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Skeletal System Lab Chapters 6 and 7 Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings An Introduction to the Axial Skeleton Structures of Bones Articulations Contacts with other bones Landmarks (Bone Markings; Marks) Areas of muscle and ligament attachment Foramina Openings for nerves and blood vessels Classification of Bones Bones are classified by Shape Internal tissue organization Bone markings (surface features; marks) Classification of Bones Figure 6–1 A Classification of Bones by Shape. Classification of Bones Bone Shapes Long bones Are long and thin Are found in arms, legs, hands, feet, fingers, and toes Flat bones Are thin with parallel surfaces Are found in the skull, sternum, ribs, and scapulae Sutural bones Are small, irregular bones Are found between the flat bones of the skull Classification of Bones Bone Shapes Irregular bones Have complex shapes Examples: spinal vertebrae, pelvic bones Short bones Are small and thick Examples: ankle and wrist bones Sesamoid bones Are small and flat Develop inside tendons near joints of knees, hands, and feet Classification of Bones Bone Markings Depressions or grooves Along bone surface Projections Where tendons and ligaments attach At articulations with other bones Tunnels Where blood and nerves enter bone Classification of Bones Classification of Bones Classification of Bones Structure of a Long Bone Diaphysis The shaft A heavy wall of compact bone, or dense bone A central space called medullary (marrow) cavity Epiphysis Wide part at each end Articulation with other bones Mostly spongy (cancellous) bone Covered with compact bone (cortex) Metaphysis Where diaphysis and epiphysis meet Classification of Bones Figure 6–2 Bone Structure. Classification of Bones Structure of a Flat Bone The parietal bone of the skull Resembles a sandwich of spongy bone Between two layers of compact bone Within the cranium, the layer of spongy bone between the compact bone is called the diploë Classification of Bones Figure 6–2 Bone Structure. Compact and Spongy Bone The Structure of Compact Bone Osteon is the basic unit Osteocytes are arranged in concentric lamellae Around a central canal containing blood vessels Perforating Canals: perpendicular to the central canal carry blood vessels into bone and marrow Circumferential Lamellae Lamellae wrapped around the long bone Bind osteons together Compact and Spongy Bone Figure 6–4 The Histology of Compact Bone. Compact and Spongy Bone Figure 6–5a The Structure of Compact Bone. Compact and Spongy Bone The Structure of Spongy Bone Does not have osteons The matrix forms an open network of trabeculae Trabeculae have no blood vessels The space between trabeculae is filled with red bone marrow: Which has blood vessels Forms red blood cells And supplies nutrients to osteocytes Yellow marrow In some bones, spongy bone holds yellow bone marrow Is yellow because it stores fat Compact and Spongy Bone Figure 6–6 The Structure of Spongy Bone. Compact and Spongy Bone Weight-Bearing Bones The femur transfers weight from hip joint to knee joint Causing tension on the lateral side of the shaft And compression on the medial side Compact and Spongy Bone Figure 6–7 The Distribution of Forces on a Long Bone. Compact and Spongy Bone Compact bone is covered with a membrane Periosteum on the outside Covers all bones except parts enclosed in joint capsules Is made up of an outer, fibrous layer and an inner, cellular layer Perforating fibers: collagen fibers of the periosteum: connect with collagen fibers in bone and with fibers of joint capsules; attach tendons, and ligaments Compact and Spongy Bone Figure 6–8a The Periosteum. Compact and Spongy Bone Functions of Periosteum Isolates bone from surrounding tissues Provides a route for circulatory and nervous supply Participates in bone growth and repair Compact and Spongy Bone Compact bone is covered with a membrane: Endosteum on the inside An incomplete cellular layer: lines the medullary (marrow) cavity covers trabeculae of spongy bone lines central canals contains osteoblasts, osteoprogenitor cells, and osteoclasts is active in bone growth and repair Compact and Spongy Bone Figure 6–8b The Endosteum. 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 The Axial Skeleton The axial skeleton The vertebral column 24 vertebrae (singular = vertebra) The sacrum The coccyx The thoracic cage 24 ribs The sternum The Axial Skeleton Figure 7–1 The Axial Skeleton. The Axial Skeleton Figure 7–1 The Axial Skeleton. The Axial Skeleton Functions of the Axial Skeleton Supports and protects organs in body cavities Attaches to muscles of Head, neck, and trunk Respiration Appendicular skeleton The Skull The skull protects The brain Entrances to respiratory system Entrance to digestive system The skull contains 22 bones 8 cranial bones: Form the braincase or cranium 14 facial bones: Protect and support entrances to digestive and respiratory tracts The Skull Figure 7–2 Cranial and Facial Subdivisions of the Skull. The Skull Sinuses Cavities that decrease the weight of the skull Lined with mucous membranes Protect the entrances of the respiratory system Sutures The immovable joints of the skull The four major sutures Lambdoid suture Coronal suture Sagittal suture Squamous suture The Cranial Bones of the Skull The Cranial Bones Occipital bone Parietal bones Frontal bone Temporal bones Sphenoid Ethmoid The Cranial Bones of the Skull The Occipital Bone Foramen Magnum Occipital Condyles External Occipital Protuberance The Cranial Bones of the Skull Figure 7–5a The Occipital and Parietal Bones. The Cranial Bones of the Skull The Parietal Bone Figure 7–5b The Parietal Bone. The Cranial Bones of the Skull The Frontal bone Frontal squama (forehead) Supra-orbital margin (protects eye) Lacrimal fossa (for tear ducts) Frontal sinuses The Cranial Bones of the Skull Figure 7–6 The Frontal Bone. The Cranial Bones of the Skull The Temporal Bones Squamous part: borders the squamous suture Mandibular fossa: articulates with the mandible Zygomatic process Inferior to the squamous portion Articulates with temporal process of zygomatic bone Forms zygomatic arch (cheekbone) Mastoid process For muscle attachment Contains mastoid air cells connected to middle ear The Cranial Bones of the Skull Styloid process To attach tendons and ligaments of the hyoid, tongue, and pharynx Petrous part Encloses structures of the inner ear Auditory ossicles Three tiny bones in tympanic cavity (middle ear) Transfer sound from tympanic membrane (eardrum) to inner ear External acoustic meatus (canal): ends at tympanic membrane Internal acoustic meatus (canal) For blood vessels and nerves of the inner ear Facial nerve Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Cranial Bones of the Skull Figure 7–7 The Temporal Bones. The Cranial Bones of the Skull The Sphenoid Sphenoid body At the central axis of the sphenoid Sella turcica Saddle-shaped enclosure On the superior surface of the body Hypophyseal fossa A depression within the sella turcica Holds the pituitary gland The Cranial Bones of the Skull Marks of the Sphenoid Sphenoidal sinuses On either side of the body Inferior to the sella turcica Lesser wings Anterior to the sella turcica Greater wings Form part of the cranial floor Sphenoidal spine Posterior wall of the orbit Pterygoid processes Form pterygoid plates To attach muscles of the lower jaw and soft palate The Cranial Bones of the Skull 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 The Cranial Bones of the Skull Figure 7–8 The Sphenoid. The Cranial Bones of the Skull Three Parts of the Ethmoid The cribriform plate Floor of the cranium Roof of the nasal cavity Contains the crista galli The two lateral masses Ethmoidal labyrinth (ethmoidal air cells) Superior nasal conchae Middle nasal conchae The perpendicular plate Part of the nasal septum The Cranial Bones of the Skull Foramina of the Ethmoid Olfactory foramina In the cribriform plate For olfactory nerves The Cranial Bones of the Skull Figure 7–9 The Ethmoid. The Facial Bones of the Skull The Facial Bones Maxillae (maxillary bones) Palatine bones Nasal bones Vomer Inferior nasal conchae Zygomatic bones Lacrimal bones Mandible The Facial Bones of the Skull Marks of the Maxillae Orbital rim:protects eye and orbit Alveolar processes: borders the mouth and supports upper teeth Palatine processes: form the hard palate (roof of mouth) Maxillary sinuses: to lighten bone The Facial Bones of the Skull Figure 7–10a The Maxillae. The Facial Bones of the Skull Palatine Bones Horizontal plate: posterior part of hard palate Perpendicular plate: from horizontal plate to orbital process of orbit floor The Facial Bones of the Skull Figure 7–10c The Palatine Bones. The Facial Bones of the Skull Zygomatic Bones Temporal process Meets the zygomatic process of the temporal bone The Facial Bones of the Skull The Lacrimal Bones Lacrimal sulcus: location of the lacrimal sac leads to the nasolacrimal canal (between orbit and nasal cavity) The Facial Bones of the Skull The Nasal Bones The Vomer Inferior Nasal Conchae The Facial Bones of the Skull Figure 7–11 The Smaller Bones of the Face. The Facial Bones of the Skull The Mandible Body of the mandible: horizontal portion Alveolar processes: support the lower teeth Mental protuberance: attaches facial muscles Ramus: ascending from the mandibular angle on either side Condylar process: articulates with temporal bone at temporomandibular joint Coronoid process: insertion point for temporalis muscle (closes the jaws) Mandibular notch: separates condylar and coronoid processes Mental foramina:for sensory nerves of lips and chin The Facial Bones of the Skull Figure 7–12a The Mandible and Hyoid Bone. The Facial Bones of the Skull Figure 7–12b The Mandible and Hyoid Bone. The Facial Bones of the Skull The Hyoid Bone Functions of the hyoid bone Supports the larynx Attaches muscles of the larynx, pharynx, and tongue The Facial Bones of the Skull Figure 7–12c The Hyoid Bone. The Orbital Complex Forms the eye sockets (orbits) Frontal bone (roof) Maxilla (floor) Maxillary, lacrimal, and ethmoid bones (orbital rim and medial wall) Sphenoid and palatine bones The Orbital Complex Figure 7–13 The Orbital Complex. The Nasal Complex Bones of the nasal cavities and paranasal sinuses 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 The Nasal Complex Figure 7–14a The Nasal Complex. The Nasal Complex Figure 7–14b The Nasal Complex. The Nasal Complex Paranasal Sinuses Air-filled chambers connected to the nasal cavities Lighten skull bones Provide mucous epithelium (flushes nasal cavities) 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 Fontanelles Fontanelles (sometimes spelled fontanels) Are areas of fibrous connective tissue (soft spots) Cover unfused sutures in the infant skull Allow the skull to flex during birth Anterior fontanelle: frontal, sagittal, and coronal sutures Occipital fontanelle: lambdoid and sagittal sutures Sphenoidal fontanelles: squamous and coronal sutures Mastoid fontanelles: squamous and lambdoid sutures Fontanelles Figure 7–15a The Skull of an Infant. Fontanelles Figure 7–15b The Skull of an Infant. The Vertebral Column The spine or vertebral column Protects the spinal cord Supports the head and body 26 bones 24 vertebrae, the sacrum, and the coccyx The Vertebral Column Figure 7–16 The Vertebral Column. The Vertebral Column Vertebrae The neck Seven cervical vertebrae The upper back 12 thoracic vertebrae Each articulates with one or more pair of ribs The lower back Five lumbar vertebrae The Vertebral Column The Sacrum and Coccyx The fifth lumbar vertebra articulates with the sacrum The sacrum articulates with the coccyx The Vertebral Column Four Curvatures of the Vertebral Column Cervical curve Thoracic curve Lumbar curve Sacral curve 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) The Vertebral Column Figure 7–17 Abnormal Curvatures of the Spine. The Vertebral Column Structure of a Vertebra 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 The Vertebral Column Figure 7–18a Vertebral Anatomy. The Vertebral Column Figure 7–18c Vertebral Anatomy. The Vertebral Column Structure of a Vertebra The vertebral arch Pedicles: walls of the vertebral arch Laminae: roof of the vertebral arch Spinous process: projection where vertebral laminae fuse Transverse process: projection where laminae join pedicles The Vertebral Column Structure of a Vertebra The articular processes Superior articular process Inferior articular process: have articular facets on articular faces The Vertebral Column Figure 7–18 Vertebral Anatomy. 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 Intervertebral Discs Are pads of fibrous cartilage Separate the vertebral bodies Absorb shocks The Vertebral Column Figure 7–18 Vertebral Anatomy. 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 Vertebral Regions Regions of the Vertebral Column Cervical (C) Thoracic (T) Lumbar (L) Sacral (S) Coccygeal (Co) Vertebral Regions The Cervical Vertebrae Small body (support only head) Large vertebral foramen (largest part of spinal cord) Concave superior surface Slopes posterior to anterior C1 (atlas) has no spinous process All others have short spinous processes tip of each spinous process is notched (bifid) Vertebral Regions Figure 7–19 The Cervical Vertebrae. Vertebral Regions The Cervical Vertebrae Transverse processes transverse foramina (protect arteries and veins) Atlas (C1) Articulates with occipital condyles of skull Has no body or spinous process Axis (C2) Supports the atlas Has heavy spinous process To attach muscles of head and neck Vertebral Regions Figure 7–19 The Cervical Vertebrae. Vertebral Regions Figure 7–19 The Cervical Vertebrae. Vertebral Regions Thoracic vertebrae (T1–T12) Have heart-shaped bodies Larger bodies than in C1–C7 Smaller vertebral foramen than in C1–C7 Long, slender spinous processes Articulate with ribs Vertebral Regions Figure 7–20a The Thoracic Vertebrae. Vertebral Regions Figure 7–20b The Thoracic Vertebrae. Vertebral Regions Figure 7–20c The Thoracic Vertebrae. Vertebral Regions Lumbar vertebrae (L1–L5) Largest vertebrae Oval-shaped bodies Thicker bodies than T1–T12 Triangular vertebral foramen Spinous process: Short, heavy For attachment of lower back muscles Vertebral Regions Figure 7–21a The Lumbar Vertebrae. Vertebral Regions Figure 7–21b The Lumbar Vertebrae. Vertebral Regions Figure 7–21c The Lumbar Vertebrae. Vertebral Regions The sacrum Is curved, more in males than in females Protects reproductive, urinary, and digestive organs The adult sacrum Consists of five fused sacral vertebrae Fuses between puberty and ages 25–30 Leaving transverse lines Sacral foramina - holes for nerves Auricular Surface - articular surface for sacroiliac joint Vertebral Regions The coccyx Attaches ligaments and a constricting muscle of the anus Mature coccyx Consists of three to five fused coccygeal vertebrae Vertebral Regions Figure 7–22 The Sacrum and Coccyx. The Thoracic Cage The skeleton of the chest Supports the thoracic cavity Consists of: thoracic vertebrae ribs sternum (breastbone) The Rib Cage Formed of ribs and sternum The Thoracic Cage Figure 7–23a The Thoracic Cage. The Thoracic Cage Figure 7–23b The Thoracic Cage. The Thoracic Cage Ribs 1–7 (true ribs) Vertebrosternal ribs Connected to the sternum by costal cartilages Ribs 8–12 (false ribs) Do not attach directly to the sternum Vertebrochondral ribs (ribs 8–10) Fuse together Merge with cartilage before reaching the sternum Floating or vertebral ribs (ribs 11–12) Connect only to the vertebrae and back muscles Have no connection with the sternum The Thoracic Cage Structures of the Ribs The head (capitulum) At the vertebral end of the rib The neck The short area between the head and the tubercle The tubercle (tuberculum) The body (shaft) The Thoracic Cage Figure 7–24a The Ribs. The Thoracic Cage Figure 7–24b The Ribs. The Thoracic Cage The sternum A flat bone In the midline of the thoracic wall Three parts of the sternum The manubrium The sternal body The xiphoid process The Thoracic Cage 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 The Thoracic Cage The sternal body Is tongue-shaped Attaches to the manubrium Attaches to costal cartilages of ribs 2–7 The xiphoid process Is the smallest part of the sternum Attaches to the sternal body Attaches to diaphragm and rectus abdominis muscles The Thoracic Cage Figure 7–23 The Thoracic Cage.
