Bones of the axial skeleton
-skull -auditory ossicles -hyoid bone -vertebral column -thoracic cage
bones of the appendicular skeleton
-scapula -clavicle -pelvic girdle -humerus, radius, ulna, hand bones -femur, fibula, tibia, foot bones
Bone is an
organ
Physis
space between the metaphysis and epiphysis -only in living individuals, seen in X-Rays
Metaphysis
where diaphysis and epiphysis meet
Collagen in bone
type 2
Osteoblasts
build bone by secreting osteoid
osteoid
unmineralized bone matrix
Osteoclasts
clear away/break bone -repair via remodelling
Osteocytes
mature bone cells -osteoblasts trapped in bone matrix
Lacunae
pores that contain osteocytes
Function of osteocytes
bone maintenance and communication -respond to need for more/less minerals -alert BMU to damaged bone
Layers of bone
periosteum and endosteum
Periosteum
fibrous membrane covering a bone
Endosteum
lining of the medullary cavity
Lamellar bone
mature bone
lamellae
sheets of mature bone, 3-7 microns thick
Haversian canal
central, longitudinal canals of bone that carry blood vessels and nerves to deliver nutrients and signals through bone matrix
Osteon
basic unit of lamellar bone -Includes osteocyte, haversian canal, and circular sheets of lamellae
Volkmann's Canals
transverse canals that connect Haversian canals, also carry blood vessels and nerves
endochondral ossification
process in which bone forms by replacing hyaline cartilage
Bone collar formation
Calcification of cartilage, cavitation begins
spongy bone forms in center shaft
Medullary cavity forms, SOCs appear, ossification continues
Ossification of epiphyses, hyaline cartilage only remains in epiphyseal plate and articular cartilage
intramembranous ossification
bone develops from a fibrous membrane
Mesenchymal stem cells differentiate into osteoblasts and form ossification center
Osteoid secreted and calcifies which traps osteoblasts to become osteocytes
Osteoid laid in random pattern, forms woven bone. Mesenchyme condenses on outer layer of woven bone and becomes periosteum
Lamellar bone replaces woven bone forming compact bone sheets and red marrow appears
Types of bones
compact (dense/cortical) and spongy (trabecular/cancellous)
functions of skeleton
Hematopoiesis, mineral/fat storage, support, protection, movement
stored in medullary cavity, mostly fat
yellow marrow
stored within cancellous tissue
red marrow
minerals in bone
mostly calcium and phosphate
Trabecular bone makes up
flat bones, articular ends of long bones
Compact bone makes up
external surfaces of bone, shaft of long bone
Bones longer than they are wide
long bone
generally cube shaped bones, or bones that form within tendons
short bones
thin, flattened and slightly curved bones
flat bones
bones with complicated shapes
irregular bones
Long bones make up the
appendicular skeleton
short bone examples
carpals, tarsals, and patella
flat bone examples
skull, ribs, sternum, and pelvis
irregular bone examples
vertebrae, mandible and parts of the splanchnocranium
Primary ossification of the humerus
diaphysis
Secondary ossification centers of the humerus
head, greater tubercle, lesser tubercle, medial epicondyle, trochlea, capitulum, lateral epicondyle
SOC's of humerus fusion age
14-16 years
Humerus muscle attachment site
deltoid tuberosity
Deltoid tuberosity
deltoid
radius muscle attachment sites
radial tuberosity, pronator teres
radial tuberosity
biceps brachaii
pronator teres
pronator teres
ulna muscle attachment sites
olecranon process, pronator quadratus ridge
olecranon process
triceps
pronator quadratus ridge
pronator quadratus
POCs of radius and ulna
diaphysis
SOCs of radius and ulna
proximal and distal epiphyses
Skull
entire head
Mandible
lower jaw alone
Cranium
skull without mandible
Calotte
skull cap (hat brim)
Splanchnocranium
facial skeleton
Neurocranium
braincase, everything the brain touches
frontonasal suture
small, horizontal suture that separates the nasal bones from the frontal
frontomaxillary suture
paired, small sutures that are found on the side of the frontal bone just lateral to the nasal bones and run diagonally to the maxilla
sinuses of the skull
frontal sinus, sphenoid sinus, maxillary sinus
sphenoid sinus
located in the body of the sphenoid
maxillary sinus
triangular in shape, located in the middle of the maxilla visible when cut in half
nasion
middle point where nasals connect with the frontal bone, 2
glabella
located just above the nasion on the metopic suture where the superciliary arch meets the rest of the frontal bone, below 17
bregma
20, intersection of coronal and sagittal sutures
dacryon
located at the junction of the lacrimal and the frontal, 3
prosthion
On the midline of the alveolar process of the maxilla, below 1
Alare
located on most lateral point of the nasal aperture, 15
ectoconchion
most lateral point on the orbital margin, between 5 and 9
euryon
greatest cranial width, along temporal line between 26 and 27
opisthocranium
point at the rear of the skull furthest from the glabella, 30
opisthion
midline posterior margin of foramen magnum
basion
midline anterior margin of foramen magnum
lambda
intersection of the sagittal and lambdoidal suture, 25
frontal ossification
intramembranous, frontal boss POC, develops in 2 halves
frontal articulations
parietals, zygomatics, nasals, maxilla, ethmoid, sphenoid, lacrimals
parietal ossification
intramembranous, parietal boss
parietal articulations
frontal, parietal, temporal, occipital, sphenoid
occipital ossification
intramembranous: squama endochondral: basilar and lateral portions
occipital articulations
temporals, parietals, sphenoid
temporal ossification
intramembranous: squama endochondral: petrous portion, zygomatic process, mastoid process
temporal articulations
parietals, occipital, sphenoid, zygomatic, mandible
nasal ossification
intramembranous, nasal halves
nasal articulations
frontal, maxilla, ethmoid, nasal
sphenoid ossification
endochondral: body, lesser wings, greater wings
sphenoid articulations
frontal, parietals, occipital, temporals, ethmoid, maxillae, palatines, zygomatics, vomer
zygomatic ossification
intramembranous, L & R
zygomatic articulations
frontal, temporal, maxillae, sphenoid
Maxilla ossification
intramembranous, L & R
Maxilla articulations
frontal, nasals, zygomatics, lacrimals, palatines, sphenoid, inferior nasal conchae, vomer
Mandible ossification
intramembranous, L & R
mandible articulations
temporals
palatine ossification
intramembranous, L & R
palatine articulations
maxilla, sphenoid, ethmoid, inferior nasal concha, vomer, palatine
Ethmoid ossification
endochondral: L&R labyrinth, perpendicular process
ethmoid articulations
frontal, sphenoid, nasals, maxilla, lacrimals, inferior nasal concha, vomer
lacrimal ossification
intramembranous, L & R
lacrimal articulations
maxilla, frontal, ethmoid, inferior nasal concha
Vomer ossification
intramembranous: L & R plates endochondral: fusion of plates
vomer articulations
sphenoid, ethmoid, palatines, maxilla
Inferior nasal concha(e) ossification
endochondral: L & R