Chapter 8 - Skeleton Flashcards
Describe the axial skeleton
80 named bones
Skull, vertebrae, sternum, ribs, sacrum, and hyoid
Describe the appendicular skeleton
126 named bones
Pectoral and Pelvic girdles
Upper and Lower extremities (limbs)
How many bones do we have at birth? In adulthood?
270 bones at birth, but number decreases with fusion
206 in a typical adult
Describe the 8 cranial bones
Protect brain & house ear ossicles
Attachment for jaw, neck & facial muscles
Very thin and remarkably strong for their weight
Two parietal, two temporal, frontal, occipital, sphenoid, and ethmoid
Name the four sutures that mark the articulations of the parietal bones. What does the parietal bone articulate with at each suture?
Coronal suture - frontal
Sagittal suture - parietal
Lambdoid suture - occipital
Squamosal or squamous suture - temporal
The ________ passes through the foramen magnum
spinal cord
What articulates with the occipital condyles? What movement does this allow for?
The atlas articulates with condyles, which allows us to nod our heads ‘yes’
Describe the 14 facial bones and what they do
Facial bones (14)—do not enclose brain
Protect delicate sense organs – smell, taste, vision
Support entrances to digestive and respiratory systems
Mandible, vomer, two maxillae, two zygomatics, two nasals, two lacrimals, two palatines, and two inferior nasal conchae
List the bones of the left orbit
Sphenoid, zygomatic, maxillae, frontal ethmoid, lacrimal, palatine
Describe the two bones of the nasal cavity
Vomer and palatine
What disorder causes a cleavage of the skin of the upper lip and the upper palate?
Cleft lip and palate
Describe the paranasal sinuses and what they do
- Paired cavities in frontal, sphenoid, ethmoid, maxillary
- Lined by mucous membranes and are air-filled & open into nasal cavity
- Resonating chambers for voice; lightens the skull
Describe the fontanels of the skull at birth and their two purposes
-They are dense connective tissue membrane-filled spaces (soft spots).
-Unossified at birth but close early in a child’s life.
2 purposes:
1) Allows fetal skull passes through the birth canal.
2) Allows rapid growth of the brain during infancy
-Skull reaches adult size by 8-9 years old
Describe the hyoid bone
- Articulates with no other bone of the body
- Suspended by ligament and muscle from the skull
- Supports the tongue & provides attachment for tongue, neck and pharyngeal muscles
- Often found broken in cases of strangulation
Name the 4 primary functions of the spine
- Supports skull and trunk and allows for their movement
- Protects spinal cord
- Absorbs stresses of movements
- Provides attachments for limbs, thoracic cage, and muscles
Variations in number of vertebrae occur in 1 in __ people
20
The backbone or spine is built of ___ vertebrae
26
We have ___ vertebral regions in the spine
5
We have: \_\_ cervical vertebrae \_\_ thoracic vertebrae \_\_ lumbar vertebrae sacrum (\_\_, fused) coccyx (\_\_, fused)
7 cervical vertebrae 12 thoracic vertebrae 5 lumbar vertebrae sacrum (5, fused) coccyx (3-5, fused)
Describe the atlas (C1) of the cervical vertebrae and name its joint
-Ring of bone
-Superior facets made for occipital condyles
>atlanto-occipital joint is a condylar joint
-Produces “yes” motion: flexion & extension
Describe the axis (C2) of the cervical vertebrae and name its joint
- Body consists of dens or odontoid process
- Atlanto-axial joint is a pivot joint
- Allows for rotation (shaking your head no)
Describe the intervertebral discs
- Between vertebrae; absorbs vertical shock
- Permits movements of the vertebral column
- Made of fibrocartilage with a pulpy center
Describe herniated discs
- A herniated disc (“ruptured” or “slipped” disc) puts painful pressure on spinal nerve or spinal cord
- Most commonly seen in lumbar region
Describe the primary curvatures of the spine
The thoracic and sacral curves; form during fetal development. This is what gives babies’ spines a C-shape (convex)
Describe the secondary curvatures of the spine and when they form
- The cervical and lumbar curves
- Cervical curve forms when infant raises head at 4 months
- Lumbar curve forms when an infant sits up & begins to walk
Describe how the overall shape of the spine changes from 0-3 years
- The spine exhibits one continuous C-shaped curve at birth (convex);
- The vertebral column is S-shaped beyond the age of 3 years
Describe kyphosis, lordosis, and scoliosis and which curvatures they’re associated with
- Kyphosis (hunchback)—exaggerated thoracic curvature
- Lordosis (swayback)—exaggerated lumbar curvature
- Scoliosis—lateral bending of the column
What are the three main abnormal curves spines can have?
Kyphosis, lordosis, and scoliosis
What are the causes of abnormal spinal curvatures?
Abnormalities result from disease, paralysis of trunk muscles, poor posture, pregnancy, or congenital defects
Lordosis is usually caused by what?
Obesity or pregnancy
Scoliosis is most common among what demographic?
Adolescent girls
What are the typical causes of kyphosis?
Osteoporosis, osteomalacia, spinal tuberculosis, or wrestling/ weight lifting in young boys.
What is the most common abnormal spinal curvature?
Scoliosis
What makes up the sternum (breastbone)?
- Manubrium
- Body
- Xiphoid process
Which ribs are true ribs? Which are false ribs? Which are floating ribs?
1-7 are true ribs
8-12 are false ribs
11-12 (floating)
There are __ bones per side for both the upper & lower limbs
30
What are the four primary sections of the appendicular skeleton?
- Pectoral girdles
- Pelvic girdle
- Upper limbs
- Lower limbs
What joints are found in the pectoral (shoulder) girdle?
- Sternoclavicular joint
- Acromioclavicular joint
- Glenohumeral joint
Describe the composition of the bony pelvis and pelvic girdle
Bony pelvis = 2 coxal bones, sacrum, and coccyx
Pelvic girdle = Two coxal bones united at the pubic symphysis
Describe the sex differences of the pelvic girdle
Male: heavier and thicker
Female: wider and shallower, and adapted to the needs of pregnancy and childbirth, larger pelvic inlet (brim) and outlet for passage of infant’s head
