Download 1 Lecture 8: Introduction to Bones Cartilage Location and basic

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Lecture 8: Introduction to Bones
Cartilage
 Location and basic structure
o Found throughout adult body
o Ear and epiglottis
o Articular cartilage and coastal cartilage
o Intervertebral discs and pubic symphysis
 Where do you find each type of cartilage?
o Is abundant in embryo
o Is surrounded by perichondrium
o Consists primarily of water
o Resilient tissue springs back to original shape.
Types
 Hyaline cartilage (glassy)
o Most abundant cartilage
o Provides support through flexibility
 Elastic cartilage
o Contains many elastic fibers
o Able to tolerate repeated bending
 Fibrocartilage
o Resists strong compression and strong tension
o An intermediate between hyaline and elastic cartilage.
Growth of Cartilage
 Appositional growth
o Chondroblasts in surrounding
o Perichondrium produce new cartilage
 Interstitial growth
o Chondrocytes within cartilage divide and secrete new matrix
Tissue in Bone
 Bones contain several types of tissues
 Dominated by bone connective tissue
 Contains nervous tissue and blood connective tissue
 Contain cartilage in articular cartilages
 Contains epithelial lining blood vessels
Functions of Bone
 Support – provides hard framework
 Movement – skeletal muscles use bones as levers
 Protections from underlying organs
 Mineral storage – reservoir for important minerals
 Blood-cell formation – bone contains red marrow.
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Classification
 Long bones – longer than wide, a shaft plus ends
 Short bones – roughly cube-shaped
 Flat bones – thin and flattened, usually curved
 Irregular bones – various shapes, do not fit into other categories
 Give an example of each type of bones
Gross Anatomy of Bones
 Compact bone – dense outer layer of bone
 Spongy (cancellous) bone – internal network of bones
Structure Typical of Long Bones
 Diaphysis – “shaft” of bone
 Epiphysis – ends of a bone
 Blood vessels – well vascularized
 Medullary cavity – hollow cavity filled yellow marrow
 Membranes
o Periosteum, perforating fibers (Sharpery’s fiber), and endosteum
Structure Typical of Flat Bones
 Flat bones, short bones, and irregular bones
 Contain bone marrow but no marrow cavity
 Diploe
o Internal spongy bone of flat bones
Bone Design and Stress
 Anatomy of a bone reflects stresses
 Compression and tension greatest at external surfaces
Bone Markings
 Pg 132, study, study, study
Chemical Composition of Bones
 35% organic components
o Composed of cells, fibers, and organic substance
o Collagen – abundant
 65% inorganic mineral salts
o Primarily calcium phosphate
o Resists compression
Bone Development
 Ossification (osteogenesis) – bone tissue formation
o Membrane bones formed directly from mesenchyme
 Intramembraneous ossification
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o Other bone – develop initially from hyaline
 Endochondral Ossification
Endochondral Ossification
 All bones except some bones of the skull and clavicles
 Bones are modeled in hyaline cartilage
 Begins forming late in the 2nd month of embryonic development
 Continues forming until early adult hood.
Anatomy of Epiphyseal Growth Areas
 Older chondrocytes signal surrounding matrix to calcify
 Older chondrocytes then die and disintegrate
o Leaves long trabeculae (spicules) of calcified cartilage on diaphysis side
o Trabeculae are partly eroded by osteoblasts.
 Osteoblasts then cover trabeculae with bone tissue
 Trabeculae finally eaten away from their tips by osteoblasts.
Lecture 9: Introduction to Bones (continued)
Anatomy of Epiphyseal Growth Areas
 In epiphyseal plates of growing bones
o Cartilage is organized for quick, efficient growth
o Cartilage cells form tall stacks
o Chondroblasts at the top of stacks divide quickly
 Pushes the epiphysis away from the diaphysis
 Lengthens the entire long bone
 Older chondrocytes signal surrounding matrix to calcify
 Older chondrocytes then die and disintegrate
o Trabeculae are partly eroded by osteoclasts.
o Osteoblasts then cover trabeculae with bone tissue
o Trabeculae finally eaten away from their tips by osteoclasts.
Postnatal Growth of Endochondral Bones
 During childhood and adolescence
o Bones lengthen entirely by growth of the epiphyseal plates.
o Cartilage is replaced with bone connective tissue as quickly as it grows.
o Epiphyseal plate maintains constant thickness
o Whole bone lengthens
Hormonal Regulation of Bone Growth
 Growth hormone – produced by the pituitary gland.
o Stimulates epiphyseal plates.
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Thyroid hormone – ensures that the skeleton retains proper proportions
Sex hormones (estrogen and testosterone)
o Promotes bone growth
o Later induces closure of epiphyseal plates.
Postnatal Growth of Endochondral Bones
 As adolescence draws to an end
o Chondroblasts divide less often
o Epiphyseal plate becomes thinner
 Cartilage stops growing
 Replaced by bone tissue
o Long bones stop lengthening when diaphysis and epiphysis fuse.
Bone Remodeling
 Bone is dynamic living tissue
 500mg of calcium may enter or leave the adult skeleton each day.
 Cancellous bone of the skeleton is replaced every 3-4 years.
 Compact bone is replaced every 10 years.
Postnatal Growth of Endochondral Bones
 Growing bones widen as they lengthen
 Osteoblasts – add bone tissue to the external surface of the diaphysis
 Osteoclasts – remove bone from the internal surface of the diaphysis.
 Appositional growth – growth of a bone by addition of bone tissue to it’s surface.
Bone Remodeling
 Bone deposit and removal
o Occurs at periosteal and endosteal surfaces.
 Peri – around
 Endo – in
 Bone Remodeling
o Bone deposition – accomplished by osteoblasts
o Reabsorption – accomplished by the osteoclasts.
Osteoblast
 Against cell with many nuclei
 Crawls along bone surfaces
 Breaks down bone tissue
o Secretes concentrated HCl
o Lysosomal enzymes are released.
Repair of Bone Fractures
 Simple and compound fractures
 Treatment by reduction
o Closed reduction – without use of surgery.
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o Open reduction – includes surgery and they use traction.
Fracture Classifications
 Simple – still remain under the skin.
 Compound – protrudes skin
 Overcompression will break bones.
Healing
 Hematoma
 Fibrocartilginous
o Blood vessels come into heal bone hyaline cartilage reforms.
 Osteoblasts start to reform the bone and start forming
 Last part…
Types of Fractures
 Comminuted – old bones fractures into more than 2 parts.
 Compressed – under pressure which cracks open bones, especially with
osteoporosis.
 Spiral – twist bone with a lot of force.
 Epiphyseal – epiphyseal plate no more fresh cells, dying.
 Depressed – flat bones goes deep and goes down into tissue.
o Hit head the skull would go in instead of out.
 Green stick – seen in children
Disorders of Bones
 Osteoporosis
o Characterized by low bone mass
o Bone reabsorption outpaces bone deposition
o Occurs most often in women after menopause.
o Common in women
 Menopause – after bone tissue formation slows down and weakens
o Men less common
 Less active males don’t use the bones so they get weak, lose fluid
and then they don’t calcify as much, use them and then they get
stronger.
 Osteomalacia
o Occurs in adults
o Bones are inadequately mineralized
 Rickets
o Occurs in children-analogous to osteomalacia
o Malformed bones
 Paget’s disease
o Characterized by excessive rate of bone deposition
 Osteosarcoma
o A form of bone cancer.
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Lecture 10: The Skeleton
Skeleton consists of
 Bones, cartilage, joints, and ligaments
 Composed of 206 named bones grouped into two divisions
o Axial skeleton (80)
o Appendicular (126)
Axial Skeleton
 Formed from 80 named bones
 Consists of the skull, vertebral column, and bony thorax
Bone Markings
 Projections that provide attachment for muscles and ligaments
 Projections that help form joints
 Depression and openings for passage of nerves
Skull
 Formed by the cranial facial bones
Cranium
 Serves to
o Enclose the brain
o Provide attachment sites for some head and neck muscles.
The Face
 Facial bones serves to
o Form framework of the face
o Form cavities for the sense organs of sight, taste, and smell
o Provide openings for the passage of air and food
o Hold the teeth in place
o Anchor muscles of the face.
Skull Geography
 Facial bones form anterior aspect
 Cranium is divided into cranial vault and the base
 Internally, prominent bony ridges
Skull contains smaller cavities
 Middle and inner ear cavity – in lateral aspect of the cranial base
 Nasal cavity – lies in and posterior to the nose
 Orbits – house the eyeballs
 Air-filled sinuses – occur in several bones around the nasal cavity.
The Skull contains approximately 85 named openings
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Foramina, canals, fissures
Provide openings for important structures
o Spinal cord
o Blood vessels serving brain
o 12 pairs of cranial nerves
Cranial Bones
 Paired bones include
o Temporal bases
o Parietal bases
 Unpaired bones
o Frontal, occipital, sphenoid, ethmoid
Frontal Bones
 Forms the forehead and roofs of the orbits
 Forms supercilliary arches
 Internally it contributes to the anterior cranial fossa
 Contains frontal sinuses
Parietal Bones
 Parietal bone form superior and lateral parts of the skull
 Four sutures of the cranium
o Coronal suture – runs in the coronal plane
 Located where parietal bones meet the frontal bones
o Squamous suture – occurs where each parietal bone meets a temporal
bone inferiorly
o Sagittal suture – occurs where right and left parietal bones meet
superiorly
o Lambdoid suture – occurs when the parietal bones meet the occipital bone
posteriorly
Sutural Bones
 Small bones that occur within sutures
 Irregular in shape, size, and location
 Not all people have sutural bones
Occipital Bones
 Forms the posterior portion of the cranium and cranial base
 Articulates with the temporal bones and parietal bones
 Forms the posterior cranial fossa.
 Foramen magnum located at its basale
 Features and Structures
o Occipital condyles
o Hypoglossal foramen
o External occipital protuberance
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o Superior nuchal lines
o Inferior nuchal lines
Temporal Bones
 Lie inferior to the parietal bones
 Form the inferior and lateral portion of the skull
 Term “temporal”
o Comes from Latin word for time
 Specific regions of temporal bones
o Squamous
o Temporal
o Petrous
o Mastoid process
The Sphenoid Bone
 Spans the width of the cranial floor
 Resemble a butterfly or bat
 Consists of a body and three pairs of processes
 Contains 5 important openings
Ethmoid Bones
 Lies between nasal and sphenoid bones
 Forms most of the medial bony region between the nasal cavity and orbits
Facial Bones
 Unpaired Bones
o Mandible, vomer
 Paird bones
o Maxillae, zymphatic bones, nasal bones, lacrimal bones, palantine bones,
inferior nasal conchae
Mandible
 The lower jawbone is the largest and strongest facial bone
 Composed of 2 main parts
o Horizontal body
o 2 upright rami
Maxillary Bones
 Articulate with all of the facial bones except the mandible
 Contains maxillary sinuses – largest paranasal sinuses
 Forms part of the inferior formal fissures
Other Bones
 Zymphatic bones – form lateral wall of orbits
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Nasal bones – form bridge of nose
Lacrimal bones – complete the posterior part of the hand palate
Vomer – forms the inferior part of the nasal septum
Inferior nasal conchae – thin, curved bones that project medially from the lateral
walls of the nasal cavity
Sinuses – to reduce weight.
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Lecture 11: The Axial Skeleton (continued)
Paranasal Sinuses
 Air-filled sinuses are located within
o Frontal bone
o Ethmoid bones
o Sphenoid bones
o Maxillary bones
 Lined with mucous membranes
 Serve to lighten the skull
The Hyoid Bone
 Lies inferior to the mandible
 The only bone with no direct articulation with any other bone
 Acts as a movable base for the tongue
Vertebral Column
 Formed from 26 bones in the adult
 Transmits weight of trunk to the lower limbs
 Surrounds and protects the spinal cord
 Serves as attachment sites for muscles of the neck and back
 Held in place by ligaments
 Anterior and posterior longitudal ligaments
o Ligamentum flavum
Intervertebral Discs
 Cushion – like pads between vertebrae
 Acts as shock absorbers
 Compose about 25% of height of the vertebral column
o Composed of
 Nucleus pulpous and annulus fibrosis
 The gelatinous inner sphere of intervertebral discs
 Enables spine to absorb compressive stresses
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Annulus Fibrosis
 An outer collar of ligaments and fibrocartilage
 Contains the nucleus pulpous
 Functions to bind vertebrae together to resist tension on the spine, and absorb
compression forces.
Herniated Disc
 May be caused by trauma to the spine
 Aging is also a contributing factor
 Nucleus pulpous loses cushioning properties
 Annulus fibrosis weakens
Regions and Normal Curvatures
 Vertebral column is about 70cm (28 inches)
 Vertebral column is divided into 5 major regions
o Cervical vertebrae
 7 vertebrae of the neck region
o Thoracic vertebrae
 12 vertebrae of the thoracic region
o Lumbar vertebrae
 5 vertebrae of the lower back
o Sacrum
 Inferior to the lumbar vertebrae
 Articulates with coxal bones
o Coccyx
 Most inferior region of the vertebral column
 4 distinct curvatures give vertebral column an S-shape
o Cervical and lumbar curvature
 Are concave posteriorly “(“
o Thoracic and sacral curvatures
 Are convex posteriorly “)”
o Curvatures increase the resilience of the spine
Go to page 171 table 7.2 and the first 4 rows.
Specific Regions of the Spine perform specific functions
 Types of movement that occur between vertebrae
o Flexion and extension
o Lateral flexion
Cervical Vertebrae
 The Atlas
o C(1) is termed the atlas
o Lacks a body and spinous process
o Supports the skull
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o Superior articular facets receive the occipital condyles.
o Allow flexion and extension of the neck
 Nodding the head yes
Axis
o Has a body and spinous process
o Dens
 (odontid process) projects superiorly
o Formed from fusion of the body of the atlas with the axis
o Acts as a point of rotation of the atlas and skull
o Participates in rotating the head from side to side.
Thoracic
 Costal facets connect to rib
Lumbar
 Heavier
 Vertebral foramen triangular
 Transverse process is thinner.
Sacrum
 Shapes the posterior wall of the pelvis
 Formed from 5 fused vertebrae
 Superior surface articulates with L(5)
 Inferiorly articulates with the coccyx
 Sacral promontory
o Where the first sacral vertebrae bulges into pelvic cavity
 Center of gravity is 1cm posterior to sacral promontory
Sacral Foramina
 Ventral foramina
o Passage for ventral rami of sacral spinal nerves
 Dorsal foramina
o Passage for dorsal rami of sacral spinal nerves
Coccyx
 Is the “tail bone”
 Formed from 3-5 fused vertebrae
 Offers only slight support to pelvic organs
Bony Thorax
 Forms framework of the chest
 Components of the bony thorax
o Thoracic vertebrae – posteriorly
o Ribs – laterally
o Sternum and costal cartilage – anteriorly
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Ribs
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Projects thoracic organs
Supports shoulder girdle and upper limbs
Provides attachment sites for muscles
True ribs – (1-7) – directly attached to the sternum
False ribs – (8-12)
Floating – 11, 12
Sternum
 Formed from 3 sections
o Manubrium – superior section
 Articulates with the medial end of the clavicles
o Body – bulk of sternum
 Sides are notched at articulations for costal cartilage of ribs 2-7
o Xiphoid process – inferior to end of sternum
 Anatomical landmarks
o Jugular notch
 Central indentation at superior border of the manubrium
o Sternal angle
 Horizontal ridge where the manubrium joins the body
Ribs
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All ribs attach to vertebral column posteriorly
True ribs – superior seven pairs of ribs
o Attach to sternum by costal cartilage
False ribs – inferior five pairs of the ribs
Ribs 11, 12 are known as floating ribs
Disorders of the Axial Skeleton
 Abnormal spinal curvatures
o Scoliosis – abnormal lateral curvatures
o Kyphosis – an exaggerated thoracic curvature
o Lordosis – an accelerated lumbar curvature sway back
o Stenosis – of the lumbar spine
 Narrowing of the vertebral canal
 Membrane bones to ossify in second month of development
 Bone tissue grows outward from ossification centers
 Fontanels
o Unossified remnants of membranes
o Anterior and posterior fontanels on skulls
 Takes 2 years to harden where structures are.
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Lecture 12: Appendicular Skeleton
Appendicular
 Pectoral Girdle
o Attaches the upper limbs to the trunk
 Pelvic Girdle
o Attaches to the lower limbs to the trunks
 Upper limbs and lower differ in function
o Share the same structural plan.
Pectoral Girdle
 Consists of the clavicle and the scapula
 Pectoral girdles do not quite encircle the body completely.
 Provides attachment for many muscles that move the upper limb
 Girdle is very light and upper limbs are mobile
o Only clavicle and upper limbs are mobile
o Socket of the shoulder joint glenoid cavity is shallow.
o Good for flexibility but bad for stability.
Clavicles
 Extend horizontally across the superior thorax.
 Sternal end articulates with the manubrium.
 Acromial end articulates with the scapula.
 Provide attachment for muscles.
 Hold the scapulae and arms laterally
 Transmit compression forces from the upper limbs to the axial skeleton.
Scapulae
 Lie on the dorsal surface of the rib cage.
 Located between ribs 2-7
 Have 3 borders
o Superior
o Medial (vertebral)
o Lateral (axillary)
 Have 3 angles
o Lateral, superior, and inferior
Upper Limb
 30 bones form each upper limb
 Grouped into the bones of the
o Arm
o Forearm – 2
o Hand
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Arm
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Region of the upper limb between the shoulder and elbow
Humerus
o The only bone of the arm
o Longest and strongest bone of the upper limb
o Articulates with the scapula at the shoulder
o Articulates with the radius and ulna at the elbow.
Humerus
 Many structures of the humerus provide sites for muscle attachment
 Other structures of the humerus provide articulation sites for other bones.
 Capitulum – half bone
 Trochlea – locks into the elbow.
Forearm
 Formed from the radius and ulna
 Proximal ends articulate with the humerus
 Distal ends articulate with carpals.
 Radius and ulna articulate with each other.
 At the proximal and distal radioulnar joints.
 The interosseous membrane.
o Interconnects radius and ulna
 In anatomical position
o The radius is lateral and the ulna is medial.
Ulna
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Main bone responsible for forming the elbow joint with the humerus
Hinge joint allows forearm to bend on arm
Distal end is separated from carpals by fibrocartilage
Plays little to no role in hand movement.
Radius
 Superior surface of the had of the radius articulates with the capitulum.
 Medially – the head of the radius articulates with the radial notch of the ulna.
 Contributes heavily to the wrist joint
 Distal radius articulates with the capral bones.
 When radius moves the hand moves with it.
Hand
 Includes the following bones
o Carpus – wrist
o Metacarpals – palm
o Phalanges – fingers.
Carpus
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Forms the true wrist – the proximal region of the hand.
Gliding movements occur between carpals
Composed of 8 marble sized bones.
Carpal bones
 Are arranged in 2 irregular rows.
 Proximal row from lateral to medial
o Scaphoid, lunate, triquetral, and pisiform
 Distal from lateral to medial
o Trapezium, trapezoid, capitate, and hamate
 A mnemonic to help remember the carpals.
o Sally left the party to take Carmen home.
Metacarpus
 5 metacarpals radiate distally from the wrist.
 Metacarpals form the palm
 Numbered 1-5 beginning with the pollex (thumb) ‘
 Articulate proximally with the distal row of carpals
 Articulates distally with the proximal phalanges.
Phalanges of the Hand
 Numbered 1-5 beginning with the pollex (thumb)
 Except for the thumb each finger has 3 phalanges
o Proximal, middle, and distal.
Pelvic Girdle
 Attaches lower limbs to the spine
 Supports visceral organs
 Attaches to the axial skeleton by strong ligaments
 Acetabulum is a deep cut that holds the head of the femur.
 Lower limbs have less freedom of movement
o Are more stable than the arm.
 Consists of paired hip bones (coxal bones or coxae)
 Hip bones unite anteriorly with each other.
 Articulates posteriorly with the sacrum.
Bony Pelvis
 A deep basin like structure
 Formed by
o Coxal bones, sacrum, and coccyx.
Coxal Bones
 Consists of 3 separate bones in childhood
o Ilium, ischium, and pubis.
 Bones fuse – retain separate names to regions of coxal bones
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Ilium
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Acetabulum
o A deep hemispherical socket on lateral pelvic surface.
Large flaring bone
Forms the superior region of the coxal bones.
Site for attachment for many muscles.
Articulation with the sacrum forms sacroiliac joint.
Ischium
 Forms posteroinferior region of the coxal bone
 Anteriorly joints the pubis
 Ischial tuberositiies
o Are the strongest part of the hip bones.
Pubis
 Forms the anterior region of the coxal bone
 Lies horizontally in anatomical position
 Pubis symphysis
o 2 pubic bones are joined by fibrocartilage at the midline
True and False Pelves
 Bony pelvis is divided into 2 regions.
 False (greater) pelvis – bounded by alae of the iliac bones.
 True (lesser) pelvis – inferior to pelvic brim
o Forms a bowl containing the pelvic organs.
The Lower Limb
 Carries the entire weight of the erect body
 Bones of lower limb are thicker and stronger than those of the upper limbs.
 Divided into 3 segments
o Thigh, leg, foot
Thigh
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The region of the lower limb between the hip and the knee
Femur – single bone of the thigh
Longest and strongest bone of the body
Ball shaped head articulates with the acetabulum.
Patella
 Triangular sesmoid bone
 Imbedded in the tendon that secures the quadriceps muscles.
 Protects the knees anteriorly
 Improves leverage of the thigh muscles across the knee.
Leg
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Refers to the region of the lower limb between the knee and ankle.
Composed of the tibia and fibula
Tibia – more massive medial bone of the leg.
o Receives weight of the body from the femur.
Fibula – stick-like lateral bone of the leg.
Interosseous membrane
o Connects the tibia and fibula
Tibia articulates with the femur at the superior end.
o Forms the knee joint
Tibia articulates with the talus at the inferior end.
o Forms the ankle joint
Fibula doesn’t contribute to the knee joint
o Stabilizes the ankle joint
The foot
 The foot is composed of
o Tarsus, metatarsals, and the phalanges.
 Important functions
o Supports body weight
o Acts as a lever to propel body forward when walking
 Segmentation makes foot pliable and adapted to uneven ground.
Tarsus
 Makes up the posterior half of the foot
 Contains 7 bones called tarsals
 Body weight is primarily borne by the talus and the calcaneous
Metatarsus
 Consists of 5 small long bones called metatarsals
 Numbered 1-5 beginning with the hallux (great toe)
 First metatarsal supports body weight.
Phalanges of the foot
 14 phalanges of the toe
 Smaller and less nimble than those of the fingers.
 Structure and arrangement are similar to phalanges of the fingers.
 Except for the great toe, each toe has 3 phalanges
o Proximal, middle, and distal.
Arches of the foot
 Foot has 3 important roles
o Medial and lateral longitudinal arch
o Transverse arch
 Arches are maintained by
o Interlocking shapes of tarsals, ligaments, and tendons
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Lecture 13: Joints
Joints
 Rigid elements of the skeleton meet at joints or articulations
 Articulations can be
o Bone to bone
o Bone to cartilage
o Teeth in bony sockets
 Structure of joints
o Enables resistance to crushing, tearing, and other forces.
Classifications
 Joints can be classified by function or structure
 Functional Classifications
o Based on amount of movement
o Synarthroses – immovable, common to axial skeleton
o Amphiarthroses – slightly movable, common to axial skeleton
o Diarthroses – freely movable, common in appendicular skeleton, and all
synovial joints.
 Structural Classifications based on
o Material that binds together
o Pressure or absence of a joint cavity
o Structural classifications include
 Fibrous
 Cartilaginous
 Synovial
Fibrous Joints
 Bones are connected by fibrous connective tissue.
 Do not have joint cavity
 Most are immovable or slightly movable
 Types
o Sutures
o Syndesmoses
o Gomphoses
Sutures
 Bones are tightly bound by a minimal amount of fibrous tissue
 Only occur between the bones of the skull
 Allow bone growth so the skull can expand with brain during childhood
 Fibrous tissue ossifies in middle age
 Synostoses – closed sutures.
Syndesmoses
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Bones are connected exclusively by ligaments
Amount of movement depends on length of fibers.
Tibiofibular joint – immovable synarthorsis
Interosseous membrane – between radius and ulna
o Freely movable diarthrosis
Gomphoses
 Tooth in a socket
 Connecting ligament – the periodontal ligament
o Short, no movement.
Cartilaginous Joints
 Bones are united by cartilage
 Lack a joint cavity
 Two types
o Synchondroses
o Symphyses
Synchondroses
 Hyaline cartilage unites bones
 Epiphyseal plates
o Hyaline
 Joint between the first rib and manubrium
Sympheses
 Fibrocartilage unites bones – resists tension and compression
 Slightly moveable joints that provide strength with flexibility
 Hyaline present which lines the surfaces of the bones.
 Intervertebral discs
 Pubic symphysis
 Hyaline cartilage – also present as articular cartilage.
Synovial Joints
 Most movable type of joint
 All are diarthroses which allow movements in all directions.
 Each contain a fluid-filled joint cavity.
General Structure
 Articular Cartilage
o Ends of opposing bones are covered with hyaline cartilage
o Absorbs compression
 Joint Cavity (synovial cavity)
o Unique to synovial cavity
o Cavity is a potential space that holds a small amount of synovial fluid.
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Articular Capsule
 Joint cavity is enclosed in a 2 layered capsule
 Fibrous capsule – dense irregular connective tissue which strengthens the joint
 Synovial membrane – loose connective tissue
o Lines joint capsule and covers internal joint surface.
o Is a blood filtrate
o Functions to make synovial fluid
o Glycoprotein makes it slippery.
Synovial Fluid
 A viscous fluid similar to raw egg white
o A filtrate of blood
o Arises from capillaries in synovial membrane
 Contains glycoprotein molecules secreted by the fibroblasts.
Reinforcing Ligaments
 Often are thickened parts of the fibrous capsule
 Sometimes are extracapsular ligaments
o Located outside the capsule
 Sometimes are intracapsular ligaments
o Located inside the capsule.
 Richly supplied with sensory nerves
 Detect pain
 Most monitor how much the capsule is being stretched.
 Have a rich blood supply
o Most supply the synovial membrane
o Extensive capillary beds produce basis of synovial fluid
o Branches of several major nerves and blood vessels.
Synovial Joins with Articular Discs
 Some synovial joints contain an articular disc
 Occur in the temporomandibular joint and at the knee
 Occur in joints whose articulating bones have somewhat different shapes.
How Synovial Joints Function
 Synovial joints are lubricating devices
 Friction could overheat and destroy joint tissue
 Are subjected to compressive forces
o Fluid is squeezed out as opposing cartilages touch
o Cartilages ride on the slippery film
Bursae and Tendon Sheath
 Bursae – is a sac.
 Bursae and tendon sheath are not synovial joints (doesn’t have to connect to bone)
 Closed bags of lubricant
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Reduce friction between body elements.
Bursae – a flattened fibrous sac lined by a synovial membrane
Tendon sheath – are elongated bursa that wraps around a tendon.
Fractures Influencing Joint Stability
 Articular surfaces – seldom play a major role in joint stability
o The elbow, knee, and the hip do provide stability
 Ligaments – the more ligaments in a joint the stronger it is.
 Muscle tone – the most important factor in joint stability
o Keeps tension on muscle tendons
o (Continuous contraction).
Movements Allowed by Synovial Joints
 Refer to page 213-216, Tables 9.3 and 9.4
 3 basic types of movement
o Gliding – one bone across the surface of another.
o Angular movement – movements change the angle between bones.
o Rotation – movement around a bone’s long axis.
Gliding Joints
 Flat surfaces of 2 bones slip across each other.
 Gliding occurs between
o Carpals, tarsals, articular process of vertebrae.
Angular Movement
 Increases or decreases angle between bones
 Movement involves
o Flexion and extension
o Abduction and adduction
o Circumduction
Rotation
 Involves turning movement of a bone around its long axis
 The only movement allowed between atlas and axis vertebrae
 Occurs at the hip and shoulder joints.
Special Movements
 Supination – forearm rotates laterally, palm faces anterior
 Pronation – forearm rotates medially, palm faces posterior
 Dorsiflexion – lifting the foot so the superior surfaces approaches the shin
 Plantar flexion – depressing the foot, pointing the toes.
 Inversion – turning the sole medially
 Eversion – turning the sole laterally.
 Protraction – nonangular movement of jutting out the jaw.
 Retraction – opposite movement to protraction
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Elevation – lifting a body superiorly
Depression – moving elevated part inferiorly.
Opposition – movement of the thumb to touch the tip of the other fingers.
Classified by Shape
Plane joint
 Articular surfaces are flat planes
 Short gliding movements are allowed
 Intertarsal and intercarpal joints
 Movements are nonaxial
 Gliding doesn’t involve rotation around any axis.
Hinge joints
 Cylindrical end of one bone fits into another bone.
 Angular movement is allowed in one plane
 Elbow, ankle, and joints between phalanges
 Movement in uniaxial – allows movement around axis only.
Pivot Joints
 Classified as uniaxial rotating bone only turns around its long axis.
 Examples
o Proximal radioulnar joint
o Joint between atlas and axis
Condyloid joints
 Allow moving bone to travel
 Side to side – abduction and adduction
 Back and forth – flexion and extension.
 Classified as biaxial-movement
 Occurs around two axes
Saddle Joints
 Each articular surface has concave and convex surfaces.
 Classified as biaxial joints.
Ball and Socket Joints
 Spherical head of one bone fits into round socket of another.
 Classified as multiaxial – allow movement in all axes
o Shoulder and hip joints.
Disorders of Joints
 Disorders of joints make them prone to traumatic stress
 Function of joints makes them subject to friction and wearing
 Affected by inflammatory and degenerative processes.
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Joint Injuries
 Sprains – ligaments of a reinforcing joint are stretched or torn.
 Dislocation – occurs when the bones of a joint are forced out of alignment
 Torn cartilage – common injury to meniscus (cartilage of the knee) of knee joint.
 Bursitis – inflammation of a bursa due to injury or friction.
 Tendonitis – inflammation of a tendon sheath
 Arthritis – describes over 100 kinds of joint damaging diseases.
o Osteoarthritis – most common type of “wear and tear” arthritis
o Rheumatoid arthritis – a chronic inflammation disorder.
o Gouty arthritis (gout) – uric acid build up causes pain in joints
o Lyme disease – inflammatory disease often resulting in joint pain.
Lecture 14: Muscle Tissue
General:
 Tendon – muscle to bone
Muscles
 Muscle is the primary tissue in the heart (cardiac muscle tissue)
 Walls of hollow organs (smooth muscle tissue)
 Skeletal muscle
o Makes up nearly half the body’s mass.
Overview of Muscle Tissue
Functions of Muscle Tissue
 Movement
o Skeletal muscles – attach to skeleton
 Moves body by moving the bones
o Smooth muscle – squeezes fluids and other substances through hollow
membranes.
 Maintenance of posture – enables the body to remain sitting or standing
 Joint stabilization
 Heat generation
o Muscle contractions produce heat
o Helps maintain normal body temperatures
Functional Features of Muscles
 Functional Features
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o Contractility
 Long cells shorten and generate pulling forces.
o Excitability
 Electrical nerve impulse stimulates the muscle cells to contract
o ?
Types of Muscle Tissue
 3 Types
o Skeletal Muscle Tissue
 Packaged into skeletal muscles.
 Makes up 40% of body weight.
 Specific banding pattern with light and dark.
o Cardiac Muscle Tissue
 Occurs only in the walls of the heart
 Branching and striations
 Intercalated discs.
o Smooth Muscle Tissue
 Cells lack striations
 One nucleus
 Nonstriated.
Similarities of Muscle Tissue
 Cells of muscles
o Are known as fibers
 Muscle contraction
o Depends on two types of myofilaments (contractile proteins)
 One type contains actin (thin)
 Another type contains myosin (thick)
 These 2 proteins generate contractile forces.
 Plasma membrane is called a sarcolemma (outside covering)
 Cytoplasm is called the sarcoplasm (inside).
Skeletal Muscle
 Each muscle is an organ
o Contained mostly of muscle tissue
o Skeletal muscle also contains
 Blood tissue
 Nerves
 Connective tissue
Basic Features of Skeletal Muscle
 Connective tissue and fasicles
o Connective tissue sheaths bind a skeletal muscle and its fibers together.
 Epimysium – dense irregular connective tissue surrounding entire
muscle.
 Perimysium – surrounds each fasicle (group of muscle fibers)
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
Endonysium – a fine sheath of connective tissue wrapping each
muscle cell.
o Helpful
 Epi – outside
 Peri – around fasicles (several bundles of fibers) (group of fibers)
 Endo – inside (individual)
o Connective tissue sheaths are continuous with tendons.
Nerves and Blood Vessels
 Each smooth muscle supplied by branches of
o One nerve
o One artery (remember: blood out to system)
o One or more veins
 Nerves and blood vessels branch repeatedly
 Smallest nerve branches serve
o Individual muscle fibers
o Neuromuscular junction – signals the muscle to contract.
Muscle Attachments
 Most skeletal muscles run from one bone to another
 One bone will move and the other bone remains fixed.
o Origin – less movable attachment
 Usually proximal
o Insertion – more movable
 Usually distal.
 Muscle attaches to origins and insertions by connective tissue
o Fleshy attachments – connective tissue fibers are short.
o Indirect attachments – connective tissue forms a tendon or aponeurosis
 Bone markings present where tendons meet bones
o Tubercles, trochanters, and crests.
Microscopic and Functional Anatomy of Smooth Muscle Tissue
 The skeletal muscle fibers
o Fibers are long and cylindrical
o Are huge cells – diameter is 10-100um
o Length – several centimeters to dozens of centimeters
 Each cell formed by fusion of embryonic cells
 Cells are multinucleate
 Nuclei are peripherally located.
Myofibrils and Sarcomeres
 Striations result from internal structure of myofibrils
 Myofibrils
o Long rods within cytoplasm
o Make up 80% of the cytoplasm
o Are a specialized contractile organelle found in muscle tissue
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
o A long row of repeating segments called sarcomeres (functional unit of
smooth muscle tissue.
Sarcomeres
o Basic unit of contraction of skeletal muscle
o 2 disc (line) – boundaries of each sarcomeres
o Thin (actin) – filaments external from the 2 disc
o Thick (myosin) filaments – located in the center of the sarcomeres
 Overlap inner ends of the thin filaments
 Contain ATPase enzymes.
Sarcomere Structure
 A bands – full length of the thick filament
o Includes inner end of thin filaments
 H zone – center part of A band where no thin filaments occur.
 M line – in center of H zone.
o Contains tiny rod that holds thick filaments together.
 I band – region with only thin filaments
o Lies within 2 adjacent sarcomeres.
Sarcoplasmic Reticulum and the T Tubules
 Sarcoplasmic Reticulum
o A specialized smooth ER
o Interconnecting tubules surround each myofibril
o Some tubules form cross channels called terminal cisternae.
o Cisternae occur in pairs on either side of a T Tubule
o Contains calcium ions – released when muscle is stimulated to contract
o Calcium ions diffuse through cytoplasm
 Trigger the sliding filaments mechanism.
Mechanism of Contraction
 Sliding filament theory
o Myosin heads attach to actin in the thin filaments
o Then pivot to pull in thin filaments inward the center of the sarcomeres.
Muscle Extension
 Muscle is stretched by a movement opposite that which contracts it.
 Muscle fiber length and force of contraction
o Greatest force produced when a fiber starts out slightly stretched.
o Myosin heads can pull along the entire length of the thin filaments.
Role of Titin
 Titin – a spring-like molecule in sarcomeres
o Resists overstretching
o Holds thick filaments in place.
o Unfolds when muscle is stretched.
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Sarcoretic T Tube
 Muscle contraction
o Ultimately controlled by nerve-generated impulse
o Impulse travels along the sarcolemma of the muscle cells
 Impulses further conducted by T Tubules
 T Tubule – a deep invagination of the sarcolemma
Innervation of Smooth Muscle
 Motor neurons innervate skeletal muscle tissue
 Neuromuscular junction – is the point where nerve ending and muscle fibers
meet.
Types of Smooth Muscle Fibers
 Skeletal muscle fibers are categorized according to
o How they manufacture energy (ATP)
o How quickly they contract
Skeletal Muscle Fibers
 Are divided into 3 classes
o Slow oxidative fibers (Type I)
 Red slow twitch
 Resist fatigue
 Postural
 Go very slow.
o Fast glycolytic fibers (Type IIx)
 White fast twitch
 Myoglobin holds oxygen for longer period of time
 Fast bursts and tired right away
 Anaerobic (meaning without oxygen)
 Upperlimbs
o Fast oxidative fibers (Type IIa)
 Intermediate fibers
 Requires oxygen
 Lower limb
Disorders of Muscle Tissue
 Muscle Dystrophy
o A group of inherited muscle destroying diseases
o Affected enlarge with fat and connective tissue
o Muscle degenerate
o What happens
 Fat replaces muscle fibers and continue to lose the muscles and
they become weak.
Lecture 15: Muscles of the Body
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Skeletal Muscles
 Produce movements
o Blinking of eye, standing on tiptoe, swallowing food, etc.
 General principle of leverage
 Muscles act with or against each other
 Criteria used in naming muscles.
Lever Systems: Bone Muscle Relations
 Movement of skeletal muscles involve leverage
o Lever – a rigid bar that moves.
o Fulcrum – a fixed point.
o Effort – applied force.
o Load – resistance.
Equation on Board
 Effort x Distance = Load x Distance
Lever Systems: Bone Muscle Relations
 Bones – act as levers
 Joints – act as fulcrums
 Muscle contraction – provides effort.
o Applies force where muscle attaches to bone.
 Load – bone, overlying tissue, and anything lifted.
 Levers allow a given effort to
o Move a heavier load
o Move a load farther
 Mechanical advantage
o Move a large load over small distances
 Mechanical Disadvantage
o Allow a load to be moved over a large distance.
First-class Lever
 Effort applied at one end
 Load is at the opposite end.
 Fulcrum is located between load and effort
 Equation
o Effort Fulcrum Load = Mechanical Advantage
 Examples:
o See saw, scissors, and lifting your head off your chest.
Second-class Lever
 Effort applied at one end
 Fulcrum is at the opposite end
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Load is between the effort and fulcrum
Examples
o Wheelbarrow, or standing on tiptoe
Uncommon type of lever in body
Work at mechanical advantage
Equation
o E L F = MA
Third-class Lever
 Effort is applied between load and the fulcrum.
 Work speedily
 Most common type
 Always at the mechanical disadvantage of the human body
 Equation
o L E F = Mechanical Disadvantage.
 Most skeletal muscles are third class
 Examples – biceps brachii,
o Fulcrum – the elbow joint.
o Force – exerted on the proximal region of the radius.
o Load – distal part of the forearm.
Arrangement of Fasicles in Muscles
 Skeletal muscles – consist of fasicles
 Fasicles – arranged in different patterns
 Fasicles arrangement – tells about action of muscle.
Types of Fasicle Arrangement
 Parallel
o fasicles run parallel to the long axis of the muscles
o Strap-like – sternocleidomastoid
o Fusiform – biceps brachii
 Convergent
o Origin of the muscle is broad
o Fasicles converge toward the tendon of insertion
o Example
 Pectoralis major
 Pennate
o Unipennate – fasicles insert into one side of the tendon
o Bipennate – fasicles insert into the tendon from both sides
 Example: rectus femorus
o Mutlipennate – fasicles insert into one large tendon from all sides
 Example: deltoid of the shoulder.
 Circular
o Fasicles – are arranged in concentric rings.
 Surrounded external body openings
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 Sphincter – general name for a circular muscle.
o Example
 Orbicularis oris (mouth)
 Bicularis oculi (eyes).
Pages NOT on the Test
 262 not on test
Interactions of Smooth Muscle in the Body
 A muscle cannot reserve the movement it produces
 Another muscle must undo the action
 Muscles with opposite actions lie on opposite sides of a joint.
Muscle Classified into Several Functional Groups
 Prime mover (agonist)
o Has major responsibility for a certain movement
 Antagonist
o Opposes or reverses a movement
 Synergist
o Helps the prime mover
 By adding extra force
 By reducing undesirable movements.
o Fixator
 A type of synergist that holds a bone firmly in place.
Muscle Compartments of the Limbs
 Dense fibrous connective tissue divides limb muscles into compartments
 Muscles in opposing compartments are
o Agonist and antagonist pairs.
 Each compartment is innervated by a single nerve.
Pages NOT on the Test
 264-271
Naming Smooth Muscle
 Location
o Example – the brachialis is located on the arm
 Shape
o Example – the deltoid (shoulder) is triangular
 Relative Size
o Maximus, minimus, and longus indicate size.
o Example: gluteus maximus, and gluteus minimus
 Direction
o Direction of fasicles and muscle fibers.
o Name tells direction in which fibers run
o Example – rectus abdominis and transervus abdominis
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Location
o Location of attachments – name reveals point of origin and insertion
o Example – brachioradialis
Number of origins
o Two, three, or four origins.
o Indicated by the words biceps, triceps, and quadriceps.
Action
o The action is part of the muscle’s name
o Indicates type of muscles movement
o Flexor, extensor, adductor, abductor
Refer to pages 273 and 274