Skeletal System: Structure and Function

Vertebrae

All vertebrae have a similar structural pattern.

Green-stick Fracture

An incomplete fracture where only part of the bone is broken. Typically seen in small children whose bones are not fully ossified.

Bone Salts

Bone is one of the hardest materials in the body, although it is light in weight. Calcium is an important mineral, and it is salt that gives the bone its hardness. While the calcium deposited in the matrix gives the bone hardness, the collagen fibers provide the bone with flexibility and tensile strength.

Saddle Joint

Joint fits together like a saddle. Movement is the same as the condyloid joint.

Osteocytes

Mature bone cells

Zygomatic Bones

Paired bones that are commonly referred to as the cheek bones.

Palatine Bones

Paired bones that form the posterior part of the hard palate

Superior and inferor articular processes

Paired projections lateral to the vertebral formen

Spinal Column

Serving as the axial support of the body, the vertebral column, or spine, extends from the skull, which it supports, to the pelvis where it transmits the weight of the body to the lower limbs. Before birth, the spine consists of 33 separate bones called vertebrae, but 9 of these eventually fuse to form the sacrum and the coccyx. Of the 24 single bones, the 7 vertebrae of the neck are cervical vertebrae, the next 12 are the thoracic vertebrae, and the 5 remaining bones, which support the lower back, are lumbar vertebrae.

Vomer Bone

Single bone is the median line of the nasal cavity.

Spinous process

Single projection from the posterior aspect of the vertebral arch

Nasal Bones

Small rectangular bones that form the bridge of the nose.

Plane Joint

Surfaces are flat, and only short slipping or gliding is allowed.

Diarthrotic joints allow

for several types of body movements.

Scoliosis

is an abnormal lateral curvature of the spine. As you look at an individual with scoliosis in anatomical position, the spine can appear as though it has an S curve laterally. To treat scoliosis, orthopedic braces are often used to hold the spine in place as it grows. Surgical treatment may also be required in severe cases.

Lordosis

is an exaggerated inward curvature of the lumbar spine, often called a swayback. It is commonly found in men and women who are severely overweight or in pregnant women. In children, you will see a prominently protruding abdomen or buttocks. To treat lordosis, braces and surgery can be used.

Spongy Bone

is composed of small, needle-like pieces of bone and lots of open space the bony tissue found inside a bone. It contains cavities that hold red bone marrow. Also called cancellous bone.

Structure of a Long Bone

is comprised of epiphyses at both ends. The epiphyses consist of a thin layer of compact bone enclosing spongy bone. The diaphysis is the shaft of the long bone producing the bone's length. The diaphysis is composed of compact bone. The medullary cavity of the shaft serves as a storage area for adipose tissue called yellow marrow. In infants, this cavity forms bloods cells and is the site for red marrow. In adults, red marrow is confined to the cavities of spongy bone of flat bones, and the epiphyses of some long bones.

Compact Bone

is dense and looks smooth and homogeneous the hard exterior surface bone. Also called cortical bone

Dorsiflexion

is the process of bending a body part backwards, such as pulling your ankle to your shin.

Flexion

is the process of bending a flexed limb or the spine.

Rotation

is the process of moving a body part around a central axis.

Abduction

is the process of moving a body part away from the midline of the body.

Retraction

is the process of moving a body part backward, such as with the jaw.

Protraction

is the process of moving a body part forward, such as with the jaw.

Circumduction

is the process of moving a body part in a circular motion, such as swinging your arm.

Adduction

is the process of moving a body part toward the midline of the body.

Extension

is the process of straightening a flexed limb or the spine.

Inversion

is the process of turning inward, such as at the ankle.

Eversion

is the process of turning outward, such as at the ankle.

Pronation

is the process of turning the hand so that the palm points downward.

Supination

is the process of turning the palm upward.

In the early years of childhood,

most of the hyaline cartilage has been converted to bone. Cartilage remains only in isolated areas such as the bridge of the nose, parts of the ribs, and the joints.

The load of the upright human body

on 52 bones in the feet. The remaining 154 bones provide connecting points for muscles and protection for the delicate tissues of the brain, spinal cord, and other organs.

Synovial joints can be classified as

plane, hinge, pivot, condyloid, saddle, and ball-and-socket.

Kyphosis

results in an exaggeration of the thoracic curvature, often called humpback. This abnormal curvature can be caused by a congenital defect, disease (such as tuberculosis, syphilis, or malignancy), a compression fracture, poor posture, osteoarthritis, rheumatoid arthritis, rickets, or osteoporosis. Treatment includes braces and surgery and often depends on the health of the person and the cause.

There are three main types of abnormal curvature: ________, _______, and ________. These abnormalities are often diagnosed (using an x-ray) early in toddlers, children, or teenagers and if not corrected at a young age, can cause significant problems and deformities with age.

scoliosis lordosis kyphosis

Functionally, joints are classified as

synarthroses (immovable), amphiarthroses (slightly moveable), or diarthroses (freely moveable).

The skeleton is divided into two parts:

the axial skeleton and the appendicular skeletal.

Ossification

the process of bone formation, involves three phases: 1. Hyaline cartilage is completely covered with bone matrix by osteoblasts. 2. Enclosed cartilage is digested away, opening up a medullary cavity within the newly formed bone. 3. The cartilage is then replaced by bone cells, or osteocytes. By birth, most hyaline cartilage models have been converted to bone except for the articular cartilages, which cover the ends of the bone and the epiphyseal plates. Articluar cartilages last throughout life.

In embryos,

the skeleton is primarily made of hyaline cartilage.

Though 14 bones make up the face,

they work with 66 others to protect the upper body's vital organs, the most important being the brain, spinal cord, heart, and lungs. The remaining 126 bones make up the lower trunk and appendages used in manipulation and locomotion. These bones support the body's weight, enable the use of tools, and make it possible to walk and jump.

The parts of the spinal column that are normally convexly curved include the __________.

thoracic and sacral areas.

The skeleton is formed from

two of the strongest and most supportive tissues in the body—cartilage and bone.

Most bones develop

using hyaline cartilage as a model.

The shapes of the bone surfaces determine

what movements are allowed in the joints.

The lower jawbone,

which is the largest and strongest bone in the human skull, is often the distinctive trademark of a person's "look."

The spinal column is divided into five curved sections, each section corresponding to sections of spinal nerves:

1. Cervical Curvature 2. Thoracic Curvature 3. Lumbar Curvature 4. Sacral Curvature 5. Coccyx

Colles' Fracture

A common type of "wrist" fracture (actually the distal end of the radius).

Synovial Fluid

A fluid secreted by the synovial membrane; lubricates joint surfaces and nourishes articular cartilages.

Oblique Fracture

A fracture at an angle to the bone.

Stress Fracture

A fracture caused by repetitive low-impact forces, such as running.

Transverse Fracture

A fracture straight across the bone, at a right angle to the bone's axis.

Impacted Fracture

A fracture where the bone fragments are pushed together.

Comminuted Fracture

A fracture where the bone is shattered, splintered, or crushed.

Spiral Fracture

A fracture where the break spirals around the bone shaft.

Compound Fracture

A fracture where the skin is broken by the bone itself (also known as an open fracture).

Closed Fracture

A fracture with no break in the skin, also called a simple fracture.

Vertebral foramen

Canal through which the spinal cord passes

The adult skeleton is composed of 206 bones. There are two basic types of osseous, or bone tissue:

Compact Bone and Spongy Bone.

Body (centrum)

Disc-like, weight-bearing part of the vertebra

Pectoral Girdle

Each shoulder girdle (pectoral girdle) consists of two bones: a clavicle and a scapula. The shoulder girdle is very light and allows the upper limb to have free movement. However, because of its flexibility, the shoulder girdle is easily dislocated.

Osteoblasts

Embryonic bone cells

Adipose

Fatty

Lacrimal Bones

Fingernail-sized bones forming the medial walls of each of the eye sockets.

Verterbral Arch

Formed from the joining of all posterior extension from the acrumal body

Maxillae

Fused bone that forms the upper jaw.

Upper Extremity

The appendicular skeleton is composed of 126 bones and is comprised of the appendages, as well as the pectoral and pelvic girdles. Thirty separate bones form the skeletal framework of each upper limb. They form the foundations of the arm, forearm, and hand. The appendicular skeleton is made up of all the bones not found in the axial skeleton and is responsible for body movement. These bones and their attached muscles make it possible for you to manipulate objects. For example, you can move the computer mouse around to complete this lesson, you can turn a doorknob, and you can kick a soccer ball across the field.

Arm and Forearm

The arm is formed by a single bone, the humerus. The forearm is made up of the radius and the ulna.

Axial Skeleton

The axial skeleton forms the longitudinal axis of the body. It is divided into three parts: the skull, vertebral column and the bony thorax. The skull is formed by two sets of bones—the cranium ahttp://quizlet.com/26194800/edit#add-rownd the facial bones. The cranium is composed of eight large, flat bones. The parietal and temporal bones are the only paired bones in the cranium.

Cartilaginous Joints

The bone ends are connected by cartilage. For example, the pubic symphysis of the pelvis includes a slightly movable cartilaginous joint connecting the right and left halves.

Synovial Joints

The bone ends are separated by a joint cavity filled with synovial fluid.

Fibrous Joints

The bones are united by fibrous tissue. For example, the sutures of the skull are immovable fibrous joints.

Hinge Joint

The cylindrical end of one bone fits into the trough-shaped surface of another bone, allowing for angular movement.

Condyloid Joint

The egg-shaped surface of one bone fits into an oval concavity of another. This allows the bone to travel side-to-side, and back and forth.

Epiphyses

The end of a long bone.

Foot

The foot consists of the tarsals, metatarsals and the phalanges. The bones in the foot are arranged to form three strong arches.

Hand

The hand consists of the carpals, metacarpals, and the phalanges.

Mandible

The lower jaw that is the largest and strongest bone in the face.

Lower Extremity

The lower limbs carry our total body weight when standing. The three segments of the lower limbs are thicker and stronger than the corresponding bones of the upper limb.

Pelvic Girdle

The pelvic girdle is formed by two coaxial bones, or coxae, also called hip bones. The hip bone is formed by the fusion of three bones: the ilium, ischium, and pubis.

Bone Growth and Remodeling

The process by which bones increase in diameter is called appositional growth, and this process is controlled by growth hormones. During puberty, this process is controlled by the sex hormones. This process ends during adolescence, when the epiphyseal plates are completely converted to bone. Bone remodeling is essential if bones are to retain normal proportions and strength during long-bone growth as the body increases in size and weight. Bone remodeling accounts for the increase in strength in areas where bulky muscles are attached.

Ossification

The process of bone formation.

Pivot Joint

The rounded end of one bone fits into a sleeve, or ring of bone, allowing the bone to turn around the long axis of the bone.

Diaphysis

The shaft portion of a long bone.

Skeletal System and Homeostasis

The skeletal system participates in homeostasis by protecting the internal organs of the other systems of the body. For example, the skull protects the brain, the spinal column protects the spinal cord, the rib cage protects the lungs and heart, and the pelvic girdle protects the reproductive organs. The skeletal system also provides support for the muscles so that the body can move about. In addition, the bones absorb vitamin D and store calcium salts, which make the bones hard. When either vitamin D or calcium is deficient, the bones become brittle and cause diseases such as osteoporosis.

Ball-and-Socket Joint

The spherical head of one bone fits into a round socket of another. This allows movement in all axes, including rotation. Joint fits together like a saddle. Movement is the same as the condyloid joint.

Bony Thorax

The sternum, ribs, and thoracic vertebrae make up the bony thorax. The bony thorax is often called the thoracic cage because it forms a protective, cone-shaped cage of slender bones around the vital organs of the thoracic cavity. The sternum (breastbone) is the typical flat bone with three important bony features: the jugular notch, sternal angle, and the xiphosternal joint. Twelve pairs of ribs form the walls of the bony thorax. The true ribs, the first seven pairs, attach directly to the sternum. The false ribs, the next five pairs, either attach indirectly to the sternum or are not attached to the sternum at all.

Thigh and Leg

The thigh is formed by a single bone, the femur. The femur is the heaviest, strongest bone in the body. The leg is made up the tibia and the fibula.

Facial Bones

There are 14 bones that make up the face. Twelve bones are paired and two bones are single.

Differences in the Male and Female Pelvis:

There are several characteristics that differ in the pelvis of a male and a female. - The female inlet is larger and more circular. - The female pelvis is more shallow, lighter, and thinner. - The female ilia flare more laterally. - The female sacrum is shorter and less curved. - The female ischial spines are shorter and further apart. - The female public arch is more rounded.

Inferior Nasal Conchae

Thin, curved bones projecting from the sides of the nasal cavity.

Transverse process

Two lateral projections from the vertebral arch

Functional Classification of Joints

With the exception of the hyoid bone, every bone in the body forms a joint with at least one other bone. Joints (articulations) hold bones together securely and give the skeleton mobility. Joints are classified in two ways: functionally and structurally. The functionally classified joints are the synarthroses, which are immovable, the amphiarthroses, which are slightly moveable, and the diarthroses, which are freely moveable joints. Structural classification consists of fibrous joints, cartilaginous joints, and synovial joints.

Abnormal curvature

_______ _______ of the spine is where a portion of the spine curves either the wrong direction or laterally.

Irregular Bones

are bones that do not fit in one of the other categories of bone. Irregular bones include vertebrae that make up the spinal column, and the hip bones.

Short Bones

are cube-shaped bones containing mostly spongy bone tissue. Short bones include bones of the wrist and ankle and also the patella, or kneecap.

Flat Bones

are thin, flattened, and usually curved bones, with a layer of spongy bone sandwiched between two thin layers of compact bone. Flat bones include most of the bones of the skull, ribs, and sternum (breastbone).

Long Bones

are typically longer than they are wide. They are mostly compact bone with heads at both ends. Long bones include all the bones of the limbs, except for the wrist and ankle bones.

Classification of Bones

bones are classified based on shape.