CH 7 Flashcards
How many bones in avg. adult skeleton?
206
Bones can be..
paired or unpaired
paired bones
2 bones of the same type located on the right and left sides of the body
how many paired bones?
86
unpaired bones
bone located on the midline of the body
how many unpaired bones
34
the skeleton is divided into what two sub-skeletons?
axial, appendicular
The axial skeleton consists of the following bones:
skull mandible sternum ribs vertebral column sacrum
The appendicular skeleton consists of the following bones:
clavicle scapula humerus ulna radius all hand bones coxal bone femur patella tib/fib all foot bones
tubercules and processes
structures exit because a ligament or tendon was attached to that surface during life
foramen
a hole that was occupied by a nerve or blood vessel during life
The axial skeleton forms the …
the upright axis of the body
the axial skeleton includes:
skull auditory ossicles hyoid bone vertebral column sternum thoracic cage
what does the axial skeleton protect?
the brain, spinal cord, vital organs housed within the thorax and the deeper internal structures/organs
the axial skeleton is separated into the…
braincase and the facial bones; composed of 22 bones
braincase
- protects the brain
- paired parietal and temporal bones, unpaired frontal occipital, sphenoid and ethmoid bones
facial bones
- protects the sensory organs of the head
- provide attachment points for muscles involves in mastication facial expression and eye movement
Facial bones (14)
maxilla (2) zygomatic (2) palatine (2) lacrimal (2) nasal (2) inferior nasal concha (2) mandible (1) vomer (1)
what two bones make up the nasal septum?
- the perpendicular plate of ethmoid bone
- vomer
- septal cartilage
what kind of cartilage is septum cartilage?
hyaline cartilage
Nasal Cavity bones:
frontal bone vomer ethmoid inferior nasal concha sphenoid bone nasal bone palatine bone lacrimal bone maxilla
Paranasal sinuses
frontal sinus
sphenoid sinus
ethmoidal sinus
maxillary sinus
cranial cavity
frontal bone sphenoid bone ethmoid bone temporal bone parietal bone occipital bone
Axial Skeleton: Hyoid Bone
- unpaired bone that “floats” in the neck
- has no direct bony attachment to the rest of the skeleton
- point of attachment for some tongue and neck muscles
The vertebral column forms the…
central axis of the skeleton (extends from the base of skull to pelvis)
functions of the vertebral column
- ) supports weight of head/neck
- ) protects spinal cord
- ) allow spinal nerves to exit the spinal cord
- ) provides a site for muscle attachment
- ) permits movement of the head and trunk
how many individual bones and regions does the vertebral column have?
26 individual bones and 5 regions
Vertebral column consists of:
7 Cervical Vert. 12 Thoracic Vert. 5 Lumbar Vert. 1 sacral bone 1 coccygeal bone
how many vertebrae does a developing embryo have?
33 or 34, but the 5 sacral fuse to form 1 bone and the 4/5 coccygeal fuse to form one bone
What’re the 4 major curvatures of the vertebral column?
Cervical (convex anteriorly)
Thoracic (concave anteriorly)
Lumbar (convex anteriorly)
Sacral/Coccygeal (concave anteriorly)
What’re the abnormal curvatures of the vertebral column?
Lordosis (lumbar)
Kyphosis (thoracic)
Scoliosis (Lateral)
what part of the vertebrae comes into contact with other vertebrae?
the facets
what makes up the vertebral arch?
lamina and pedicle
Intervertebral Disks
pads of fibrocartilage located between the bodies of adjacent vertebrae
Function of intervertebral disks:
- allow the vert. column to bend
- absorb shock between the vert. bodies
intervertebral disks consist of:
annulus fibrosus (external, fibrous ring) nucleus pulposus (internal, gelatinous)
With age, intervertebral disks…
- become more comprssed
- distance between vertebrae and overall height decrease
- annulus fibrosus becomes weaker and more susceptible to herniation
Herniated or Ruptured Disks
- breakage of ballooning of the annulus fibrosus with a partial or complete release of the nucleus pulposus
- may push against spinal nerves, impairing function and causing pain
what causes pain in a bulging disc?
when it pushes on the spinal nerve and causes a pain response, it is NOT because the bony structures are rubbing each other
Atlas
- 1st C Vert.
- holds up the head
- NO body, IOT rotate off of dens on the axis
- articulates with the occipital condyles on the base of the skull; allows head to move in a YES motion or tilt from side to side
Axis
- 2nd C Vert.
- has dens, which the atlas rotates on to make the NO motion of the head
Most C. vertebrae have spinous processes except…
atlas and C7; they have a bifid (2 parts)
which vertebrae has the most prominent spinous process?
C7, vertebrae prominens
Thoracic vertebrae
- sites of attachment for the ribs
- the first 10 T. vertebrae have rib facets on their transverse processes where they articulate with the tubercles of the ribs
- have long, thin spinous processes that are directed inferiorly
facet
smooth spots where bones touch each other
Lumbar Vertebrae
- large, thick bodies
- heavy, rectangular transverse and spinous processes
- superior articular facets face medially and the inferior articular facets face laterally
what causes lumbar vertebrae to lock together?
the articular facet orientation ; gives more stability and less rotation than other parts
4 parts of cervical vertebrae:
- small body (except in C1 where there is no body)
- transverse foramen
- spinous process (except in C1 and bifid in others)
- articular facets face superior/inferior
4 parts of thoracic vertebrae
- medium-sized body with articular facets for ribs
- articular facets for ribs, except T11 and T12
- spinous process is long, angled inferiorly
- articular facets face obliquely
4 parts of lumbar vertebrae
- large body
- square transverse process
- square spinous process
- articular facets face medial/lateral
Sacrum
4-5 vertebrae fused into a single bone
when is the interior of the sacrum ossified?
midlife
what fuses to form the lateral parts of the sacrum?
transverse process
Auricular Surfaces
lateral, ear-shaped surfaces that join the sacrum to the pelvic bones
median sacral crest
spinous process of the first 4 sacral vertebrae fuse
sacral hiatus
spinous process of the 5th sacral vertebrae does not fuse (used to give injections)
sacral promontory
landmark that separates the abdominal cavity from the pelvic cavity
coccyx (tailbone)
consists of 4 vertebrae that’re extremely reduced (no foramina or processes)
The thoracic cage protects the…
vital organs within the thorax and forms a semi-rigid chamber that changes volume during breathing
Ribs
- 12 pairs (numbered 1-12 starting superiorly)
- all ribs articulate posteriorly with the thoracic vertebrae
true ribs
- ribs #1-7
- attach directly through their costal cartilage to the sternum
- superior 7 pairs of ribs
False ribs
- ribs #8-12
- don’t attach to the sternum
- inferior 5 pairs of ribs
- 3 superior are joined by a common cartilage to the costal cartilage of the seventh true rib (attaches to the sternum)
- 2 inferior floating ribs (11 and 12) do not attach to the sternum in anyway
3 parts of the sternum:
- ) manubrium
- ) body
- ) xiphoid process