Ch. 7 - Axial Skeleton Flashcards
Axial skeleton and homeostasis
The bones of the axial skeleton contribute to homeostasis by protecting many of the body’s organs
- The cranium surrounds the brain
- The vertebrae surround the spinal cord
- The ribs surround the heart and lungs
-Bones also support the storage and release of calcium, an important ion
how many bones in the human skeleton?
206
How many and what bones are in the axial skeleton?
80 bones;
skull bones, auditory ossicles, hyoid bone, ribs, sternum, vertebrae and sacrum
How many and what bones are in the appendicular skeleton?
126 bones;
bones of the upper and lower extremities and the bones forming the girdles that connect the limbs to the axial skeleton
Describe long bones.
greater in length than width.
describe short bones.
cube shaped.
describe flat bones
thin layers of parallel plates.
describe irregular bones.
complex shape like vertebra
describe sesamoid bones
shaped like a sesame seed.
Bone Surface Markings- Depression and openings
- Allow the passage of soft tissues
- Form joints
Bone Surface Markings- Processes
- Projections or outgrowths that form joints
- Serve as attachment points for ligaments and tendons
Bone Surface Markings- Depression and openings— fissure
Narrow slit between bones for passage of blood vessels or nerves
Bone Surface Markings- Depression and openings—foramen
Hole for passage of blood vessels, nerves or ligaments.
Bone Surface Markings- Depression and openings—fossa
Shallow depression
Bone Surface Markings- Depression and openings—meatus
tubelike opening
Bone Surface Markings- Depression and openings—sulcus
Furrow on a bone for passage of blood vessel, nerve or tendon (see humerus, Fig. 8.4a)
Bone Surface Markings- processes — condyle
Rounded projection with a smooth articular surface
Bone Surface Markings- processes — facet
Smooth, flat, slightly concave articular surface
Bone Surface Markings- processes — head
Usually rounded articular process supported on a neck
Bone Surface Markings- processes — crest
Prominent ridge or elongated process
Bone Surface Markings- processes — epicondyle
Usually roughened projection on a condyle
Bone Surface Markings- processes — line
Long, narrow ridge or border (less prominent than a crest
Bone Surface Markings- processes — spinous process
Sharp, slender projection; think about the spine vertebra
Bone Surface Markings- processes — tronchanter
Very large projection found ONLY on the femur
Bone Surface Markings- processes — tubercle
Variably sized rounded projection
Bone Surface Markings- processes — tuberosity
Variably sized projection with rough, bumpy surface
Sutural bones are…
small, extra bone plates located within the sutures of cranial bones;
a suture is an immoveable joint.
Found in the skull holding bones, such as the temporal and parietal, together
Coronal suture
the junction between the frontal and parietal bones
Squamous suture
the junction between the parietal and temporal bones
Lambdoidal suture
the junction between the parietal and occipital bones
Sagittal suture
the junction between the two parietal bones
Fontanels
areas of a fetus/baby where unossified mesenchyme develop into dense connective tissue
They close up through intramembranous ossification by 2 years of age
The skull has how many bones?
The skull contains 22 bones, not including the 3 middle ear bones in both ears
Skull- frontal bone
The frontal bone is a bone of the skull found in the forehead region.
It is one of eight bones that form the cranium, or brain case.
The frontal bone plays a vital role in supporting and protecting the delicate nervous tissue of the brain.
It gives shape to the skull and supports several muscles of the head.
Skull- Parietal and Temporal
One parietal bone is located on each side of the skull just behind the frontal bone. It is shaped like a curved plate and has four borders. Together, the parietal bones form the bulging sides and roof of the cranium. They are fused in the middle along the sagittal suture, and they meet the frontal bone along the coronal suture.
Skull - occipital bone
The occipital bone joins the parietal bones along the lambdoidal suture.
It forms the back of the skull and the base of the cranium.
There is a large opening on its lower surface called the foramen magnum, through which nerve fibers from the brain pass and enter the vertebral canal to become part of the spinal cord.
Skull - sphenoid bone
include:
-lesser wing
- sella turcica:
+tuberculum sellae
+hypophyseal fossa
+dorsum sellae
Skull - ethmoid bone
nose bone
facial bones
Vomer, maxillae, and zygomatic bones
facial bones - mandible
The mandible (lower jawbone) is the largest and strongest facial bone. Other than the middle ear bones (auditory ossicles), it is the only moveable skull bone.
What are unique features of the skull?
Paranasal sinuses - mucous membrane-lined cavities in the frontal, maxillary, sphenoid and ethmoid bones
- -Used as resonating chambers to enhance the voice
- -Increase the surface area of the nasal mucosa and help to moisten it as well
Sinusitis
As the sinuses directly continue from the nasal cavity, infections of the upper respiratory tract, such as the flu, or rhinitis, can easily spread into the sinus cavities, leading to a condition called sinusitis [2].
Characteristic symptoms include a sinus headache, facial pain or tenderness, and feeling of astuffy nose [16].
Most commonly affecting the maxillary sinuses [17], inflammation or infection in this area may cause pain in the maxillary teeth as both are innervated by the maxillary nerve [9].
Any blockage in a sinus passage may cause mucus to accumulate, also leading to bacterial or viral infections [18].
Hyoid bone (adam’s apple)
Does not articulate with any other bone
Supports the tongue and provides an attachment site for some muscles of the neck and pharynx
Vertebral Column- how many vertebrae?
Also known as the spinal column, backbone or spine
Composed of 26 vertebrae
Vertebral Column- divided into how many regions?
divided into 5 regions
Vertebral Column- function?
Protects the spinal cord
Curves of the Vertebral column:
- Cervical curve - 7
- Thoracic curve - 12
- lumbar curve - 5
- sacral curve - 5 fused sacral vertebrae
Where are intervertebral disc located?
Located between the bodies of the vertebrae from the second cervical to the sacrum
what are intervertebral discs composed of?
Composed of an outer ring of fibrocartilage (annulus fibrosus) and an inner, soft nucleus (nucleus pulposus) with a layer of hyaline cartilage on the top and bottom of each disc
what are intervertebral discs’ function?
Absorb shock and separate the vertebrae from one another
Function of the thoracic vertebrae? structure?
Support the ribs and have special structures for rib head and tubercle attachment.
LOOKS LIKE A GIRAFFE
Function of the lumbar vertebrae? Structure?
The largest and strongest vertebrae
No special structures that are specifically associated with these vertebrae.
LOOKS LIKE A MOOSE.
Function of the cervical vertebra?
support the skull.
LOOKS SMALL AND BUG LIKE
Structure of the sacrum.
The triangular-shaped sacrum is part of the pelvic girdle and is composed of 5 vertebrae that fuse
structure of the coccyx.
The coccyx is much smaller than the sacrum but is also triangular in shape and is composed of 4 vertebrae that fuse.
What is the thorax and what is it composed of?
The thorax is the entire chest region.
The bones that compose the thoracic cage are the sternum, ribs and costal cartilages
What is the sternum composed of?
part of the thorax.
Composed of 3 segments:
- The upper manubrium
- The middle body
- The lower xiphoid process
What bone does the sternum articulate with?
The sternum articulates with the clavicles and the costal cartilages.
Thorax: RIBS - how many are there?
12 pairs
Thorax: RIBS - function?
Provide structural support to the thoracic cavity
Thorax: RIBS - true (vertebrosternal) ribs?
True (vertebrosternal) ribs – first 7 pairs; their cartilage is directly connected to the sternum
Thorax: RIBS - false (vertebrochondral) ribs?
False (vertebrochondral) ribs – next 5 pairs; cartilage is indirectly connected to the sternum
Thorax: RIBS - floating (vertebral) ribs?
Floating (vertebral) ribs – last 2 pairs; these are not connected to the sternum
Disorders: what is a herniated disc?
In the vertebral column, a herniated disc may occur due to trauma or sometimes is simply associated with aging
Disorders: scoliosis?
(increased lateral curvature)
Disorders: kyphosis?
(increased thoracic curve-bent forward)
Disorders: Lordosis?
(increased lumbar curve-bent backwards)
Disorders: spina bifida?
Spina bifida is a congenital defect of the vertebral column where the laminae do not develop normally
The degrees of this deformity vary from minor (spina bifida occulta) to severe (spina bifida with meningomyelocele)
