Chapter 5 The Skeletal System

Chapter 5 The Skeletal System
Essentials of Human Anatomy & Physiology Seventh Edition Elaine N. Marieb Chapter 5 The Skeletal System Slides 5.1 – 5.15 Lecture Slides in PowerPoint by Jerry L. Cook Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The Skeletal System Parts of the skeletal system
Bones (skeleton) Joints Cartilages Ligaments Divided into two divisions Axial skeleton Appendicular skeleton Slide 5.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Functions of Bones Support of the body Protection of soft organs
Movement due to attached skeletal muscles Storage of minerals and fats Blood cell formation Slide 5.2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bones of the Human Body The skeleton has 206 bones
Two basic types of bone tissue Compact bone Homogeneous Spongy bone Small needle-like pieces of bone Many open spaces Figure 5.2b Slide 5.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Classification of Bones
Long bones Typically longer than wide Have a shaft with heads at both ends Contain mostly compact bone Examples: Femur, humerus Slide 5.4a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Classification of Bones on the Basis of Shape
Figure 5.1 Slide 5.4c Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Flat bones Thin and flattened Usually curved Thin layers of compact bone around a layer of spongy bone Examples: Skull, ribs, sternum Slide 5.5a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Classification of Bones on the Basis of Shape
Figure 5.1 Slide 5.5c Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Gross Anatomy of a Long Bone
Diaphysis Shaft Composed of compact bone Epiphysis Ends of the bone Composed mostly of spongy bone Figure 5.2a Slide 5.6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Structures of a Long Bone
Periosteum Outside covering of the diaphysis Fibrous connective tissue membrane Sharpey’s fibers Secure periosteum to underlying bone Arteries Supply bone cells with nutrients Figure 5.2c Slide 5.7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Articular cartilage Covers the external surface of the epiphyses Made of hyaline cartilage Decreases friction at joint surfaces Figure 5.2a Slide 5.8a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Medullary cavity Cavity of the shaft Contains yellow marrow (mostly fat) in adults Contains red marrow (for blood cell formation) in infants Figure 5.2a Slide 5.8b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bone Markings Surface features of bones
Sites of attachments for muscles, tendons, and ligaments Passages for nerves and blood vessels Categories of bone markings Projections and processes – grow out from the bone surface Depressions or cavities – indentations Slide 5.9 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Microscopic Anatomy of Bone
Osteon (Haversian System) A unit of bone Central (Haversian) canal Opening in the center of an osteon Carries blood vessels and nerves Perforating (Volkman’s) canal Canal perpendicular to the central canal Slide 5.10a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Lacunae Cavities containing bone cells (osteocytes) Arranged in concentric rings Lamellae Rings around the central canal Sites of lacunae Figure 5.3 Slide 5.11a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Changes in the Human Skeleton
In embryos, the skeleton is primarily hyaline cartilage During development, much of this cartilage is replaced by bone Cartilage remains in isolated areas Bridge of the nose Parts of ribs Joints Slide 5.12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Development of Bone Intramembranous ossification (cont.)
Large amounts of ground substance accumulate around each osteoblast Collagenous fibers become embedded in the ground substance and constitute the bone matrix Bone matrix calcifies when calcium salts are deposited Trabeculae appear and join in a network to form spongy bone Apposition growth occurs by adding of osseous tissue

Bone Growth Epiphyseal plates allow for growth of long bone during childhood New cartilage is continuously formed Older cartilage becomes ossified Cartilage is broken down Bone replaces cartilage Slide 5.13a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bone Growth Bones are remodeled and lengthened until growth stops
Bones change shape somewhat Bones grow in width Slide 5.13b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Long Bone Formation and Growth
Figure 5.4a Slide 5.14a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Long Bone Formation and Growth
Figure 5.4b Slide 5.14b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Types of Bone Cells Osteocytes Osteoblasts Osteoclasts
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 osteoblasts and osteoclasts Slide 5.15 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bone Fractures

Mechanisms of Disease— Bone Fractures
Fracture defined as partial or complete break in continuity of a bone Mechanical stress and traumatic injury are most common causes Pathological or spontaneous fractures occur in absence of trauma Stress fractures may not be apparent in clinical examination or standard x-ray images but can be seen in bone scans Bone damage is microscopic Caused by repetitive trauma (e.g., marathon runners)

Fracture defined (cont.) Displaced, open or compound fractures—do not produce a break in the skin and pose less danger of infection Nondisplaced, closed or simple fractures—do not produce a break in the skin and pose less danger of infection Fracture types: Impacted—one end of fracture driven into diaphysis of other fragment

Mechanisms of Disease—Bone Fractures
Fracture types (cont.) Avulsion—bone fragments pulled away from underlying bone surface or bone totally torn from body part Linear—fracture line parallel to the bone’s long axis Transverse—fracture line at right angle to long axis of bone Oblique—fracture line slanted or diagonal to longitudinal axis Spiral—fracture line spirals around long axis Hairline—common in skull—fracture components small and aligned; if fracture is pushed downward, called a depressed fracture Complete—break extends across entire section of bone Incomplete—some fracture components still partially joined Dentate—fracture components jagged and fit together like teeth on a gear Comminuted—crushed, small, crumbled bone fragments near fracture

Fracture types (cont.) Greenstick—bone bent but broken only on one side (common in children) Pott’s—fracture of lower tibia Colles’—fracture of distal radius LeFort—fracture of face and/or base of skull Hangman’s—fracture of posterior elements in upper cervical spine, especially the axis Blowout—fracture of the eye orbit

Osgood-Schlatter disease Avulsion fracture of tibial tuberosity fragments the surface Caused by powerful contraction of quadriceps muscle group pulling on patellar ligament attached to tibial tuberosity Common in adolescent athletes in whom patellar ligament is stronger than underlying bone

Mechanisms of Disease— Treatment of Fractures
Clinical signs of fracture include pain, loss of function, false motion, soft tissue edema, deformity, and crepitus Initial treatment is realignment and immobilization of bone fragments Closed reduction—alignment completed without surgery Open reduction—surgery required to align and internally immobilize bone fragments with screws, wires, plates, or other orthopedic devices After reduction, immobilization generally accomplished by casts, splints, and bandages Traction sometimes used—especially in children Restoration of function is treatment priority following healing

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) Cranial bones Frontal bone (Figure 8-8, C) 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

Axial Skeleton Cranial bones (cont.) Parietal bones (Figure 8-8, A)
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

Axial Skeleton Cranial bones (cont.) Temporal bones (Figure 8-8, B)
Form the lower sides of the cranium and part of the cranial floor Contain the inner and middle ears

Axial Skeleton Cranial bones (cont.) Occipital bone (Figure 8-8, D)
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

Axial Skeleton Cranial bones (cont.) Sphenoid bone (Figure 8-8, E)
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

Axial Skeleton Cranial bones (cont.) Ethmoid bone (Figure 8-8, F)
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

Axial Skeleton Facial bones (Table 8-4)
Maxilla (upper jaw) (Figure 8-8, H) Two maxillae form the keystone of the face Maxillae articulate with each other and with nasal, zygomatic, inferior concha, and palatine bones Forms parts of the orbital floors, roof of the mouth, and floor and sidewalls of the nose Contains maxillary sinuses

Axial Skeleton Facial bones (cont.)
Mandible (lower jaw) (Figure 8-8, M) Largest, strongest bone of the face Forms the only movable joint of the skull with the temporal bone Zygomatic bone (Figure 8-8, I) Shapes the cheek and forms the outer margin of the orbit Forms the zygomatic arch with the zygomatic process of the temporal bones

Nasal bone (Figures 8-8, L, and 8-10) Both nasal bones form the upper part of the bridge of the nose, whereas cartilage forms the lower part Articulates with the ethmoid bone, nasal septum, frontal bone, maxillae, and the other nasal bone

Axial Skeleton Facial bones (cont.) Lacrimal bone (Figure 8-8, K)
Paper-thin bone that lies just posterior and lateral to each nasal bone Forms the nasal cavity and medial wall of the orbit Contains groove for the nasolacrimal (tear) duct Articulates with the maxilla and the frontal and ethmoid bones

Axial Skeleton Facial bones (cont.) Palatine bone (Figure 8-8, J)
Two bones form the posterior part of the hard palate Vertical portion forms the lateral wall of the posterior part of each nasal cavity Articulates with the maxillae and the sphenoid bone

Inferior nasal conchae (turbinates) Form lower edge projecting into the nasal cavity and form the nasal meati Articulate with ethmoid, lacrimal, maxillary, and palatine bones Vomer bone (Figure 8-8, G) Forms posterior portion of the nasal septum Articulates with the sphenoid, ethmoid, and palatine bones and maxillae

Axial Skeleton Eye orbits (Figure 8-7) Right and left eye orbits
Contain eyes, associated eye muscles, lacrimal apparatus, blood vessels, and nerves Thin and fragile orbital walls separate orbital structures from cranial and nasal cavities and paranasal sinuses Traumatic injuries may result in “blowout fractures” (Figure 8-7, C) “Raccoon eyes”—clinical sign of blowout fracture (Figure 8-7, D)

Developmental Aspects of the Skeletal System
At birth, the skull bones are incomplete Bones are joined by fibrous membranes – fontanelles Fontanelles are completely replaced with bone within two years after birth Slide 5.55 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Axial Skeleton Fetal skull (Figure 8-11)
Characterized by unique anatomic features not seen in adult skull Fontanels or “soft spots” (4) allow skull to “mold” during birth process and permit rapid growth of brain (Table 8-5)

Axial Skeleton Fetal skull (cont.)
Permits differential growth or appearance of skull components over time Face—smaller proportion of total cranium at birth (1/8) than in adult (1/2) Head at birth is ¼ total body height; at maturity is about 1/8 body height Sutures appear with skeletal maturity (Table 8-5) Paranasal sinuses—change in size and placement with skeletal maturity (Figure 8-9) Appearance of deciduous and, later, permanent teeth

Axial Skeleton Hyoid bone (Figure 8-12)
U-shaped bone located just above the larynx and below the mandible Suspended from the styloid processes of the temporal bone Only bone in the body that articulates with no other bones

Axial Skeleton Vertebral column (Figure 8-13)
Forms the flexible longitudinal axis of the skeleton Consists of 24 vertebrae plus the sacrum and coccyx Segments of the vertebral column: Cervical vertebrae, 7 Thoracic vertebrae, 12 Lumbar vertebrae, 5 Sacrum—in adult, results from fusion of five separate vertebrae Coccyx—in adult, results from fusion of four or five separate vertebrae

Axis Atlas Atlas and Axis Second cervical vertebrae
Dens joins axis to atlas Atlas and axis allow the head to turn from side to side Atlas First cervical vertebrae Supports the skull

Axial Skeleton Vertebral column (cont.)
Characteristics of the vertebrae (Figure 8-14; Table 8-6) All vertebrae, except the first, have a flat, rounded body anteriorly and centrally, a spinous process posteriorly, and two transverse processes laterally All but the sacrum and coccyx have vertebral foramen Second cervical vertebra has upward projection, the dens, to allow rotation of the head Seventh cervical vertebra has long, blunt spinous process Each thoracic vertebra has articular facets for the ribs

Axial Skeleton Vertebral column (cont.)
Vertebral column as a whole articulates with the head, ribs, and iliac bones Individual vertebrae articulate with each other in joints between their bodies and between their articular processes

Axial Skeleton Sternum (Figure 8-15)
Dagger-shaped bone in the middle of the anterior chest wall made up of three parts: Manubrium—the upper, handle part Body—the middle, blade part Xiphoid process—the blunt cartilaginous lower tip, which ossifies during adult life

Sternum Consists of three bones Manubrium Body Xiphoid Process

Axial Skeleton Sternum (cont.)
Manubrium articulates with the clavicle and first rib Next nine ribs join the body of the sternum, either directly or indirectly, by means of the costal cartilage

Axial Skeleton Ribs (Figures 8-15 and 8-16)
Twelve pairs of ribs, with the vertebral column and sternum, form the thorax Each rib articulates with the body and transverse process of its corresponding thoracic vertebra Ribs 2 through 9 articulate with the body of the vertebra above

Axial Skeleton Ribs (cont.)
From its vertebral attachment, each rib curves outward, then forward and downward Rib attachment to the sternum: Ribs 1 through 8 join a costal cartilage that attaches it to the sternum Costal cartilage of ribs 8 through 10 joins the cartilage of the rib above to be indirectly attached to the sternum Ribs 11 and 12 are floating ribs, because they do not attach even indirectly to the sternum

Appendicular Skeleton
Upper extremity (Table 8-7) Consists of the bones of the shoulder girdle, upper arm, lower arm, wrist, and hand Shoulder girdle (Figure 8-17) Made up of scapula and clavicle Clavicle forms only bony joint with trunk, the sternoclavicular joint At its distal end, clavicle articulates with the acromion process of the scapula

Upper extremity (cont.) Humerus (Figures 8-18 and 8-19) The long bone of the upper arm Articulates proximally with the glenoid fossa of the scapula and distally with the radius and ulna

Upper extremity (cont.) Ulna Long bone found on little finger side of forearm Articulates proximally with humerus and radius and distally with a fibrocartilaginous disk

Upper extremity (cont.) Radius Long bone found on thumb side of forearm Articulates proximally with capitulum of humerus and radial notch of ulna; articulates distally with scaphoid and lunate carpals and with head of ulna

Upper extremity (cont.) Carpal bones (Figure 8-20) Eight small bones that form wrist Carpals are bound closely and firmly by ligaments and form two rows of four carpals each Proximal row is made up of pisiform, triquetrum, lunate, and scaphoid Distal row is made up of hamate, capitate, trapezoid, and trapezium The joints between radius and carpals allow wrist and hand movements

Upper extremity (cont.) Metacarpal bones Form framework of hand Thumb metacarpal forms the most freely movable joint with the carpals Heads of metacarpals (knuckles) articulate with phalanges

Lower extremity Consists of the bones of hip, thigh, lower leg, ankle, and foot (Table 8-8)

Lower extremity (cont.) Pelvic girdle is made up of the sacrum and the two coxal bones, bound tightly by strong ligaments (Figure 8-21) A stable circular base that supports the trunk and attaches the lower extremities to it Each coxal bone is made up of three bones that fuse together (Figure 8-22): Ilium—largest and uppermost Ischium—strongest and lowermost Pubis—anteriormost

The Pelvis Figure 5.23a Slide 5.38a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The Pelvis Figure 5.23b Slide 5.38b

Gender Differences of the Pelvis
Figure 5.23c Slide 5.39 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Male Pelvis is deep and funnel shaped with a narrow subpubic angle
Female pelvis is shallow, broad, and flaring with a wider subpubic angle

The Female Pelvis

Lower extremity (cont.) Femur—longest and heaviest bone in the body (Figure 8-23) Patella—largest sesamoid bone in the body Tibia The larger, stronger, and more medially and superficially located of the two leg bones Articulates proximally with the femur to form the knee joint Articulates distally with the fibula and the talus

Lower extremity (cont.) Fibula The smaller, more laterally and deeply placed of two leg bones Articulates with tibia

Lower extremity (cont.) Foot (Figures 8-24 and 8-25) Structure is similar to that of the hand, with adaptations for supporting weight Foot bones are held together to form spring arches Medial longitudinal arch is made up of calcaneus, talus, navicular, cuneiforms, and medial three metatarsals Lateral longitudinal arch is made up of calcaneus, cuboid, and fourth and fifth metatarsals

Arches of the Foot Bones of the foot are arranged to form three strong arches Two longitudinal One transverse Figure 5.26 Slide 5.42 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Joints Articulations of bones Functions of joints
Hold bones together Allow for mobility Ways joints are classified Functionally Structurally Slide 5.43 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Functional Classification of Joints
Synarthroses – immovable joints Amphiarthroses – slightly moveable joints Diarthroses – freely moveable joints Slide 5.44 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Structural Classification of Joints
Fibrous joints Generally immovable Cartilaginous joints Immovable or slightly moveable Synovial joints Freely moveable Slide 5.45 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Fibrous Joints Bones united by fibrous tissue Examples Sutures
Syndesmoses Allows more movement than sutures Example: distal end of tibia and fibula Figure 5.27d, e Slide 5.46 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Synovial Joints Articulating bones are separated by a joint cavity
Synovial fluid is found in the joint cavity Figure 5.27f–h Slide 5.48 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Features of Synovial Joints
Articular cartilage (hyaline cartilage) covers the ends of bones Joint surfaces are enclosed by a fibrous articular capsule Have a joint cavity filled with synovial fluid Ligaments reinforce the joint Slide 5.49 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Structures Associated with the Synovial Joint
Bursae – flattened fibrous sacs Lined with synovial membranes Filled with synovial fluid Not actually part of the joint Tendon sheath Elongated bursa that wraps around a tendon Slide 5.50 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The Synovial Joint Figure 5.28 Slide 5.51

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 Slide 5.53 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Clinical Forms of Arthritis
Osteoarthritis Most common chronic arthritis Probably related to normal aging processes Rheumatoid arthritis An autoimmune disease – the immune system attacks the joints Symptoms begin with bilateral inflammation of certain joints Often leads to deformities Slide 5.54a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Clinical Forms of Arthritis
Gouty Arthritis Inflammation of joints is caused by a deposition of urate crystals from the blood Can usually be controlled with diet Slide 5.54b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Abnormal Spine Curvatures

Mechanisms of Disease— Abnormal Spinal Curvatures
Normal curvature of spine is convex through the cervical and lumbar regions Normal curves give spine strength for support of body and balance required to stand and walk Abnormal curvatures Lordosis—abnormally accentuated lumbar curve (“swayback”) Frequently seen during pregnancy May be secondary to traumatic injury

Abnormal curvatures (cont.) Kyphosis—abnormally accentuated thoracic curvature (“hunchback”) Frequent consequence of vertebral compression fractures in osteoporosis Sign of Scheuermann’s disease, which may develop in children at puberty

Abnormal curvatures (cont.) Scoliosis—abnormal side-to-side spinal curvature Often appears before adolescence Treatments vary with severity of curvature Milwaukee brace Transcutaneous stimulation Surgical grafting to the deformed vertebrae of bone from elsewhere in skeleton or of metal rods

Mechanisms of Disease—Mastoiditis
Inflammation of air spaces within mastoid portion of temporal bone Pus may enter mastoid air spaces from middle ear infection or otitis media Mastoid air cells do not drain into nose as do paranasal sinuses Infectious material may erode thin, bony partition separating air cells from cranial cavity, causing intracranial infection Treatment is antibiotic therapy and surgical incision of eardrum to drain pus from middle ear Surgical removal of part of mastoid process of temporal bone—mastoidectomy—is rare

Cycle of Life: The Aging Skeleton
Aging changes begin at fertilization and continue over a lifetime Changes can be positive or negative Normal bone development is a skeletal aging process Intramembranous ossification Endochondral ossification Appearance of ossification centers and closure of epiphyseal plates can be used to estimate potential growth and height

Characteristics of bone during age Bone produced early in life is properly calcified but not brittle Osteoblastic activity during early periods of bone remodeling results in deposition of more bone than is resorbed Prior to puberty results in growth of bones After puberty and until early thirties, replaced bone is stronger

Negative outcomes of skeletal aging begin between 30 and 40 years of age Decrease in osteoblast numbers with production of lower quality matrix Increase in osteoclast numbers and activity with increased bone loss Mature osteocytes coalesce and shrink, producing a honeycomb of tiny holes in the compact bone

Negative outcomes (cont.) Skeleton as a whole loses strength, and fracture risk increases Decrease in number of trabeculae in spongy bone in vertebral bodies and other bones results in “spontaneous” as well as compression fractures Overall height decreases beginning at about age 35 Osteoporosis is a common and very serious bone disease in old age

The Big Picture Skeletal system is a good example of increasing structural hierarchy in the body Skeletal tissues are grouped into discrete organs—bones Skeletal system consists of bones, blood vessels, nerves, and other tissues grouped to form a complex operational unit Integration of skeletal system with other body organ systems permits homeostasis to occur Skeletal system is more than an assemblage of individual bones—it represents a complex and interdependent functional unit of the body

Chapter 5 The Skeletal System

Similar presentations

Presentation on theme: "Chapter 5 The Skeletal System"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Chapter 5 The Skeletal System

Similar presentations

Presentation on theme: "Chapter 5 The Skeletal System"— Presentation transcript:

Similar presentations

About project

Feedback