Skeletal System PDF

SKELETAL SYSTEM OBJECTIVES:  Describe the main functions of the skeletal system  Describe the structures and functions of each part of the skeletal system (bones).  Discuss the pathophysiology of the common diseases associated with the FACTS:  The human bone consists of...

SKELETAL SYSTEM OBJECTIVES:  Describe the main functions of the skeletal system  Describe the structures and functions of each part of the skeletal system (bones).  Discuss the pathophysiology of the common diseases associated with the FACTS:  The human bone consists of 206 bones  For infants and children, they have more than 206  FUNCTION:  Support  Protection  Assist in movements  Blood cell production  Triglyceride storage BONE TEXTURES  COMPACT BONE- forms the sturdy protective layer  SPONGY BONE/ TRABECULAR BONE- composes of honeycomb of small needle-like or flat pieces called trabeculae  TYPES OF BONES  LONG BONES- longer than wide SHORT BONES - cube-shaped and are nearly equal in length and width  FLAT BONES- thin and provide extensive areas for muscle attachment  IRREGULAR BONES- complex in shape  SESAMOID BONES- develop where there is considerable friction, tension, and physical stress - protect tendons from excessive wear and tear BONE STRUCTURE: LONG BONE  DIAPHYSIS- shaft of long bone; made up mostly of compact bone  EPIPHYSIS- broad end of long bone; mostly spongy bone  METAPHYSIS- growth area between diaphysis and epiphysis BONE STRUCTURE: LONG BONE  EPIPHYSEAL LINE – remnant of epiphyseal plate  PERIOSTEUM- covers the external surface of the entire bone except the joint surfaces MICROSCOPIC ANATOMY OF BONE  BONE MATRIX 25% water, 25% collagen fibers, 50% mineral salts  BONE CELLS 1. OSTEOGENIC CELLS- stem cells which produces daughter cells “osteoblasts”; found in periosteum & endosteum 2. OSTEOBLASTS- bone-forming cells MICROSCOPIC ANATOMY OF BONE 3. OSTEOCYTES- mature bone cells that maintains the bone matrix *2 MAIN FUNCTIONS: 1. maintain the protein and mineral content of the surrounding matrix 2. Take part in repair and damage of bone 4. OSTEOCLASTS- cells that absorb bone matrix  BONE SURFACE MARKINGS DEPRESSIONS AND OPENINGS *FISSURE- narrow slit between adjacent parts of bones *FORAMEN- opening for blood vessels, nerves, ligaments *FOSSA- shallow depression *SULCUS- Furrow along a bone surface *MEATUS- Tube-like opening  BONE SURFACE MARKINGS PROCESSES THAT FORMS JOINTS: *Condyle- Large, round protuberance at the end of the bone *Facet- smooth articular surface *Head- rounded articular projection supported on the neck of the bone  BONE SURFACE MARKINGS:  PROCESSES THAT FORM ATTACHMENT POINTS FOR CONNECTIVE TISSUE: *CREST- Prominent ridge of elongated projection *EPICONDYLE- Projection above a Condyle *Trochanter- Very large projection *Tubercle- Small rounded projection *Tuberosity- large, rounded, usually roughened projection SKELETAL SYSTEM TWO DIVISIONS: A.AXIAL B.APPENDICULAR AXIAL SKELETON SKULL  General Features  Forming the large cranial cavity  Mandible: the only movable bone of the skull  Attachment of muscles for facial expressions  Protect the brain  Stabilize the position of the brain, blood vessels, lymphatic vessels, and nerves  SKULL  8 Cranial bones * FRONTAL- Forms the forehead *PARIETAL- the greater portion of the sides and roof of the cranial cavity *TEMPORAL- form the inferior lateral aspects of the cranium and part of the cranial floor *OCCIPITAL- forms the posterior part and most of the base of the cranium *SPHENOID- lies at the middle part of the base of the skull *ETHMOID- spongelike in appearance and is located on the midline in the anterior part of the cranial floor medial to the orbits  ETHMOID BONE Situated anteriorly; cubical in shape SPHENOID BONE Centrally located; wedge-shaped bone TEMPORAL BONES ? situated laterally or at the sides OCCIPITAL BONE Closes the posterior wall of the braincase  SKULL  14 Facial bones *NASAL- forms the bridge of the nose *2 MAXILLAE- unite to form the upper jawbone *2 ZYGOMATIC BONES- commonly called cheekbones, form the prominences of the cheeks and part of the lateral wall and floor of each orbit *2 LACRIMAL BONES- are thin and roughly resemble a fingernail in size and shape *2 PALATINE BONES- L-shaped *2 INFERIOR NASAL CONCHAE- increase the surface area of the nasal cavity and help swirl and filter air before it passes into the lungs SKULL  VOMER – Triangular bone which forms the inferior portion of the nasal septum  MANDIBLE- lower jawbone, is the largest, strongest facial bone  NASAL SEPTUM- vertical partition of the nasal cavity 2 TYPES OF PALATE  Hard palate: bony platform SOFT PALATE  Soft palate: fleshy tissue HARD PALATE Hyoid Bone  Does not articulate with other bones  Suspended from the styloid process of the temporal bones by ligaments and muscles  Located in the anterior neck between the mandible and larynx  Vertebrae  Functions  Encloses spinal cord  Supports head  Point of attachment for muscles of back, ribs and pelvic girdle  Regions (from superior to inferior) 7 cervical  12 thoracic 5 lumbar 1 sacrum and 1 coccyx  Cervical Area  Cervical (C1-C7 from superior to inferior)  Spinous process often bifid with transverse foramina on transverse processes  C1: atlas  Articulates with head, specialized to support head  Lacks body and spinous process  C2: axis  Has body and spinous process  Called dens (“tooth”) that creates a pivot for head rotation Cervical Vertebrae Other Vertebrae  Thoracic (T1-T12)  Larger than cervical  Have facets for articulations with ribs  Lumbar (L1-L5)  Largest and strongest; spinous processes short and thick  Sacrum (S1-S5 fused into one unit)  Foundation for pelvic girdle  Contain sacral foramina for nerves and blood vessels  Coccyx: 4 coccygeal vertebrae fused into 1  Lumbar Vertebrae Copyright 2010, John Wiley & Sons, Inc. Copyright 2010, John Wiley & Sons, Inc.  Sacrum and Coccyx Copyright 2010, John Wiley & Sons, Inc.  Normal Curves in Column  Four normal curves  Cervical and lumbar curves are convex (bulge anteriorly)  Thoracic and sacral curves are concave (bulge posteriorly)  Curves increase strength, help in balance and absorb shocks Copyright 2010, John Wiley & Sons, Inc.  Vertebral Column Copyright 2010, John Wiley & Sons, Inc.  Structure of Vertebra  Body: disc-shaped anterior portion  Vertebral arch: posteriorly back from body  With the body, creates a hole called vertebral foramen  Seven processes from this arch  Transverse process extending laterally on each side  Spinous process extending dorsally  Two each of superior and inferior articular processes that form joints with vertebrae RIBS  sometimes fuse with vertebrae or articulate with them  sites for secure muscle attachment  protective case around viscera (rib cage) *TRUE RIBS *FALSE RIBS *FLOATING RIBS RIBS APPENDICULAR SKELETON PECTORAL GIRDLE  Function: attach bones of upper limbs to axial skeleton  Clavicles and scapulas: bilateral  Upper Limb  Humerus: arm bone  Articulates with scapula (glenoid cavity) at shoulder joint  Articulates with radius and ulna at elbow  Ulna: medial bone  Radius: lateral bone (thumb side)  Right Humerus Copyright 2010, John Wiley & Sons, Inc.  Right Ulna and Radius Copyright 2010, John Wiley & Sons, Inc.  Right Ulna and Radius Copyright 2010, John Wiley & Sons, Inc.  Wrist and Hand  Carpus (wrist): 8 bones  Metacarpals: 5 bones of palm of hand  Number 1-5 starting with thumb  Phalanges: 14 bones of fingers  Numbered 1-5 metacarpals  Each finger except the thumb has proximal, middle and distal phalanges; thumb lacks middle phalanx Copyright 2010, John Wiley & Sons, Inc.  Right Wrist and Hand Copyright 2010, John Wiley & Sons, Inc.  Pelvic (Hip) Girdle  Pelvic girdle includes two hip (coxal) bones  Joined anteriorly at pubic symphysis  Posteriorly attached to sacrum at sacroiliac joint  Basin-like pelvis is formed by two hip bones (pelvic girdle) + sacrum and coccyx  False (greater) pelvis: broad region superior to pelvic brim; contains abdominal organs  True (lesser) pelvis: small region inferior to pelvic brim; contains urinary bladder + internal reproductive organs Copyright 2010, John Wiley & Sons, Inc.  Pelvic Girdle (Female) Copyright 2010, John Wiley & Sons, Inc. Copyright 2010, John Wiley & Sons, Inc.  Parts of Each Hip (Coxal) Bone  3 separate bones fuse by age 23 to form a hip bone  Ilium: largest and most superior  Ischium: lower posterior part  Pubis: lower anterior part  Bones meet at the acetabulum of the hip bone (socket for head of femur) Copyright 2010, John Wiley & Sons, Inc.  Right Hip Bone Copyright 2010, John Wiley & Sons, Inc.  Lower Limb  Femur (thigh bone): largest bone in the body  Articulates with hip proximally and with the tibia and patella distally  Head (fits into acetabulum) and greater trochanter at proximal end  Patella: kneecap in anterior of knee joint  Tibia: shin bone  Large medial, weight-bearing bone of leg  Fibula: longest, thinnest bone in body  Lateral to tibia and smaller  Does not articulate with femur  Right Femur Copyright 2010, John Wiley & Sons, Inc.  Right Tibia and Fibula Copyright 2010, John Wiley & Sons, Inc. Ankle and Foot  Tarsus (ankle) has 7 bones  Large talus (ankle bone) and  Calcaneus (heel bone)  Metatarsals (foot bones)  Numbered 1 to 5 from medial to lateral  Phalanges (toe bones)  Big toe has proximal and distal phalanges while others have proximal, medial and distal phalanges. Numbered like metatarsals from 1-5  Right Right Foot Foot Copyright 2010, John Wiley & Sons, Inc. Copyright 2010, John Wiley & Sons, Inc.  Arches of the Right Foot Copyright 2010, John Wiley & Sons, Inc.  Male and Female Differences  Males usually have heavier bones  Related to muscle size and strength  Female pelvis is wider and shallower than male pelvis: allows for birth Aging and Skeletal System  Birth through adolescence: more bone formed than lost  Young adults: gain and loss about equal  As levels of sex steroids decline with age: bone resorption > bone formation  Bones become brittle and lose calcium  Osteoporosis Copyright 2010, John Wiley & Sons, Inc.  DISEASES  Herniated (Slipped) Disc  theanterior and posterior ligaments of the discs become injured or weakened, the pressure developed in the nucleus pulposus may be great enough to rupture the surrounding fibrocartilage (annulus fibrosus)  DISEASES – ABNORMAL CURVES  Scoliosis  lateral bending of the vertebral column, usually in the thoracic region Copyright 2010, John Wiley & Sons, Inc.  DISEASES – ABNORMAL CURVES  Kyphosis  an increase in the thoracic curve of the vertebral column that produces a “hunchback” look Copyright 2010, John Wiley & Sons, Inc.  DISEASES – ABNORMAL CURVES  Lordosis  sometimes called hollow back, is an increase in the lumbar curve of the vertebral column Copyright 2010, John Wiley & Sons, Inc.  DISEASES  Spina Bifida  congenital defect of the vertebral column in which laminae of L5 and/or S1 fail to develop normally and unite at the midline Copyright 2010, John Wiley & Sons, Inc.