Lecture 4 - The Skeletal System (1) PDF

The Skeletal System Human Anatomy & Physiology with Pathophysiology Lecture 4 Chapter 04 The Skeletal System Anatomy, Physiology, & Disease Foundations for the Health Professions Third Edition Deborah Roiger and Nia Bullock...

The Skeletal System Human Anatomy & Physiology with Pathophysiology Lecture 4 Chapter 04 The Skeletal System Anatomy, Physiology, & Disease Foundations for the Health Professions Third Edition Deborah Roiger and Nia Bullock © 2023 McGraw Hill, LLC. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill, LLC. Anatomy of the Skeletal System SKELETAL SYSTEM: OVERVIEW The skeletal system is composed of bones, cartilages, and ligaments. It is a dynamic system that changes daily. The skeletal system’s functions are: Supports Helps movement Protects organs Produces blood cells Maintains electrolyte and acid/base balance SKELETAL SYSTEM: OVERVIEW SKELETAL SYSTEM: OVERVIEW SKELETAL SYSTEM: OVERVIEW CLASSIFICATION OF BONES Bones can be classified by shape: Long bones are longer than they are wide and have clubby ends. Example: tibia. Short bones are not longer than they are wide. Example: carpal bones. Flat bones look like they are a sheet of clay that has been molded. Example: parietal bone. Irregular bones have many projections and spines. Example: vertebrae. Sesamoid bones grow in tendons where there is a lot of friction. Example: patella. 8 THE SKELETON The usual number of bones in the human skeleton: 206 bones Divided into: AXIAL & APPENDICULAR AXIAL: 80 bones Skull bones: 28 Hyoid bone: 1 Vertebral bones: 26 Ribs: 25 APPENDICULAR: 126 bones Upper Extremities: 64 bones Lower Extremities: 62 bones AXIAL BONES AXIAL = 80 bones Part of body Name of bone Part of body Name of bone 1. SKULL (28) Frontal (1) 2. SPINAL COLUMN (26) Cervical vertebrae (7) Parietal (2) Thoracic vertebrae (12) Temporal (2) Lumbar vertebrae (5) Occipital (1) Sacrum (1) Cranium Sphenoid (1) Coccyx (1) Ethmoid (1) Face Nasal (2) 3. STERNUM AND RIB Sternum (1) Maxillary (2) True Ribs (14) Zygomatic (2) (25) False Ribs (10) Mandible (1) Lacrimal (2) Palatine (2) Inferior nasal concha (2) Vomer (1) Ear Bones Malleus (Hammer) (2) 4. HYOID BONE (1) Hyoid (Lingual) (1) Incus (Anvil) (2) Stapes (Stirrup) (2) 1. SKULL CRANIAL BONES Frontal bone Sphenoid bone Anterior part of cranium Forms part of cranium floor, lateral Parietal bones posterior portions of eye orbits, lateral portions of cranium anterior to Sides and roof of cranium temporal bones Occipital bones Sella turcica Posterior portion and floor of cranium Ethmoid bone Temporal bones Anterior portion of cranium, including Inferior to parietal bones on each side medial surface of eye orbit and roof of of the cranium nasal cavity Temporomandibular joint Nasal conchae 11 The Skull (Anterior View) The Skull (Lateral View) (b) Christine Eckel/McGraw Hill Education 12  Cranial Floor of the Skull (b) Christine Eckel/McGraw Hill Education Access the text alternative for slide images. 13 The Skull (Medial View) 14 The Skull (Inferior View) (b) Christine Eckel/McGraw Hill Education 15  The Skull (Superior View) (b) Christine Eckel/McGraw Hill 16 1. SKULL FACIAL BONES Maxillae Lacrimal bones Form upper jaw, anterior Medial surfaces of eye orbits portion of hard palate, part of Nasal bones lateral walls of nasal cavity, Form bridge of nose floors of eye orbits Maxillary sinus Vomer In midline of nasal cavity Palatine bones Forms nasal septum with the Form posterior portion of hard ethmoid bone palate, lateral wall of nasal Inferior nasal conchae cavity Attached to lateral walls of Zygomatic bones nasal cavity Cheek bones Mandible Also form floor and lateral wall Lower jawbone of each eye orbit Only movable skull bone The Skull (Anterior View) 17 Some skull bones contain sinuses: Sphenoid sinus Frontal sinus Ethmoid sinus Maxillary sinus 18 2. SPINAL COLUMN BONES: Cervical vertebrae (7) Thoracic vertebrae (12) Lumbar vertebrae (5) Sacrum (1) Coccyx (1) 2. SPINAL COLUMN Extends from skull to pelvis Flexible and sturdy longitudinal support for trunk Formed by 24 movable vertebrae, a sacrum, and a coccyx Possess intervertebral disks Shock absorbers Possess four distinct curvatures 2. SPINAL COLUMN CLINICAL CORRELATE: ABNORMAL CURVATURES OF THE SPINAL COLUMN Scoliosis: lateral curvature Kyphosis: hunchback Lordosis: swayback 21 CLINICAL CORRELATE: HERNIATED DISK 22 2. SPINAL COLUMN STRUCTURE OF A VERTEBRA All vertebrae from C3 to L5 have certain common features: Vertebral foramen Spinous process Transverse process Body 2. SPINAL COLUMN CERVICAL VERTEBRAE Support neck Possess unique transverse foramen ATLAS: cervical vertebra 1 Articulates occipital condyles of occipital bone Supports head AXIS: cervical vertebra 2 Possesses the odontoid process (dens) Serves as a pivot point for atlas 24 2. SPINAL COLUMN THORACIC VERTEBRAE Larger vertebra with longer spinous process then cervical vertebrae Ribs articulate on the facets of the transverse processes and bodies Thoracic Vertebra Lumbar Vertebra LUMBAR VERTEBRAE Christine Eckel/McGraw Hill Heavy, thick bodies to support greater stress and weight Larger processes for attachment of back muscles 25  Anterior 2. SPINAL COLUMN Posterior SACRUM Five fused sacral bones Forms posterior wall of pelvic girdle COCCYX Tailbone Three to five fused rudimentary vertebrae Christine Eckel/McGraw Hill 26 3. STERNUM AND RIBS Sternum (1) → flat bone forming the anterior rib cage Manubrium Body Xiphoid process True Ribs (14) The superior 7 pairs of ribs attach directly to the sternum by way of the costal cartilages False Ribs (10) The inferior 5 pairs of ribs do not directly connect to the sternum The upper 3 pairs of false ribs indirectly connect to the sternum via the costal cartilages of true ribs; The last 2 pairs do not connect in any way, so they are called floating ribs  Rib 6 Attachment to T5 and T6 Christine Eckel/McGraw Hill 28 4. HYOID BONE U-shaped bone Only bone of the body that does not articulate with any other bone Found in anterior portion of neck, inferior to mandible Function: attachment for tongue muscles and connective tissue associated with the larynx (voice box) APPENDICULAR BONES APPENDICULAR = 126 bones Part of body Name of bone UPPER EXTREMITIES (64) Clavicle (2) Scapula (2) Humerus (2) Radius (2) Ulna (2) Carpals (16) Metacarpals (10) Phalanges (28) LOWER EXTREMITIES (62) Coxal Bones (2) Femur (2) Patella (2) Tibia (2) Fibula (2) Tarsals (14) Metatarsals (10) Phalanges (28) APPENDICULAR BONES The appendicular skeleton is composed of the bones of the limbs and the bones of the girdles that connect the limbs to the axial skeleton. 1. UPPER EXTREMITIES Pectoral (Shoulder) Girdle Arm and Forearm Wrist and Hand 2. LOWER EXTREMITIES Pelvic Girdle Thigh and Leg Ankle and Foot 1. UPPER EXTREMITIES UPPER EXTREMITIES Pectoral (Shoulder) Girdle CLAVICLE 2 bones Articulates with sternum and scapula SCAPULA 2 bones Located on each side of vertebral column Held in place by muscles to allow free shoulder movement 1. UPPER EXTREMITIES UPPER EXTREMITIES Arm HUMERUS: Articulates with scapula at the shoulder and ulna and radius at the elbow Bony markings include: Head Greater and lesser tubercles Deltoid tuberosity Capitulum Trochlea Medial and lateral epicondyles Olecranon fossa 1. UPPER EXTREMITIES UPPER EXTREMITIES Forearm RADIUS Lateral bone in the forearm Bone that rotates when the hand is rotated Bony markings include the head and styloid process ULNA Medial bone in forearm Bone does not move with hand rotation Bony markings include the olecranon, trochlear notch, and styloid process  ELBOW (d, e) Christine Eckel/McGraw Hill 35 1. UPPER EXTREMITIES UPPER EXTREMITIES Wrist and Hand Carpals Wrist bones Metacarpals Bones of the palm of the hand Phalanges Bones of the fingers 2. LOWER EXTREMITIES LOWER EXTREMITIES Pelvic Girdle Consists of two coxal bones (ossa coxae) Coxal bones attached to one another at the pubic symphysis Parts: Ilium Ischium Pubis Function: forms a rigid, bony pelvis with sacrum and coccyx Pelvic Girdle (lateral view) Pelvic Girdle (Medial View) (b) Christine Eckel/McGraw Hill 38 2. LOWER EXTREMITIES Female pelvis is/has: Wider and shallower More rounded pelvic brim Larger pelvic inlet/opening Female Male 39 2. LOWER EXTREMITIES LOWER EXTREMITIES Thigh Femur Thigh bone Longest and strongest bone in the body Patella Kneecap Sesamoid bone in tendon that extends anterior to knee 2. LOWER EXTREMITIES LOWER EXTREMITIES Leg Tibia Shinbone Larger of the lower leg bones Bears body weight Fibula Slender, lateral bone in lower leg 2. LOWER EXTREMITIES LOWER EXTREMITIES Ankle and Foot Tarsals Ankle bones Metatarsals Bones of the instep Phalanges Toe bones ARCHES OF THE FOOT The tarsal and metatarsals form arches Longitudinal arch Transverse arch 43 Histology of the Skeletal System HISTOLOGY OF THE SKELETAL SYSTEM The skeletal system contains: 1. BONE CONNECTIVE TISSUE 2. CARTILAGE CONNECTIVE TISSUE 45 HISTOLOGY OF THE SKELETAL SYSTEM 1. BONE CONNECTIVE TISSUE Cells of Bone Connective Tissue: Osteoblasts build bone tissue by making matrix with collagen fibers and allowing hydroxyapatite (calcium phosphate crystals) to deposit. Collagen fibers give bone some flexibility. Calcium phosphate crystals make bone hard. Osteoclasts destroy bone. 46 HISTOLOGY OF THE SKELETAL SYSTEM An Osteon 1. BONE CONNECTIVE TISSUE Types of Bone Form A. Compact bone is well organized into osteons (Haversian systems). Osteons Osteonic canals Lamellae Canaliculi (a) Science Stock Ph otogr aphy/Science Source; (c) Stev e Gschmeissn er/Science Source 47 HISTOLOGY OF THE SKELETAL SYSTEM 1. BONE CONNECTIVE TISSUE B. Cancellous bone (spongy bone)is loosely organized as trabeculae. Interior of small bones, skull bones, and epiphyses Consists of trabeculae and spaces filled with red bone marrow Reduces bone weight without reducing strength 48 HISTOLOGY OF THE SKELETAL SYSTEM 2. CARTILAGE CONNECTIVE TISSUE Cells of Cartilage Connective Tissue: Chondrocytes produce a matrix composed of proteoglycans and water. 49 HISTOLOGY OF THE SKELETAL SYSTEM 2. CARTILAGE CONNECTIVE TISSUE Types of Cartilage A. Hyaline Cartilage Hyaline cartilage matrix is smooth and clear. Found as nasal cartilages, costal cartilages, and articular cartilages covering the ends of long bones. 50 HISTOLOGY OF THE SKELETAL SYSTEM 2. CARTILAGE CONNECTIVE TISSUE Types of Cartilage B. Elastic Cartilage Elastic cartilage matrix has fibers going in all directions so as to be elastic Found in the pinna of the ear and the epiglottis 51 HISTOLOGY OF THE SKELETAL SYSTEM 2. CARTILAGE CONNECTIVE TISSUE Types of Cartilage C. Fibrocartilage Fibrocartilage matrix has fibers going in one direction to act as a shock absorber. Found in the intervertebral disks, the menisci of the knee, and the pubic symphysis 52 HISTOLOGY OF THE SKELETAL SYSTEM ANATOMY OF A LONG BONE Epiphyses are the clubby ends of the bone. They are composed mostly of cancellous bone. The diaphysis is the shaft of the bone. It is composed of compact bone. The periosteum covers the diaphysis of the bone. The endosteum lines the marrow (medullary) cavity. Red bone marrow is found in the epiphyses. The marrow cavity in the diaphysis is filled with yellow bone marrow. 53 JOINTS JOINTS JOINTS Joints can be classified on the basis of their anatomy. A. Fibrous joints have fibrous tissue between bones. Sutures. This is formed by the membranes of intramembranous ossification. Gomphoses. This is formed by ligaments holding the tooth in its socket. Syndesmoses. This is formed by an interosseous membrane. 55 JOINTS JOINTS B. Cartilaginous joints have cartilage between the bones. There are 2 types: Symphyses. This is formed by fibrocartilage between the pubic bones. Synchondroses. This is formed by hyaline cartilage between the diaphysis and the epiphyses of bones in children. 56 JOINTS JOINTS C. Synovial joints are lined by a synovial membrane and have synovial fluid in the joint space. 57 JOINTS JOINTS The knee is a relatively unstable joint held together by five ligaments: the medial and lateral collateral ligaments the anterior and posterior cruciate ligaments the patellar ligament It also contains fibrocartilage pads called menisci that act as shock absorbers. 58 JOINTS JOINTS C. Synovial Joints There are six types of synovial joints: hinge, ball and socket, saddle, gliding, ellipsoid, pivot 1. Hinge Joints Allow movement in one direction only Example: knee and elbow joints 2. Ball-and-Socket Joints A rounded head of one bone fits into a concavity on another bone Movement may be rotational or in any plane Example: hip and shoulder joint 59 JOINTS JOINTS C. Synovial Joints 3. Saddle Joints Ends of each bone are saddle shaped Movement is side to side and back and forth Example: joint between trapezium and metacarpal of thumb 4. Gliding Joints Involve sliding of bones across each other Example: carpal and tarsal bones 60 JOINTS JOINTS C. Synovial Joints 5. Ellipsoid Joints Allow movement from side to side and back and forth Example: between carpals and bones of forearm 6. Pivot Joints Allow rotational movement Example: atlas on the axis 61  Rheumatoid Arthritis JOINTS Joint Replacement DISEASES OF THE JOINTS Osteoarthritis is wear and tear on a joint. Most people develop osteoarthritis as they age. Rheumatoid arthritis is an autoimmune disease. Anyone, including children, can develop rheumatoid arthritis. Joint replacement may be necessary with severe arthritis. (a) Southern Illinois University/Science (a) Antonia Reeve/Science Source; (b) TEK Image/SPL/Getty Source; (b) CNRI/SPL/Science Source Image; (c) Mehau Kulyk/SPL/Science Source 62 Physiology of the Skeletal System PHYSIOLOGY OF THE SKELETAL SYSTEM MINERAL DEPOSITION Osteoblasts produce a chemical that allows calcium phosphate crystals to be deposited. This is a positive feedback mechanism starting with a seed crystal. 64 PHYSIOLOGY OF THE SKELETAL SYSTEM BONE DEVELOPMENT Flat bones are formed through intramembranous ossification. Long bones are formed through endochondral ossification. 65 PHYSIOLOGY OF THE SKELETAL SYSTEM Bone Development Intramembranous Ossification of the Skull A. Intramembranous Ossification Forms most skull bones Fontanelles present at birth Steps involved: Connective tissue membranes form at sites of future intramembranous bones. Some cells become osteoblasts. Osteoblasts deposit spongy bone beginning at center of bone. Osteoblasts form layer of compact bone atop the spongy bone. b(i) Science Stock Photography/Science Source; b(ii) Christine Eckel/McGraw Hill 66 PHYSIOLOGY OF THE SKELETAL SYSTEM Bone Development B. Endochondral Ossification Forms most bones of the body Example: long bones 67 PHYSIOLOGY OF THE SKELETAL SYSTEM Bone Development B. Endochondral Ossification Steps involved: Bones are preformed in hyaline cartilage Primary ossification center forms in center of cartilage Periosteal osteoblasts form a compact bone collar around primary ossification center Cartilage in the primary center calcifies and chondrocytes die Blood vessels and nerves penetrate the center, bring osteoblasts with them Osteoblasts form spongy bone at the primary ossification center 68 PHYSIOLOGY OF THE SKELETAL SYSTEM 69 PHYSIOLOGY OF THE SKELETAL SYSTEM Bone Development B. Endochondral Ossification Steps involved: Secondary ossification center forms in the epiphyses Osteoclasts remove the spongy bone and form the medullary cavity Bone continues to grow At the end of the process, the epiphyseal plate separates the epiphyses from the diaphysis 70 PHYSIOLOGY OF THE SKELETAL SYSTEM Bone Growth Appositional Bone Growth Long bones continue to grow longer after birth through endochondral growth until the epiphyseal plates are closed. Create epiphyseal line Appositional growth makes bones more massive. It occurs along lines of stress. Biophoto Associates/Science Source 71 X-ray of a Child’s Hand Steven Needell/Science Source 72 PHYSIOLOGY OF THE SKELETAL SYSTEM Bone Remodeling Bone remodeling is done by osteoclasts. They remove bone by producing hydrochloric acid, which dissolves the calcium phosphate crystals. Bones act as a reservoir for calcium. Bone remodeling depends on blood calcium levels and the stress applied to the bone. 73 PHYSIOLOGY OF THE SKELETAL SYSTEM Nutritional Requirements of the Skeletal System Calcium sources Dairy products, green leafy vegetables, broccoli, collards, kale, turnip greens, and Bok choy Phosphorus for phosphates found in dairy products and meats Vitamin D needed for calcium absorption Vitamin D is activated by the liver and kidneys to become calcitriol. Calcitriol increases calcium absorption in the small intestines. 74 PHYSIOLOGY OF THE SKELETAL SYSTEM Hormonal Regulation of Bone Deposition The Parathyroid Gland and Reabsorption Bone deposition and reabsorption are regulated by hormones on the basis of blood calcium levels. If blood levels of calcium are too high, calcitonin tells osteoblasts to deposit bone. If blood levels of calcium are too low, PTH tells osteoclasts to reabsorb bone. 75 Homeostasis of Calcium 76 PHYSIOLOGY OF THE SKELETAL SYSTEM Hormonal Regulation of Bone Deposition and Reabsorption Estrogen and testosterone speed up deposition at puberty and serve as a lock on calcium in the bone. 77 PHYSIOLOGY OF THE SKELETAL SYSTEM Functions of the Skeletal System 1. Support. Vertebral column allows the body to be erect. 2. Movement. The arrangement of bones and joints allows a range of movements. 3. Protection. The cranial bones protect the brain. The sternum and rib cage protect the lungs and heart. 4. Acid-base balance. Phosphate ions can bind to excess hydrogen ions to buffer the pH of the blood. 5. Electrolyte balance. Bones serve as a reservoir for calcium. 6. Blood formation. Red blood cells, white blood cells, and platelets are produced in the red bone marrow. 78 Effects of Aging on the Skeletal System EFFECTS OF AGING ON THE SKELETAL SYSTEM The ratio of deposition to reabsorption changes as we age: Deposition > Reabsorption from Birth to age 25 Increasing bone mass and density Deposition = Reabsorption from Ages 25 to 45 Maintaining bone mass and density Deposition < Reabsorption at Age 45 and over Decreasing bone mass and density 80 EFFECTS OF AGING ON THE SKELETAL SYSTEM Decreases in estrogen and testosterone levels are responsible for the change. Vertebrae thin out, and the spinal column becomes more curved and compressed The elderly are more prone to falls, resulting in fractures Joints stiffen and become less flexible Minerals may deposit in joints 81 Fractures FRACTURES Types of Fractures Fractures can be classified by using descriptive terms. Fractured bones can be set back into proper alignment by closed or open reduction. 83 FRACTURES Types of Fractures Closed. A closed fracture (formerly called a simple fracture) does not cause a break in the skin. A shattered bone may not break through the skin, but it hardly seems appropriate to refer to it as simple. Open. An open fracture (formerly called a compound fracture) breaks through the skin. Complete. The bone is in two or more pieces. Displaced. The bone is no longer in proper alignment. 84 FRACTURES Types of Fractures Nondisplaced. The bone is in proper alignment. Hairline. There is a crack in the bone. Greenstick. The bone has broken through one side but not completely through the other side. Depressed. The bone has been dented. This fracture is found where there is cancellous bone, as in skull fractures. 85 FRACTURES Types of Fractures Transverse. The bone is broken perpendicular to its length. Oblique. The break in the bone is at an angle. Spiral. The break in the bone spirals up the bone. → This type of break often results from twisting the bone. This may occur when children fall while kneeling on a chair at the table with their feet sticking through the chair’s spokes. 86 FRACTURES Types of Fractures Epiphyseal. The break occurs at the epiphyseal plate in a child. Comminuted. The bone (commonly referred to as shattered) is broken into three or more pieces. Compression. Cancellous bone has been compressed. This type of fracture may occur in the vertebrae. 87  X-Rays of Fractures (a) Scott Camazine/Science Source; (b) Howard Kingsnorth/The Image Bank/Getty Images; (c) Lester V. Bergman/Corbis NX/Getty Images; (d) Biophoto Associates/Science Source Access the text alternative for slide images. 88 Open Reduction of an Ankle Fracture (a) Feellife/E+/Getty Images 89 FRACTURES Fracture Healing 1. Hematomas form due to bleeding. 2. The healing of a fracture starts with stem cells forming a soft callus in a hematoma. 3. Osteoblasts deposit bone in the soft callus to form a hard callus. 4. Osteoclasts finish the healing of the fracture by remodeling the hard callus to reestablish the marrow cavity. 90 The Healing of a Bone Fracture 91 Diagnostic Tests for Skeletal Disorders Diagnostic Tests for Skeletal System Disorders TABLE 4.4 Common Diagnostic Tests for Skeletal System Disorders Diagnostic Test or Screening Description DEXA (dual-energy X-ray The use of low-dose radiation to measure absorptiometry) scan bone density in the hip and vertebrae X-ray The use of electromagnetic radiation that sends photons through the body to create a visual image of dense structures such as bone 93 Skeletal System Disorders SKELETAL SYSTEM DISORDERS Bone-softening disorders include osteoporosis, rickets, and osteomalacia. Brittle bones is another name for osteogenesis imperfecta. Abnormal spinal curvatures include scoliosis, kyphosis, and lordosis. Joint inflammations include osteoarthritis and rheumatoid arthritis. 95 SKELETAL SYSTEM DISORDERS Osteoporosis Osteoporosis is a severe lack of bone density. Osteomyelitis Osteomyelitis is a bone infection. (a) Michael Klein/Photolibrary/Getty Images; (b) Dr. P. Marazzi/Science Source; (c) Dr. P. Marazzi/SPL/Getty Images 96 SKELETAL SYSTEM DISORDERS Cancers Affecting the Skeletal System Osteosarcomas are malignant bone tumors that occur in immature bone. Chondrosarcomas are cancerous tumors that occur in cartilage. 97 SKELETAL SYSTEM DISORDERS Gout (b) Du Cane Medical Imaging Ltd./Science Source; (c) Dr. P. Marazzi/Science Source 98 SKELETAL SYSTEM DISORDERS (c) PeopleImages/Getty Images (b) Biophoto Associates/Science Source 99 SKELETAL SYSTEM DISORDERS Mastoiditis (b) Mediscan/Alamy Stock Photo 100 Because learning changes everything. ® www.mheducation.com © 2023 McGraw Hill, LLC. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill, LLC.