Human Osteology Midterm

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 1. Bone collar formation 2. Calcification of cartilage, cavitation begins 3. spongy bone forms in center shaft 4. Medullary cavity forms, SOCs appear, ossification continues 5. Ossification of epiphyses, hyaline cartilage only remains in epiphyseal plate and articular cartilage

intramembranous ossification

bone develops from a fibrous membrane 1. Mesenchymal stem cells differentiate into osteoblasts and form ossification center 2. Osteoid secreted and calcifies which traps osteoblasts to become osteocytes 3. Osteoid laid in random pattern, forms woven bone. Mesenchyme condenses on outer layer of woven bone and becomes periosteum 4. 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

inferior nasal concha articulations

lacrimals, ethmoid, palatines, maxilla

auditory ossicles

stapes, incus, malleus

Supraorbital foramen

frontal bone; supraorbital nerve, artery, and vein

optic canal

Sphenoid; optic nerve and ophthalmic artery

carotid canal

temporal; internal carotid nerve and artery

hypoglossal canal

occipital; hypoglossal nerve

foramen magnum

occipital; spinal cord, vertebral arteries

mental foramen

mandible; mental nerve, artery, and vein

crown

1

root

2

enamel

3

dentin

4

pulp cavity

5

periodontal ligament

7

cementum

border between yellow tooth root and pink periodontal ligament

enamel composition

96% inorganic hydroxyapatite, hardest tissue in body, organic: proteins and water

dentin composition

70% inorganic, 30% organic

cementum composition

nonvascular bone, rich in collagen fibers

Antimere

left and right symmetry

isomere

top and bottom symmetry

Incisal surface

cutting edge, biting surface of incisors and canines

occlusal surface

chewing surface of premolars and molars

lingulum

ridge of enamel at base of tooth on lingual surface

amelogenesis

process of enamel formation

ameloblasts

enamel forming cells

dentinogenesis

process of dentin formation

odontoblasts

dentin forming cells

4 stages of tooth development

bud, cap, bell, eruption

bud stage

8th week; dental laminae give rise to tooth buds

cap stage

11th week; invagination of buds create caps (called tooth germs by the end). Tooth crown, dentin, pulp cavity, cementum and periodontal ligament all formed

bell stage

12th week; hard tissue begins to form, odontoblasts and ameloblasts are differentiated

Cervical vertebrae

7, make up neck

thoracic vertebrae

12, make up upper back (connections for ribs)

lumbar vertebrae

5, sometimes 6, make up lower back

sacrum

5 fused verts (variable #: 4-6)

coccyx

4 fused verts, most variable in #

Kyphosis

anterior pinching of the thoracic, sacral, and caudal vertebrae

Lordosis

posterior pinching of the cervical and lumbar vertebrae

Fibrous joint

strong and stiff fibrous cartilage that offers little movement

synovial joint

cartilage covered articular surfaces separated and lubricated by synovial fluid, offers free movement

fibrous

type of joint found between vertebral disks

synovial

type of joint found between spinus processes

annulis fibrosis

dense fibrous connection that seals in soft nucleus of intervertebral disks

intervertebral disk

fibrous joint between the bodies of two vertebrae

nucleus pulposus

soft inner center of intervertebral disks made of water and loose collagen fibers

Vertebrae ossification

endochondral

POCs of vertebrae

body, L & R halves of neural arch

SOCs of vertebrae

superior and inferior border of the body, tip of the spinus process, L & R tips of transverse processes

neural arch halves fuse together

1-3 years

neural arch fuses to body

3-6 years

vertebral ligaments

anterior and posterior longitudinal, interspinal, supraspinus, and ligamentum flavum

ligamentum flavum

A

posterior longitudinal ligament

C

anterior longitudinal ligament

D

supraspinous ligament

E

interspinal ligament

F

Sacrum ossification

endochondral, 21 POCs

Pelvis

L & R innominate, sacrum, and coccyx

innominate

ilium, ischium, pubis

pelvis articulation

sacrum @ auricular surface, femur @ acetabulum, innominate @ pubic symphysis

acetabulum joint type

synovial

auricular surface joint type

synovial

pubic symphysis joint type

symphyseal

Pelvis ossification

endochondral

POCs and fusion times of innominate

ilium, ischium, pubis; fuse by 14-16 years

SOCs of innominate

iliac crest, ischial tuberosity, acetabulum, anterior inferior iliac spine, pubic symphysis

triradiate cartilage

nonarticulating structure that runs through the acetabulum and separates the three bones of the innominate

sternum ossification

endochondral; manubrium, sternebrae, xiphoid process*

Sternebrae

small horizontal disks of sternal bone that ossify together to form the sternal body

POCs of the sternum

manubrium (1st segment), sternebrae (segments 2-4)

sternoclavicular joint

saddle (synovial) joint

sternocostal joint

synovial (plane) joint