the skeletal system by: alaa alshaibani and alexis samuelson
TRANSCRIPT
The Skeletal System
By: Alaa Alshaibani and Alexis Samuelson
System Structures
and locationlink to video:
http://www.youtube.com/watch?
v=gp4SBFiP4-Y
The Skull
• Made up of the cranium and the facial bones
• It is located at the top of the body, the head of the body
• Made up of roughly 22 bones:
Cranial Bones:
• Frontal bones
• Parietal bones
• Occipital bone
• Temporal bone
• Sphenoid bone
• Ethmoid bone
Facial bones:
• Mandible
• Maxillae
• Palatine bones
• Zygomatic bones
• Lacrimal bones
• Nasal bones
• Vomer bone
• Inferior nasal conchae
Vertebral Column
• Begins at the base of the skull and ends at the pelvis.
• Composed of vertebrae that are separated by intervebral discs
• The column is divided into three parts
• The final five is what creates the lumbar vertebrae
• The sacrum forms the bottom of the lumbar vertebrae, the tip being the coccyx
Vertebral Column
Cervical Vertebrae
• The first seven vertebrae
• The first two are the atlas and axis and they help to rotate the head
• The vertebrae are special in that they have transverse foramina and their spinous processes are bifid.
Thoracic Vertebrae
• The next 12 bones of the vertebral column
• Long pointed spinous process, the bodies increase in size as you go down
• Connects to the ribs
Lumbar Vertebrae
• The final five vertebrae
• The sacrum forms the bottom of the lumbar vertebrae, the tip being the coccyx
Thoracic Cage
• Made up of: • The ribs • Thoracic
vertebrae • Sternum • Costal
cartilages
• 24 ribs total which attach to each of the thoracic vertebrae
• The sternum is made up of the manubrium, body, and xiphone together are the breast bone
Pectoral Girdle
• Located at the shoulder
• Made up of the clavicles (collarbones) and scapulae (shoulder blades)
Upper Limb
Upper Limb
• Bones form framework for arm, forearm, and hand
• Provide attachments for muscles, function in levers
• Bones include: humerus, radius, ulna, carpals, metacarpals, and phalanges
Upper Limb - Humerus
• Extends from the scapula to the elbow
• Greater and lesser tubercles provide attachments for muscles
• Deltoid tuberosity provides attachment for deltoid muscle that raises the upper limb horizontally to the side
• Coronoid fossa receives a process of the ulna when the elbow bends
• Olecranon fossa receives ulnar process when upper limb straightens at elbow
• The capitulum helps the humerus articulate with the radius
Upper Limb - Humerus
Upper Limb - Radius
• Located on thumb side of forearm; extends from elbow to wrist and crosses over ulna when palm faces backward
• Head at upper end of radius articulates with humerus and a notch of the ulna
• Allows radius to rotate freely
Upper Limb - Ulna
• Longer than radius; overlaps the end of the humerus posteriorly
• Trochlear notch articulates with the humerus
• Olecranon process and coronoid process provide attachments for muscles
• Head articulates laterally with a notch of the radius
Upper Limb – Radius and Ulna
Upper Limb - Hand
• Made up of the wrist, palm, and fingers
• Eight small carpal bones that are bound in two rows of four bones
• Five metacarpal bones form framework of the palm
• Each finger has three phalanges (proximal, middle, and distal phalanx), except for thumb
Upper Limb - Hand
Pelvic Girdle
• Consists of two coxae which articulate with each other anteriorly and with the sacrum posteriorly
• Sacrum, coccyx, and pelvic girdle form pelvis
• Girdle supports trunk of the body, provides attachments for lower limbs, protects the urinary bladder and reproductive organs
• Each coxa develops from an ilium, an ischium, and a pubis
Pelvic Girdle
Pelvic Girdle
Lower Limb
Lower Limb
• Bones form frameworks of the thigh, leg, and foot
• Includes femur, tibia, fibula, tarsals, metatarsals, and phalanges
Lower Limb - Femur
• Extends from hip to knee
• Large, rounded head projects medially into acetabulum of the coxa
• Patella (kneecap) articulates with femur
• Lateral and medial condyles articulate with tibia
Lower Limb - Femur
Lower Limb - Tibia
• Larger of the two leg bones, located on medial side
• Medial and lateral condyles articulate with condyles of the femur
• Tibial tuberosity provides an attachment for patellar ligament
• Inferior surface of tibia’s distal end articulates with the talus of the ankle
Lower Limb - Fibula
• Long, slender bone on lateral side of the tibia
• Head articulates with tibia just below the lateral condyle, but does not enter into the knee joint
Lower Limb – Tibia and Fibula
Lower Limb - Foot
• Made up of the ankle, the instep, and the toes
• Ankle is composed of seven tarsal bones (largest is calcaneus)
• Instep is made up of five elongated metatarsal bones that articulate with the tarsus
• Phalanges align and articulate with the metatarsals; each toe has three phalanges except for the great toe (no middle phalanx)
Lower Limb - Foot
Skeletal System
Information
Function of Skeleton
• The skeleton serves to: • Protect vital organs • Support the body• Create blood cells• Help to stabilize and shape the body
Bones, Tendons, Ligaments
• Bones: the organs of the skeletal system made up of cartilage, bone tissue, dense connective tissue, and nervous tissue
• Tendons: white fibrous connective tissue that attaches muscle to bone
• Ligaments: connective tissue that ties together two or more bones at a joint
Structures of a long bone
• Epiphysial plates, articular cartilage, compact bone, medullary cavity, yellow marrow, periosteum, proximal epiphyses, diaphysis, distal epiphysis, endosteum
Bone growth• Endochondral bones begin as a cartilaginous model.
As it grows the diaphysis in the middle, with the help of osteoblasts replace the cartilage with spongy bone—the primary ossification center, and form a thin layer of compact bone around it.
• Secondary ossification centers form in the epiphyses, an epiphyseal plate separates the two ossification centers, which expands, causing the bone to lengthen.
• The extracellular matrix calcifies, osteoclasts break it down, osteoblasts release new bone tissue to replace it.
• The bone continues to lengthen, only stopping once the diaphysis and epiphysis ossification centers meet.
Joints
Joints
• Bind parts of skeletal system, allow bones to grow, permit the skeleton to change shape during childbirth, and let the body respond to skeletal muscle contractions
• Can be immovable, slightly movable, or freely movable
• Vary in structure and function
Classification of Joints by Tissue
Classification - Fibrous
• Lie between bones that closely contact one another
• Formed by thin layer of dense connective tissue
• Doesn’t allow much movement
• Examples: • Sutures between pairs of flat bones of the
skull• Articulations of teeth in jaw bones
(gomphosis)
Classification - Cartilaginous
• Hyaline cartilage (fibrocartilage), makes for slight flexibility
• Helps to absorb shock and equalize pressure
• Examples:• Intervertebral discs are composed of a
band of fibrocartilage surrounding gelatinous core
• Symphysis pubis
Classification - Synovial
• Allow free movement, make up a majority of joints within skeletal system
• Articular ends of bones in synovial joints are covered with hyaline cartilage and a surrounding capsule of dense connective tissue
• This + an outer layer of ligaments + inner lining of synovial membrane = joint capsule
Classification - Synovial
• Menisci – flattened, shock-absorbing pads of fibrocartilage between articulating surfaces of bones
• Bursae – fluid-filled sacs lined with synovial membrane• Commonly located between tendons
and bony prominences (patella, elbow, etc.)
6 Types of Synovial
Joints
Ball-and-Socket Joint
• Consists of a bone with a ball-shaped head that articulates with the cup-shaped cavity of another bone
• Allows widest range of motion and movements in all planes, in addition to rotational movement
• Example:• Shoulder and hip joints
Condyloid Joint
• Oval-shaped condyle of one bone fits into elliptical cavity of another
• Permits a variety of movement in different planes, but not rotational movement
• Example:• Joints between metacarpals and
phalanges
Gliding Joints
• Articulating surfaces are nearly flat or slightly curved
• Allow sliding and twisting movements
• Examples:• Most joints within the wrist and ankles• Sacroiliac joints and joints formed
between ribs 2-7 that connect with the sternum
Hinge Joint
• Convex surface of one bone fits into concave surface of another
• Resembles the hinge of a door• Permits movement in one plane only
• Examples:• Elbow• Joints of phalanges
Pivot Joint
• Cylindrical surface of one bone rotates within a ring formed of bone and ligament
• Movement limited to rotation around central axis
• Example:• Joint between proximal ends of the
radius and the ulna
Saddle Joint
• Forms between bones whose articulating surfaces have both concave and convex regions
• Surface of one bone fits the complementary surface of the other
• Permits variety of movements
• Example:• Joint between carpal (trapezium) and
metacarpal bones of thumb
Types of Joint
Movement
Joint Movements
• One end of muscle is attached to a relatively immovable part on one side of joint, other end fastened to movable part
• When muscle contracts, the fibers pull the insertion (movable end) towards the origin (fixed end)
Joint Movements
• Flexion: Bending parts at a joint so the parts come closer together (angle between decreases)
• Extension: Straightening parts so that they move further apart (angle between widens)
• Dorsiflexion: Bending the foot at the ankle upwards
• Plantar flexion: Bending the foot downwards
Joint Movements
• Hyperextension: Excess extension of the parts at a joint beyond anatomical position
• Abduction: Moving a part away from the midline
• Adduction: Moving a part towards the midline
• Rotation: Moving a part around an axis
• Circumduction: Moving a part in a circular motion
Joint Movements
• Pronation: Turning the hand so that the palm is facing downwards
• Supination: Turning the hand so the palm is facing upward
• Eversion: Turning the foot so that the sole faces laterally
• Inversion: Turning the foot so that the sole faces medially
Joint Movements
• Retraction: Moving a part backward
• Protraction: Moving a part forward
• Elevation: Raising a part
• Depression: Lowering a part
Distinguish Between the Appendicular and Axial Skeletons
Axial Skeleton
• Consists of the bony and cartilaginous parts that support and protect the organs of the head, neck, and trunk
1.Skull – Composed of the cranium and facial bones
2.Hyoid bone – Located between lower jaw and larynx; supports the tongue and is an attachment for muscles that move the tongue
Axial Skeleton
3. Vertebral column – Consists of many vertebrae separated by cartilaginous intervertebral discs, the sacrum, and the coccyx
4. Thoracic cage – Protects the organs of the thoracic cavity and upper abdominal cavity; composed of 12 pairs of ribs, and the sternum
Appendicular Skeleton
• Consists of the bones of the upper and lower limbs and the bones that anchor the limbs to the axial skeleton
1.Pectoral girdle – Scapula and clavicle form the pectoral girdle on both sides of body; connects bones of upper limbs and aids in movement
2.Upper limbs – Each consists of a humerus, radius, and ulna, which articulate with each other at the elbow joint. At the distal end are carpals, metacarpals, and phalanges.
Appendicular Skeleton
3. Pelvic girdle – Two coxae connect the bones of the lower limbs to the axial skeleton; form the pelvis with the sacrum and coccyx
4. Lower limbs – Each consists of femur, tibia, fibula, and a foot. The patella covers the anterior surface of the knee joint. The foot consists of tarsals, metatarsals, and phalanges.
Diseases/Disorders
Osteogenisis Imperfecta
• Literally translated to mean: “bone that is imperfectly made from the beginning of life.”
• A genetic bone disorder, caused by a mutation that prevents the creation of collagen, resulting in extremely brittle bones, bones break easily
Hemarthrosis
• When there is bleeding in a joint, due to joint pain/ swelling
Rickets
• Caused by a lack of either Vitamin D, Phosphate, or calcium
• Bones become weakened and curve
Osteochondritis Dissecans
• Occurs when a fragment of bone in a joint separates from the rest of the bone because its blood supply was not sufficient
• The joint will become inflamed and painful, and can catch or lock during movements
• Most common in the knee, but can also occur in other joints, such as the hip or ankle
• Can be caused by repeated stress on the joint, inherited faulty genes, or ischemia, which restricts a bone’s blood supply
Osteochondritis Dissecans
Osteoid Osteoma
• A benign bone tumor that has a center of growing cells surrounded by a shell of thickened bone
• Most common in long bones, but can occur in any bone of the body
• Occurs primarily in males of 4-25 years of age
• Can sometimes disappear on its own, or be treated surgically
Osteoid Osteoma
Epiphysiolysis
• The loosening or separation of the epiphysis from the shaft of the bone
• Some treatments include physical therapy or prosthetic implants
• Occurs often in hip and leg bones
Epiphysiolysis