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© 2015 Pearson Education Inc.
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An Introduction to the Axial Skeleton
Learning Outcomes 7-1 Identify the bones of the axial skeleton, and specify their functions. 7-2 Identify the bones, foramina, and fissures of the cranium and face, and explain the significance of the markings on the individual bones. 7-3 Describe the structure and functions of the orbital complex, nasal complex, and paranasal sinuses. © 2015 Pearson Education Inc.
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An Introduction to the Axial Skeleton
Learning Outcomes 7-4 Describe the key structural differences among the skulls of infants, children, and adults. 7-5 Identify and describe the curvatures of the spinal column, and indicate the function of each. 7-6 Identify the vertebral regions, and describe the distinctive structural and functional characteristics of vertebrae in each region. 7-7 Explain the significance of the articulations between the thoracic vertebrae and the ribs, and between the ribs and sternum. © 2015 Pearson Education Inc.
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7-1 The Axial Skeleton The Axial Skeleton
Forms the longitudinal axis of the body Has 80 bones The skull 8 cranial bones 14 facial bones Bones associated with the skull 6 auditory ossicles The hyoid bone © 2015 Pearson Education Inc.
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An Anterior View of the Appendicular Skeleton (Part 1 of 2).
SKELETAL SYSTEM 206 AXIAL SKELETON 80 APPENDICULAR SKELETON 126 (see Figure 7–1) Clavicle 2 Pectoral girdles 4 Scapula 2 Humerus 2 Upper limbs 60 Radius 2 Ulna 2 Carpal bones 16 Metacarpal bones 10 Phalanges 28 Pelvic girdle 2 Hip bone 2
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7-1 The Axial Skeleton The Axial Skeleton The vertebral column
24 vertebrae (singular vertebra) The sacrum The coccyx The thoracic cage 24 ribs The sternum © 2015 Pearson Education Inc.
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Figure 7-1a The Axial Skeleton.
SKELETAL SYSTEM 206 APPENDICULAR SKELETON AXIAL SKELETON 80 (see Figure 8-1) 8 Cranium Skull 14 Face Skull and associated bones Auditory ossicles 29 6 Associated bones 1 Hyoid 1 Sternum Thoracic cage 25 24 Ribs 24 Vertebrae 1 Sacrum 26 Vertebral column 1 Coccyx a An anterior view of the entire skeleton, with the axial components highlighted. The numbers in the boxes indicate the number of bones in the adult skeleton.
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7-1 The Axial Skeleton Functions of the Axial Skeleton
Supports and protects organs in body cavities Attaches to muscles of head, neck, and trunk Performs respiratory movements Stabilizes parts of appendicular skeleton © 2015 Pearson Education Inc.
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Figure 7-1b The Axial Skeleton.
Skull Cervical vertebrae Sternum Thoracic vertebrae Ribs Costal cartilages Lumbar vertebrae Sacrum Coccyx Anterior (left) posterior (right) axial skeleton. b
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Figure 7-2 Cranial and Facial Subdivisions of the Skull (Part 1 of 3).
8 cranial bones Form the braincase, or cranium FACE 14 CRANIUM 8 ASSOCIATED BONES 7 7 Maxillae 2 Occipital bone 1 Palatine bones 2 Parietal bones 2 1 Hyoid bone 1 Auditory ossicles enclosed in temporal bones (detailed in Chapter 17) 6 Nasal bones 2 Frontal bone Inferior nasal conchae 2 Temporal bones 2 Zygomatic bones 2 Sphenoid 1 Lacrimal bones 2 Ethmoid 1 Vomer 1 Mandible 1 Hyoid bone 14 facial bones Protect and support entrances to digestive and respiratory tracts
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Figure 7-2 Cranial and Facial Subdivisions of the Skull (Part 2 of 3).
Cranial Bones Enclose the cranial cavity Which contains the brain And its fluids, blood vessels, nerves, and membranes Facial Bones Superficial facial bones For muscle attachment Deep facial bones Separate the oral and nasal cavities Form the nasal septum Frontal bone Parietal bone Nasal bone Lacrimal bone Vomer Temporal bone Zygomatic bone Ethmoid Maxilla Sphenoid Occipital bone Mandible Facial bones protect and support the entrances to the digestive and respiratory tracts. Cranial bones surround and protect the brain.
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Figure 7-3a The Adult Skull.
Major Sutures of the Skull Sagittal suture Parietal bone (left) Parietal bone (right) Lambdoid suture Occipital bone Squamous suture Temporal bone Mastoid process Styloid process Occipital condyle External occipital protuberance Mandible Posterior view a
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Figure 7-3b The Adult Skull.
Occipital bone Major Sutures of the Skull Lambdoid suture Separates occipital from parietal bones may contain sutural (Wormian) bones Parietal bone (right) Parietal bone (left) Sagittal suture Between the parietal bones From lambdoid suture to coronal suture Form boundaries between temporal bones and parietal bones Coronal suture Attaches frontal bone to parietal bones The calvaria (skullcap) Consists of occipital, parietal, and frontal bones Frontal bone Zygomatic Bone Nasal bones Superior view b
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7-2 The Cranial Bones of the Skull
The Occipital Bone: Forms the posterior and inferior surfaces of the cranium Marks of the occipital bone External occipital protuberance External occipital crest Occipital condyles articulate with neck Inferior and superior nuchal lines: attachment sites of muscles and ligaments © 2015 Pearson Education Inc.
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7-2 The Cranial Bones of the Skull
The Parietal Bones: Form part of the superior and lateral surfaces of the cranium Marks of the parietal bones Superior and inferior temporal lines To attach temporalis muscle Grooves for cranial blood vessels
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7-2 The Cranial Bones of the Skull
The Frontal Bone: Forms the anterior cranium and upper eye sockets Contains frontal sinuses Marks of the frontal bone Frontal squama (forehead) Supraorbital margin (protects eye) Lacrimal fossa (for tear ducts) Frontal sinuses
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7-2 The Cranial Bones of the Skull
The Temporal Bones Part of lateral walls of cranium and zygomatic arches Articulate with mandible Surround and protect inner ear Attach muscles of jaws and head
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Figure 7-3c The Adult Skull.
Major Sutures of the Skull Parietal bone Frontal bone Coronal suture Sphenoid Squamous suture Supraorbital foramen Temporal bone Nasal bone Lambdoid suture Lacrimal bone Squamous part of temporal bone Form boundaries between temporal bones and parietal bones Ethmoid Infraorbital foramen Occipital bone Maxilla External acoustic meatus Zygomatic bone Mastoid process Styloid process Mandible Zygomatic process of temporal bone Mental foramen Zygomatic arch Temporal process of zygomatic bone Mental protuberance Lateral view c
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Figure 7-3d The Adult Skull.
Sagittal suture Foramen or Fissure Major Structures Using Passageway Parietal bone Coronal suture Frontal Bone Nasal bone Supraorbital foramen Supraorbital nerve (branch of N V) Ethmoid Supraorbital artery Temporal bone Sphenoid Palatine bone Optic canal • Optic nerve (N II) • Ophthalmic artery Lacrimal bone Superior orbital fissure • Oculomotor nerve (N III), trochlear nerve (N IV), opthalmic branch of trigeminal nerve (N V), and abducens nerve (N VI) Zygomatic bone Mastoid process of temporal bone Inferior orbital fissure • Maxillary branch of trigeminal nerve (N V) Middle nasal concha (part of ethmoid) Maxilla Inferior nasal concha Infraorbital foramen • Infraorbital nerve, branch of maxillary nerve (N V) Bony nasal septum • Infraorbital artery Perpendicular plate of ethmoid Mandible Vomer Anterior view Mental foramen • Mental nerve, branch of mandibular nerve (N V) d Mental protuberance • Mental vessels
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Figure 7-3e The Adult Skull.
Frontal bone Sphenoid Maxilla Foramen lacerum (with temporal and occipital bones) • Internal carotid artery after leaving carotid canal Palatine bone Zygomatic bone • Auditory tube Zygomatic arch Foramen ovale • Mandibular branch of trigeminal nerve (N V) Medial and lateral pterygoid processes Temporal Bone Vomer External acoustic meatus • Air in meatus conducts sound to eardrum Styloid process Mandibular fossa Occipital condyle Carotid canal • Internal carotid artery Stylomastoid foramen • Facial nerve (N V) Mastoid process Occipital Bone Foramen magnum • Medulla oblongata (most caudal portion of brain) Lambdoid suture Occipital bone • Accessory nerve (XI) • Vertebral arteries External occipital protuberance Jugular foramen • Glossopharyngeal, vagus, and accessory nerves (N IX, X, XI) (with temporal bone) Inferior view e
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Figure 7-5a The Occipital and Parietal Bones.
Foramen magnum connects cranial and spinal cavities Jugular foramen for jugular vein Hypoglossal canals for hypoglossal nerves Hypoglossal canal Occipital condyle Foramen magnum External occipital crest Inferior nuchal line Superior nuchal line External occipital protuberance a Occipital bone, inferior view
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Figure 7-5b The Occipital and Parietal Bones.
Superior temporal line Inferior temporal line b Right parietal bone, lateral view
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Figure 7-6a The Frontal Bone.
Frontal (metopic) suture Frons Supraorbital foramen For blood vessels of eyebrows, eyelids, and frontal sinuses Supraorbital notch An incomplete supraorbital foramen Superior temporal line Glabella Supraorbital margin Supraorbital notch a Anterior surface
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Figure 7-6b The Frontal Bone.
Supraorbital foramen Frontal sinus Supraorbital margin Lacrimal fossa Inferior (orbital) surface Sinuses Cavities that decrease the weight of the skull Lined with mucous membranes Protect the entrances of the respiratory system
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7-2 The Cranial Bones of the Skull
The Temporal Bones Squamous part Zygomatic process Mandibular fossa Mastoid process Styloid process Petrous part Auditory ossicles © 2015 Pearson Education Inc.
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7-2 The Cranial Bones of the Skull
Auditory Ossicles Three tiny bones in tympanic cavity (middle ear) Transfer sound from tympanic membrane (eardrum) to inner ear © 2015 Pearson Education Inc.
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7-2 The Cranial Bones of the Skull
The Temporal Bones Foramina of the temporal bones Carotid canal for internal carotid artery Foramen lacerum For carotid and small arteries Hyaline cartilage Auditory tube © 2015 Pearson Education Inc.
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Figure 7-7a The Temporal Bones.
Petrous part: Encloses structures of the inner ear Mandibular Fossa : Articulates with the mandible Squamous part (cerebral surface) Borders the squamous suture Internal acoustic meatus: For blood vessels and nerves of the inner ear Facial nerve Mastoid process: muscle attachment and contains mastoid air cells connected to middle ear Zygomatic process Forms zygomatic arch (cheekbone) Styloid process: To attach tendons and ligaments of the hyoid, tongue, and pharynx Medial view of the right temporal bone
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7-2 The Cranial Bones of the Skull
The Sphenoid Part of the floor of the cranium Unites cranial and facial bones Strengthens sides of the skull Contains sphenoidal sinuses Sphenoid Body: At the central axis of the sphenoid Sella Turcica: Holds the pituitary gland Hypophyseal Fossa: Holds the pituitary gland Sphenoidal Sinuses: On either side of the body and Inferior to the sella turcica Lesser Wings: Anterior to the sella turcica © 2015 Pearson Education Inc.
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7-2 The Cranial Bones of the Skull
The Sphenoid Foramina of the sphenoid Optic canals for optic nerves Superior orbital fissure for blood vessels and nerves of the orbit Foramen rotundum for blood vessels and nerves of the face Foramen ovale for blood vessels and nerves of the face Foramen spinosum for blood vessels and nerves of the jaws © 2015 Pearson Education Inc.
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Superior surface Foramen rotundum Optic groove Optic canal Lesser wing
Figure 7-8a The Sphenoid. Foramen rotundum Optic groove Optic canal Lesser wing Foramen ovale Greater wing Foramen spinosum Sphenoidal spine Sella turcica: Saddle-shaped enclosure On the superior surface of the body Superior surface
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Superior orbital fissure
Figure 7-8b The Sphenoid. Superior orbital fissure Sphenoidal sinus Lesser wing Greater wing Orbital surface Body Foramen rotundum Pterygoid process Pterygoid plates Anterior surface
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7-2 The Cranial Bones of the Skull
The Ethmoid Forms anteromedial floor of the cranium Roof of the nasal cavity Part of the nasal septum and medial orbital wall Contains ethmoidal air cells (network of sinuses) © 2015 Pearson Education Inc.
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7-2 The Cranial Bones of the Skull The parts of the ethmoid
The Cribriform Plate: Floor of the cranium and Roof of the nasal cavity The Two Lateral Masses: Ethmoidal labyrinth (ethmoidal air cells) Superior nasal conchae Middle nasal conchae The Perpendicular Plate: Part of the nasal septum © 2015 Pearson Education Inc.
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Superior surface Lateral mass containing ethmoidal labyrinth Olfactory
Figure 7-9a The Ethmoid. Lateral mass containing ethmoidal labyrinth Olfactory foramina Cribriform plate Contains the crista galli Crista galli Perpendicular plate a Superior surface
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Posterior surface Crista galli Superior nasal concha
Figure 7-9b The Ethmoid. Crista galli Superior nasal concha Perpendicular plate Middle nasal concha Posterior surface b
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7-2 The Facial Bones of the Skull
1. Maxillae (maxillary bones) 2. Palatine bones 3. Nasal bones 4. Vomer 5. Inferior nasal conchae 6. Zygomatic bones 7. Lacrimal bones 8. Mandible © 2015 Pearson Education Inc.
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7-2 The Facial Bones of the Skull
The Maxillae Support upper teeth Form inferior orbital rim Form lateral margins of external nares Form upper jaw and hard palate Contain maxillary sinuses (largest sinuses) Foramina of the maxillae Infraorbital foramen For sensory nerve to brain (via foramen rotundum of sphenoid) Inferior orbital fissure For cranial nerves and blood vessels © 2015 Pearson Education Inc.
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Figure 7-10a The Maxillae and Palatine Bones.
Orbital rim: protects eye and orbit Infraorbital foramen: For sensory nerve to brain Anterior nasal spine Alveolar process: border the mouth and support upper teeth Zygomatic process a An anterolateral view of the right maxilla.
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7-2 The Facial Bones of the Skull
The Palatine Bones Functions of the palatine bones Form the posterior portion of the hard palate Contribute to the floors of the orbits © 2015 Pearson Education Inc.
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7-2 The Facial Bones of the Skull
The Nasal Bones Support the bridge of the nose Connect to cartilages of the distal part of the nose (external nares) The Vomer: Forms the inferior portion of the bony nasal septum Articulations of the vomer Sphenoid Ethmoid Palatine bones Maxillae Cartilaginous part of the nasal septum © 2015 Pearson Education Inc.
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7-2 The Facial Bones of the Skull
The Inferior Nasal Conchae To create air turbulence in the nasal cavity To increase the epithelial surface area To warm and humidify inhaled air © 2015 Pearson Education Inc.
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7-2 The Facial Bones of the Skull
The Zygomatic Bones Contribute to the rim and lateral wall of the orbit Form part of the zygomatic arch Articulations of the zygomatic bones Sphenoid Frontal bone Temporal bones Maxillae © 2015 Pearson Education Inc.
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7-2 The Facial Bones of the Skull
The Lacrimal Bones The smallest facial bones and form part of the medial wall of the orbit Articulations of the lacrimal bones Frontal bone Maxillae Ethmoid © 2015 Pearson Education Inc.
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Figure 7-11 The Smaller Bones of the Face (Part 1 of 2).
Supraorbital foramen Nasal bone Sphenoid Temporal bone Zygomaticofacial foramen Zygomatic bone Infraorbital foramen Maxilla Perpendicular plate of ethmoid Vomer Bony nasal septum
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Figure 7-11 The Smaller Bones of the Face (Part 2 of 2).
Lacrimal sulcus Optic canal Superior orbital fissure Lacrimal bone Middle nasal concha Inferior nasal concha Temporal process of zygomatic bone Mastoid process Perpendicular plate of ethmoid Vomer Bony nasal septum
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7-2 The Facial Bones of the Skull
The Mandible Forms the lower jaw Articulations of the mandible: Mandibular fossae of the temporal bones Marks of the mandible Body of the mandible is horizontal portion Alveolar processes support the lower teeth Foramina of the mandible Mental foramina: For sensory nerves of lips and chin Mandibular foramen: Entrance to the mandibular canal and for blood vessels and nerves of lower teeth © 2015 Pearson Education Inc.
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7-2 The Facial Bones of the Skull
The Hyoid Bone Supports the larynx and attaches muscles of the larynx, pharynx, and tongue Articulations of the hyoid bone Connects lesser horns to styloid processes of temporal bones © 2015 Pearson Education Inc.
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7-2 The Facial Bones of the Skull
The Hyoid Bone Marks of the hyoid bone Body of the hyoid Attaches muscles of larynx, tongue, and pharynx © 2015 Pearson Education Inc.
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A lateral and slightly superior view of the mandible
Figure 7-12a The Mandible. Articular surface for temporomandibular joint Coronoid process Teeth Mandibular notch Head Ramus Mental protuberance Condylar process Body Mental foramen Angle a A lateral and slightly superior view of the mandible
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A medial view of the right mandible
Figure 7-12b The Mandible. Articular surface Alveolar process Condylar process Coronoid process Mandibular foramen Mylohyoid line Depression for submandibular salivary gland A medial view of the right mandible b
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Figure 7-13 An Anterior View of the Hyoid Bone.
Lesser horns (lesser cornua) Attach stylohyoid ligaments Support hyoid and larynx Greater horns (greater cornua) Support larynx Attach muscles of the tongue Greater horn Lesser horn Body Body of the hyoid Attaches muscles of larynx, tongue, and pharynx An anterior view of the hyoid bone
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7-3 The Orbital and Nasal Complexes
The Eye Sockets (Orbits) Frontal bone (roof) Maxilla (floor) Maxillary, lacrimal, and ethmoid bones (orbital rim and medial wall) Sphenoid and palatine bones © 2015 Pearson Education Inc.
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Figure 7-14 The Orbital Complex (Part 1 of 2).
Frontal bone Supraorbital notch Sphenoid Optic canal Ethmoid Superior orbital fissure Lacrimal bone Lacrimal sulcus Interior orbital fissure Nasolacrimal canal Zygomatic bone Palatine bone Infraorbital groove Infraorbital foramen Maxilla
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Figure 7-14 The Orbital Complex (Part 2 of 2).
Supraorbital notch Frontal bone Sphenoid Optic canal Superior orbital fissure Ethmoid Nasolacrimal canal Inferior orbital fissure Infraorbital groove Zygomatic bone Maxilla Infraorbital foramen
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7-3 The Orbital and Nasal Complexes
Bones of the Nasal Cavities and Paranasal Sinuses Make Up the Nasal Complex Frontal bone, sphenoid, and ethmoid Superior wall of nasal cavities Maxillae, lacrimal bones, ethmoid, and inferior nasal conchae Lateral walls of nasal cavities Maxillae and nasal bones Bridge of nose © 2015 Pearson Education Inc.
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Figure 7-15a The Nasal Complex.
Frontal sinus Ethmoid air cells Sphenoidal sinus Maxillary sinus Paranasal Sinuses Air-filled chambers connected to the nasal cavities a Locations of the paranasal sinuses.
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7-4 Fontanelles The Infant Skull Grows rapidly
Is large compared to the body Has many ossification centers Fusion is not complete at birth Two frontal bones Four occipital bones Several sphenoidal and temporal elements © 2015 Pearson Education Inc.
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7-4 Fontanelles Fontanelles
Are areas of fibrous connective tissue (soft spots) Cover unfused sutures in the infant skull Allow the skull to flex during birth © 2015 Pearson Education Inc.
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Figure 7-16a The Skull of an Infant.
Fontanelles Sphenoidal fontanelle Mastoid fontanelle Coronal suture Parietal bone Frontal bone Greater wing of sphenoid Nasal bone Maxilla Mandible Temporal bone Squamous suture Occipital bone Lambdoid suture Lateral view a
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Figure 7-16b The Skull of an Infant.
Fontanelles Anterior fontanelle Posterior fontanelle Coronal suture Parietal bone Occipital bone Frontal bone Sagittal suture Frontal suture Frontal bone Parietal bone Lambdoid suture Coronal suture b Superior view
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7-5 The Vertebral Column The Vertebral Column (Spine)
Protects the spinal cord Supports the head and body 26 bones 24 vertebrae, the sacrum, and the coccyx © 2015 Pearson Education Inc.
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Figure 7-17 The Vertebral Column.
Spinal Curves Vertebral Regions Primary curves develop before birth, and secondary curves after birth. Regions are defined by anatomical characteristics of individual vertebrae. C1 The cervical curve, a secondary curve, develops as the infant learns to balance the weight of the head on the vertebrae of the neck. C2 C3 C4 Cervical (7 vertebrae) C5 C6 C7 T1 T2 T3 T4 T5 The thoracic curve, a primary curve, accommo- dates the thoracic organs. T6 T7 Thoracic (12 vertebrae) T8 T9 T10 T11 T12 L1 The lumbar curve, a secondary curve, balances the weight of the trunk over the lower limbs; it develops with the ability to stand. L2 L3 Lumbar (5 vertebrae) L4 L5 The sacral curve, a primary curve, accommodates the abdominopelvic organs. Sacral Coccygeal
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7-5 The Vertebral Column Vertebrae The neck The upper back
Seven cervical vertebrae The upper back 12 thoracic vertebrae Each articulates with one or more pair of ribs The lower back Five lumbar vertebrae © 2015 Pearson Education Inc.
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7-5 The Vertebral Column The Sacrum and Coccyx Four Spinal Curves
The fifth lumbar vertebra articulates with the sacrum The sacrum articulates with the coccyx Four Spinal Curves Cervical curve Thoracic curve Lumbar curve Sacral curve © 2015 Pearson Education Inc.
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7-5 The Vertebral Column Thoracic and Sacral Curves
Are called primary curves (present during fetal development) Or accommodation curves (accommodate internal organs) Lumbar and Cervical Curves Are called secondary curves (appear after birth) Or compensation curves (shift body weight for upright posture) © 2015 Pearson Education Inc.
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Clinical Note 7-2a Kyphosis, Lordosis, and Scoliosis.
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7-5 The Vertebral Column Vertebral Anatomy
The vertebral body (centrum): Transfers weight along the spine The vertebral arch: Posterior margin of vertebral foramen The articular processes: Lateral projections between laminae and pedicles © 2015 Pearson Education Inc.
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Figure 7-18a Vertebral Anatomy.
Vertebral arch Articular processes Walls of the vertebral arch Pedicle Vertebral body a The major components of a typical vertebra
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Figure 7-18b Vertebral Anatomy.
Superior articular process Pedicle Transverse process Vertebral body Spinous process Inferior articular facet Arrow passing through vertebral foramen Inferior articular process b A lateral and slightly inferior view of a vertebra
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Figure 7-18c Vertebral Anatomy.
Spinous process Superior articular process Inferior articular process Transverse process Inferior articular facet Pedicle Vertebral foramen Vertebral body c An inferior view of a vertebra
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7-5 The Vertebral Column Vertebral Foramina Intervertebral foramina
Gaps between pedicles of adjacent vertebrae For nerve connections to spinal cord Vertebral canal Formed by vertebral foramina Encloses the spinal cord © 2015 Pearson Education Inc.
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Figure 7-18d Vertebral Anatomy.
Superior articular facets Superior articular process Lamina of vertebral arch Spinous process Are pads of fibro cartilage Separate the vertebral bodies absorb shocks Intervertebral disc Transverse process Vertebral body Inferior articular process d A posterior view of three articulated vertebrae
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7-6 Vertebral Regions Vertebral Regions
Vertebrae are numbered by region, from top (superior) to bottom (inferior) C1 articulates with skull, L5 with sacrum Vertebrae of each region Have characteristics determined by functions Cervical (C) Thoracic (T) Lumbar (L) Sacral (S) Coccygeal (Co) © 2015 Pearson Education Inc.
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7-6 Vertebral Regions The Cervical Vertebrae
Small body (support only head) Large vertebral foramen (largest part of spinal cord) Concave superior surface Slope posterior to anterior C1 (atlas) has no spinous process All others have short spinous processes © 2015 Pearson Education Inc.
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A lateral view of the cervical vertebrae, C1–C7.
Figure 7-19a The Cervical Vertebrae Transverse processes, are fused to costal processes Which encircle transverse foramina (protect arteries and veins) C1 C2 C3 C4 C5 C6 Spinous process of vertebra prominens C7 A lateral view of the cervical vertebrae, C1–C7. a
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Figure 7-19d The Cervical Vertebrae.
Atlas (C1) Articulates with occipital condyles of skull has no body or spinous process has a large, round foramen within anterior and posterior arches Dens of axis Anterior arch Transverse ligament Atlas (C1) Posterior arch : Supports the atlas has spinous process to attach muscles of head and neck. Axis (C2) d
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7-6 Vertebral Regions The Cervical Vertebrae Vertebra prominens (C7)
Transitions to thoracic vertebrae Has a long spinous process with a broad tubercle Has large transverse processes Ligamentum nuchae (elastic ligament) extends from C7 to skull © 2015 Pearson Education Inc.
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Figure 7-20a The Thoracic Vertebrae.
Ligamentum nuchae (elastic ligament) Vertebra prominens C7 T1 T2 Intervertebral foramen T3 T4 T5 Thoracic Vertebrae (T1–T12) T1–T10 Have transverse costal facets on thick transverse processes for rib articulation T1–T8 articulate with two pairs of ribs at superior and inferior costal facets T9–T11 articulate with one pair of ribs T10–T12 transition to lumbar vertebrae T6 T7 Thoracic vertebrae (T1–T12) T8 T9 T10 T11 T12 L1 a A lateral view of the thoracic region of the vertebral column.
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Figure 7-20b The Thoracic Vertebrae.
Spinous process Transverse process Lamina Transverse costal facet Superior articular facet Vertebral foramen Superior costal facet Vertebral body b Thoracic vertebra, superior view.
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Figure 7-20c The Thoracic Vertebrae.
Superior costal facet for head of superior rib Transverse costal facet for tubercle of superior rib Transverse process Vertebral body Spinous process Inferior costal facet for head of inferior rib c Thoracic vertebra, lateral view.
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7-6 Vertebral Regions Lumbar Vertebrae (L1–L5) Largest vertebrae
Oval-shaped bodies Thicker bodies than T1–T12 No costal or transverse costal facets Triangular vertebral foramen Superior articular processes: (Face up and in) Inferior articular processes: (Face down and out) © 2015 Pearson Education Inc.
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Figure 7-21a The Lumbar Vertebrae.
Lumbar Vertebrae (L1–L5) Transverse processes and slender project dorso laterally spinous processes short, heavy for attachment of lower back muscles L3 L4 L5 Sacrum Coccyx A lateral view of the lumbar vertebrae, sacrum, and coccyx a
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Figure 7-21b The Lumbar Vertebrae.
Superior articular process (Face up and in) Pedicle Transverse process Vertebral body Spinous process Inferior articular process Inferior articular facet (Face down and out) b A lateral view of a typical lumbar vertebra
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Figure 7-21c The Lumbar Vertebrae.
Spinous process Superior articular facet Lamina Superior articular process Transverse process Transverse process Vertebral foramen Pedicle Vertebral body c A superior view of the same vertebra shown in part b
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Table 7-1 Regional Differences in Vertebral Structure and Function (Part 1 of 2).
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Table 7-1 Regional Differences in Vertebral Structure and Function (Part 2 of 2).
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7-6 Vertebral Regions The Sacrum
Protects reproductive, urinary, and digestive organs Attaches:The axial skeleton to pelvic girdle of appendicular skeleton and broad muscles that move the thigh The adult sacrum Consists of five fused sacral vertebrae Fuses between puberty and ages 25–30 Sacral canal Replaces the vertebral cana © 2015 Pearson Education Inc.
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7-6 Vertebral Regions The Coccyx
Attaches ligaments and a constricting muscle of the anus Mature coccyx: Consists of three to five fused coccygeal vertebrae First two coccygeal vertebrae have transverse processes and unfused vertebral arches Coccygeal cornua: Formed by laminae of first coccygeal vertebra © 2015 Pearson Education Inc.
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Figure 7-22a The Sacrum and Coccyx.
Articular process: Entrance to sacral canal Thick, flattened area , Articulates with pelvic girdle Sacral tuberosity: Rough area, attaches ligaments of the sacroiliac joint Lateral sacral: Fused transverse processes Attach to muscles of lower back and hip Median sacral: Four pairs of sacral foramina open to either side Sacral hiatus: Opening at the inferior end of the sacral canal and formed by ridges of sacral cornua , covered by connective tissues Sacral cornu: Is horn shaped and form by laminae of the fifth sacral vertebra Which do not meet at midline Coccygeal cornu A posterior view a
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Figure 7-22b The Sacrum and Coccyx.
Sacral promontory Auricular surface Lateral sacral crest Median sacral crest Sacral curve Sacral cornu Coccygeal cornu Coccyx A lateral view from the right side b
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Figure 7-22c The Sacrum and Coccyx.
The broad superior surface Base: Sacral promontory At the center of the base Ala Wings at either side of the base To attach muscles Ala Sacral foramina Transverse lines The narrow inferior portion, articulates with the coccyx Apex Coccyx An anterior view c
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Figure 7-23b The Thoracic Cage.
The skeleton of the chest supports the thoracic cavity Consists of: Thoracic vertebrae Ribs and Sternum (breastbone) The Rib Cage Formed of ribs and sternum C7 T1 1 T2 1 2 T3 2 3 3 T4 4 4 T5 5 T6 5 True ribs (ribs 1–7) 6 T7 6 7 T8 7 8 T9 8 T10 9 9 T11 10 T12 10 11 False ribs (ribs 8–12) L1 11 12 12 A posterior view, showing the articulations of the ribs and vertebrae b
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Figure 7-23a The Thoracic Cage.
Jugular notch T1 Clavicular articulation 1 Sternum Manubrium 2 3 Sternum is a flat bone in the midline of the thoracic wall Three parts of the sternum Body True ribs (ribs 1–7) 4 Xiphoid process 5 Costal cartilages 6 10 T11 7 T12 11 Vertebrochondral ribs (ribs 8–10) 12 8 9 False ribs (ribs 8–12) Floating ribs (ribs 11-12) Connect only to the vertebrae and back muscles have no connection with the sternum a An anterior view, showing the costal cartilages and the sternum
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7-7 The Thoracic Cage Functions of the Thoracic Cage
Protects organs of the thoracic cavity, heart, lungs, and thymus Attaches muscles For respiration Of the vertebral column Of the pectoral girdle and the upper limbs © 2015 Pearson Education Inc.
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7-7 The Thoracic Cage Ribs (Costae)
Are 12 pairs of long, curved, flat bones Extending from the thoracic vertebrae Ribs are divided into two types True ribs (1–7) Connected to the sternum by costal cartilages False ribs (8–12) Do not attach directly to the sternum © 2015 Pearson Education Inc.
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Transverse costal facet
Figure 7-24a The Ribs. Transverse costal facet Tubercle of rib : A small dorsal elevation has an auricular facet that contacts the facet of its thoracic vertebra (at T1–T10 only) Angle The short area between the head and the tubercle Neck Demifacet Head (capitulum) At the vertebral end of the rib Has superior and inferior articular facet A superior view of the details of rib structure and the articulations between the ribs and thoracic vertebrae a
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Attachment to costal cartilage (sternal end)
Figure 7-24b The Ribs. Head Neck Articular facets Attachment to costal cartilage (sternal end) Tubercle Body Angle Costal groove A posterior view of the head of a representative rib from the right side (ribs 2–9) b The tubular body (shaft): Attaches muscles of the pectoral girdle and trunk attaches to the intercostal muscles that move the ribs
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7-7 The Thoracic Cage Parts of Sternum 1. Manubrium
The superior portion of sternum Broad, triangular shape Articulates with clavicles (collarbones) Articulates with cartilages of first rib pair Has a jugular notch, a shallow indentation between clavicular articulations © 2015 Pearson Education Inc.
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7-7 The Thoracic Cage 2. The Sternal Body 3. The Xiphoid Process
Is tongue-shaped Attaches to the manubrium Attaches to costal cartilages of ribs 2–7 3. The Xiphoid Process Is the smallest part of the sternum Attaches to the sternal body Attaches to diaphragm and rectus abdominis muscles Can easily be broken away © 2015 Pearson Education Inc.
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© 2015 Pearson Education Inc.
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