Skeleton & Bone structure/composition Flashcards
Anatomical position
feet, face, and palms forward
2 divisions if skeletal system
axial (down the midline of the body)
appendicular
Axial skeleton consists of
80 bones total
- skull
- hyoid bone
- vertebral column
- thoracic cage (sternum and ribs)
Appendicular skeleton consists of
126 bones total
- pectoral girdle
- pelvic girdle
- upper limbs
- lower limbs
3 main bone groupings in the skull
- cranium (8 bones)
- facial bones (14 bones)
- auditory ossicles (6 bones)
Bones in the cranium
- frontal
- 2 parietal
- 2 temporal
- sphenoid
- ethmoid
- occipital
Bones of the facial bones
- 2 nasal
- 2 maxillae (upper jaw)
- 2 zygomatic (eye socket and cheekbone)
- 2 lacrimal (side of nose and eye socket)
- 2 palatine (in the pallet)
- 2 inferior nasal chonchae
- 1 vomer (behind the pallet)
- 1 mandible (lower jaw)
Bones in the auditory ossicles (middle ear)
- 2 incus
- 2 malleus
- 2 stapes
Hyoid bone
- no articulations
- attaches muscle of tongue and neck.
- assists in swallowing
- horn shaped
Vertebral column divided into 5 regions
- cervical (7)
- thoracic (12)
- lumbar (5)
- sacral (1)
- coccyx (1)
Body of vertebral structure
thick and located anterior end
Spinous process of vertebral structure
median posterior projection (1), attachment site for muscles and ligament
Transverse process of vertebral structure
lateral bony projections for muscle attachment (2)
Vertebral foramen of vertebral structure
hole for spinal cord which lines up to form a canal
Superior and inferior articular facets of vertebral structure
attachment sites with vertebrae above and below
contain smooth surfaces formed from hyaline cartilage (facets)
Cervical region vertebrae
7 vertebrae (C1-C7) -smallest lightest weight vertebrae
C1 vertebrae
atlas
- no body or spinous process
- articulates superiorly w/ occipital condyle
- allows nodding “yes” motion
C2 vertebrae
axis
- contains knoblike process called dens (=odontoid process)
- pivot joint around which atlas swivels
- allows shaking “no” motion
Thoracic vertebrae
12 vertebrae(T1-T12)
- ALL articulate posteriorly with ribs via facets
- thoracic vertebrae increase in size from first to last
Lumbar vertebrae
5 vertebrae (L1-L5)
- support upper body weight.
- ALL have larger bodies and rectangular spinous processes
- referred to as small of the back
Sacrum vertebrae
5 fused vertebrae,
- articulates with ilium (pelvis) and 5th lumbar vertebra (L5)
- contain intervertebral foramina (exit site for nerves)
Coccyx vertebrae
3-5 fused vertebrae (usually 4)
-known as tailbone
Curvature of spinal column
- cervical and lumbar concave posteriorly. looks like )
- thoracic and sacrum convex posteriorly looks like (
3 Abnormal curvatures
- scoliosis
- kyphosis
- lordosis
Scoliosis
spinal column curves laterally (on side dips down)
Kyphosis
exaggerated thoracic curve. can be caused by osteoporosis (hunchback)
Lordosis
exaggerated lumbar curve (can be caused by pregnancy/potbelly) (swayback)
Thoracic cage consists of
sternum and ribs
Sternums (breast bone) 3 parts:
- manubrium (superior)
- body (middle)
- xiphoid process (inferior)
Ribs
12 total pairs that articulate posteriorly with thoracic vertebrae
True ribs
7 pairs
attach directly to sternum via costal (hyaline) cartilage
False ribs
5 pairs
(8-10) attach indirectly to sternum via costal cartilage
(11 and 12) floating ribs don’t attack to sternum (embedded in muscle)
Pectoral girdle consists of..
- clavicle
- scapula
Clavicle
(collarbone)
- articulates with sternum and scapula.
- connects the axial and appendicular skeletons
Scapula consists of
- acromion process
- glenoid fossa/cavity
- coracoid proces
Acromion process articulates with ..
clavicle
Glenoid fossa/cavity articulates with ..
head of humerus
Coracoid process attaches ..
muscles for arm and chest
Pelvic girdle
composed of 2 os coxa
Os coxa composed of..
- ilium
- ischium
- pubis
Ilium articulates ..
with the sacrum at iliac crest
Ischium
- bears weight of body while sitting
- most inferior surface is called ischial tuberosity
Pubis
Left and right side joined by pubic symphysis (cartilaginous disk)
Joints in the pelvic girdle
- pubic symphysis (joins pubic bones with cartilage)
- sacroiliac joint ( synovial joint)
- acetabulum
Acetabulum
socket that articulates with head of femur (hip bone)
-synovial joint (ball and socket)
Upper limb (arm) consists of..
- humerus
- radius/ulna
- carpals
- metacarpals
- phalanges
Carpals
wrist bones (8 per arm) (2 rows per wrist)
Metacarpals
palm (5 per arm)
Phalanges
fingers/digits (14 per arm)
Lower limb consists of ..
- femur
- patella (knee cap)
- tibia/fibula
- tarsals (ankle)
- metatarsals
- phalanges
Tarsals
(7 per leg) talus- articulates with tibia
-calcaneus (heel bone)
Metatarsals
(5 per leg) sole of foot
Phanlanges (foot)
(14 per leg) toes/digits
Long bone composed of :
- diaphysis
- epiphysis
- epiphyseal plate
- epiphyseal line
- medullary cavity
- periosteum membrane
- endosteum
- articular cartilage
Diaphysis
shaft/body of bone. composed of compact bone
Epiphysis
proximal and distal entities
Epiphyseal plate
hyaline cartilage,
used for bone growth in length
(bone growth is called endochondral ossification)
Epiphyseal line
replaces plate with bone when growth completed
where diaphysis and epiphyses meet
Periosteum membrane
- external surface
- allows bone to grow in diameter
- double membrane of CT that covers everything besides joint
- outer = dense irregular
- inner = osteogenic (mainly osteoblasts+ osteoclasts)
Medullary cavity
red marrow in child, yellow in adult
contains fat
lined with endosteum
Endosteum
- very delicate connective tissue
- lines internal surfaces of cavity and canals
- contain osteoblasts and osteoclasts
Articular cartilage
- hyaline
- prevents friction between bones
- found on epiphyseal surfaces of long bones
Bone consists of..
cells and matrix
Bone osteoprogenitor cells give rise to ..
- osteoblasts (build matrix)
- osteocytes (maintain matrix)
- osteoclasts (breakdown and reabsorb matrix)
The cells of the bone are separated by a matrix that consists of..
- ground substance (hydroxyapetite crystals for strength)
- collagen fibres (flexibility)
- water
2 types of bone:
- compact
- spongy
Compact bone
covers the external surfaces of ALL bones
Compact bone structure composed of..
individual structural units called osteons or haversian systems
Osteons composed of..
- Lamellae
- Osteocytes (found in lacunae)
- Canaliculi
- Haversian canals
- Volkmanns canals
Lamellae
concentric circles of matrix. osteocytes present between the lamellae
Lacunae
between lamellae, space within matrix where osteocytes live
Canaliculi
small channels that connect osteocytes to blood supple to each other
Haversian canals
contain blood vessels and nerves, lined with endosteum
Volkmann’s canal
found at a right angle to haversian canal, caries blood supply from periosteum to haversian canals and medullary cavity
Spongy bone
- not organized into osteons
- plates of bone are called trabeculae
Spongy bone found in..
- in the epiphyses of long bone
- in flat bones such as the skull and the ribs
Hyaline cartilage structure
- chondrocytes in lacunae
- matrix (water, collagen fibres, ground substance)
- avascular tissue
Articulations/joints
point of contact between 2 or more bones
2 classes of articulations/joints
structure and function
Structural classification is based on
- presence/absence of joint cavity
- type of tissue connecting two bones
Types of structural joints
- Fibrous
- cartilaginous
- synovial
Fibrous joint
no joint cavity
fibrous CT
ex: sutures of the skull
Cartilaginous joint
no joint cavity
composed of cartilage
ex: pubic symphysis and intervertebral disks
Synovial examples
shoulder, elbow, hip, knee
Synovial joints contain …
-joint cavity (contains fluid)
-bones are held together by a joint cavity and ligaments
(all diarthoritic joints are synovial joints)
Articular cartilage
- Hyaline cartilage located on the ends of the bone
- Reduces friction
Joint capsule
- Contains an outer layer of fibrous connective tissue that attaches to the periosteum
- An inner synovial membrane which secretes synovial fluid
Types of synovial joints
- plane/gliding
- hinge
- pivot
- ball and socket
Plane/gliding joint
flat surfaces (sacroiliac joint) amphiarthrotic
Hinge joint
concave/convex surfaces (knee)
diarthrotic
Pivot joint
projection in ring (dens in atlas)
amphiarthrotic
Ball and socket joint
great freedom of movement (femur and acetabulum, which is hip)
diarthrotic
Functional classification
based on degree of movement
Types of functional joints
- synarthotic
- amphiarthrotic
- diarthrotic
Syntharotic joint
immovable (skull)
Amphiarthrotic joint
slightly moveable (pubic symphysis)
Diarthrotic joint
freely moveable (shoulder, elbow, knee)
What is anterior direction and posterior
- anterior is to the front
- posterior is to the back
C3 to C7
distinguishing feature found on all of these vertebrae is the transverse forming (opening in the transverse process where artless pass to service brain)
Anatomical position of upper and lower limbs for medial bones
- Ulna
- Tibia
- Bones of the big toe
- Bones of the little finger (PALMS FACING UP)
Anatomical position of upper and lower limbs for lateral bones
- Radius (in line with the thumb)
- Fibula (in line with the bones of the little toe)
Long bones include..
- humerus
- radias
- unla
- fibula
- tibia
- femur
2 primary tissue of skeletal system
- bone
- cartilage
Trabeculae are//
irregularly arranged lamellae contain osteocytes
osteocytes are located in lacunae and connected by canaliculi
The spaces of the spongey bone contain ..
red bone marrow and produce blood cells (provides supply to developing osteocytes)
All synovial joints contain
- articular cartilage
- joint cavity
- joint capsule
