Anatomy Notes
BONES
. Hardest structure
. Pinkish white externally and deep red inside
CLASSIFICATION ACCORDING TO SHAPE:
: LONG BONES...
The articular surface of ends of bones covered by hyaline cartilage
Longer than they are wide
2 articular (joints) surfaces called epiphysis
Examples: upper limb( humerus,radius,ulna,metacarpals and phalanges) , lower
limb(femur,tibia,fibula,metacarpals and phalanges).
: SHORT BONES...
Roughly cube shaped bones
Having thin layers of compact bones surrounding a spongy interior
Examples: bones of wrist and ankles (trapezoid, scaphoid etc.)
: FLAT BONES...
Thin and generally curved. Resemble shallow plates and form boundaries of
certain body cavity.
2 parallel layers of compact bones sandwiching and layer spongy bone.
,Examples: mostly skull bones, sternum and scapula.
: IRREGULAR BONES...
Thin layer of compact bones surrounding a spongy interior. Irregular and
complicated.
Examples: bones of spines, base of skull and hips.
: Sesamoid...
Embedded in tendons / joint capsule. Have no any periosteum, ossify after birth.
There function is to resist pressure, minimize friction. Alter direction of pull of
muscle and maintain local circulation.
Examples: patella and pisiform
: Pneumatic bones.
Certain irregular bones contain large air spaces lined by epithelium. Make skull
light in weight, help in resonance of voice, acts as air conditioning chambers for
inspired air.
Examples: maxilla, sphenoid, ethmoid.
CLASSIFICATION ACCORDING TO STRUCTURE:
Bone is not a smooth or uniform structure but it has some spaces between hard
elements.
COMPACT BONE
. Also called cortical bone. Outer hard layer is compact bone tissue. Less gaps and
spaces. Due to this tissue bones is smooth, white and solid. 80% of total bone
mass of an adult skeleton.
TRABECULAR BONE:
Filling the interior of the organ is the trabecular bone tissue (an open cell porous
network also called cancellous or spongy bone).
, Have network of rod or plate like elements that make the overall organ lighter
and allowing room for blood vessels and marrow. Remaining 20% of total bone
mass, but has nearly 10 times the surface area of compact bone.
Connective tissue: tissue having less
quantity of cells and high quantity of
extracellular material.
Bone is also a CT, has less bone cells
(2%) but high amount of bone matrix
(98%).
Organic inorganic
(1\3) (2\3)
Collagen hydroxyapatite crystals
WOVEN AND LAMELLAR BONES:
Woven bones are weak, small and randomly oriented collagen fibers, forms
quickly high amount of osteocytes. These are temporary will replace later. Found
in fetus \ newborn, heling after fracture, sometimes in some bone disease.
Lamellar bones are stronger and have many collagen fibers parallel to other
fibers. They are permanent, having less osteocytes and are fully developed\
mature bone. These bones are found in adults. In each layer collagen fiber
arranged neatly and run in same direction, it makes a bone strong and able to
resist twisting (torsion) forces. It forms very slowly and replaces woven bone
during growth or after fracture healing. This replacement process occurs often
over calcified hyaline cartilage, it is known as bony substitution.
PERIOSTEUM:
BONES
. Hardest structure
. Pinkish white externally and deep red inside
CLASSIFICATION ACCORDING TO SHAPE:
: LONG BONES...
The articular surface of ends of bones covered by hyaline cartilage
Longer than they are wide
2 articular (joints) surfaces called epiphysis
Examples: upper limb( humerus,radius,ulna,metacarpals and phalanges) , lower
limb(femur,tibia,fibula,metacarpals and phalanges).
: SHORT BONES...
Roughly cube shaped bones
Having thin layers of compact bones surrounding a spongy interior
Examples: bones of wrist and ankles (trapezoid, scaphoid etc.)
: FLAT BONES...
Thin and generally curved. Resemble shallow plates and form boundaries of
certain body cavity.
2 parallel layers of compact bones sandwiching and layer spongy bone.
,Examples: mostly skull bones, sternum and scapula.
: IRREGULAR BONES...
Thin layer of compact bones surrounding a spongy interior. Irregular and
complicated.
Examples: bones of spines, base of skull and hips.
: Sesamoid...
Embedded in tendons / joint capsule. Have no any periosteum, ossify after birth.
There function is to resist pressure, minimize friction. Alter direction of pull of
muscle and maintain local circulation.
Examples: patella and pisiform
: Pneumatic bones.
Certain irregular bones contain large air spaces lined by epithelium. Make skull
light in weight, help in resonance of voice, acts as air conditioning chambers for
inspired air.
Examples: maxilla, sphenoid, ethmoid.
CLASSIFICATION ACCORDING TO STRUCTURE:
Bone is not a smooth or uniform structure but it has some spaces between hard
elements.
COMPACT BONE
. Also called cortical bone. Outer hard layer is compact bone tissue. Less gaps and
spaces. Due to this tissue bones is smooth, white and solid. 80% of total bone
mass of an adult skeleton.
TRABECULAR BONE:
Filling the interior of the organ is the trabecular bone tissue (an open cell porous
network also called cancellous or spongy bone).
, Have network of rod or plate like elements that make the overall organ lighter
and allowing room for blood vessels and marrow. Remaining 20% of total bone
mass, but has nearly 10 times the surface area of compact bone.
Connective tissue: tissue having less
quantity of cells and high quantity of
extracellular material.
Bone is also a CT, has less bone cells
(2%) but high amount of bone matrix
(98%).
Organic inorganic
(1\3) (2\3)
Collagen hydroxyapatite crystals
WOVEN AND LAMELLAR BONES:
Woven bones are weak, small and randomly oriented collagen fibers, forms
quickly high amount of osteocytes. These are temporary will replace later. Found
in fetus \ newborn, heling after fracture, sometimes in some bone disease.
Lamellar bones are stronger and have many collagen fibers parallel to other
fibers. They are permanent, having less osteocytes and are fully developed\
mature bone. These bones are found in adults. In each layer collagen fiber
arranged neatly and run in same direction, it makes a bone strong and able to
resist twisting (torsion) forces. It forms very slowly and replaces woven bone
during growth or after fracture healing. This replacement process occurs often
over calcified hyaline cartilage, it is known as bony substitution.
PERIOSTEUM:
