Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 1 Chapter 8 Skeletal System

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 2 Introduction  Skeletal tissues form bones—the organs of the skeletal system  The relationship of bones to each other and to other body structures provides a basis for understanding the function of other organ systems  The adult skeleton is composed of 206 separate bones

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 3 Divisions of Skeleton  Axial skeleton—the 80 bones of the head, neck, and torso; composed of 74 bones that form the upright axis of the body and six tiny middle ear bones

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 4 Divisions of Skeleton  Appendicular skeleton—the 126 bones that form the appendages to the axial skeleton; the upper and lower extremities

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 5 Axial Skeleton  Skull—made up of 28 bones in two major divisions: cranial bones and facial bones (Figures 8-2 to 8-7; Table 8-3)

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 6 Cranial bones Frontal bone Frontal bone  Forms the forehead and anterior part of the top of the cranium  Contains the frontal sinuses  Forms the upper portion of the orbits  Forms the coronal suture with the two parietal bones

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 7 Cranial bones Parietal bones Parietal bones  Form the bulging top of the cranium  Form several sutures: lambdoidal suture with occipital bone; squamous suture with temporal bone and part of sphenoid; and coronal suture with frontal bone

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 8 Cranial bones Temporal bones Temporal bones  Form the lower sides of the cranium and part of the cranial floor  Contain the inner and middle ears

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 9 Cranial bones Occipital bone Occipital bone  Forms the lower, posterior part of the skull  Forms immovable joints with three other cranial bones and a movable joint with the first cervical vertebra

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 10 Cranial bones Sphenoid bone Sphenoid bone  A bat-shaped bone located in the central portion of the cranial floor  Anchors the frontal, parietal, occipital, and ethmoid bones and forms part of the lateral wall of the cranium and part of the floor of each orbit (Figure 8-7)  Contains the sphenoid sinuses

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 11 Cranial bones Ethmoid bone Ethmoid bone  A complicated, irregular bone that lies anterior to the sphenoid and posterior to the nasal bones  Forms the anterior cranial floor, medial orbit walls, upper parts of the nasal septum, and sidewalls of the nasal cavity  The cribriform plate is located in the ethmoid