Chapter 6: The Skeleton: Bones and Joints

Overview

Key Terms amphiarthrosis epiphysis periosteum articulation extremity resorption bursa fontanel skeleton circumduction joint synarthrosis diarthrosis marrow synovial diaphysis osteoblast osteocyte endosteum osteoclast osteon

The Skeleton The skeletal system is made up of bones, joints, and supporting connective tissue.

Figure 6-1 The skeleton.

Bones Learning Outcomes 1. List the functions of bones. 2. Describe the structure of a long bone. Differentiate between compact bone and spongy bone with respect to structure and location.

Bones Bone Functions Act as a framework for body Protect delicate structures Examples: Brain and spinal cord Work as levers to produce movement Store calcium Produce blood cells

Bones Bone Structure Diaphysis Marrow Red Yellow Membranes Periosteum Endosteum Tissues Compact Spongy

Figure 6-2 The structure of a long bone. What are the membranes on the outside and the inside of a long bone called?

Figure 6-3 Bone tissue. What cells are located in the spaces of compact bone? 10

Bones Learning Outcomes 4. Name the three different types of cells in bone and describe the functions of each. 5. Explain how a long bone grows. 6. Name and describe various markings found on bones.

✓ Bones Checkpoints 6-1 What are the scientific names for the shaft and the ends of a long bone? 6-2 What are the two types of osseous (bone) tissue and where is each type found? 12

? Bones Pop Quiz Which protein makes up a major component of bone matrix? Keratin Collagen Melanin Calcium

? Bones Pop Quiz Answer Which protein makes up a major component of bone matrix? Keratin Collagen Melanin Calcium

Bones Bone Growth, Maintenance, and Repair Long bone formation Epiphyseal plates Bone resorption Osteoclasts resorb bone tissue. Types of bone cells Osteocytes maintain and repair the existing bone matrix. Ossification is conversion of cartilage to bone.

Bones Bone Growth, Maintenance, and Repair Long bone Growth Ossification is conversion of cartilage to bone. Cartilage begins to turn into bone. Epiphyseal plates develop across bone ends. Bones continue to lengthen. Bones stop lengthening. Bone resorption and formation continues.

Bones Bone Resorption Osteoclasts resorb bone tissue.

18

Bones Bone Markings Projections Depressions or Holes Head Foramen Process Sinus Condyle Fossa Crest Meatus Spine

Figure 6-4 Sinuses.

21

✓ Bones Checkpoints 6-3 What are the three types of cells found in bone and what is the role of each? 6-4 What compounds are deposited in the intercellular matrix of the embryonic skeleton to harden it? 6-5 What are the centers for secondary growth of a long bone called? 6-6 What are some functions of bone markings?

Bones of the Axial Skeleton Learning Outcomes Name, locate, and describe the bones in the axial skeleton. Describe the normal curves of the spine and explain their purpose.

Bones of the Axial Skeleton Two main groups of bones: Axial skeleton—80 bones of the head and trunk Appendicular skeleton—126 bones of the extremities

Bones of the Axial Skeleton Framework of the Skull Bone Description Cranial bones Frontal bone Single bone forming forehead Contains frontal sinuses Parietal bones Paired bones forming most of top and sides of cranium Temporal bones Paired bones forming part of side and base of skull Each bone has a bony prominence behind the ears that is called a mastoid process. Each mastoid process contains mastoid sinus Ethmoid bone Single bone located between eye orbits forming superior part of nasal septum Contains ethmoid sinus

Bones of the Axial Skeleton Framework of the Skull Bone Description Cranial bones (continued) Sphenoid bone Single bone forming the skull base anterior to the temporal bones Contains sphenoid sinus Contains depression called sella turcica for housing the pituitary gland Occipital bone Single bone forming the posterior skull and base Contains foramen magnum for passage of spinal cord

Bones of the Axial Skeleton Framework of the Skull Bone Description Facial bones Mandible Single bone forming the lower jaw   Maxillae Paired bones forming the upper jaw and anterior hard palate Each bone contains a maxillary sinus Zygomatic bones Paired bones forming the “cheek bones” Nasal bones Paired bones forming the bridge of the nose Lacrimal bones Paired bones forming parts of anterior eye orbit Vomer Single bone forming inferior part of nasal septum

Bones of the Axial Skeleton Framework of the Skull Bone Description Facial bones (continued) Palatine bones Paired bones forming posterior hard palate Inferior nasal conchae Paired bones located along lateral walls of nasal cavities

Bones of the Axial Skeleton Framework of the Skull Other bones Ear ossicles Hyoid bone Sutures Coronal suture Squamous sutures Lambdoid suture

Figure 6-5 The skull. What type of joint is between the bones of the skull? What two bones make up each side of the hard palate? What is a foramen? 30

Figure 6-6 The skull, sagittal section. What bone makes up the superior and middle conchae? 31

32

Figure 6-7 Infant skull, showing fontanels. Which is the largest fontanel? 33

Bones of the Axial Skeleton Framework of the Trunk Vertebral column Cervical vertebrae Thoracic vertebrae Lumbar vertebrae Sacral vertebrae (sacrum) Coccygeal vertebrae (coccyx)

Figure 6-8 Vertebral column, left lateral view. From an anterior view, which group(s) of vertebrae form a convex curve? Which group(s) form a concave curve? 35

Figure 6-9 The vertebral column and vertebrae. Which vertebrae are the largest and heaviest? Why? 36

Figure 6-10 The first two cervical vertebrae. What is missing in these two vertebrae that is present in all other vertebrae? 37

Bones of the Axial Skeleton Framework of the Trunk Thorax Sternum Ribs True ribs False ribs Manubrium Clavicular notch Sternal angle Xiphoid process

Figure 6-11 Bones of the thorax, anterior view. To what bones do the costal cartilages attach? 39

40

Bones of the Axial Skeleton ✓ Bones of the Axial Skeleton Checkpoints 6-7 What bones make up the skeleton of the trunk? 6-8 What are the five regions of the vertebral column? 41

Bones of the Axial Skeleton ? Bones of the Axial Skeleton Pop Quiz Which bone forms the back and part of the base of the skull? Parietal bone Temporal bone Occipital bone Sphenoid bone

Bones of the Axial Skeleton ? Bones of the Axial Skeleton Pop Quiz Answer Which bone forms the back and part of the base of the skull? Parietal bone Temporal bone Occipital bone Sphenoid bone

Bones of the Appendicular Skeleton Learning Outcome 9. Name, locate, and describe the bones in the appendicular skeleton.

Bones of the Appendicular Skeleton

Figure 6-12 The shoulder girdle. What does the prefix supra mean? What does the prefix infra mean? 46

Figure 6-13 Bones of the upper extremity. What is the medial bone of the forearm? 47

48

Figure 6-14 Movements of the forearm. 49

Figure 6-15 Left elbow, lateral view. What part of what bone forms the bony prominence of the elbow? 50

Figure 6-16 Bones of the right hand, anterior view. How many phalanges are there on each hand? 51

Figure 6-17 The pelvic bones. What bone is nicknamed the “sit bone”? 52

Figure 6-18 Comparison of male and female pelvis, anterior view. 53

Figure 6-19 Bones of the lower extremity. What is the lateral bone of the leg? Which bone of the leg is weight bearing? 54

Figure 6-20 Bones of the right foot. Which tarsal bone is the heel bone? Which tarsal bone forms a joint with the tibia? 55

56

57

Bones of the Appendicular Skeleton ✓ Bones of the Appendicular Skeleton Checkpoint 6-9 What division of the skeleton consists of the bones of the shoulder girdle, hip, and extremities? 58

Bones of the Appendicular Skeleton ? Bones of the Appendicular Skeleton Pop Quiz Which of the following bones is found in the shoulder girdle? Sternum Humerus Scapula Ulna

Bones of the Appendicular Skeleton ? Bones of the Appendicular Skeleton Pop Quiz Answer Which of the following bones is found in the shoulder girdle? Sternum Humerus Scapula Ulna

Joints Learning Outcomes Describe three types of joints and give examples of each. Demonstrate six types of movement that occur at synovial joints.

Joints Type Movement Material Between the Bones Examples Fibrous Immovable (synarthrosis) No joint cavity; fibrous connective tissue between bones Sutures between skull bones Cartilaginous Slightly movable (amphiarthrosis) No joint cavity; cartilage between bones Pubic symphysis; between vertebral bodies Synovial Freely movable (diarthrosis) Joint cavity containing synovial fluid Gliding, hinge, pivot, condyloid, saddle, ball-and-socket joints

Joints More About Synovial Joints Bones are joined by other structures in synovial joints. Synovial joint structure Ligaments Joint capsule Hyaline (articular) cartilage Medial meniscus and lateral meniscus Fat Bursae

Figure 6-21 Structure of a synovial joint. What is the purpose of the greater trochanter of the femur? What type of tissue covers and protects the ends of the bones? 64

Figure 6-22 The knee joint, sagittal section. 65

Joints Types of Synovial Joints Type of Joint Type of Movement Examples Gliding joint Flat bone surfaces slide over one another with little change in joint angle Joints in the wrist and ankles Hinge joint Allows movement in one direction, changing the angle of the bones at the joint, as in flexion and extension Elbow joint; joints between phalanges of fingers and toes Pivot joint Allows rotation around the length of the bone Joint between the first and second cervical vertebrae; joint at proximal ends of radius and ulna

Joints Types of Synovial Joints (continued) Type of Joint Type of Movement Examples Condyloid joint Allows movement in two directions; flexion and extension, abduction and adduction Joint between the metacarpal Saddle joint Like a condyloid joint but with deeper articulating surfaces and movement in three directions; rotation, flexion and extension, abduction and adduction Joint between the wrist and the metacarpal bone of the thumb Ball-and-socket joint Allows the greatest range of motion; permits movement in three directions around a central point, as in circumduction Shoulder joint and hip joint

Joints Movements at Synovial Joints Flexion Extension Abduction Adduction Circumduction Rotation

Joints Movements Characteristic of Forearm and Ankle Supination Pronation Inversion Eversion Dorsiflexion Plantar flexion

Figure 6-23 Movements at synovial joints. 70

✓ Joints Checkpoints 6-10 What are the three types of joints classified according to the type of material between the adjoining bones? 6-11 What is the most freely movable type of joint? 71

? Joints Pop Quiz Freely movable joints are also called Fibrous joints Cartilaginous joints Diarthroses Amphiarthroses

? Joints Pop Quiz Answer Freely movable joints are also called Fibrous joints Cartilaginous joints Diarthroses Amphiarthroses

Effects of Aging on the Skeletal System Learning Outcome Describe how the skeletal system changes with age.

Effects of Aging on the Skeletal System Bone Loss of calcium salts and collagen Bone weakening Reduction in collagen Joints Thinning of cartilage Decreased flexibility

Case Study Learning Outcome Using the case study, discuss the process of bone repair. 76

Case Study The Body’s Bone Repair Process Blood clot forms around fracture Blood vessels grow into clot, pulling connective tissue with them Fibroblasts and chondroblasts convert clot into a soft callus Macrophages remove remains of blood clot and osteoclasts resorb dead bone tissue Osteoblasts convert soft callus into a hard callus of spongy bone Osteoclasts and osteoblasts remodel hard callus into compact bone

Word Anatomy Learning Outcome 14. Show how word parts are used to build words related to the skeleton. 78

Word Anatomy Word Part Meaning Example oste/o bone, bone tissue The periosteum is the fibrous membrane around a bone. -clast break An osteoclast breaks down bone in the process of resorption. cost/o rib Intercostal spaces are located between the ribs. supra- above, superior The supraspinous fossa is a depression superior to the spine of the scapula. infra- below, inferior The infraspinous fossa is a depression inferior to the spine of the scapula. ab- away from Abduction is movement away from the midline of the body. ad- toward, added to Adduction is movement toward the midline of the body.

80