Skeletal system includes both: Axial skeleton Skull Auditory ossicles and hyoid bone Vertebral column Thoracic cage Appendicular skeleton Pectoral and pelvic girdles Upper and lower limbs

Figure 7.1b The Axial Skeleton

The skull Consists of the cranium and the bones of the face The cranium encloses cranial cavity Facial bones surround and protect the entrances to the respiratory and digestive tracts Superficial landmarks include the sutures Lambdoid Coronal Sagittal Squamous

Figure 7.2 Cranial and Facial Subdivisions of the Skull

Figure 7.3 The Adult Skull Figure 7.3a, b

Figure 7.3 The Adult Skull Figure 7.3c

Figure 7.3 The Adult Skull Figure 7.3d

Figure 7.3 The Adult Skull Figure 7.3e

Focus: The Individual Bones of the Skull Cranial Bones one occipital bone foramen magnum two parietal bones one frontal bone frontal sinuses two temporal bones auditory ossicles one sphenoid one ethmoid

Figure 7.4 The Sectional Anatomy of the Skull Figure 7.4a

Figure 7.4 The Sectional Anatomy of the Skull Figure 7.4b

Figure 7.5 The Occipital and Parietal Bones

Figure 7.6 The Frontal Bone

Figure 7.7 The Temporal Bones

Figure 7.8 The Sphenoid Figure 7.8

Figure 7.9 The Ethmoid Figure 7.9

Facial bones Maxillary bones Mandible Palatine bones Nasal bones Vomer Inferior nasal conchae Zygomatic bones Lacrimal bones Hyoid

Maxillae Largest facial bones Form the upper jaw and most of the hard palate

Figure 7.10 The Maxillary and Palatine Bones

Palatine and Nasal Bones Palatine bones Small “L” shaped bones Form the posterior hard palate and floor of the nasal cavity Nasal bones Superior border of external nares

Vomer, Zygomatic and Lacrimal bones Inferior portion of the nasal septum Zygomatic bone Temporal process articulates with zygomatic process of temporal bone Lacrimal bones Smallest bones of the face Sit medially in orbit

Figure 7.11 The Smaller Bones of the Face

Mandible and Hyoid bones Bone of the lower jaw Hyoid Suspended by stylohyoid ligaments Supports the larynx

Figure 7.12 The Mandible and Hyoid Bones Figure 7.12a

Figure 7.12 The Mandible and Hyoid Bones Figure 7.12b, c

The orbital and nasal complexes Seven bones in the orbital complex Nasal complex = bones that enclose the nasal cavities and paranasal sinuses

Figure 7.14 The Orbital Complex

Skulls of infants and children Fontanels permit skulls of infants and children to continue growing

Vertebral column Vertebrae, sacrum, coccyx 7 cervical vertebrae 12 thoracic vertebrae 5 lumbar vertebrae Sacrum and coccyx are fused vertebrae

Figure 7.16 The Vertebral Column

Spinal curvature Four spinal curves Primary (accommodation) curves = thoracic and sacral Secondary (compensation) curves = lumbar and cervical

Vertebral anatomy Typically has a body and vertebral arch Superior and inferior articular processes Separated by intervertebral discs

Figure 7.18 Vertebral Anatomy

Vertebral regions Cervical Has distinctive shape Large relative size of vertebral foramen Costal processes with transverse foramina Notched spinous processes

Figure 7.19 The Cervical Vertebrae

Thoracic vertebrae Heart-shaped body Long slender spinous processes Articulations for ribs

Figure 7.20 The Thoracic Vertebrae Figure 7.20a

Figure 7.20 The Thoracic Vertebrae PLAY Animation: Axial Dissections Figure 7.20b, c

Lumbar vertebrae Most massive Least mobile Subjected to great stresses

Figure 7.21 The Lumbar Vertebrae

Sacrum Protects reproductive, digestive and urinary organs Articulates with pelvic girdle and fused elements of coccyx

Figure 7.22 The Sacrum and Coccyx

Thoracic cage Thoracic vertebrae Ribs Sternum Ribs and sternum forms the rib cage

Figure 7.23 The Thoracic Cage Figure 7.23a

Figure 7.23 The Thoracic Cage Figure 7.23b

The ribs Ribs 1-7 are attached to vertebrae 8-12 are vertebrochondral ribs 11-12 are floating ribs

Typical rib Has a head, neck, tubercle and a body Costal groove marks pathway of blood returning to the heart

The Sternum consists of Manubrium Body Xiphoid process

Figure 7.23 The Thoracic Cage PLAY Animation: Axial Dissections Figure 7.23