Chapter 5- Skeletal System Flashcards
axial skeleton
skull, vertebral column, bony thorax
appendicular skeleton
bones of pectoral girdle, upper limbs, pelvic girdle, and lower limbs
skull bones
-skull (22)= cranial bones (8) + facial bones (14)
cranial bones (cranium)
enclose the brain in cranial cavity (protects brains)
-cranial vault (calvarium)
-cranial base
provides sites of attachment for head and neck muscles
cranial vault
- superior, lateral, posterior, anterior skulls
- removed during autopsy
cranial base
anterior, middle, and posterior cranial fosse (rounded depression) of inferior skull
facial bones
-framework of face
-cavities for special sense
organs for sight, taste, and smell
-openings for air and food passage
-sites of attachment for teeth and muscles of facial expression
-protect eyes, nose, and mouth
parietal bones and sutures
superior aspects of cranial vault 4 sutures: -coronal suture -sagittal suture -lambdoidal suture -squamous (squamosal) suture -pterion
coronal suture
between parietal bones and frontal bone
sagittal suture
between right and left parietal bones
lambdoidal suture
between parietal bones and occipital bone (upside down Y)
squamous suture
between parietal and temporal bones on each side of skull
pterion
where temporal, frontal, sphenoid, and parietal bones meet
sphenoid bone
keystone bone of cranium
- lies in centre of skull and articulates with all other cranial bones
- has a depression (sella turcica) to house and protect pituitary gland
- has wings for muscle attachments and foramina to allow nerves and blood vessels to pass through it
ethmoid bone
- deepest bone in skull
- crista galli is a sharp point that anchors dural meninges around the brain
- cribriform plate has foramen for olfactory nerves to pass from nasal cavity to brain
- perpendicular plate extends into nasal cavity forming the superior and middle nasal conchae
- contributes to eye socket
hyoid bone
- lies inferiorly to mandible
- only bone that does not articulate with any other bone
- anchored by ligaments to the styloid process of temporal bones
- acts as movable base for tongue and neck/larynx muscles (speech/swallowing)
vertebral column
- comprised of 26 irregular bones arranged to give a flexible, curved structure
- extends from skull to pelvis
- arched to support more weight
vertebral column regions
- cervical= 7 bones (concave)
- thoracic= 12 bones (convex)
- lumbar= 5 bones (concave)
- sacral= 5 bones (fused) (convex)
- cocyx= 3-4 bones (fused)
vertebral structures
- body/centrum
- vertebral arch
- vertebral foramina
- intervertebral foramina
body/centrum
anterior weight-bearing region
vertebral arch
composed of pedicles and laminae that, along wth centrum, encloses vertebral foramen
vertebral foramina
make up vertebral canal for spinal cord
intervertebral foramina
- lateral openings between adjacent vertebrae for spinal nerves formed by superior and inferior intervertebral notches of adjacent vertebrae
- allow nerves to exit spinal cord
vertebral structures
- spinous process: projects posteriorly
- transverse processes (2): project laterally
- superior articular processes (2): protrude superiorly
- inferior articular processes (2): protrude inferiorly
cervical vertebrae
- very flexible, not very strong
- C1-C7: smallest, lightest vertebrae
- C3-C7: oval body
- spinous processes are bifid (split at tip except for C7)
- large, triangular foramen
- transverse foramen in each transverse process fro vessels in your neck (ie; carotid artery)
- C7 is vertebra pro minus (palpable through skin)
atlas
C1: no body or sinus process
- anterior and posterior arches and two lateral masses
- superior surface of lateral masses articulate with occipital condyles
- no centrum
- movement for “yes”
axis
C2: first vertebrae to have a body
- dens projects superiorly into anterior arch of atlas. C1 locks onto C2 by the dens
- dens is pivot for rotation of atlas
- movement for “no”
thoracic vertebrae
T1-T12
- all articulate with ribs at facet and demifacets
- long, spinous process that points inferiorly, for protection
- circular vertebral foramen for spinal cord
- location of articular facets allow for rotation
- T11 and T12 lock transverse costal facets (surface on vertebrae that attach to ribs
lumbar vertebrae
L1-L5
-biggest, thickest, bears most weight
-very strong, not very flexible
-receives most stress, a shock absorber
-short, thick pedicles and laminae
flat hatchet-shaped spinous process points posteriorly
-vertebral foramen triangular or squished circle
-articular facets locks lumbar vertebra together to prevent rotation
sacrum
- formed from 5 bones fused during fetal development
- articulates with surfaces of hip bones
- sacral canal accommodates spinal cord
- sacral foramina allow passage of sacral nerves and blood vessels
coccyx
formed from 3-5 smaller bones fused during fetal development
tail remnant
bony thorax
- manubrium
- body
- xiphoid process
manubrium
- superior portion
- articulates with clavicles, scapula and ribs 1 & 2
body (midportion)
articulates with costal cartilage of ribs 2-7
xiphoid process
- inferior end
- site of muscle attachment
- not ossified until age 40, cartilaginous until then
ribs
- 12 pair
- attached posteriorly to bodies and transverse processes of thoracic vertebrae
ribs 1-7
- true (vertebrosternal) ribs
- attach directive to sternum by individual costal cartilage
ribs 8-12
- false ribs
- 8-10 are vertebrochondral ribs
- attach indirectly to sternum by joining costal cartilage to rib above
ribs 11-12
- vertebral (floating) ribs
- no attachment to sternum
- buried in tissue and muscle
pectoral girdle
- incomplete girdle, does not wrap full around body for freedom to move shoulders
- the clavicle and scapula
- attaches upper limb to trunk and provides attachment sites for muscles that move upper limb
clavicles
- anchors muscles
- acromial end joins with scapula (lateral)
- sternal end joins with sternum (medial)
- holds scapula and arms out laterally
- most commonly broken bone in body
scapula
- on dorsal surface of rib cage between 2 and 7
- 3 borders and 2 angles
- large fosse named according to location
- shovel
upper limb
30 bones in each upper limb
- arm
- forearm
- hand
humerus
- largest, longest bone of upper limb
- articulates superiorly with glenoid cavity of scapula
- articulates inferiorly with radius/ulna
anatomical neck
closer to the head
surgical neck
where humerus breaks more often
ulna
- medial bone of forearm
- forms major portion of elbow joint
- longer, less mobile
radius
- lateral bone in forearm
- head articulates with humerus and ulna
- forms major joints with carpals
- shorter, more mobile
interosseous membrane
connects radius and ulna/tibia and fibula along the entire length
hand
-carpals (8)
-metacarpals (5)
-phalanges (14)
1= tumb
5=pinkie
pelvic girdle
- complete girdle
- 2 hip bones and sacrum
- less mobile, more stable
- bony pelvis formed by coral bones, sacrum, and coccyx
function of pelvic girdle
- attach lower limbs to axial skeleton with strong ligaments
- transmit weight of upper body to lower limbs
- support/protect pelvic organs
os coxae (coxal bone)
3 fused bones
- ilium
- ischium
- pubis
ilium
- superior region
- articular surface joins with sacrum (sacroiliac joint)
- iliac crest is important for muscle attachment
-ischium
- posterioinferior part of hip bone
- sitting weight on ischial tuberosity
pubis
- anterior portion
- joins at pubic symphysis by fibrocartilage
- acetabulum out laterally, where head of femur sits, formed by all 3 bones of os coxae
- obturato foramen for blood vessels and nerves
- sciatic notches where sciatic nerve exits
female pelvis
- lighter
- thinner
- tilted more forward
- broader pubic arch 90 degrees or bigger(subpubic angle)
- wider pelvic inlet
- larger sciatic notch (short but wide)
- obturator foramen is smaller and more triangular
male pelvis
- heavier
- thicker
- tilted less forward
- less broad pubic arch 90 degrees or smaller
- narrower pelvic inlet
- smaller pelvic arch (tall and thin)
- obturator foramen bigger and less triangular
lower limb
-carries entire weight of body
-subjected to exceptional forces
3 segments
-thigh
-leg
-foot
femur
- largest and strongest bone of body (many blood vessels)
- 1/4 of a persons height
- articulates proximally with acetabulum of hip
- articulates distally with tibia and patella
- fracture close to head will occur on neck
- greater trochanter important for walking muscle
- patellar surface is where the patella articulates
patella
- sesamoid bone in quadriceps tendon
- secures anterior thigh muscles to tibia
tibia
- medial leg bone, larger
- receives weight of body from femur
- articulates with femur
fibula
- not weight bearing
- does not articulate with femur
- articulates proximally and distally with tibia
foot
-support body wight
-acts as lever to propel body forward during motion
-tarsals (7)
-metatarsals (5)
-phalanges (14)
talus is where tibia meets ankle
mandible
- largest, strongest bone of face
- only freely movable joint in skull (temporomandibular joint)
- mental foramen allows passage of nerves and blood vessels
maxilla
- fused to form upper jaw and central portion of facial skeleton
- keystone bone of face
lacrimal bones
- in medial walls of orbits
- lacrimal fossa houses lacrimal sac
zygomatic bones
inferolateral margins of orbits
palatine bones
- L-shaped with horizontal and vertical plates
- posterior one-third of hard palate
vomer
- plow-shaped
- inferior bony part of nasal septum
fontanelle
- soft spots
- Brian grows faster than cranium
- tough connective tissue
- start to close at 1 month and closed by 19-24 months
orbit (7)
-cavities that encase eyes and lacrimal glands
-sites of attachment for eye muscles
-formed by:
maxilla
sphenoid
ethmoid
lacrimal
frontal
zygomatic
palatine
nasal cavity
formed by:
- ethmoid
- palatine
- maxillary
- inferior nasal conchae
nasal septum
- divides right and left nasal cavities
- composed of bone (vomer and ethmoid) and cartilage (septal cartilage)
tarsals
- 7 tarsals
- talus is only one articulating with tibia and fibula
- body weight carried primarily by talus and calcaneus
3 arches of foot
- lateral longitudinal
- medial longitudinal
- transverse
