Human Anatomy Exam 2.1

# of bones in body

206

# of bones in Axial skeleton

80

# of bones in Appendicular skeleton

126

Spongy bone characteristics

- Internal layer

- Protects Medullary Cavity

- Yellow & Red bone marrow

- Trabeculae

Spongy bone arrangement and reason

- Parallel thick branching plates/bars called trabeculae

- Reduce weight of skeleton, easier bone movement

Compact bone characteristics

- External wall

- Osteon functional unit

Large bone: Epiphysis

Superior and Inferior sections (2)

Large bone: Metaphysis

Small sections between Epiphysis and Diaphysis (2)

Large bone: Diaphysis

Middle section of the bone, the shaft (1)

Large bone: Head

- Round

- Separated from shaft by neck

- Forms part of joint

Bone functions

- Support

- Mineral storage

- Blood cell production

- Protection

- Movement

- Production of osteocalcin (fat storage & insulin production)

4 bone specialized cells

- Osteoprogenitor

- Osteoclast

- Osteoblast

- Osteocyte

Osteoprogenitor cell

- Stem cell

- Divides to produce osteoblasts

Osteoclast cell

- Multi-nucleate cell

- Secretes acids and enzymes to dissolve bone matrix

Osteoblast cell

- Immature bone cell

- Secretes osteoid (organic bone matrix)

Osteocyte cell

- Mature bone cell

- Maintains bone matrix

Osteogenesis & cells

Bone formation

- Osteocyte

- Osteoblast

Osteolysis & cells

Bone destroying

- Osteoprogenitor

- Osteoclast

Bone blood supply: Nutrient artery & vein

Through nutrient foramen in diaphysis

Bone blood supply: Epiphyseal vessels

- Through foramina of epiphysis

- To medullary cavities of epiphysis

Bone blood supply: Metaphyseal vessels

- Through artery & vein of metaphysis

- To diaphyseal surface

Bone blood supply: Periosteal vessels

- Through periosteum

- To superficial osteons (compact bone)

Periosteum

Thin membrane of dense irregular connective tissue that covers bone outer surface

Periosteum functions

- Isolate and protect bone

- Provide route and place of attachment for insertion of ligaments and tendons

- Bone growth and repair

Endosteum

Thin membrane of connective tissue that lines bone inner surface

Endosteum functions

Bone growth and repair

7 categories of bone shape

- Sutural

- Pneumatized

- Short

- Irregular

- Flat

- Long

- Sesamoid

Sutural bone characteristics

- Small

- Flat

- Oddly shaped

- Along sutures

Sutural bone example

Inca bone (suture where parietal & occipital bones meet)

Pneumatized bone characteristics

- Hollow

- Air pockets

Pneumatized bone example

Ethmoid bone

Short bone characteristics

- Boxlike

- Exterior compact & interior spongy

Short bone example

Carpal bones

Irregular bone characteristics

- Complex shape

- Short, flat, notched, or ridged surfaces

Irregular bone example

Vertebrae of spinal column

Flat bone characteristics

- Thin, roughly parallel surfaces of compact bone

- Spongy bone sandwich

Flat bone example

Ribs

Long bone characteristics

- Long

- Slender

- 2 epiphysis, 2 metaphysis, diaphysis, marrow cavity

Long bone example

Humerus

Sesamoid bone characteristics

- Small

- Round

- Flat

Sesamoid bone example

Patella

Depressions and openings

- Foramen

- Groove

- Notch

- Fissure

- Fossa

- Meatus

- Sinus

Bone marking: Foramen

Round or oval opening through a bone

Bone marking: Groove

Furrow

Bone marking: Fissure

Narrow, slit-like opening

Bone marking: Notch

Indentation at edge of structure

Bone marking: Fossa

Shallow basin-like depression, often serving as articular surface

Bone marking: Meatus

Canal-like passageway

Bone marking: Sinus

Cavity in a bone, filled with air and mucus

Surfaces that form joints

- Head

- Facet

- Condyle

Bone marking: Head

Bony expansion carried on narrow neck

Bone marking: Facet

Smooth, nearly flat articular surface

Bone marking: Condyle

Rounded articular projection

Projections that are sites of muscle or ligament attachment

- Tuberosity

- Crest

- Trochanter

- Line

- Tubercle

- Epicondyle

- Spine

Bone marking: Tuberosity

Large rounded projection, may be roughened

Bone marking: Crest

Narrow ridge of bone, usually prominent

Bone marking: Trochanter

Very large, blunt, irregularly shaped process (only example is femur)

Bone marking: Line

Narrow ridge of bone, less prominent than crest

Bone marking: Tubercle

Small rounded projection or process

Bone marking: Epicondyle

Raised area on or above a condyle

Bone marking: Spine

Sharp, slender, often pointed projection

Elevations and projections

- Process

- Ramus

Bone marking: Process

Any projection or bump

Bone marking: Ramus

Extension of a bone that forms an angle with the rest of the structure

Bone fracture

Break or crack in a bone

Fracture: Comminuted

- Bone fragments in multiple pieces

- Common in aged

Fracture: Compression

- Bone is crushed

- Common in porous bones subjected to trauma (fall)

Fracture: Spiral

- Ragged break with excessive twisting forces

- Common in sports

Fracture: Epiphyseal

- Epiphysis separates from diaphysis along epiphyseal plate

- Common where cartilage cells are dying and calcification of matrix is occurring

Fracture: Depressed

- Broken portion is pressed forward

- Common in skull

Fracture: Greenstick

- Bone breaks incompletely, one side of shaft breaks & other bends

- Common in children

Foramen magnum

Occipital bone

- Large hole (inferior view)

Occipital condyles

Occipital bone

- Bumps next to foramen magnum

- Make joints with 1st vertebrae of column

Hypoglossal canal

Occipital bone

- Small holes next to occipital condyles

- Room for blood vessels & nerves

Nuchal lines

Occipital bone

- Attachment of nuchal ligament that maintains straight forward position

- 2 lines: Superior & Inferior

External occipital protuberance

Occipital bone

- Small ridge, attachment for ligaments or muscle

External occipital crest

Occipital bone

- Small ridge inferior of protuberance

Superior border

Parietal bone

- Border of sagittal suture

Parietal eminence

Parietal bone

- Lump in the middle

Parietal bone lines

- Superior & Inferior

- Horizontal

- Indicate attachment of temporalis muscle

Inferior border

Parietal bone

- Border of squamous suture

- Connects to neck

Frontal bone shape

Shell

Frontal bone: Squamous part

Anterior surface (forehead)

Metopic suture

Frontal bone

- Indicates frontal bone used to be 2 parts, then bind into 1

- Only in some skulls

Supra-orbital margin & notch

Frontal bone

- Where eyes are

Supra-orbital foramen

Frontal bone

- Move eyes via cranial nerves

Superciliary arch

Frontal bone

- Where eyebrows are

Lacrimal fossa

Frontal bone

- Holds lacrimal gland that makes us cry

Frontal air cells

Ethmoid bone

- Lots of little holes connected to sinuses

Orbital part

Frontal bone

- Forms roof of each orbit

- Protects eyes

Superior margin

Frontal bone

- Posterior section

- Margin of coronal suture

Frontal crest

Frontal bone

- Posterior section

- Attach membranes that protect brain

Frontal bone notch

- Posterior section

- Notch for ethmoid

Temporal bone articulations

- Zygomatic

- Parietal

- Occipital

- Sphenoid

- Mandible

Temporal bone 3 parts

- Squamous

- Tympanic

- Petrous

Temporal bone squamous shape

Scale-like

Temporal bone squamous location

- Right superior

- Above zygomatic process

Zygomatic process

Temporal bone

- Ends squamous part

- Long stem that sticks out

- Cheek arch

Temporal bone tympanic part

- Internal ear organs

- Right below external acoustic meatus (middle inferior)

Mastoid process

Temporal bone

- Attachment site for muscles that rotate head