Lab 2: Osteology: The Axial Skeleton (Excluding Head/Face and Foramen Chart)

axial skeleton

consists of 80 bones

5 major functions of skeletal system

1. support

2. movement

3. protection

4. storage of minerals

5. protection of blood cells

compact bone

looks smooth and homogeneous

spongy bone

composed of small trabeculae (tiny beams and struts) of bone with lots of open spaces

4 bone classifications (gross anatomy)

long, short, flat, and irregular

long bones

- longer than they are wide

- generally consist of a shaft with heads at either end

- primarily composed of compact bone

short bones

- roughly cube shaped

- contain more spongy bone than compact bone

flat bones

- generally flattened along a major aspect of their geometry, but can be curved

- two wafer-like layers of compact bone between a layer of spongy bone

irregular bones

do not fit into the other major 4 categories due to their morphology, vertebra

periosteum

- what encapsulates the bone

- tough fibrous membrane that appears glossy

- covers the compact bone surface

- composed of 2 layers

- outer fibrous layer where muscle tendons and bone ligaments attach

- inner cellular layer that produces osteoblasts

diaphysis

- long, central shaft of the bone

- wall is made of compact bone

- inside is hollow

proximal epiphysis

on the end of the long bone closest to the trunk of the body

distal epiphysis

on the end of the long bone furthest from the trunk of the body

articular cartilage

a layer of hyaline cartilage that covers the place where the epiphysis articulates with another bone

marrow (medullary) cavity

the hollow interior of the diaphysis that contains yellow marrow

yellow marrow

high concentration of lipids within the medullary cavity

endosteum

lines the medullary cavity

metaphysis

the space between the diaphysis and either epiphysis

epiphyseal line

- formation indicates bone growth/bone transition from juvenile stage to adult stage

- bony remnant of the growth plate

bone growth stops

when the cartilage of the epiphyseal plate disappears and is replaced by the bone...

cortex of the bone

- compact bone layers of the flat bones

- broken into external and internal tables

external and internal tables

are thick in order to provide strength for the bone

diploe

spongy bone between the external and internal tables in a flat bone that is filled with red marrow

red marrow

type of loose connective tissue that is made up of stem cells from which all blood cells arise

bone markings

reveal where bones form joints with other bones, where muscles, tendons, and ligaments were attached, and where blood vessels and nerves pass

projections and depressions

two categories of bone markings

projections

processes that grow out from the bone and serve as sites of muscle attachment or help form joints

depressions

indentations or openings in the bone that often serve as conduits for nerves and blood vessels

tuberosity

large rounded projection

crest

narrow ridge of a bone; usually prominent

trochanter

very large, blunt, irregularly shaped process

line

narrow ridge of bone; less prominent than a crest

tubercle

small rounded projection or process

epicondyle

raised area on or above condyle

spine

sharp, slender often pointed projection

process

any bone prominence

projections that are sites of muscle and ligament attachment

tuberosity, crest, trochanter, line, tubercle, epicondyle, spine, process

surfaces that form joints

head, facet, condyle, ramus

head

body expansion carried on a narrow neck

facet

smooth, nearly flat articular surface

condyle

rounded articular projection, often articulates with a corresponding fossa

ramus

arm-like bar of bone

depressions and openings

foramen, groove, fissure, notch, fossa, meatus, sinus

foramen

round or oval opening through a bone

groove

furrow

fissure

narrow, slit-like opening

notch

indentation at the end of a structure

fossa

shallow, basin-like depression in a bone, often serving as an articular surface

meatus

canal-like passageway

sinus

bone cavity, filled with air and lined with mucous membrane

5 types of vertebrae

cervical (7), thoracic (12), lumbar (5), sacral, and coccygeal

unfused vertebrae

cervical, thoracic, and lumbar

cervical vertebrae (C1-C7)

- less confined articulations, allows for a wide range of motion in the head and neck

- have bifid spinous process and transverse foramen

- transverse foramina transmit the vertebral arteries which form the basilar artery and deliver blood to the brain

thoracic vertebrae (T1-T12)

- articulate with the ribs, which limits flexion in the thorax

- articular process is directed anterior and posterior, decreasing flexion and extension in the thorax

lumbar vertebrae (L1-L5)

- directed medially and laterally, limiting rotation in lower spine

- spinal cord proper stops here

- spinal taps are done in this area to avoid hitting spinal cord

- largest vertebrae in the human body

cauda equina

the spot at L1 where the spinal cord proper stops and becomes hanging "roots"

between L3 and L4

where a spinal tap is performed in order to avoid hitting the spinal cord

sacrum

- made up of 5 fused vertebrae

- foramina transmit blood vessels and spinal nerves to the lower body

- provides a stable anchoring point for the bones of the pelvic girdle

coccyx

- tail bone

- made up of four fused vertebrae

- an attachment point for several ligaments and muscles of the pelvic floor

4 natural curvatures of the spinal cord

cervical, thoracic, lumbar, sacral

cervical curvature

thoracic curvature

lumbar curvature

sacral curvature

articular process of vertebrae

- inferior articulates with the superior of the vertebrae below it

- when determining which is superior and inferior, it is based on their position on the vertebra (NOT in the joint!)

superior view of cervical vertebrae

lateral view of cervical vertebrae

superior view of thoracic vertebrae

lateral view of thoracic vertebrae

superior view of lumbar vertebrae

lateral view of lumbar vertebrae

cervical vertebrae

- kidney bean shaped body

- spinous process is horizontal with a bifid spine in 3-6

- hyoid bone does not actually articulate with them

atlas

- first cervical vertebra (C1)

- no body

- large vertebral foramen

- articulates with the skull

- has no spinous process

axis

- second cervical vertebra (C2)

- articulates with the atlas

- primary function is to provide the atlas with a pivot point for when the head is turned laterally and medially

anterior arch of atlas

superior articular facet of atlas

transverse foramen of atlas

transverse process of atlas

vertebral foramen of atlas

posterior arch of atlas

facet for the dens of C2 on atlas

inferior articular facet of atlas

dens of axis

superior articular facet of axis

transverse foramen of axis

transverse process of axis

inferior articular process of axis

spinous process of axis

vertebral foramen of axis

lamina of axis

spinous process of cervical vertebrae

vertebral foramen of cervical vertebrae

lamina of cervical vertebrae

superior articular process of cervical vertebrae

pedicle of cervical vertebrae

transverse foramen of cervical vertebrae

transverse process of cervical vertebrae

body of cervical vertebrae

inferior articular process of cervical vertebrae

spinous process of thoracic vertebrae