Download Skeletal Development

Appendicular Skeleton
and
Bone Development
September 13th and 18th, 2007
The Appendicular Skeleton
Shoulder Girdle
• clavicle
• scapula
Arm
• Humerus
• radius, ulna
• carpals
• metacarpals
• phalanges
Pelvic Girdle
• ilium, ischium, pubis
Leg
• femur, patella
• tibia, fibula
• tarsals
• metatarsals
• phalanges
Articulation
A joint - the junction
of two or more
bones.
CLAVICLE
HUMERUS
SCAPULA
SCAPULA
Spine of Scapula
Superscapula notch
CLAVICLE
Acromial End
Sternal End
HUMERUS
Head
Lateral
Epicondyle
Medial
Epicondyle
Trochlea
HUMERUS
Lesser
Trochanter
Greater
Trochanter
Radius
Trochlear Notch
Ulna
HAND
Phalanges
Metacarpals
(1-5)
Carpals
Trapezoid
Hamate
Pisiform
Lunate
Trapezium
Scaphoid
Capitate
COXAL BONE
Iliac Crest
Obturator
foramen
Pubic Arch
Ilium
Pubis
Ischium
FEMUR
Greater
Trochanter
Head
Lesser
Trochanter
Neck
Lateral
Epicondyle
Medial
Epicondyle
Lateral
Condyle
Medial Condyle
Lateral
Condyle
Medial Condyle
Head
Fibula
Tibia
Metatarsals
Tarsals
Phalanges
Differences in Male and Female
• Bone usually heavier in male
• Bone markings usually more pronounced
in male
• Angle of pubic arch <90o in male
• Sciatic notch size of thumb in male
Joints
A joint is where two or more bones come
together.
Three types of joints:
1. Synarthroses – immovable joints
2. Amphiarthroses – semimovable joints
3. Diarthroses – freely movable joints
Synarthroses Joints
• Consist of two adjacent edges of bones
separated by a small amount of fibrous
tissue.
• Found in the skull. The joints are usually
sutures.
Amphiarthroses Joints
• Consists of two adjacent bones separated
by a substantial amount of cartilage.
• Found between the bodies of vertebrae
and the two pubic portions of the pelvic
bone.
Diarthroses Joints
•
•
Consist of two bones encased within a cavity
called the synovial cavity. Therefore called a
synovial joint.
Types:
1.
2.
3.
4.
5.
6.
Hinge joint
Pivot joint
Ball-and-socket
Condyloid joint
Saddle joint
Gliding joint
Types of Diarthroses Joints
• Hinge joint – movement occurs only in one
plane. (Elbow – b/w humerus and elbow)
• Pivot joint – permits rotation. The cylinder
surface of one joint rotates w/in a ring formed by
another bone. (1st two bones of vertebral
column)
• Ball-and-socket joint – where a ball-like head fits
into a cuplike cavity. Most freedom of movement.
(Shoulder and hip)
Types of Diarthroses Joints
• Condyloid joint – rotation not possible, but other
movements can occur. (radius and carpals of the
hand)
• Saddle Joint – rotation restricted. Have a
concave and convex surface that fits in with
each other. (metacarpals of the thumb)
• Gliding joint – permits a gliding movement.
(where vertebrae come together)
Bone Development
• The growth of the skeletal determines the size
and proportions of the body.
• Bone growth begins about 6 weeks after
fertilization when the embryo is about 12 mm
long. At this time rods of hyaline cartilage
develop with shapes of long bones.
• Growth continues until adolescence, some
portions do not stop growing until between 18
and 25.
Bone Development
• Bone formation is called ossification.
• Bones from by replacing existing connective tissues in
two ways:
1. Intramembranous ossification-bones originate b/w
sheetlike layers of connective tissue.
(Ex. large, flat bones of the skull)
2. Endochondral bones begin as masses of
cartilage that bone tissue later replaces.
(Ex. Most bones of the skeleton.)
Intramembranous Ossification
1. Osteoblasts migrate into the membranes and form
clusters called ossification centers.
2. Osteoblasts secrete the bony matrix composed of
collagen, calcium phosphate, and calcium carbonate.
3. The centers are soon surrounded by bone.
4. As the bony regions spread out, they merge to form a
trabeculae of spongy bone.
5. Red bone marrow develops in the spaces, and
osteoblasts at the periosteum deposit a layer of
compact bone on the surface.
Endochondral Ossification
1. Blood vessels grow into the center of the rod of the
hylaine cartilage.
2. Osteoblasts develop within the membrane surrounding
the cartilage rod.
3. The osteoblasts deposit compact bone around the
cartilage rod.
4. Formation continues at the outer surface of the rod but
not in the interior areas.
5. The interior areas remain as the large cavity to will
contain the marrow of the bone.
Endochondral Ossification
1. The collar of the compact bone is thickening and
lengthening.
2. The cartilage rod is continuing to grow at the ends.
3. A zone of cartilage remains beyond the ossifcation
centers. This is where the bone will continue to
lengthen.
4. After puberty, the zone of cartilage narrows to form the
epiphyseal plate, and when this plate turns entirely to
bone, lengthening ceases.
5. This is all under the control of hormones.
Skeletal Development of a Fetus
Multiple Cellular Origins
1 - Paraxial Mesoderm
•Somite, Sclerotome
•Axial Skeleton (e.g. vertebra)
2 - Lateral Plate Mesoderm
•Appendicular Skeleton – (e.g. limb)
3 - Neural Crest
•Head Skeleton
•Established as
􀂾1 - Hyaline Cartilage – replaced by
Endochondral Ossification
􀂾2 – Intramembranous Bone Formation direct ossification
Cartilage template of the limb in the Chick wing
Endochondral Bone
• Primary ossification center - initiation of ossification
• Perichondrial cells differentiate into Osteoblasts –
deposit matrix as a collar in center of long bone –
diaphysis
Bone Growth
Bone lengthening occurs at
diaphyseal-epiphyseal
junction - epiphyseal
cartilage plate (growth plate)
Epiphysis - chondrogenic
Secondary ossification centers
in the epiphysis after birth
After growth termination the
epiphyseal cartilage plate is
replaced with spongy bone
Skeletal Review
1. The skull bones, ribs, and bones of the pelvis
are types of bones classified as ___.
2. These bones that bear the weight of the body
are classified as ___.
3. All the bones of the skull, vertebral column,
and the rib cage are considered together as
the ___ skeleton.
4. Carpals are to wrist, as ___ is to ankle.
5. Bones support, protect, store minerals and
form ___.
Skeletal Review
6. The interior portion of the epiphysis of the bone
consists of ___.
7. The marrow cavity of long bones is filled with
____ bone marrow.
8. Spongy bone contains networks of bony plates
and rods known as ___.
9. The histological and physiological unit of
compact bone is the __.
10. The microscopic spaces that contain
osteocytes of bone are the __.
Skeletal Review
11. Bone formation take place by a process called
___.
12. Bone formation occurring within membranes is
known as ___.
13. Bone formation taking place near the ends of
bones is ___.
14. Before puberty, the long bone lengthens as a
zone of cartilage beyond the ossification center
called ___.
15. Semimoveable joints are called ___.
Skeletal Review
16. An immovable joint consisting of two adjacent
edges of bone are separated by ___.
17. An example of a synarthrosis occuring in the
skull is ___.
18. Where bones have a concave and convex
surface that articulates is a __ joint.
19. A diarthrotic joint that permits rotation is __.
20. Where the radius meets up with the carpals is
a __ joint.