Anatomy of Bone and Joints PDF

ANATOMY OF BONE AND JOINTS (General Considerations of Bones, Axial Skeleton, Appendicular Skeleton) COMPONENTS OF SKELETAL SYSTEM Bones Cartilages Tendons Ligaments SKELETAL SYSTEM  DIVISION OF THE SKELETAL SYSTEM  THE AXIAL SKELETON The ax...

ANATOMY OF BONE AND JOINTS (General Considerations of Bones, Axial Skeleton, Appendicular Skeleton) COMPONENTS OF SKELETAL SYSTEM Bones Cartilages Tendons Ligaments SKELETAL SYSTEM  DIVISION OF THE SKELETAL SYSTEM  THE AXIAL SKELETON The axial skeleton is the central axis of the body, comprising the bones of the head, neck, torso, and back. It protects vital organs like the spinal cord, heart, and lungs, and serves as an attachment site for muscles that facilitate movement and respiration. The distinction between axial and appendicular skeletons is based on the type of movement the bones enable, rather than their location.  THE APPENDICULAR SKELETON The appendicular skeleton includes all bones of the upper and lower limbs, plus the bones that attach each limb to the axial skeleton. There are 126 bones in the appendicular skeleton of an adult.  FIGURE AT THE AXIAL AND APPENDICULAR SKELETONS BONES OF THE SKELETAL SYSTEM Copyright © McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education. SKELETAL SYSTEM FUNCTIONS 1. Support 2. Function 3. Movement 4. Storage 5. Blood cell production  EXTRACELLULAR MATRIX Bone, Cartilage, tendons, and ligaments of the skeletal system are all connective tissues. Their characteristics are largely determined by their composition of their extracellular matrix. The matrix always contains collagen, ground substance, and other organic molecules, as well as water and minerals.  EXTRACELLULAR MATRIX Collagen is a tough, ropelike protein. Proteoglycans are large molecules consisting of many polysaccharides attaching to and encircling core proteins. The proteoglycans form large aggregates and attract water. The extracellular matrix of tendons and ligaments contains large amounts of collagen fibers, making these structures very tough, like ropes or cables.  CARTILAGE EXTRACELLULAR MATRIX The extracellular matrix of cartilage contains collagen and proteoglycans. Collagen makes cartilage tough, whereas the water-filled proteoglycans make it smooth and resilient. As a result, cartilage is relatively rigid, but it springs back to its original shape after being bent or slightly compressed. It is an excellent shock absorber  BONE EXTRACELLULAR MATRIX The extracellular matrix of bone contains collagen and minerals, including calcium and phosphate. The ropelike collagen fibers lend flexible strength to the bone. The mineral component gives bone compression (weight-bearing) strength. Most of the mineral in bone is in the form of calcium phosphate crystals called hydroxyapatite.  SHAPE CLASSIFICATION OF BONES There are four bone shape classifications: long, short, flat, and irregular. Long bones are longer than they are wide; examples are upper and lower limb bones. Short bones are approximately as wide as they are long; examples are the bones of the wrist and ankle.  SHAPE CLASSIFICATION OF BONES Flat bones have a relatively thin, flattened shape; examples are bones of the skull and sternum. Irregular bones include the vertebrae and facial bones, which have shapes that do not fit readily into the other three categories.  LONG BONE STRUCTURES Diaphysis: Shaft compact bone tissue (on outside) Epiphysis: ends spongy bone tissue Articular cartilage: covers epiphyses reduces friction  LONG BONE STRUCTURES Epiphyseal plate: site of growth between diaphysis and epiphysis Medullary cavity: center of diaphysis red or yellow marrow  LONG BONE STRUCTURES Periosteum: membrane around bone’s outer surface Endosteum: membrane that lines medullary cavity STRUCTURE OF LONG BONE  BONE MARROW Bones contain cavities, such as the large medullary cavity in the diaphysis, as well as smaller cavities in the epiphyses of long bones and in the interior of other bones. These spaces are filled with soft tissue called marrow. Red marrow is the location of blood forming cells. Yellow marrow is mostly fat.  BONE MARROW In newborns most bones have blood making red bone marrow. In adults red marrow in the diaphysis is replaced by yellow bone marrow. In adults most red bone marrow is in the flat bones and the long bones of the femur and humerus.  COMPACT BONE TISSUE Location: outer part of diaphysis (long bones) and thinner surfaces of other bones Osteon: structural unit of compact bone includes lamella, lacunae, canaliculus, central canal, osteocytes Lamella: rings of bone matrix  COMPACT BONE TISSUE Lacunae: spaces between lamella Canaliculus: tiny canals transport nutrients and remove waste Central canal: center of osteon contains blood vessels STRUCTURE OF BONE TISSUE  SPONGY (CANCELLOUS) BONE TISSUE Spongy bone It is located at the epiphyses of long bones and center of other bones. It has trabeculae, which are interconnecting rods, and spaces that contain marrow. It has no osteons. SPONGY BONE TISSUE  BONE CELLS Osteoblasts: responsible for the formation of bone and the repair and remodeling of bone. Osteocytes: cells that maintain bone matrix and form from osteoblast after bone matrix has surrounded it. Osteoclasts: contribute to bone repair and remodeling by removing existing bone, called bone reabsorption.  BONE FORMATION Ossification is the formation of bone by osteoblasts. Bone formation that occurs within connective tissue membranes is called intramembranous ossification. Bone formation that occurs inside hyaline cartilage is called endochondral ossification. Both types of bone formation result in compact and spongy bone.  INTRAMEMBRANOUS OSSIFICATION Intramembranous ossification occurs when osteoblasts begin to produce bone within connective tissue. This occurs primarily in the bones of the skull. Osteoblasts line up on the surface of connective tissue fibers and begin depositing bone matrix to form trabeculae.  INTRAMEMBRANOUS OSSIFICATION The process begins in areas called ossification centers and the trabeculae radiate out from the centers. Usually, two or more ossification centers exist in each flat skull bone and mature skull bones result from fusion of these centers as they enlarge. The trabeculae are constantly remodeled and they may enlarge or be replaced by compact bone. BONE FORMATION IN THE FETUS  ENDOCHONDRAL OSSIFICATION Endochondral bone formation is bone formation within a cartilage model. The cartilage model is replaced by bone. Initially formed is a primary ossification center, which is bone formation in the diaphysis of a long bone. A secondary ossification center is bone formation in the epiphysis.  STEPS IN ENDOCHONDRAL OSSIFICATION 1. Chondroblasts build a cartilage model, the chondroblasts become chondrocytes. 2. Cartilage model calcifies (hardens). 3. Osteoblasts invade calcified cartilage and a primary ossification center forms diaphysis. 4. Secondary ossification centers form epiphysis. 5. Original cartilage model is almost completely ossified and remaining cartilage is articular cartilage. ENDOCHONDRAL OSSIFICATION OF A LONG BONE  BONE GROWTH IN WIDTH Bone growth occurs by the deposition of new bone lamellae onto existing bone or other connective tissue. As osteoblasts deposit new bone matrix on the surface of bones between the periosteum and the existing bone matrix, the bone increases in width, or diameter. This process is called appositional growth.  BONE GROWTH IN LENGTH Growth in the length of a bone, which is the major source of increased height in an individual, occurs in the epiphyseal plate. This type of bone growth occurs through endochondral ossification. Chondrocytes increase in number on the epiphyseal side of the epiphyseal plate.  BONE GROWTH IN LENGTH Then the chondrocytes enlarge and die. The cartilage matrix becomes calcified. Much of the cartilage that forms around the enlarged cells is removed by osteoclasts, and the dying chondrocytes are replaced by osteoblasts.  BONE GROWTH IN LENGTH The osteoblasts start forming bone by depositing bone lamellae on the surface of the calcified cartilage. This process produces bone on the diaphyseal side of the epiphyseal plate. ENDOCHONDRAL BONE GROWTH  BONE REMODELING Bone remodeling involves: removal of existing bone by osteoclasts and deposition of new bone by osteoblasts occurs in all bones responsible for changes in bone shape, bone repair, adjustment of bone to stress, and calcium ion regulation  BONE REPAIR 1. Broken bone causes bleeding and a blood clot forms. 2. Callus forms which is a fibrous network between 2 fragments. 3. Cartilage model forms first then, osteoblasts enter the callus and form cancellous bone this continues for 4-6 weeks after injury. 4. Cancellous bone is slowly remodeled to form compact and cancellous bone. BONE REPAIR  BONE AND CALCIUM HOMEOSTASIS Bone is a major storage site for calcium Movement of calcium in and out of bone helps determine blood levels of calcium Calcium moves into bone as osteoblasts build new bone Calcium move out of bone as osteoclasts break down bone Calcium homeostasis is maintained by parathyroid hormone (PTH) and calcitonin CALCIUM HOMEOSTASIS  BONE ANATOMICAL TERMS Foramen: hole Example - foramen magnum Fossa: depression Example - glenoid fossa Process: projection Example - mastoid process  BONE ANATOMICAL TERMS Condyle: smooth, rounded end Example - occipital condyle Meatus: canal-like passageway Example - external auditory meatus Tubercle: lump of bone Example - greater tubercle  AXIAL SKELETON The axial skeleton is composed of the skull, the vertebral column, and the thoracic cage. The skull has 22 bones divided into those of the braincase and those of the face. The braincase, which encloses the cranial cavity, consists of 8 bones that immediately surround and protect the brain. The bony structure of the face has 14 facial bones.  AXIAL SKELETON Thirteen of the facial bones are rather solidly connected to form the bulk of the face. The mandible, however, forms a freely movable joint with the rest of the skull. There are also three auditory ossicles in each middle ear (six total).  CRANIAL BONES Frontal bone Anterior part of cranium Parietal bones Sides and roof of cranium Occipital bones Posterior portion and floor of cranium Temporal bones Inferior to parietal bones on each side of the cranium Temporomandibular joint  CRANIAL BONES Sphenoid bone Forms part of cranium floor, lateral posterior portions of eye orbits, lateral portions of cranium anterior to temporal bones Sella turcica Ethmoid bone Anterior portion of cranium, including medial surface of eye orbit and roof of nasal cavity Nasal conchae  FACIAL BONES Maxillae Form upper jaw, anterior portion of hard palate, part of lateral walls of nasal cavity, floors of eye orbits Maxillary sinus Palatine bones Form posterior portion of hard palate, lateral wall of nasal cavity  FACIAL BONES Zygomatic bones Cheek bones Also form floor and lateral wall of each eye orbit Lacrimal bones Medial surfaces of eye orbits Nasal bones Form bridge of nose  FACIAL BONES Vomer In midline of nasal cavity Forms nasal septum with the ethmoid bone Inferior nasal conchae Attached to lateral walls of nasal cavity Mandible Lower jawbone Only movable skull bone THE SKULL THE SKULL THE SKULL THE SKULL THE SKULL  PARANASAL SINUSES Several of the bones associated with the nasal cavity have large cavities within them, called the paranasal sinuses which open into the nasal cavity. The paranasal sinuses are: Frontal Ethmoid Sphenoid Maxillary PARANASAL SINUSES  HYOID BONE The hyoid bone is an unpaired, U-shaped bone that is not part of the skull and has no direct bony attachment to the skull or any other bones. The hyoid bone has the unique distinction of being the only bone in the body that does not articulate with another bone. The hyoid bone provides an attachment for some tongue muscles, and it is an attachment point for important neck muscles that elevate the larynx. HYOID BONE  VERTEBRAL COLUMN The vertebral column, or spine, is the central axis of the skeleton, extending from the base of the skull to slightly past the end of the pelvis. In adults, it usually consists of 26 individual bones, grouped into five regions. The adult vertebral column has four major curvatures: cervical, thoracic, lumbar and sacrococcygeal. The cervical region curves anteriorly. The thoracic region curves posteriorly. The lumbar region curves anteriorly The sacral and coccygeal regions together curve posteriorly  VERTEBRAL COLUMN 7 cervical vertebra 12 thoracic vertebra 5 lumbar vertebra 1 sacrum 1 coccyx Atlas: 1 st vertebra holds head Axis: 2nd vertebra rotates head FUNCTIONS OF VERTEBRAL COLUMN Supports body weight Protects the spinal cord Allows spinal nerves to exit the spinal cord Provides a site for muscle attachment Provides movement of the head and trunk VERTEBRAL COLUMN VERTEBRA REGIONAL DIFFERENCES IN VERTEBRAE SACRUM  THORACIC CAGE Protects vital organs 12 pair of ribs Sternum: breastbone True ribs: attach directly to sternum by cartilage False ribs: attach indirectly to sternum by cartilage Floating ribs: not attached to sternum THORACIC CAGE  BONES OF THE PECTORAL GIRDLE Scapula: shoulder blade Clavicle: collar bone PECTORAL GIRDLE SCAPULA AND CLAVICLE  UPPER LIMB BONES Humerus: upper limb Ulna: forearm Radius: forearm Carpals: wrist Metacarpals: hand UPPER LIMB BONES THE HUMERUS ULNA AND RADIUS BONES OF THE WRIST AND HAND THAT'S ALL THANK YOU!!!