bones

BONES

Osteology= study of bones

• Tissue: Connective• Functions: – Support– Protect soft tissue– Points of attachment for muscles– House blood producing cells– Store inorganic salts

• 206 bones• 2 main divisions– Axial– Appendicular

Axial

• Head, Neck, Trunk• Skull• Hyoid bone• Vertebral column• Thoracic Cage (ribs, 12 pairs)• Sternum

APPENDICULAR

• limbs and bones connecting the limbs to the: PECTORAL GIRDLE (scapula & clavicle), UPPER LIMBS (arms)PELVIC GIRDLE (coxal bones), LOWER LIMBS (legs)

Bone Classification

• Long bones• Short bones• Flat bones• Irregular bones* Sesamoid bones

1. Long Bones- have long longitudinal axes ad expanded ends

• EX: forearm, thigh bones2. Short Bones- cube like with lengths/ widths

roughly equal• Ex: wrist, ankles

3. Flat Bones- platelike structures with broad surfaces

Ex: Ribs, scapulae

4. Irregular bones- variety of shapes, connected to several bones

Ex: vertebrae, facial bones5. Sesamoid or round bones- small and nodularEx: kneecap

Long Bone

• Epiphysis- expanded portion at each end of bone, articulates (forms a joint)

• Diaphysis- shaft of bone• Articular cartilage- layer of hyaline cartilage– Proximal epiphysis – nearest to torso– Distal epiphysis- end furthest from torso

• Periosteum- bone covered in a tough vascular covering of fibrous tissue

pg 194

• Processes- bony projections for sites of attachment– Provide attachment sites, grooves/openings for

passageways of blood vessels and nerves

2 Bone Types

1. Compact bone (Cortical) - tightly packed tissue, solid, strong- Wall of diaphysis

2. Spongy Bone (cancellous) - many branching bone plates, covered with a layer of compact bone.

• Medullar Cavity- hollow chamber within the diaphysis connects to spaces in spongy bone. Filled with soft specialized tissue called bone marrow.

• Endosteum- thin membrane containing bone-forming cells lining medullar cavity

• Marrow- Red Marrow - mainly in spongy bone in adults.

Produces blood cellsYellow Marrow - fat storage. Replaces much of

the red marrow in diaphysis through childhood

Microscopic Structures pg 196

• Bone Extracellular Matrix = collagen / inorganic salts

• Osteocytes- located in tiny bony chambers called lacunae– Transport nutrients and waste

Compact Bone

• Osteon- (harversian system) cylinder unit around central canal– Contain blood vessels, nerve tissue, loose CT

• Central canals – extend longitudinally through bone

• Perforating canal (Volkmann’s canals)- transverse canals connect central canals– Contain blood vessels and nerves

Spongy bone

• Cells lie within trabeculae• Nutrients from subs. diffusing into the canaliculi

BONE DEVELOPMENT AND GROWTH

Two types of bones based on development

• 1. INTRAMEMBRANOUS BONES = broad, flat bones of the skull.

• form from membrane-like sheets of connective tissue

• 2. ENDOCHONDRAL BONES =masses of cartilage that are later replaced by bone tissue

• EX: long bones

Intramembranous Bones

• Osteoblasts appear in CT• Bone forming cells

• Fibers appear in matrix• Calcification occurs– Deposits of salts in matrix

• Osteoblasts become osteocytes

Endochondral

• Skeleton in cartilage• Bone replaces cartilage• Ossification centers– Areas where bone formation starts– Blood vessels penetrate cartilage

• ALL BONES START AS HYALINE CARTILAGE, areas gradually turn to bone

• PRIMARY OSSIFICATION CENTER (shaft) • SECONDARY OSSIFICATION CENTER (ends)

• Epiphyseal disk (growth plate) is a band of cartilage b/w the epiphysis and diaphysis

• These areas increase bone length as the cells ossify

• Cartilage becomes osteoblasts become osteocytes

• RESORPTION• OSTEOCLASTS - dissolve bone tissue to release

minerals, process is called RESORPTION

Factors Affecting Bone Growth

• Absence of Calcium– Deforms bones – children= rickets– Adults= osteomalacia

• Lack/Excess of growth hormone– Lack - Child= pituitary dwarfism– Excess- child= pituitary gigantism

• Stress- causes bones to grow, lack of exercise causes bone tissue to waste away

BONE FRACTURES

Axial

• Skull Cranium and facial bones• Hyoid bone- floats, helps with swallowing/

supports tongue• Vertebral Column– Sacrum– Coccyx

• Thoracic Cage- 12 pairs of ribs and sternum

Appendicular

• Pectoral girdle- scapula– Clavicle

• Upper limbs- humerous, radius, ulna, carpals, metacarpals, phalanges

• Pelvic girdle- coxa, pelvis• Lower Limbs- femur, tibia(large),

fibula(slender), patella, tarsals, metatarsals, phalanges

3 Basic Types of Joints (articulations):

1. SYNARTHROTIC – immoveable joint, such as bones in the skull, these junctions are called SUTURES

2. AMPHIARTHOTIC – slightly moveable joint, vertebrae 3. DIARTHROTIC – freely moveable joint, such as

shoulders, hips, knees, elbows, wrists, fingers…--these joints are enclosed within a fibrous capsule which

contains a lubricating fluid called SYNOVIAL fluid. These are called SYNOVIAL JOINTS.

Cranium Bones

1. Frontal - anterior portion above eyes2. Parietal – one on each side of the skull, just behind

frontal bone3. Occipital – forms the back of the skull and base of the

cranium4. Temporal – forms parts of the sides and base of

cranium5. Sphenoid – wedged between several other bones in

anterior portion of the cranium6. Ethomoid – form roof of nasal cavity

Sutures

• 1. Coronal – between frontal and parietal bones

• 2. Lambdoidal – between occipital and parietal bones

• 3. Squamous – between temporal and parietal bones

• 4. Sagittal - between parietal bones

Facial Bones

immovable and 1 movable jawbone1. Maxillary bones2. Palatine bones3. Zygomatic bones4. Lacrimal bones5. Nasal bones6. Vomer bones7. Inferior nasal conchae8. mandible

Foremens

• Allow blood vessels/nerves to travel through bone

• Supraorbital foremen• Infraorbital foremen• Mental foremen

Vertebral column

• 26 bones• Composed of vertebrae• Intravertebral discs connected by ligaments• Protects spinal cord

Vertebrae

• Cervical = 7 bones• Thoracic = 12 bones• Lumbar= 5 bones• Sacrum=5 fused into 1 bone• Coccyx= 4 fused into 1 bone

Parts to know

• Body• Intervertebral notch• Lamina• Pedicle• Spinous process• Superior articular process• Transverse foramen • Transverse process

Sacrum

• Sacral promontory• Superior articular process• Anterior sacral foramen• Posterior sacral foramen• Sacral hiatus• Tubercle of median sacral crest• coccyx

Thoracic Cage

• Ribs = 24 or 12 pairs• First 7 rib pairs= true ribs, joined to sternum• Last 5 rib pairs= false ribs, – Upper 3 pairs attached by cartilage– Lower 2 pairs= floating ribs

• Sternum• 3 parts– Upper manubrium– Body– Xiphoid process

• Jugular notch

Pectoral Girdle

• 2 clavicles• 2 scapulae• Supports upper limbs and attachment for

muscles that move them

Clavicles

• Articulate with sternum and scapulae

Scapulae

– Supraspinous fossa– Infraspinous fossa– Acromion process– Coracoid process– Glenoid cavity– Superior border – lateral border (axillary)– Medial border (vertebral)

Upper Limb

• Framework of arm, forearm, hand• Provide attachments for muscles • Humerus• Radius• Ulna• Carpals• Metacarpals• phalanges

Humerus

• Long bone, extends from scapulae to elbow• Head fits in glenoid cavity of scapula• Greater tubercle• Lesser tubercle• Intertubercular groove• Anatomical neck• Surgical neck• Deltoid tuberosity• Coronoid fossa• Lateral epicondyle• Capitulum• Olecranon fossa• Medial epicondyle• Trochlea

Radius

• Thumb side• Shorter than ulna• Top is disk like– Radial tuberosity– Styloid process

Ulna

• Longer than radius– Trochlear notch– Olecranon process– Coronoid process– Styloid process

Hand

• Carpals (8)• Mass of 8 bones = carpus– Scaphoid– Capitate– Trapezoid– Trapezium– Lunate– Hamate – Triquetrum– pisiform

• Metacarpals = 5 bones• Thumb is opposable (#1)

• Phalanges- finger bones• Proximal/middle/distal phalanx• Thumb lacks middle• Fingers= 14 bones

Pelvic Girdle

• 2 coxae (hip bones)• Pelvis- coxae, sacrum, coccyx• Supports trunk of body, provides attachments

for lower limbs, protects organs

Coxae

• Illium, Ischium, Pubis= fuse to form acetabulum

• Illium- largest– Illiac crest– Illiac fossa– Posterior superior iliac spine– Greater sciatic notch– Lesser sciatic notch

• Ischium- lowest portion of coxa– Ischial tuberosity– Ischial spine

• Pubis- anterior portion of coxa– Symphysis pubis– Pubic arch– Obturator foramen

Differences b/w male and female

Female bones are broader

Lower Limbs

• Femur• Patella• Tibia• Fibula• Foot

Femur

• Longest bone in body• Fovea capitis• Neck• greater trochanter/ lesser trochanter• Linea aspera• Lateral/medial condyles• Medial epicondyle• Lateral epicondyle• Gluteal tuberosity

Tibia

• Intercondylar eminence• Medial condyle/lateral condyle• Tibial tuberosity• Medial malleolus

Fibula

• Smaller than tibia• Connects to ankle• Lateral malleolus• head

Foot

• Ankle= tarsus• 7 bones– Talus– Calcaneus- largest– Navicular– Cuboid– Lateral cuneiform– Intermediate cuneiform– Medial cuniform

• Metatarsals = 5• Phalanges- shorter than fingers• Proximal phalanx• Middle phalanx• Distal phalanx