The Axial Skeleton

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

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

Cranial Bones one occipital bone two temporal bones foramen magnum two parietal bones one frontal bone frontal sinuses two temporal bones auditory ossicles one sphenoid one ethmoid

Figure 7.2 Cranial and Facial Subdivisions of the Skull

Superficial landmarks include the sutures Lambdoid Coronal Sagittal Squamous

Figure 7.3 The Adult Skull Figure 7.3a, b

Figure 7.3 The Adult Skull – lateral view Tympanic region of temporal bone Figure 7.3c

Paranasal Sinuses Hollow portions of bones surrounding the nasal cavity Functions of paranasal sinuses: Lighten the skull Give resonance and amplification to voice Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 7.12 The Mandible and Hyoid Bones Figure 7.12a

The Hyoid Bone The only bone that does not articulate with another bone Serves as a moveable base for the tongue Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 7.3 The Adult Skull Figure 7.3d

Figure 7.11 The Bones of the Face

Figure 7.3 The Adult Skull Figure 7.3e

Figure 7.4 The Sectional Anatomy of the Skull Lesser wing Greater wings Figure 7.4b

The Axial Skeleton

SECTION 7-3 The Vertebral Column

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

Spinal curvature Four spinal curves Primary (accommodation) curves = thoracic and sacral Appear in fetal development / accommodate the thoracic and abdominal viscera Secondary (compensation) curves = lumbar and cervical Appear several month after birth / help shift weight from trunk to lower limbs

Figure 7.16 The Vertebral Column Primary/acommodation curves Secondary,compensation curves Figure 7.16

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

Figure 7.18 Vertebral Anatomy

Structure of a Typical Vertebrae Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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 (“true ribs”) 8-12 are attached to the cartilage of the 7th rib (“false 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