ligaments and muscles bone) Squamous part: Attachment site of some jaw muscles Zygomatic process: Articulates with zygomatic bone to form zygomatic arch © McGraw Hill 16  Cranial Bones and Features 2 Table 7.2 Cranial Bones and Selected Features Bone(s) and Associated Passageways Bone Boundaries Within the Skull Selected Features and Their Functions Occipital bone Forms posteroinferior part of skull, including External occipital crest: Attachment Foramen magnum most of the posterior cranial fossa; forms part site for ligaments Hypoglossal canal of base of skull External occipital protuberance: Jugular foramen (with temporal bone) Attachment of muscles that move head Inferior and superior nuchal lines: Attachment of neck ligaments and muscles Occipital condyles: Articulate with first cervical vertebra (atlas) Sphenoid bone Forms part of base of skull, posterior part of Body: Houses sphenoidal sinuses Foramen lacerum (with temporal and eye orbit, part of anterior and middle cranial Sella turcica: Houses pituitary gland occipital bones) fossae Optic canals: House optic nerves (CN Foramen ovale II) Foramen rotundum Medial and lateral pterygoid plates: Foramen spinosum Attachment site for two muscles of Optic canal mastication (chewing muscles) Superior orbital fissure Lesser wings: Form part of anterior cranial fossa; contain optic canal Greater wings: Form part of middle cranial fossa and orbit Sphenoidal sinuses: Moisten inhaled air and give resonance to voice © McGraw Hill 17  Cranial Bones and Features 3 Table 7.2 Cranial Bones and Selected Features Bone(s) and Associated Bone Boundaries Within the Selected Features and Their Passageways Skull Functions Ethmoid bone Forms part of the anterior cranial Crista galli: Attachment site for Cribriform foramina fossa; part of nasal septum; roof cranial dural septa to help stabilize and lateral walls of nasal cavity; brain within skull part of medial wall of eye orbit Ethmoidal labyrinths: Contain the ethmoidal sinuses and nasal conchae Ethmoidal sinuses: Lighten bone, moisten inhaled air, and give resonance to voice Nasal conchae (superior and middle): Increase airflow turbulence in nasal cavity so air can be adequately moistened and cleaned by nasal mucosa Orbital plate: Forms part of medial wall of the orbit Perpendicular plate: Forms superior part of nasal septum © McGraw Hill 18  Anterior View of the Frontal Bone Figure 7.10 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 19  Lateral View of the Parietal Bone Figure 7.11 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 20  Temporal Bone Figure 7.12 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 21  Occipital Bone Figure 7.13 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 22  Sphenoid Bone, Superior View Figure 7.14a © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 23  Sphenoid Bone, Posterior View Figure 7.14b © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 24  Articulations of Sphenoid and Ethmoid Bones Figure 7.15 © McGraw Hill 25  Ethmoid Bone Figure 7.16 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 26  Cranial Fossae 1 A fossa is a depression in a bone The floor of the cranial cavity contains three cranial fossae: Anterior cranial fossa Middle cranial fossa Posterior cranial fossa © McGraw Hill 27  Cranial Fossae 2 Figure 7.17 © McGraw Hill 28  Bones of the Face Fourteen facial bones give shape to the face Form part of the orbital and nasal cavities Support teeth Serve as attachment sites for muscles of expression and chewing © McGraw Hill 29  Facial Bones and Selected Features 1 Table 7.3 Facial Bones and Selected Features Bone and Associated Description and Boundaries Selected Features and Their Functions Passageways of Bone Zygomatic bones Each forms the cheek and Frontal process: Articulates with frontal lateral part of the orbit bone Maxillary process: Articulates with maxilla Temporal process: Articulates with temporal bone to form zygomatic arch Lacrimal bones Each forms part of the medial Lacrimal groove: Contains nasolacrimal wall of the orbit duct Nasal bones Each forms the anterosuperior bridge of the nose Vomer Forms inferior and posterior Ala: Articulates with the sphenoid bone parts of nasal septum Vertical plate: Articulates with perpendicular plate of ethmoid bone Inferior nasal conchae Curved bones that project from Increase airflow turbulence in nasal lateral walls of the nasal cavity cavity © McGraw Hill 30  Facial Bones and Selected Features 2 Table 7.3 Facial Bones and Selected Features Bone and Associated Passageways Description and Boundaries of Selected Features and Their Functions Bone Palatine bones Each forms posterior part of hard Horizontal plate: Forms posterior part of Greater and lesser palatine foramina palate; forms small part of nasal palate cavity and orbit wall Perpendicular plate: Forms part of nasal cavity and orbit Maxillae Each forms anterior portion of face; Alveolar process: Houses the teeth Incisive foramen forms upper jaw and parts of the Frontal process: Forms part of lateral Infraorbital foramen hard palate, inferior parts of orbits, aspect of nasal bridge and part of the walls of nasal cavity Infraorbital margin: Forms inferolateral border of orbit Maxillary sinus: Lightens bone Palatine process: Forms most of bony palate Zygomatic process: Articulates with zygomatic bone Mandible Forms the lower jaw Alveolar process: Houses the teeth Mandibular foramen Coronoid process: Attachment of Mental foramen temporalis muscle Head of mandible: Articulates with temporal bone Mental protuberance: Forms the chin Mylohyoid line: Attachment site for mylohyoid muscle © McGraw Hill 31  Zygomatic Bone Figure 7.18 © McGraw Hill 32  Vomer Figure 7.19 © McGraw Hill 33  Palatine Bone Figure 7.20 © McGraw Hill 34  Maxilla Figure 7.21 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 35  Mandible Figure 7.22 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 36  Nasal Complex 1 The nasal complex is composed of bones and cartilages forming the nasal cavities and paranasal sinuses Superior border: cribriform plate of ethmoid, parts of frontal and sphenoid Inferior border: maxillae and palatine bones Lateral walls: ethmoid, maxillae, inferior nasal conchae, palatine bones, and lacrimal bones © McGraw Hill 37  Nasal Complex 2 Figure 7.23 © McGraw Hill ©McGraw-Hill Education/Photo and Dissection by Christine Eckel 38  Paranasal Sinuses 1 The paranasal sinuses are air-filled spaces within the skull bones surrounding the nasal cavity Functions: Mucous lining humidifies and warms inhaled air Lighten skull Resonant chambers for sound production while speaking © McGraw Hill 39  Paranasal Sinuses 2 Figure 7.24 © McGraw Hill 40  Orbital Complex The orbits are bony cavities in skull that hold and protect the eyes, and the orbital complex consists of multiple bones that form each orbit Borders: Roof of orbit: frontal bone and lesser wing of sphenoid bone Floor: mainly the maxilla bone Medial wall: maxilla, lacrimal, and ethmoid bones Lateral wall: zygomatic, greater wing of sphenoid, and frontal bones Posterior wall: mainly the sphenoid bone © McGraw Hill 41  Left Orbit Figure 7.25 © McGraw Hill 42  Bones Associated with the Skull Auditory ossicles: Three tiny bones in petrous part of each temporal bone are for hearing: Malleus Incus Stapes Hyoid bone: located between the mandible and larynx Does not articulate with another bone Contains a midline body and two hornlike processes, the greater cornu and lesser cornu The hyoid serves as an attachment site for tongue and muscles of larynx used in swallowing © McGraw Hill 43  Hyoid Bone Figure 7.26 © McGraw Hill 44  Sex Differences in the Skull 1 Human male and female skulls show differences in shape and size; this is called sexual dimorphism Typical female features are delicate and small, whereas typical male features are larger, sturdier, and bulkier Features on the skull and rest of skeleton make it possible to determine the sex of an individual © McGraw Hill 45  Sex Differences in the Skull 2 Table 7.4 Sex Differences in the Skull View Female Skull Male Skull Anterior View Lateral View © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 46  Aging of the Skull Infant cranial bones are connected by flexible areas of dense regular connective tissue called fontanelles Major fontanelles: Mastoid fontanelle Sphenoidal fontanelle Posterior fontanelle Anterior fontanelle © McGraw Hill 47  Fetal Skull Figure 7.27 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 48  Vertebral Column The vertebral column is composed of 26 bones, including 24 individual vertebrae Functions of the vertebral column: Provide vertical support for the body Supporting the weight of the head Help maintain upright body position Transfer weight of upper body to lower limbs Protection of spinal cord Provide passageways for spinal nerves © McGraw Hill 49  Division of the Vertebral Column Seven cervical vertebrae (C1-C7) form the bones of the neck Twelve thoracic vertebrae (T1-T12) form the superior regions of the back Each thoracic vertebra articulates with a pair of ribs Five lumbar vertebrae (L1-L5) form the lower back The sacrum (S1-S5) is formed from five fused sacral vertebrae The coccyx (“tailbone”) is formed from four coccygeal vertebrae (Co1-Co4) Begin to fuse during puberty © McGraw Hill 50  Vertebral Column 2 Figure 7.28 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 51  Spinal Curvatures Four spinal curvatures present in adult: Cervical curvature Thoracic curvature Lumbar curvature Sacral curvature Primary curves appear in fetal development Thoracic and sacral curvatures Secondary curves appear at 3–4 months of age Cervical and lumbar curvatures Help shift trunk’s weight over the legs © McGraw Hill 52  Vertebral Anatomy 1 Most vertebrae have the following features: Body: weight-bearing region Adjacent bodies separated by pad of fibrocartilage (intervertebral disc) Vertebral arch: attaches to body to form vertebral foramen Pedicles: feet of the arch Laminae: posterior extensions of the arch Stacked vertebral foramina form vertebral canal (contains spinal cord) and intervertebral foramina (passage for spinal nerves) Processes: Spinous processes project posteriorly Transverse processes project laterally Inferior articular processes of each vertebra attach to the superior articular processes of the vertebra immediately inferior to it Each articular process has smooth articular facet © McGraw Hill 53  Vertebral Anatomy 2 Figure 7.29 © McGraw Hill 54  Characteristic Features of Cervical, Thoracic, and Lumbar Vertebrae 1 Table 7.5 Characteristic Features of Cervical, Thoracic, and Lumbar Vertebrae View (a) Cervical Vertebra (b) Thoracic Vertebra Superior View © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 55  Characteristic Features of Cervical, Thoracic, and Lumbar Vertebrae 2 Table 7.5 Characteristic Features of Cervical, Thoracic, and Lumbar Vertebrae View (a) Cervical Vertebra (b) Thoracic Vertebra Lateral View © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 56  Characteristic Features of Cervical, Thoracic, and Lumbar Vertebrae 3 Table 7.5 Characteristic Features of Cervical, Thoracic, and Lumbar Vertebrae View (c) Lumbar Vertebra Superior View Lateral View © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 57  Atlas (C1) The atlas is the first cervical vertebra, which articulates with the occipital condyles of the skull and functions in supporting the head Figure 7.30a © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 58  Axis (C2) The axis is the second cervical vertebra, which contains a process called the dens Figure 7.30a © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 59  Atlantoaxial Joint The dens of axis serves as a pivot point for atlas, permitting rotation of the head Figure 7.30c © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 60  Sacrum and Coccyx 1 Sacrum: triangular bone forming posterior wall of pelvic cavity Apex: points inferiorly; base is broad superior surface Transverse ridges mark fusion points of the five vertebrae Sacral canal is continuation of vertebral canal Sacral hiatus in inferior opening Anterior and posterior sacral foramina allow nerves to exit Has an auricular surface at sacroiliac joint Coccyx: fusion of four small vertebrae Attachment site for ligaments and muscles Coccygeal cornua are the laminae of the first coccygeal vertebrae © McGraw Hill 61  Sacrum and Coccyx 2 Figure 7.31 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 62  Thoracic Cage 1 The bony framework of the chest is called the thoracic cage, which is composed of: Thoracic vertebrae posteriorly Ribs laterally Sternum anteriorly Protects heart, lungs, trachea, esophagus, and other thoracic organs © McGraw Hill 63  Thoracic Cage 2 Figure 7.32 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 64  Sternum Adult sternum: the “breastbone” in anterior midline of thoracic wall Composed of three major parts: Manubrium Body Xiphoid process © McGraw Hill 65  Ribs Elongated, curved, flat bones that articulate posteriorly with thoracic vertebrae and end in the anterior wall of the thorax Articular facets on the head and tubercle of each rib articulate with vertebral body and transverse process, respectively 12 pairs total True ribs: ribs 1–7; articulate anteriorly with the sternum via costal cartilages False ribs: ribs 8–12; their costal cartilages do not attach directly to the sternum Floating ribs: false ribs (pairs 11 and 12) that do not articulate with the sternum © McGraw Hill 66  Rib Anatomy and Articulation with Thoracic Vertebrae Figure 7.33 © McGraw Hill ©McGraw-Hill Education/Christine Eckel, photographer 67  Aging of the Axial Skeleton Many bones fuse as we age Skeletal mass and density become reduced Bones can become more porous and brittle (osteoporosis), enhancing chance of fracture Articulating surfaces deteriorate, contributing to arthritic conditions © McGraw Hill 68  Development of the Axial Skeleton 1 Most bones form from cartilage (endochondral ossification) Flat skull bones develop from mesenchyme (intramembranous ossification) Sternum develops from cartilaginous sternal bars that fuse medially Figure 7.34 Access the text alternative for slide images. Figure 7.35 © McGraw Hill 69  Development of the Axial Skeleton 2 Ribs and vertebrae develop from sclerotomes of somites Figure 7.36 © McGraw Hill 70  End of Main Content Because learning changes everything. ® www.mheducation.com © 2021 McGraw Hill. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill.