Anaphy Reviewer Skeletal System PDF

ANAPHY REVIEWER MODULE 6: SKELETAL SYSTEM LIGAMENTS - are strong bands of fibrous HUMAN SKELETON connective tissue that attach to...

ANAPHY REVIEWER MODULE 6: SKELETAL SYSTEM LIGAMENTS - are strong bands of fibrous HUMAN SKELETON connective tissue that attach to -is the internal framework of the human bones and hold them together. -is constructed of two of the most 2. PROTECTION supportive tissues found in the human BONE body— cartilage and bone. -is hard and protects the organs it LIGAMENTS surrounds. -fibrous cords that bind the bones together -For example, the skull encloses and at joints. (bones-bones) protects the brain, and the vertebrae JOINTS surround the spinal cord. -give flexibility and allow movement to -rib cage protects the heart, lungs, and occur. (where bone meets another bone) other organs of the thorax. THE SKELETON IS DIVIDED INTO 2 PARTS: 3. MOVEMENT -skeletal muscles attach to bones by 1. AXIAL SKELETON tendons- which are strong bands of -the bones that form the longitudinal axis connective tissue. of the body -Contraction of the skeletal muscles moves 2. APPENDICULAR SKELETON the bones, producing body movements. - the bones of the limbs and girdles that JOINTS attach them to the axial skeleton. -which are formed where two or more bones come together, allow movement between bones. SMOOTH CARTILAGE -covers the ends of bones within some joints, allowing the bones to move freely. LIGAMENTS allow some movement between bones but prevent excessive movements. 4. STORAGE -Some minerals in the blood are taken into bone and stored. -are calcium and phosphorus (minerals). FUNCTIONS OF THE SKELETAL SYSTEM (SSPBM) -If blood levels of these minerals decrease, the minerals are released from bone into 1. SUPPORT the blood. -Rigid, strong bone is well suited for -Fat (adipose tissue) is also stored within bearing weight and is the major supporting bone cavities: as a source of energy. tissue of the body. 5. BLOOD CELL PRODUCTION Cartilage provides a firm yet flexible -Many bones contain cavities filled with red support within certain structures. bone marrow -gives rise to blood cells and platelets  BONE MATRIX -mineral component, like the concrete itself, -contains extracellular materials of the gives the bone compression (weight- bone bearing) strength. -bone, cartilage, tendons, and ligaments of -mineral in bone is in the form of calcium the skeletal system are all connective phosphate crystals called HYDROXYAPATITE tissues. GENERAL FEATURES OF BONE MATURE BONE -35% organic (collagen and “4 CATEGORIES OF BONE: based on SHAPE” proteoglycans) and 65% inorganic 1. LONG BONES (calcium phosphate) material. ORGANIC MATERIAL - collagen and -are longer than they are wide. -Most of the bones of the upper and lower proteoglycans. INORGANIC MATERIAL - calcium limbs are long bones. 2. SHORT BONES phosphate -are approximately as wide as they are long EXTRACELLULAR MATRIX -examples are the bones of the wrist and ankle. COLLAGEN 3. FLAT BONES -is a tough, ropelike protein. -have a relatively thin, flattened shape. PROTEOGLYCANS -Examples of flat bones are certain skull -are large molecules consisting of bones, the ribs, the scapulae (shoulder polysaccharides attached to core proteins blades), and the sternum. -similar to the way needles of a pine tree 4. IRREGULAR BONES are attached to the tree’s branches. -include the vertebrae and facial bones -attract and retain large amounts of water -which have shapes that do not fit readily between their polysaccharide “needles.” into the other three categories TENDONS and LIGAMENTS -contains large amounts of collagen fibers, making these structures very tough, like ropes or cables. CARTILAGE -contains collagen and proteoglycans. -Collagen makes cartilage tough, whereas the water-filled proteoglycans make it smooth and resilient. -As a result: rigid, but it springs back to its original shape after being bent or slightly compressed -Excellent shock absorber STRUCTURE OF A LONG BONE BONE DIAPHYSIS -contains collagen and minerals, including -(growing between) central shaft of long calcium and phosphate. bone -ropelike collagen fibers, like the reinforcing EPIPHYSIS steel bars in concrete, lend flexible strength -(growing upon) the two end to the bone.  ARTICULAR CARTILAGE ENDOSTEUM - A thin layer of cartilage, covers the ends -surface of the medullary cavity is lined of the epiphyses where the bone with a thinner connective tissue membrane articulates (joins) with other bones. EPIPHYSEAL PLATE -composed of cartilage, between each epiphysis and the diaphysis -is where the bone grows in length. -for female: closes around 14-15 y/o -for male: closes around 21 y/o EPIPHYSEAL LINE -When bone growth stops, the cartilage of each epiphyseal plate is replaced by bone MEDULLARY CAVITY “BONE CELLS” -cavities in the bone, such as the large 1. OSTEOBLASTS (IMMATURE) cavity in the diaphysis, as well as smaller -(bone-forming cells), which function in the cavities in the epiphyses of long bones. formation of bone, as well as in the repair MARROW and remodeling of bone. -soft tissue in the medullary cavities of the -produce collagen and proteoglycans, which bone are packaged into vesicles by the Golgi apparatus -released from the cell by exocytosis. OSSIFICATION (OSTEOGENESIS) -is the formation of bone by osteoblasts. OSTEOCHONDRAL PROGENITOR CELLS (from this to osteoblasts) -are stem cells that can become osteoblasts -are located in the inner layer of “MARROW” the periosteum, and the 1. YELLOW MARROW endosteum. -consists mostly of adipose tissue. 2. OSTEOCYTES (MATURE) -more in old bones -osteoblasts become surrounded by matrix 2. RED MARROW (bone cells). -consists of blood-forming cells and is the -it is a mature bone cell only site of blood formation in adults -spaces occupied by the osteocyte cell -Children’s bones have proportionately bodies are called LACUNAE more red marrow than do adult bones -spaces occupied by the osteocyte cell PERIOSTEUM processes are called CANALICULI -outer surface of bone is covered by dense 3. OSTEOCLAST connective tissue; consists of two layers and -(bone-eating cells) are also present and contains blood vessels and nerves contribute to bone repair and remodeling by removing existing bone  BONE TISSUE FOUND THROUGHOUT THE VOLKMANN’S OR PERFORATING SKELETON IS DIVIDED INTO 2 MAJOR CANALS TYPES: -canals running horizontally to 1. COMPACT BONE harvesian canal, and also contain -is mostly solid matrix and cells. blood vessels 2. SPONGY BONE (CANCELLOUS BONE) -consists of a lacy network of bone with many small, marrow-filled spaces. ]] HISTOLOGY OF BONE: COMPACT BONE 1. COMPACT BONE or Cortical Bone -Nutrients leave the blood vessels of the central -Forms the perimeter of the diaphysis of a canals and diffuse to the osteocytes through the long bone canaliculi. -Thinner surface of all other bone -More matrix and is denser, with fewer -Waste products diffuse in the opposite pores direction. OSTEONS -blood vessels in the central canals, in turn, are -Compose of predictable pattern of connected to blood vessels in the periosteum repeating units and endosteum. -the whole system LAMELLAE -osteon consists of concentric rings -the layers or rings HARVESIAN or CANTRAL CANAL -running parallel to the surface of the bone; small canals containing blood vessels (capillaries/arterioles/venules) LACUNAE -tiny cavities between two lamellae CANALUCULI -give osteon the appearance of having tiny cracks within the lamellae  2. SPONGY BONE INTRAMEMBRANOUS OSSIFICATION -spongy bone, so called because of its -bone formation that occurs within appearance connective tissue membranes -Very porous ENDOCHONDRAL OSSIFICATION -Located in the epiphyses of the long -bone formation that occurs inside cartilage bone -Both types of bone formation result in -Less bone matrix compact and spongy bone. -More open space INTRAMEMBRANOUS OSSIFICATION -It forms the interior of all other bones. -occurs when osteoblasts begin to TRABECULAE produce bone in connective tissue -delicate interconnecting rods membranes. or plates of bone -primarily in the bones of the skull. -which resemble the beams or -Osteoblasts line up on the surface of scaffolding of a building connective tissue fibers and begin -Add strength to the bone depositing bone matrix to form (scaffolding) trabeculae. -Spaces filled with marrow. -process begins in areas called -no blood vessels - no central ossification centers, and the trabeculae canals. radiate out from the centers. -Nutrients exit vessels in the -trabeculae are constantly remodeled marrow and pass by diffusion after their initial formation > compact (canaliculi to the osteocytes of bone the trabeculae) ENDOCHONDRAL OSSIFICATION -bones at the base of the skull and most of the remaining skeletal system develop through the process of endochondral ossification from cartilage models. -cartilage models have the general shape of the mature bone -chondrocytes, increase in number, enlarge, and die -Then the cartilage matrix becomes calcified BONE OSSIFICATION OSSIFICATION is the formation of bone by osteoblasts. -After an osteoblast becomes completely surrounded by bone matrix, it becomes a mature bone cell, or osteocyte. -fetus begins at 3rd month of fetal age -occurring in the center of the cartilage -calcified cartilage matrix is removed by model, blood vessels accumulate in the osteoclasts, and the osteoblasts line up on the perichondrium. remaining calcified matrix and begin to form -presence of blood vessels in the outer bone trabeculae. surface of future bone causes some of -medullary cavity forms in the center of the the unspecified connective tissue cells diaphysis as osteoclasts remove bone on the surface to become osteoblasts. -osteoblasts then produce a collar of -calcified cartilage – replace by bone marrow. bone around part of the outer surface of the diaphysis, and the -SECONDARY OSSIFICATION centers form in the perichondrium becomes periosteum in epiphyses that area. BONE GROWTH -process is called APPOSITIONAL GROWTH- osteoblasts deposit new bone matrix on the -Blood vessels also grow into the surface of bones between the periosteum and center of the diaphyses, bringing in the existing bone matrix, the bone increases in osteoblasts and stimulating width, or diameter. ossification. ▪ Growth in the length of a bone, which is the -center part of the diaphysis, where major source of increased height in an bone first begins to appear, is called individual, occurs in the epiphyseal plate-occurs the PRIMARY OSSIFICATION CENTER through endochondral ossification -Osteoblasts invade spaces in the center of the bone left by the dying cartilage ▪ Bone elongation occurs at the epiphyseal cells. plate as chondrocytes proliferate, enlarge, die, and are replaced by bone. FACTORS AFFECTING BONE GROWTH ❖ NUTRITION VITAMIN D - necessary for the normal absorption of calcium from the intestines  The body can either synthesize or BONE REMODELLING ingest vitamin D -Involves the removal of existing bone by Insufficient vitamin D in children causes osteoclasts and the deposition of new bone rickets by osteoblasts. RICKETS -Bones are remodeled continually in -a disease in CHILDREN resulting from response to changes in two factors: reduced mineralization of the bone ▪ calcium ion level in the blood matrix. (insufficient VIT D) ▪ pull of gravity and muscles on the Low vitamin D levels can be one cause of skeleton. “adult rickets,” -Bone remodeling is essential, to retain OSTEOMALACIA normal proportions and strength during -a softening of the bones in ADULTS long-bone growth as the body increases in due to calcium depletion. size and weight. VITAMIN C -bones become thicker and form large -is necessary for osteoblasts to synthesize projections to increase their strength in collagen. areas where bulky muscles are attached -old collagen breaks down, new collagen is STAGES OF BONE REMODELLING synthesized to replace it. -deficiency results in bones and cartilage 1. RESORPTION with fewer collagen fibers - collagen -Osteoclast remove bone mineral and synthesis is impaired. matrix, creating erosion cavity (3-4 weeks) -In children, deficiency can retard growth. 2. REVERSAL -In both children and adults, deficiency in -Mononuclear cells prepare bone surface VIT C can result in SCURVY, which is marked for new osteoblasts to begin building bone by ulceration and hemorrhage in almost 3. FORMATION any area of the body. -Osteoblasts synthesize a matrix to replace ❖ GROWTH HORMONE resorbed bone with new bone (3 – 4 -from the anterior pituitary increases months) general tissue growth, including overall 4. RESTING bone growth -A prolonged resting period follows until a GIGANTISM new remodeling begins. -Excessive growth hormone secretion BONE REPAIR DWARFISM Insufficient growth hormone secretion ▪ Sometimes a bone is broken and needs to be ❖ THYROID HORMONE repaired. -required for normal growth of all tissues, including cartilage ▪ When this occurs, blood vessels in the bone -decrease in this hormone can result in a are also damaged smaller individual ▪ vessels bleed, and a clot (HEMATOMA) forms ❖ ESTROGEN AND TESTOSTERONE in the damaged area -cause increased bone growth and closure of the epiphyseal plate. -During puberty, the levels of these hormones increase dramatically ▪ 2 - 3 days after the injury, blood vessels and BONE FRACTURE CLASSIFICATION cells from surrounding tissues begin to invade 1. mechanism of fracture the clot. 2. soft-tissue damage ▪ Some of these cells produce a fibrous network of connective tissue between the broken bones, 3. displacement vs. non – displacement which holds the bone fragments together and fills the gap between them. 4. fracture pattern ▪ Other cells produce islets of cartilage in the 5. number of fragments in the fractured bone fibrous network. 1. MECHANISM OF FRACTURE ▪ CALLUS -network of fibers and islets of The first criterion for bone fracture type falls cartilage between the two bone fragments under the category of the mechanism by which the fracture occurred. 1. through a trauma to the bone (TRAUMATIC) 2. through a pathology (disease) of the bone (PATHOLOGIC) 2. SOFT TISSUE DAMAGE The next criterion by which bone fractures are classified is by the amount of soft-tissue damage. 1. CLOSED (STABLE OR SIMPLE) - no visible damage to the skin at the ▪ Osteoblasts enter the callus and begin forming injury site spongy bone 2. OPEN (COMPOUND) ▪ Spongy bone formation in the callus is usually -there is visible damage to the skin at complete 4–6 weeks after the injury. the trauma site, possibly including a fragment of the fracture bone ▪ Immobilization of the bone is critical up to protruding from the skin. this time 3. DISPLACED VS. NON – DISPLACED ▪ Spongy bone is slowly remodeled to form compact and spongy bone, and the repair is Two possibilities exist for the position of the complete fractured bone ends after the fracture has occurred: 1. DISPLACED -where the ends of the bones are offset from each other and are not aligned anatomically 2. NON – DISPLACED -where the ends of the bone remain in anatomical alignment. 4.FRACTURE PATTERN 1. INCOMPLETE FRACTURE -a fracture that only traverses’ part of This classification is based on the pattern of the the bone fracture on the bone. These include: 2. COMPLETE FRACTURE 1. LINEAR FRACTURE - runs parallel to the -a fracture that completely separates length of the bone the bone into at least two fragments 3. COMMINUTED FRACTURE 2. SPIRAL FRACTURE - results from twisting of -a fracture where the bone breaks into one part of the bone multiple fragments 3. AVULSION FRACTURE - separation of a bone fragment from the rest of the bone 4. STRESS (HAIRLINE) FRACTURE - incomplete fracture resulting from overuse of the bone 5. COMPRESSION FRACTURE - the bone collapses; common in spongy bone, often due to weakening of the bone such as in osteoporosis CALCIUM HOMEOSTASIS ▪ Bone is the major storage site for calcium in the body ▪ movement of calcium into and out of bone helps determine blood calcium levels ▪ Calcium (Ca2+) moves into bone as OSTEOBLASTS BUILD new bone and out of bone as OSTEOCLASTS BREAK down bone ▪ When osteoblast and osteoclast activity is balanced, the movements of calcium into and out of a bone are equal 1. Decreased blood Ca2+ stimulates PTH (parathyroid hormone) secretion from parathyroid glands. 2. PTH stimulates osteoclasts to break down bone and release Ca2+ into the blood. 5. NUMBER AND ARRANGEMENT OF BONE 3. In the kidneys, PTH increases Ca2+ FRAGMENTS reabsorption from the urine. Fractures are categorized by the completeness of the break 4. PTH also stimulates active Vitamin D AXIAL SKELETON formation. Vitamin D promotes Ca2+ -can be divided into three parts: the SKULL, absorption from the small intestine into the the VERTEBRAL COLUMN, and the blood THORACIC CAGE. -This division of the skeleton forms the ▪ Increased blood Ca2+ stimulates calcitonin longitudinal axis of the body and PROTECTS: secretion from the thyroid gland. (5) the brain, spinal cord, heart, and lungs. ▪ Calcitonin inhibits osteoclasts, which allows 1. SKULL for enhanced osteoblast uptake of Ca2+ from - Sits on top of the vertebral the blood to deposit into bone.(6) column ▪ Two sets of bones CARTILAGES OF THE SKELETON ▪ Cranium (8 bones) HYALINE CARTILAGE ▪ Facial bones (14 bones) -provides sturdy support with some ▪ Bones are joined by sutures flexibility. ▪ Only the mandible is attached by -Most skeletal cartilages are composed of a freely movable joint hyaline cartilage CRANIUM ELASTIC CARTILAGE -Eight Osseous Parts Forms The Skull -is much more flexible than hyaline -T & P is paired cartilage, and it tolerates repeated bending. CRANIUM DIVIDED INTO 2 MAJOR AREAS -external ear and the epiglottis (which flops over and covers the larynx when we 1. CRANIAL VAULT OR CALVARIA - forming the swallow) superior, lateral, and posterior walls of the skull FIBROCARTILAGE 2. CRANIAL BASE - forming the skull bottom. -has great tensile strength and can withstand heavy compression FRONTAL BONE ▪ intervertebral discs and knee joint -Forms the forehead, superior part of the orbit, THE MOST IMPORTANT OF THE ADULT and the floor of the anterior cranial fossa SKELETAL CARTILAGES CRANIUM 1. ARTICULAR CARTILAGES ❖ PARIETAL BONE – 2 -which cover the bone ends at movable -Form the superior and lateral aspects of joints the skull. 2. COSTAL CARTILAGES ❖ TEMPORAL BONES – 2 -which connect the ribs to the sternum -Form the inferolateral aspects of the skull (breastbone) sides of the head, close to ears. 3. NASAL CARTILAGES -Commonly called the temples -which support the external nose -Includes the external auditory meatus 4. INTERVERTEBRAL DISCS -Opening for the ear -which separate and cushion the -Includes the zygomatic process vertebrae -Part of the cheekbone ▪ Newborn human has 350 bones -“Process” like zygomatic means nagdudugtong sa bones ▪ Adult human has 206 bones  ❖ ETHMOID (1) -Contributes to the anterior cranial fossa ❖ OCCIPITAL BONE -forms part of the nasal septum and the -Forms the posterior aspect and most of the nasal cavity base of the skull. -contributes to the medial wall of the orbit. -back and base of the cranium FORAMEN MAGNUM -Large opening in the base of the bone, which allows the spinal cord to join with the brain stem. ❖ SPHENOID BONE (1) -Bat-shaped bone that is described as the keystone bone of the cranium because it articulates with all other cranial bones. -parts of orbits of the eyes Includes SELLA TURCICA -where pituitary gland sits ▪ OPTIC CANALS - cranial nerve II (optic nerve) passes through to serve the eye. 4 MAJOR SUTURES ▪ FORAMEN ROTUNDUM - a branch of cranial 1. SAGITTAL SUTURE nerve V (maxillary division) passes through. -Occurs where the left and right ▪ FORAMEN OVALE - a branch of cranial nerve V parietal bones meet superiorly in the (mandibular division) passes through. midline of the cranium 2. LAMBDOID SUTURE ▪ FORAMEN SPINOSUM - provides passageway -Occurs where the parietal bones meet for the middle meningeal artery the occipital bone posteriorly 3. SQUAMOUS SUTURE ▪ CRANIAL BASE -Occurs where each parietal bone -has 3 distinct depressions: the meets the temporal bone, on each ANTERIOR, MIDDLE, AND lateral aspect of the skull POSTERIOR cranial fossae 4. CORONAL SUTURE ▪ The BRAIN sits in these fossae, -Running in the frontal plane, occurs completely enclosed by the cranial anteriorly where the parietal bones vault. meet the frontal bone FACIAL BONE ❖ NASAL (2) – -Small rectangular bones forming the bridge of the nose. ❖ LACRIMAL (2) -Each forms part of the medial orbit in between the maxilla and ethmoid bone. ❖ ZYGOMATIC (2) -Commonly called the cheekbones; each forms part of the lateral orbit ❖ INFERIOR NASAL CONCHA (2) -each forms part of the lateral walls of the nasal cavities -improves the airflow through the nasal cavity ❖ MAXILLA (2) -Keystone facial bones because they articulate with all other facial bones except the mandible -form the upper jaw and parts of the hard palate, orbits, and nasal cavity. ❖ PALATINE (2) -Forms the posterior hard palate, a small part of the nasal cavity, and part of the orbit. ❖ VOMER (1) -Thin, blade-shaped bone that forms the inferior nasal septum THE FETAL SKULL ❖ FONTANELLES -are the spaces or opening where the skull bones join ❖ ANTERIOR FONTANELLE – located at the junction of two parietal bones. It is a diamond in shape. normally closes at 12 to 18th months of age ❖ POSTERIOR FONTANEL –located at the junction of parietal bones and occipital ❖ MANDIBLE (1) bone. It is a triangular in shape. Closes by -lower jawbone, which articulates with the the end of the 2nd month temporal bone -carries the lower teeth “3 TINY BONES” - transmit vibrations -anterior portion forms the chin ▪ All derived from Latin words -Only freely movable joint in the skull CLEFT PALATE 1. MALLEUS (HAMMER), -Failure of the palatine and/or 2. INCUS (ANVIL) maxillary bones to fuse. 3. STAPES (STIRRUP)- Smallest bone in the body OTHER PARTS ❖ PARANASAL SINUSES -the sinuses found in the frontal bone, the ethmoid bone, the sphenoid bone, and the maxilla bone -sinuses are openings within particular bones that open into the nasal cavity. sinuses have two major functions: ▪ they decrease the weight of the skull THE VERTEBRAL COLUMN ▪ they act as a resonating chamber when VERTEBRAL COLUMN speaking. -extending from the skull to the pelvis ❖ HYOID BONE -forms the body’s major axial support. -U shaped -it surrounds and protects the delicate -Found in the upper neck spinal cord -The only bone that does not articulate -column consists of 24 single bones called with another bone VERTEBRAE and 2 composite, or fused, -It serves as a point of attachment for many bones (the SACRUM AND COCCYX) tongue and neck muscles. VERTEBRAL COLUMN ▪ CERVICAL VERTEBRAE -7 bones of the neck are called ▪ THORACIC VERTEBRAE -the next 12 ▪ LUMBAR VERTEBRAE -5 supporting the lower back are STRUCTURE OF A TYPICAL VERTEBRA ▪ TRANSVERSE PROCESSES NOTE: Remembering common mealtimes for -Two lateral projections from the vertebral breakfast, lunch, and dinner (7 a.m., 12 noon, arch. and 5 p.m.) ▪ SPINOUS PROCESS -Single medial and posterior projection from the vertebral arch. ▪ SUPERIOR AND INFERIOR ARTICULAR PROCESSES -Paired projections lateral to the vertebral foramen that enable articulation with adjacent vertebrae. ▪ INTERVERTEBRAL FORAMINA -openings, for spinal nerves to leave the spinal cord between adjacent vertebrae. INTERVERTEBRAL DISC -separate the vertebrae -pads of fibrocartilage that cushion the vertebrae and absorb shocks. -2 MAJOR REGIONS: 1. NUCLEUS PULPOSUS -a central gelatinous that behaves like a rubber ball 2. ANULUS FIBROSUS - an outer ring of encircling collagen fibers that stabilizes the disc CERVICAL VERTEBRAE -articulation between C1 and C2 allows you to rotate your head from side to side ▪ 7 cervical vertebrae (referred to as C1 through C7) form the neck portion of the vertebral column. ▪ first 2 cervical vertebrae (atlas and axis) are highly modified to perform special functions ATLAS (C1) -lacks a body -its lateral processes contain large concave depressions on their superior surfaces that receive the occipital condyles of the skull. - The more typical cervical vertebrae (C3 this joint enables you to nod through C7) -are distinguished from the thoracic and lumbar vertebrae by several features - are the smallest, lightest vertebrae -vertebral foramen is triangular. -SPINOUS PROCESS is short and often bifurcated (divided into two branches). SPINOUS process of C7 -is not branched -substantially longer than that of the other cervical vertebrae. -spinous process of C7 is visible through the skin at the base of the neck -it is called the VERTEBRA PROMINENS and is used as a landmark for counting the vertebrae. TRANSVERSE PROCESSES OF THE CERVICAL VERTEBRAE -are wide -contain foramina through which the vertebral arteries pass superiorly on their way to the brain. ▪ OCCIPITAL CONDYLES –rests on the first vertebra of the vertebral column AXIS (C2) -acts as a pivot for the rotation of the atlas (and skull) above. -It bears a large vertical process, the dens, that serves as the pivot point.  THORACIC VERTEBRAE LUMBAR VERTEBRAE ▪ 5 LUMBAR VERTEBRAE (L1 THROUGH L5) ▪ 12 THORACIC VERTEBRAE (REFERRED TO AS T1 THROUGH T12) -support the majority of the body’s weight -have a larger body than the cervical vertebrae -they have massive bodies and heavy, -body is somewhat heart shaped rectangular transverse and spinous processes. -vertebral foramen is oval or round, and -SUPERIOR ARTICULAR FACETS face the spinous process is long, with a sharp posteromedially; the inferior ones are directed downward hook. ANTEROLATERALLY. -forming the thoracic part of the spine -adds strength to the inferior portion of the vertebral column and limits rotation of the lumbar vertebrae THE SACRUM -is a composite bone formed from the fusion of five vertebrae -Superiorly - articulates with L5 -Inferiorly - connects with the coccyx. -located between the two hip bones -form the posterior aspect of the thoracic cage -It articulates with each hip bone by way of the -only vertebrae that articulate with the ribs. auricular surfaces, forming the sacroiliac joint ARTICULAR FACETS on the transverse -As part of the pelvic girdle, it provides stable processes articulate with the tubercles of support for our lower limbs. the ribs. THE COCCYX -is formed from the fusion of 3-5 small irregularly shaped vertebrae. -literally the human tailbone - coccyx is attached to the sacrum by ligaments. THE THORACIC CAGE THE RIBS -consists of the bony thorax, which is composed -12 pairs of ribs form the walls of the thoracic of the sternum, ribs, and thoracic vertebrae, cage plus the costal cartilages -articulate posteriorly with the vertebral -Its cone-shaped, cagelike structure protects column via their heads and tubercles the organs of the thoracic cavity, including the VERTEBROSTERNAL (TRUE RIBS) critically important heart and lungs. -First 7 pairs, called the true, ribs, attach directly to the sternum by their “own” costal cartilages. -All the 12 ribs articulate posteriorly with the vertebrae of the spine. Each rib forms 2 joints: ▪ COSTOTRANSVERSE JOINT -Between the tubercle of the rib, and the transverse costal facet of the corresponding vertebrae. ▪ COSTOVERTEBRAL JOINT -Between the head of the rib, superior costal STERNUM (BREASTBONE) facet of the corresponding vertebrae, and the -a typical flat bone inferior costal facet of the vertebrae above. -is a result of the fusion of 3 bones—the manubrium, body, and xiphoid process. -It is attached to the first 7 pairs of ribs. 1. MANUBRIUM (“sword handle”) -superior most; looks like the knot of a tie; it articulates with the clavicle (collarbone) laterally. 2. BODY or GLADIOLUS (“blade”) -forms the bulk of the sternum. 3. XIPHOID PROCESS (“sword tip”) -constructs the inferior end of the FALSE RIBS sternum and lies at the level of the 5th -next 5 pairs are called; they attach intercostal space. indirectly to the sternum or entirely lack -made of hyaline cartilage in children, it a sternal attachment. is usually ossified in adults over the age VERTEBROCHONDRAL RIBS of 40 -8–10, have indirect cartilage attachments to the sternum via the costal cartilage of rib 7. FLOATING/ VERTEBRAL RIBS -11 - 12, have no sternal attachment.  APPENDICULAR SKELETON -medial end it articulates with the - composed of the 126 BONES manubrium of the sternum. -appendages and the pectoral and pelvic -clavicle holds the upper limb away girdles, which attach the limbs to the axial from the body, it facilitates the limb’s skeleton. mobility ❖ PECTORAL GIRDLE ❖ ARM/BRACHIUM -Also called the SHOULDER GIRDLE -contains a single bone - HUMERUS. -consists of 2 pairs of bones, 4 bones; 2 -Proximally its rounded head fits into the scapulae + 2 clavicles shallow glenoid cavity of the scapula. -attach the upper limbs to the axial -head is separated from the shaft by the skeleton and provide attachment points for anatomical neck and the more constricted many trunk and neck muscles. surgical neck - which is a common site of -is exceptionally light and allows the upper fracture. limb a degree of mobility CAPITULUM SCAPULA -rounded lateral condyle that -commonly known as the SHOULDER articulates with the radius BLADE TROCHLEA -is a flat, triangular bone that can easily -flared medial condyle that articulates be seen and felt in a living person with the ulna ACROMION PROCESS -form the point of the shoulder; attachment points for some of the shoulder muscles. GLENOID CAVITY -located in the superior lateral portion of the bone, articulates with the head of the humerus. CLAVICLE -commonly known as THE COLLARBONE -is a long bone with a slight sigmoid (S- shaped) curve. ❖ FOREARM/ANTEBRACHIUM -It articulates with the scapula and the - The forearm has 2 bones: sternum. ▪ulna and radius -lateral end it articulates with the acromion process.  ULNA proximal row of carpal bones, lateral to -is medial, the same side as the little medial finger 1. SCAPHOID ▪ TROCHLEAR NOTCH -boat-shaped -C-shaped portion of the ulna that 2. LUNATE articulates with the humerus is the -moon-shaped -rotates over the trochlea of the 3. TRIQUETRUM humerus when bending the elbow. -three-cornered RADIUS 4. PISIFORM -is lateral, the same side as the thumb. -pea-shaped ▪HEAD -portion of the radius that articulates with the humerus -rotates over the capitulum of the humerus when bending the elbow. ▪ulna and radius articulate with the humerus at the elbow joint. distal row of carpal bones, from medial to lateral 1. HAMATE -has a hooked process on its palmar side 2. CAPITATE -head-shaped 3. TRAPEZOID -named for its resemblance to a 4- sided geometric form two parallel sides 4. TRAPEZIUM -named after a 4-sided geometric form with no two sides parallel. ❖ METACARPALS – PALM HAND/ MANUS: -5 metacarpal bones - attached to the ❖ WRIST carpal bones -wrist is a relatively short region between -central portion of the hand the forearm and the hand -in the resting position, the palm of the -composed of 8 carpal bones arranged into hand is concave. two rows of four each  -distal ends of the metacarpal bones help LOWER LIMBS form the knuckles of the hand ❖ THIGH ❖ PHALANGES FEMUR -5 digits of each hand include one thumb -thigh bone (pollex) and four fingers. -heaviest, strongest bone in the body. -digit consists of small long bones called PHALANGES ▪HEAD OF THE FEMUR -thumb has 2 phalanges, called proximal – articulates with the acetabulum of and distal. the coxal bone -Each finger has three phalanges, ▪CONDYLES designated proximal, middle, and distal. – articulates with the tibia ❖ PELVIC GIRDLE ▪EPIDONDYLES -formed by the 2 hip bones and the sacrum. – points of ligaments attachments -are heavy and massive, and they attach securely to the axial skeleton. 1. ILIUM – most superior 2. ISCHIUM – inferior and posterior; sit down bone 3. PUBIS – inferior and anterior ❖ PATELLA -knee cap -Triangular bone located within a tendon PUBIC SYMPHYSIS that passes over the knee. -where coxal bones join anteriorly SACROILIAC JOINTS -joins the sacrum posteriorly ACETABULUM -socket of the hip joint OBTURATOR FORAMEN -large hole in each coxal bone ▪Male pelvis: larger and massive; Female pelvis; broader ❖ LEGS - 2 bones, the TIBIA and the FIBULA, form the skeleton of the leg  TIBIA (SHINBONE) ❖ FOOT -is the larger, medial, weight-bearing ❖ Tarsal (7) – ankle bone of the leg. ❖ Metatarsals (5) – sole ▪ MEDIAL CONDYLE ❖ Phalanges (14) – toes -Slightly concave surface that articulates with the medial condyle of 7 TARSAL BONES include: the femur 1. Calcaneus FIBULA -thin and sticklike that forms the lateral 2. Talus -lies parallel to the tibia, takes no part 3. Cuboid in forming the knee joint. -proximal head articulates with the 4. Navicular lateral condyle of the tibia. 5. Media cuneiforms 6. Intermediate cuneiforms 7. Lateral cuneiforms ▪Body weight is concentrated on the 2 largest tarsals, which form the posterior aspect of the ❖ ANKLE foot. larger calcaneus (heel bone) and the talus -consists of the distal ends of the tibia and fibula forming a partial socket that ▪metatarsals are numbered I through V, medial articulates with a bone of the foot (the to lateral. talus) ▪ toe has 3 phalanges except the great toe, -A PROMINENCE can be seen on each side which has 2 phalanges. of the ankle -These are the medial malleolus of the ▪ bones in the foot are arranged to produce 3 distal tibia and the lateral malleolus of the strong arches distal fibula. ▪ 2 longitudinal arches (medial and lateral) and one transverse arch 2 main functions of the foot: 1. to support the body in its upright position 2. SYNDESMOSES both while standing and in forward movement – bones are separated by some during walking distance and held together by ligaments; radius and ulna 2. to push the body forward during walking and 3. GOMPHOSES to absorb shock when the foot contacts the – consists of pegs fitted into sockets ground. and held in place by ligaments; joint ❖ ARTICULATIONS/JOINTS bet. a tooth and its socket -2 FUNCTIONS FOR THE BODY: CARTILAGINOUS JOINTS 1. hold the bones together -Unites 2 bones by means of cartilage 2. allow the rigid skeletal system some -Slight movement can occur flexibility so that gross body movements 1. SYNCHONDROSIS (HYALINE CARTILAGE) can occur. -costal cartilage of rib 1 and the sternum -Ways joints are classified -epiphyseal plate in growing long bones ▪ By their function ▪ Synarthrosis (immovable) ▪ By their structure 2. SYMPHYSIS (FIBROCARTILAGE) -Intervertebral discs between adjacent “FUNCTIONAL CLASSIFICATION OF JOINTS” vertebrae ▪ SYNARTHROSES – immovable joints -anterior connection between the pubic bones ▪ AMPHIARTHROSES – slightly moveable joints ▪ Amphiarthrosis (slightly movable) ▪ DIARTHROSES – freely moveable joints SYNOVIAL JOINTS -Freely movable joints “STRUCTURAL CLASSIFICATION OF JOINTS” -Contains fluid in a cavity surrounding the ▪ FIBROUS JOINTS - Generally immovable ends of articulating bones -Reinforced by ligaments ▪ CARTILAGINOUS JOINTS - Immovable or slightly moveable Synovial joints typically have the following structural characteristics: ▪ SYNOVIAL JOINTS - Freely moveable JOINT (ARTICULAR) CAVITY -A space between the articulating bones. The cavity is filled with synovial fluid. ARTICULAR CARTILAGE -Hyaline cartilage that covers the surfaces of the bones forming the joint. ARTICULAR CAPSULE FIBROUS JOINTS -2 layers that enclose the joint cavity. -2 bones that are united by fibrous tissue 1. external layer is the fibrous layer -Exhibit little or no movement composed of dense irregular connective 1. SUTURES tissue – bet. the bones of the skull; squamous, 2. inner layer is the synovial membrane lambdoid, coronal composed of loose connective tissue.  3. PIVOT JOINTS -restrict movement to rotation around a single axis -rotation that occurs bet. the axis and atlas -articulation bet. the ulna and radius 4. PLANE/GLIDING JOINTS -2 opposed flat surfaces that glide over each other -Limited but complex movement -Between tarsal bone 5. SADDLE JOINTS -2 saddle shaped articulating surfaces SYNOVIAL FLUID oriented at right angles -A viscous fluid, the consistency of egg -joint bet. the metacarpal bone and the whites, located in the joint cavity - fluid carpal bone of the thumb acts as a lubricant 6. ELLIPSOD/CONDYLOID JOINTS REINFORCING LIGAMENTS -elongated ball and socket joints -Synovial joints are reinforced by -joint bet. the occipital condyles (skull) ligaments outside and inside the and the atlas (vertebral column) articular capsule -joints bet. the metacarpals and NERVES AND BLOOD VESSELS phalanges -Sensory nerve fibers detect pain and joint stretching. -Most of the blood vessels supply the synovial membrane. 6 TYPES OF SYNOVIAL JOINTS 1. HINGE JOINT -permit movement in one plane only -elbow and knee joints TYPES OF BODY MOVEMENT FLEXION -is a movement, generally in the sagittal plane, that decrease the angle of the joint and brings two bones closer together EXTENSION 2. BALL AND SOCKET JOINTS -the opposite of flexion, so it is a movement -consist of a ball (head) and a socket that increases the angle, or the distance, -Bones can move in many directions between two bones or parts of the body. -shoulder and hip joints  ROTATION SUPINATION -is movement of a bone around a -occurs when the forearm rotates laterally longitudinal axis; it is a common movement so that the palm faces anteriorly and the of ball-and-socket joints. radius and ulna are parallel PRONATION -occurs when the forearm rotates medially so that the palm faces posteriorly. OPPOSITION -In the palm of the hand, the saddle joint between metacarpal 1 and the carpals allows opposition of the thumb. ABDUCTION -is moving the limb away from the midline, or median plane, of the body. ADDUCTION -is the opposite of abduction, so it is the movement of a limb toward the body midline. INVERSION AND EVERSION. -To invert the foot, turn the sole medially (INVERSION); to evert the foot, turn the sole laterally (EVERSION). DORSIFLEXION AND PLANTAR FLEXION. -DORSIFLEXION Lifting the foot so that its superior surface approaches the shin -PLANTAR FLEXION. whereas depressing the foot CIRCUMDUCTION - is a combination of flexion, extension, abduction, and adduction commonly seen in ball-and-socket joints; the proximal end is stationary, and its distal end moves in a circle.