The Skeletal System

Essentials of Human Anatomy & Physiology

Seventh Edition Foundation

• Physical Foundation of the Body The Skeletal System – 206 Bones • Osteology – science of the anatomy, structure, and function of bones – “Os” means Bone • With the exception of teeth, bone IS the hardest substance in the body

The Skeletal System

• Parts of the skeletal system • Bones (skeleton) • Joints • Cartilages • Ligaments (bone to bone)(tendon=bone to muscle) • Divided into two divisions • Axial skeleton • Copyright © 2003Appendicular Pearson Education, Inc. publishing as Benjaminskeleton Cummings – limbs and girdle

1 Functions of Bones Bones of the Human Body

• The skeleton has 206 bones • Support of the body • Two basic types of bone tissue • Protection of soft organs • Compact bone • Movement due to attached skeletal • Homogeneous muscles • Spongy bone • Storage of minerals and fats (K, Mg, • Small needle-like pieces of bone Na) Figure 5.2b • Many open spaces • Blood cell formation (White and Red) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Classification of Bones Classification of Bones

• Long bones • Short bones • Typically longer than wide • Generally cube-shape • Have a shaft with heads at both ends • Contain mostly spongy bone • Contain mostly compact bone •Examples: Carpals, tarsals • Examples: Femur, humerus

2 Classification of Bones on the Classification of Bones Basis of Shape • Flat bones • Thin and flattened • Usually curved • Thin layers of compact bone around a layer of spongy bone •Examples: Skull, ribs, sternum

Figure 5.1

Classification of Bones Classification of Bones on the Basis of Shape

• Irregular bones • Irregular shape • Do not fit into other bone classification categories •Example: Vertebrae and hip

Figure 5.1

3 Bone Growth Bone Growth

• Epiphyseal plates allow for growth of long bone during childhood • Bones are remodeled and lengthened • New cartilage is continuously formed until growth stops • Older cartilage becomes ossified • Bones change shape somewhat •Cartilage is broken down • Bones grow in width •Bone replaces cartilage

Long Bone Formation and Growth Types of Bone Cells • Osteocytes • Mature bone cells • Osteoblasts • Bone-forming cells • Osteoclasts • Bone-destroying cells • Break down bone matrix for remodeling and release of calcium • Bone remodeling is a process by both Figure 5.4 osteoblasts and osteoclasts

4 Bone Fractures Common Types of Fractures

• A break in a bone • Types of bone fractures • Closed (simple) fracture – break that does not penetrate the skin • Open (compound) fracture – broken bone penetrates through the skin • Bone fractures are treated by reduction and immobilization • Realignment of the bone Table 5.2

Repair of Bone Fractures Stages in the Healing of a Bone Fracture • Hematoma (blood-filled swelling) is formed • Break is splinted by fibrocartilage to form a callus • Fibrocartilage callus is replaced by a bony callus • Bony callus is remodeled to form a Figure 5.5 permanent patch

5 The Axial Skeleton The Axial Skeleton

• Forms the longitudinal part of the body • Divided into three parts • Skull • Vertebral column • Bony thorax

The Skull Bones of the Cranium • Two sets of bones 1. Occipital – hindmost bone of the skull, • Cranium below the parietal, forms the back of the skull • Facial bones 2. Parietal – forms top (crown) and sides of • Bones are joined by sutures skull 3. Frontal – Forms the forehead • Only the mandible is attached by a 4. (2) Temporal- forms the side of the skull freely movable joint in the Ear region

6 The Skull Human Skull, Superior View

Figure 5.8 Figure 5.7

Paranasal Sinuses Bones of the Face • Hollow portions of bones surrounding 1. (2) Nasal Bones – form the bridge of the nose the nasal cavity 2. Lacrinal Bones – small, thin bones located at the front inner wall of the orbits (eye sockets) 3. (2) Zygomatic or malar bones – cheekbones 4. (2) maxillae – Bones of the upper jaw 5. Mandible – lower jawbone; LARGEST and strongest bone of the face

Figure 5.10

7 Paranasal Sinuses Bones of the Skull

• Functions of paranasal sinuses • Lighten the skull • Give resonance and amplification to voice

Figure 5.10 Figure 5.11

Human Skull, Inferior View Bones of the Neck: The Hyoid Bone • The only bone that does not articulate with another bone

• U-shaped bone that Serves as a moveable base for Figure 5.9 the tongue Figure 5.12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.24 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

8 The Vertebral Column Bones of the Neck: • Vertebrae Cervical Vertebrae separated by • Cervical intervertebral discs Vertebrae – 7 • bones of the top The spine has a part of the normal curvature vertebral column (neck region) • Each vertebrae is given a name according to its

Structure of a Typical Vertebrae The Appendicular Skeleton

• Limbs (appendages) • Pectoral girdle • Pelvic girdle

Figure 5.16

9 The Appendicular Skeleton Bones of the Chest, Shoulder, & Back - 1 1. Thorax – chest; elastic, bony cage that serves as a protective framework for the heart, lungs, and other major organs 2. Ribs-12 pairs of bones forming the walls of the thorax 3. Scapula-One of a pair of shoulder blades (a large, flat triangular bone of the shoulder 4. Sternum – Breastbone – flat bone that forms the ventral (front) support of ribs

The Bony Thorax The Bony Thorax

• Forms a • Made-up of cage to three parts protect • Sternum major organs • Ribs • Thoracic vertebrae

Figure 5.19a

10 Bones of the Chest, Shoulder, & Back - 2 Bones of the Shoulder Girdle 1. The Pectoral (Shoulder) Girdle Composed of two bones • Clavicle – collarbone • Scapula – shoulder blade • These bones allow the upper limb to have exceptionally free movement

Bones of the Upper Limb Bones of the Upper Limb

• The arm is • The forearm formed by a has two bones single bone • Ulna • Humerus • Radius

11 Bones of the Upper Limb Bones of the Pelvic Girdle • Hip bones • Composed of three pair of fused bones • The hand • Ilium • Carpals – wrist • Ischium • Pubic bone • Metacarpals – • The total weight of the upper body rests on the palm pelvis • Phalanges – • Protects several organs fingers • Reproductive organs • Urinary bladder Figure 5.22 • Part of the large intestine

The Pelvis Gender Differences of the Pelvis

Figure 5.23a Figure 5.23c

12 Bones of the Lower Limbs Bones of the Lower Limbs

• The leg has two bones • The thigh has • Tibia – larger of the 2 one bone bones below the KNEE • Femur – thigh • Fibula – smaller of the bone/the 2 bones below the heavy long KNEE bone above the KNEE

Bones of the Lower Limbs Bones of the Ankle • The foot = 26 bones • The ANKLE • Tarsal bones – ankle •Talus, Calcaneous, • Talus – ankle navicular, 3 • Tibia cuneiform bones, and the cuboid • Fibula • Metatarsals – sole (5) • Phalanges – toes (14) = 3 in each toe except for the big toe which Figure 5.25

13 Joints Patella • -Also called the Articulations of bones Accessory bone • Functions of joints

• Hold bones together -Forms the knee cap joint • Allow for mobility • Ways joints are classified

http://www.ehealthyland.com/health/knee- • Functionally disorders/chondromalacia/chondromalacia-what-are- chondromalacia-patella.html • Structurally

Functional Classification of Joints Structural Classification of Joints

• Fibrous joints • Synarthroses – immovable joints • Generally immovable • Amphiarthroses – slightly moveable • Cartilaginous joints joints • Immovable or slightly moveable • Diarthroses – freely moveable joints • Synovial joints • Freely moveable

14 Fibrous Joints Cartilaginous Joints – mostly • Bones united by fibrous tissue – amphiarthrosis synarthrosis or largely immovable. • Bones connected by cartilage • Examples • Pubic symphysis • Intervertebral joints

Figure 5.27d, e Figure 5.27b, c

Synovial Joints Features of Synovial Joints- Diarthroses • Articulating • Articular cartilage (hyaline cartilage) bones are covers the ends of bones separated by a • joint cavity Joint surfaces are enclosed by a fibrous articular capsule • Synovial fluid • is found in the Have a joint cavity filled with synovial joint cavity fluid • Ligaments reinforce the joint Figure 5.27f–h

15 Types of Synovial Joints Based on Types of Synovial Joints Based on Shape Shape

Figure 5.29a–c Figure 5.29d–f

Inflammatory Conditions Associated with Joints

• Bursitis – inflammation of a bursa usually caused by a blow or friction • Tendonitis – inflammation of tendon sheaths • Arthritis – inflammatory or degenerative diseases of joints • Over 100 different types • The most widespread crippling disease in the United States