2. skeletal system Flashcards
anatomical position
-feet, face and palms forward
superior (cranial)
toward the head end or upper part of a structure of the body; above
-the head is superior to the abdomen
inferior (caudal)
- away from the head end or toward the lower part of a structure of the body; below
- the navel is inferior to the chin
anterior (ventral)
toward or at the front of the body; in front of
-the breastbone is anterior to the spine
posterior (dorsal)
- toward or at the back of the body; behind
- the heart is posterior to the breastbone
medial
- toward or at the midline of the body; on the inner side of
- the heart is medial to the arm
lateral
- away from the midline of the body; on the outer side of
- the arms are lateral to the chest
intermediate
- between a more medial and a more lateral structure
- the collar bone is intermediate between the breastbone and shoulder
proximal
- closer to the origin of the body part or the point of attachment of a limb to the body trunk
- the elbow is proximal to the wrist
distal
- farther from the origin of a body part or the point of attachment of a limb to the body trunk
- the knee is distal to the thigh
superficial (external)
- toward or at the body surface
- the skin is superficial to the skeletal muscles
deep (internal)
away from the body surface; more internal
-the lungs are deep to the skin
skeletal system
- axial skeleton
- appendicular skeleton
how many bones in the axial skeleton
- 80
- skull
- hyoid bone
- vertebral column
- thoracic cage (sternum and ribs)
how many bones are in the appendicular skeleton
-126 (limbs and bones that attach them to axial skeleton (girdles)) -pectoral girdle -pelvic girdle -upper limb (arm, forearm, and hand) -lower limb (thigh, leg and foot)
articulations
connections between bones
eg. the humerus articulates with the scapula
skull has three main bone groupings
- cranium (8 bones next to brain)
- facial bones (14 bones)
- auditory ossicles 6 (3 bones on each side in the middle ears)
cranium
- 1 frontal (forehead)
- 2 parietal
- 2 temporal
- 1 sphenoid
- 1 ethmoid (forms superior + middle nasal chonchae)
- 1 occipital
facial bones
- 2 nasal
- 2 maxillae
- 2 zygomatic
- 2 lacrimal
- 2 palatine
- 2 inferior nasal chonchae
- 1 vomer
- 1 mandible
hard palate
-2 palatine and 2 maxillae
auditory ossicles
- incus
- malleus
- stapes
hyoid bone
- no articulations (joints/connections to other bones)
- attaches muscles of tongue and neck, assists in swallowing
Bones in the vertebral column
25 vertebrae
- cervical(7)
- thoracic (12)
- lumbar (5)
- sacrum (1)
- coccyx (1)
typical vertebral structure:
- body -think anterior portion
- spinous process (1)- median posterior projection
- transverse process (2)-lateral bony projections for muscle attachment
- lamina (2) - connects the two processes
- pedicle (2) - connects body to transverse process
- vertebral foramen -hole for spinal cord
- superior and inferior articular facets -articulate with vertebrae above and below
- intervertebral foramina -exit for spinal nerves
characteristics of vertebrae by region
- cervical (C1-C7)
- thoracic (T1-T12)
- lumbar (L1-L5)
- sacrum
- coccyx
atlas
-no body, no spinous process
-articulates with occipital condyle of skull
(allows nodding (yes) motions)
C1
axis
C2
- dens (=odontoid process)
- pivot joint around which atlas swivels
- allows shaking (no) motion
Cervical C1-C7
- C1,C2= atypical
- C3-C7= typical
- C1=atlas
- C2=axis
thoracic (T1-T12)
all articulate with ribs by costal facets
lumbar (L1-L5)
support upper body weight
-all have large bodies and rectangular spinous processes
sacrum
- 5 fused vertebrae
- articulates with ilium (appendicular skeleton) and 5th lumbar vertebra (L5)
coccyx
- 3-5 fused vertebrae, usually 4
- tailbone
curvature of the spinal column
- cervical and lumbar (curved convex anteriorly = concave posteriorly)
- thoracic and sacrum (curved concave anteriorly = concave posteriorly)
abnormal curvature:
- scoliosis (spinal column curves laterally)
- kyphosis (exaggerated thoracic curve (hunchback))
- lordosis (exaggerated lumbar curve (swayback))
Thoracic cage
sternum and ribs
sternum (breast bone)
-3 parts
manubrium-superioir
body-middle
xiphoid process-inferior
ribs
- 12 pairs total (articulate posteriorly with T1-T12)
- 7 pairs = true ribs
- attach directly to sternum by costal cartilage (hyaline cartilage)
- 5 pairs = false ribs
- attach indirectly to sternum by costal cartilage (8-10) or not all = floating ribs (11,12 - embedded in muscle)
appendicular skeleton
- pectoral girdle (upper limb girdle)
- pelvic girdle (lower limb girdle)
- upper limb (in anatomical position)
- lower limb (in anatomical position)
pectoral girdle
-clavicle and scapula
clavicle
(collarbone)
- articulates with sternum(manubrium) and scapula (acromion process)
- connects axial and appendicular skeletons
scapula
- spine (on posterior)
- acromion process- articulates with clavicle
- glenoid fossa/cavity - articulates head of humerus
- coracoid process-attaches muscles for arm and chest
pelvic girdle (lower limb girdle)
- composed of 2 os coxae (hip bones) each with 3 bones:
- ilium-articulates with sacrum
- ischium- most inferior part = ischial tuberosity
- pubis-left and right joined by pubic symphysis
- joints:
- pubic symphysis
- sacroiliac joint -sacrum and ilium
- acetabulum-articulates with head of femur (all 3 bones of os coxa join here)
upper limb (in anatomical position)
- humerus
- radius (lateral)/ ulna (medial)
- carpals (8) - wrist
- metacarpals (5) - palm
- phalanges (14) - digits (fingers)
note: all are long bones (except carpals)
lower limb (in anatomical position)
-femur
-patella (knee cap)
-Tibia (medial) / fibula (lateral)
-tarsals (7) : talus - articulates with tibia
calcaneus - heal bone
-metatarsals (5) = sole
-phalanges (14 ) -digits (toes)
note: all are long bones (except patella and tarsals)
differentiating right vs. left
requires 2 features:
*anterior/posterior
*medial/lateral
eg. scapula (spine-posterior/glenoid fossa-lateral)
humerus (olecranon fossa-posterior)/head-medial)
femur (lateral/medial condyles (posterior) / head (medial))
tibia (tibial tuberosity (anterior)/ medial malleolus (medial))
long bone components (8)
diaphysis epiphyses epiphyseal plate epiphyseal line medullary cavity periosteum endosteum articular cartilage
Diaphysis
shaft (body)
epiphyses
proximal and distal extremities
epiphyseal plate
hyaline cartilage
used for bone growth (length)
epiphyseal line
- replaces plate with bone when growth completed
- plate/line-where the diaphysis and epiphyses meet
periostesum
- external surface
- 2 layers of connective tissue
- outer=dense irregular
- inner=mainly osteoblasts and osteoclasts
- allows bone to grow in diameter
endosteum
lines medullary cavity and canals
contains osteoblasts and osteoclasts
medullary cavity
red marrow in child, yellow marrow in adult
articular cartilage
hyaline (only at articulation points)
prevents friction between bones (no periosteum here)
histology
bone and cartilage
bone consists of :
a) cells:
osteoblasts
osteocytes
osteoclasts
b) matrix: ground substance -hydroxyapatite=insoluble Ca2+ phosphate salts (strength) collagen fibres (flexibility) water
2 types of bone
compact bone
spongy bone
compact bone
-converts external surfaces of all bones
-composed of osteons
-each osteon contains:
lamellae
lacunae (with osteocytes)
canaliculi
central canal
perforating canal
lamellae
concentric circles of matrix
lacunae (with osteocytes)
between lamellae (space within matrix where osteocytes live)
canaliculi
small channels that connect osteocytes to blood supply and to each other
central canal
contains blood vessels and nerves
lined with endosteum
perforating canal
- perpendicular to central canal
- carry bloody supply from periosteum to central canals and medullary cavity
spongy bone
-no osteons
-have trabeculae (irregularly arranged lamellae)
-canaliculi connect osteocytes in lacunae
-spaces contain bone marrow
(red marrow produces blood cells)
where is spongy bone found?
*flat and irregular bone (eg. skull, ribs, vertebrae)
*long bones:
epiphyses
lining medullary cavity
Cartilage (CT)
hyaline cartilage
non-vascular
structure:
chondrocytes in lacunae
matrix:
- shiny ground substance contains chondroitin sulphate and hyaluronic acid
- collagen fibres
- water
articulations/joints
point of contact between 2 or more bones
2 classes: structural and functional
structural classification (anatomical) based on:
- presence / absence of joint cavity
- type of CT
types of structural joints
fibrous
cartilaginous
synovial
fibrous
no joint cavity
fibrous CT
eg. sutures in skull (fontanels in a newborn)
cartilaginous
- no joint cavity
- cartilage attaches bones
- eg. pubic symphysis, costal cartilages of ribs
synovial
eg. shoulder, elbow, hip, knee structure: -articular cartilage (hyaline) -joint cavity -articular/joint capsule
joint cavity
contains synovial fluid
articular / joint fluid
outer layer = fibrous capsule -attaches to periosteum -may have ligaments within (capsule=thickened) or separate inner layer=synovial membrane (CT only) -secretes synovial fluid
types of structural
grouped according to shape of articulating bones
- plane/gliding
- hinge
- pivot
- ball and socket
plane/gliding
- flat surfaces
eg. sacroiliac
hinge
concave/convex surfaces
eg. elbow, knee
pivot
projection in ring
eg. dens (on axis) in atlas
ball and socket
great freedom of movement
eg. humerus in glenoid fossa
eg. femur in acetabulum (hip)
functional classification (physiological) based on:
degree of movement
types of functional joints
synarthrotic
amphiarthrotic
diarthrotic
synarthrotic
immovable
eg. skull sutures
amphiarthrotic
slightly moveable
eg. pubic symphysis
diarthrotic
freely moveable
eg. hip, shoulder
