Week 2 // Chapter 7 // Axial Skeleton Flashcards
How do the bones of the axial skeleton contribute to homeostasis?
By protecting many of the body’s organs and
supporting the storage and release of calcium
How many bones are there in the human skeleton?
206
What are the two principal divisions of the human skeleton?
Axial skeleton (80 bones) and Appendicular skeleton (126 bones)
Which bones are a part of the axial skeleton? (overview)
Axial skeleton (80 bones) skull bones, auditory ossicles, hyoid bone, ribs, sternum, vertebrae and sacrum
Which bones are a part of the appendicular skeleton? (overview)
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
What are the 5 main types of bones?
(shapes)
Long (greater length than width)
Short (cube shaped)
Flat (thin layers of parallel plates)
Irregular (complex shapes)
Sesamoid (shaped like a sesame seed)
What are sutures?
Sutures are the jointed areas where flat bones come together (skull)
It is an immoveable joint
- Found in the skull holding bones, such as the temporal and parietal, together
- Coronal, sagittal, lambdoid, squamous
What are sutural bones?
Sutural bones are small, extra bone plates located within the sutures of cranial bones
Where are the following bones/ structures located?
Parietal Bone
Zygomatic
Temporal Bone
Frontal Bone
Occipital Bone
Mastoid Process
Bone depressions and openings
These bone surface markings
> allow the passage of soft tissues (nerves, blood vessels, ligaments, tendons)
> form joints
Bone processes
> Projections or outgrowths that form joints
> Serve as attachment points for ligaments and tendons
Fissure
( a type of depression / opening)
Narrow slit between adjacent parts of bones through which blood vessels or nerves pass.
Fossa
(depression / opening)
Shallow despression
Sulcus
(depression / opening)
Furrow along bone surface that accommodates blood vessel, nerve, or tendon.
See sulcus of humerus.
Meatus
(depression / opening)
Tubelike opening (ex. “External acoustic meatus” which is the ear hole in the skull on the temporal bone)
Condyle
(processes)
Large, round protuberance with a smooth articular surface at end of bone.
(the round prominence at the end of a bone)
Facet
(processes)
Smooth, flat, slightly concave or convex articular surface.
Head
(processes)
Usually rounded articular projection supported on neck (constricted portion) of bone.
Crest
(processes that attach to connective tissue)
Prominent ridge or elongated projection.
Epicondyle
Usually roughened projection on a condyle
Line
Long, narrow ridge or border (less prominent than a crest)
Spinous process
Sharp, slender projection off the posterior (back) of each vertebra
Trochanter
Very large projection found only on the femur
Tubercle
Variably sized rounded projection (a small rounded point of a bone)
Tuberosity
Variably sized projection with rough, bumpy surface
(A moderate prominence where muscles and connective tissues attach)
How many bones does the skull contain?
22 (not including the 3 middle ear bones in both ears)
Frontal Bone
Parietal Bone
Temporal Bone
Sphenoid Bone
Occipital Bone
Zygomatic Bone
Occipital Bone
Ethmoid Bone
Clinical Connection:
What is Temporomandibular Joint (TMJ) Dysfunction?
- Dull pain around ear, tender jaw muscles, clicking noise when opening/closing mouth
- Caused by by improperly aligned teeth, grinding of teeth, trauma to the head, arthritis, etc
- Treatment includes moist heat or ice, soft foods and pain relievers
Clinical Connection
Deviated Nasal Septum
- Occurs when septum does not run along the midline of nasal cavity
- Caused by trauma to the nose or developmental abnormality
- May lead to infection, inflammation, congestion, headaches and nosebleeds
- May require surgery to fix
Vomer
the small, thin bone separating the left and right nasal cavities
Maxilla
The maxilla (plural: maxillae) is the upper fixed part of the jaw. In humans, the upper jaw includes the hard palate in the front of the mouth.
Mandible
The mandible is the lower jawbone (jaw) and is the largest and strongest facial bone. Other than the middle ear bones (auditory ossicles), it is the only moveable skull bone.
Orbit
The bones around the eye. that form the eye socket
Nasal Septum
Bone and hyaline cartilage that divides the two nostrils
Fontanels
Areas of a fetus/baby’s skull where “unossified mesenchyme develops into dense connective tissue. “
(These are the baby’s soft spots where bone formation isn’t complete. They close by 2 years of age.)
Hyoid bone
The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. (Front of neck )
- Does not articulate with any other bone
- Supports the tongue and provides an attachment site for some muscles of the neck and pharynx
Vetebral column (How mnay vertebrae? What does it protect?)
(Also known as the spinal column, backbone or spine)
- Composed of 26 vertebrae divided into 5 regions
- Protects the spinal cord
How many regions does the vetebral column have?
5
What are the regions of the vetebral column?
Cervical, Thoracic, Lumbar, Sacrum, Coccyx
Intervertebral Discs
(Where, what are they composed of, what do they do?)
Discs between bodies of the vertebrae from the second cervical to the sacrum.
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
They absorb shock and separate the vertebrae from one another
Transverse process and spinous process
Spinous process is a bony projection off the posterior (back) of each vertebra
Transverse process is a small bony projection off the right and left side of each vertebrae
How many cervical veterbae?
7
(C1- C7)
C1 and C2 are also called this
C1 The Atlas
C2 The Axis
What do the Thoracic vertabrae do?
Support the ribs and have special structures for rib head and tubercle attachment
How many Thoracic Vertabrae are there?
12
T1 - T12
?how many lumbar vetebrae are there?
5
(These are the largest and strongest vertebrae)
How many foramina do the Cervical, Thoracic and Lumbar vertabrae have?
Cervical = 3 holes / One main vertebral foramen (large hole in middle) and two tranverse formamina (small holes on the side)
Thoracic = 1 / One main vertebral formen
Lumbar = 1 / One main vertebral foramen
How many bones are in the Sacrum and Coccyx?
The triangular-shaped sacrum is part of the pelvic girdle and is composed of 5 vertebrae that fuse
The coccyx is much smaller than the sacrum but is also triangular in shape and is composed of 4 vertebrae that fuse
What bones compose the Thorax?
The thorax is the entire chest region
The bones that compose the thoracic cage are the sternum, ribs and costal cartilages
How many sections does the Sternum have?
The Sternum is composed of 3 segments:
- The upper manubrium
- The middle body
- The lower xiphoid process
(The sternum articulates with the clavicles and the costal cartilages)
How many pairs of ribs are there?
12
What do the ribs do?
The ribs provide structural support to the thoracic cavity
What is a true rib?
A true rib’s cartilage is directly connected to the sternum
Explain true, false and floating ribs
True ribs (vertebrosternal ribs/ pairs 1-7).
The costal cartilage from each of these ribs attaches directly to the sternum.
False ribs (vertebrochondral ribs / pairs 8-12).
The costal cartilages from these ribs do not attach directly to the sternum.
For ribs 8–10, the costal cartilages are attached to the cartilage of the next higher rib.
Floating ribs (The last two false ribs pair 11–12)
These do not attach to the sternum at all.
What is a false rib?
A false rib (vertebrochondral) rib’s cartilage is indirectly connected to the sternum (connected to another rib instead)
How many true, false and floating rib pairs do we have?
Most humans have 7, 5 and 2 pairs
Vetebral column curve-related patholgies include
- Scoliosis (increased lateral curvature) /side to side S
- Kyphosis (increased thoracic curve—bent forward)
- Lordosis (increased lumbar curve—bent backwards) / can happen in pregnancy
Fractures of the vertebral column most commonly occur at
Fractures of the vertebral column most commonly occur at C1, C2, C4-T, and T12-L2
Spinal cord or nerve damage may occur as a result of a fracture
