2401 A&P-I
Minimum Departmental Requirements for Lab
2401 Anatomy & Physiology I
Exercise 13
Organization of the Skeleton
What you need to be able to do:
1. Classify bones as to belonging to the axial or appendicular skeleton, according to their shape (e.g. long or
irregular) or body parts (e.g. bones of skull or pelvic girdle).
2. Identify the areas of the body where cartilage is found and indicate the type of cartilage.
3. Identify micro-anatomical features of bone and connective tissue associated with bone (see below) on a model
or histology slide.
Cartilage
In embryos most of skeleton is comprised of hyaline cartilage which ossifies (becomes bone) in adults.
In adults most cartilage is hyaline cartilage and is replaced by bone. Cartilage in adults is only found in isolated
areas such as
 External ear (elastic cartilage)
 Distal end and lateral region of nose (hyaline cartilage)
 Larynx (hyaline cartilage except epiglottis which is elastic cartilage)
 Trachea (hyaline cartilage)
 Parts of rib cage (hyaline cartilage)
 Joints
o The skeleton is make up of joints/articulations with cartilage between bones forming joints
o Vertebral discs and pubic symphysis are fibrocartilage
o Most other joints are composed of articular cartilage, which is similar to hyaline cartilage but lacks
a connective tissue covering called a perichondrium
Skeleton:
 Axial: bones near the body’s center of gravity
 Appendicular: bones of limbs/appendages
Classification of Bones based on type of osseous tissue:
1. Compact bone: smooth and homogenous
2. Spongy/Cancellous bone: made of trabeculae and has a lot of open space
Classification of bones based on their relative gross anatomy:
1. Long bone:
a. Longer than they are wide
b. Predominantly compact bone
c. Examples: femur, phalanges
2. Short bone:
a. Cube shaped
b. Contain more spongy, and less compact bone
c. Examples: tarsals, carpals
3. Flat bone:
a. Generally thin
b. 2 wafer-like layers compact bone sandwiches a thin layer of spongy bone
c. Examples: Bones of the skull cap, sternum, scapula
4. Irregular bone:
a. Bones that do not fall into any of the above categories of gross anatomy
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b. Example: vertebrae, sacrum, ethmoid, sphenoid
5. Sesamoid bone:
a. Special category of short bones formed within tendons
b. Example: patella
c. Except for patella, other sesamoid bones are not counted in the bone count of 206 bones.
6. Wormian/sutural bone:
a. Tiny bones between cranial bones
b. Not counted in the bone count of 206 bones.
Bone Markings:
1. Projections that are sites of muscle and ligament attachment
a. Tuberosity
g. Spine
b. Crest
h. Process
c. Trochanter
i. Head
d. Line
j. Facet
e. Tubercle
k. Condyle
f. Epicondyle
l. Ramus
2. Projections that help form joints
a. Head
d. Ramus
b. Facet
e. Trochlea
c. Condyle
3. Cavities
a. Sinus
4. Depressions and openings that allow blood vessels and nerves to pass
a. Meatus
d. Fissure
b. Fossa
e. Foramen
c. Groove
Gross anatomy of the typical long bone:
a. Diaphysis (shaft)
b. Periosteum (fibrous membrane)
c. Perforating (Sharpey’s) fibers
d. Epiphysis (end of long bone)
e. Articular cartilage
f. Epiphyseal line
g.
h.
i.
j.
k.
Medullary cavity (shaft)
Yellow marrow and its location
Red marrow and its location
Trabeculae of spongy bone
Nutrient artery
Microscopic structure of compact bone:
a. Central (Haversian) canal
b. Lacunae
c. Osteocytes
d. Circumferential lamellae
e. Concentric lamellae
f.
g.
h.
i.
Interstitial lamellae
Osteon (Haversian system)
Canaliculi
Perforating (Volkmann) canals
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