The skull
The Axial SkeletonThe Axial Skeleton
Functions of the Axial Skeleton Supports and protects organs in body cavities Attaches to muscles of Head, neck, and trunk Respiration Appendicular skeletonThe 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
Cranial and Facial Subdivisions of the Skull.The Skull
The Adult Skull.
The Skull
The SkullThe Skull
The Adult Skull.The Skull
The SkullThe Sectional Anatomy of the Skull.
The SkullSuperficial Facial Bones Maxillae = maxillary bones Lacrimal Nasal Zygomatic Mandible Deep Facial Bones Palatine bones Inferior nasal conchae Vomer
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 sutureThe Cranial Bones of the Skull
The Occipital Bone Functions of the occipital bone Forms the posterior and inferior surfaces of the cranium Articulations of the occipital bone Parietal bones Temporal bones Sphenoid First cervical vertebra (atlas) Marks of the occipital bone External occipital protuberance External occipital crest: to attach ligamentsThe Cranial Bones of the Skull
The Temporal Bones.The Orbital Complex
The Orbital Complex.The Orbital Complex
The Nasal Complex.
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 elementsFontanelles
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 suturesFontanelles
Figure 7–15a The Skull of an Infant.Fontanelles
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 coccyxThe Vertebral Column
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 vertebraeThe Vertebral Column
The Sacrum and Coccyx The fifth lumbar vertebra articulates with the sacrum The sacrum articulates with the coccyxThe Vertebral Column
Four Curvatures of the Vertebral Column Cervical curve Thoracic curve Lumbar curve Sacral curveThe Vertebral Column
Vertebral Anatomy.The Vertebral Column
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 shocksThe Vertebral Column
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 functionsVertebral 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
The Cervical Vertebrae.Vertebral Regions
The Cervical Vertebrae Transverse processes Are fused to costal processes Which encircle transverse foramina (protect arteries and veins) Atlas (C1) Articulates with occipital condyles of skull Has no body or spinous process Has a large, round foramen within anterior and posterior archesVertebral Regions
The Cervical Vertebrae.Vertebral Regions
The Cervical Vertebrae Axis (C2) Supports the atlas Has heavy spinous process To attach muscles of head and neck Axis and atlas bodies fuse during development to form the dens 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 skullVertebral Regions
The Cervical Vertebrae.Vertebral Regions
Thoracic vertebrae (T1–T12)Have heart-shaped bodiesLarger bodies than in C1–C7Smaller vertebral foramen than in C1–C7Long, slender spinous processesDorsolateral surfaces of body have costal facets:Which articulate with heads of ribsVertebral Regions
The Thoracic Vertebrae.Vertebral Regions
The Thoracic Vertebrae.Vertebral Regions
The Thoracic Vertebrae.Vertebral Regions
Lumbar vertebrae (L1–L5)Largest vertebraeOval-shaped bodiesThicker bodies than T1–T12No costal or transverse costal facetsTriangular vertebral foramenSuperior articular processesFace up and inInferior articular processesFace down and outVertebral Regions
Figure 7–21a The Lumbar Vertebrae.
Vertebral Regions
The Lumbar Vertebrae.Vertebral Regions
The Lumbar Vertebrae.Vertebral Regions
The sacrumIs curved, more in males than in femalesProtects reproductive, urinary, and digestive organsAttachesThe axial skeleton to pelvic girdle of appendicular skeletonBroad muscles that move the thighThe adult sacrumConsists of five fused sacral vertebraeFuses between puberty and ages 25–30Leaving transverse linesVertebral 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 Have unfused vertebral arches Coccygeal cornua Formed by laminae of first coccygeal vertebraThe 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 sternumThe Thoracic Cage
The Thoracic Cage.The Thoracic Cage
The Thoracic Cage.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 Of the upper limbsThe Thoracic Cage
Ribs Are mobile Can absorb shock Functions of ribs Rib movements (breathing): affect width and depth of thoracic cage changing its volumeThe Thoracic Cage
The Ribs.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 False ribs
The Thoracic Cage
Ribs 1–7 (true ribs)Vertebrosternal ribsConnected to the sternum by costal cartilagesRibs 8–12 (false ribs) Do not attach directly to the sternumVertebrochondral 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 musclesHave no connection with the sternumThe Thoracic Cage
The Ribs.The Thoracic Cage
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 processThe 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 articulationsThe Thoracic Cage
The sternal bodyIs tongue-shapedAttaches to the manubrium Attaches to costal cartilages of ribs 2–7The xiphoid processIs the smallest part of the sternumAttaches to the sternal bodyAttaches to diaphragm and rectus abdominis muscles