Skeletal System

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Functions of the SkeletonThe skeletal system is a living, dynamic system, with networks of infiltrating blood vessels. Living mature bone is about 60% calcium compounds and about 40% collagen. All humans were born with over 300 bones but some bones, such as those in the skull and lower spine, fuse during growth, thereby reducing the number. Although mature bones consist largely of calcium, most bones in the skeleton of vertebrates, including humans, began as cartilage.

SupportThe skeleton is the

framework of the body, it supports the softer tissues and provides points of attachment for most skeletal muscles.

ProtectionThe skeleton provides mechanical protection for many of the body's internal organs, reducing risk of injury to them.

For example, cranial bones protect the brain, vertebrae protect the spinal cord, and the ribcage protects the heart and lungs.

Assisting in Movement

Skeletal muscles are attached to bones, therefore when the associated muscles contract they cause bones to move.

Storage of Minerals

Bone tissues store several minerals, including calcium and phosphorus. When required, bone releases minerals into the blood - facilitating the balance of minerals in the body.

Production of Blood Cells

The red bone

marrow inside some

larger bones

produces blood cells.

Storage of Chemical Energy

With increasing age some bone marrow changes from 'red bone marrow' to 'yellow bone marrow'.

Yellow bone marrow consists mainly of adipose cells, and a few blood cells. It is an important chemical energy reserve.

Connections with other systems•Skeletal System holds the structure of body which allows the muscular system to move the body.•Skeletal System has bone marrow which forms blood. This complements the cardiovascular system.•The Nervous System sends messages for movement or reactions in the body which relates back to the skeletal and muscular system for movement.•The Respiratory System is related because oxygen is needed to the cardiovascular system for movement in the body. This relates back to the muscular and skeletal system.•The Immune System is related because white blood cells and T cells with immunity functions are sent made and released in the bone marrow.•The Digestive System is related because minerals like calcium and vitamin D are separated through digestion and sent throughout the body through the cardiovascular system. These minerals will reach the skeletal system.•The Lymphatic System is related because bone marrow is considered a lymph organ. Also many immunity cells released from the marrow will rest in the thymus which is also part of the lymphatic system.

Axial Skeleton

SkullCranium (8) – Frontal bone (1) – forms forehead and superior

surface of orbits – Parietal bones (2) – found on both sides of the skull,

posterior to the frontal bone – Occipital bone (1) – forms the posterior and inferior

portions of the cranium – Temporal bones (2) – found below the parietal bones,

contributing to the sides and base of the cranium – Sphenoid bone (1) – forms part of the floor of the

cranium – Ethmoid bone (1) – found anterior to the sphenoid

bone, consisting of two honeycombed masses of bone

Skull• Facial (14)

– Maxillary bones (2) – forms the floor and medial portion of the orbit rim, walls of the nasal cavity, and the anterior roof of the mouth (hard palate)

– Zygomatic bones (2) – found on each side of the skull, articulating with the frontal bone and the maxilla to complete the lateral wall of the orbit. Along the lateral margin, each gives rise to a slender bony extension that curves laterally and posteriorly to meet a process from the temporal bone, together forming the zygomatic arch.

– Palatine bones (2) – form the posterior surface of the hard palate. The superior surfaces of each horizontal portion contribute to the floor of the nasal cavity. The superior tip of the vertical portion of each forms a small portion of the inferior wall of the orbit.

– Mandible (1) – forms the lower jaw. – Lacrimal bones (2) – located within the orbit on its medial surface and

articulate with the frontal, ethmoid, and maxillary bones. – Nasal bones (2) – form the bridge of the nose and articulate with the

superior frontal bone and the maxillary bones. – Inferior nasal conchae (2) – project from the lateral walls of the nasal cavity. – Vomer (1) – The inferior margin articulates with the paired palatine bones

and, with the ethmoid bone, supports a prominent partition that forms part of the nasal septum.

SkullMiddle Ear (Auditory

Ossicles) – Malleus (2) – attaches at three

points to the interior surface of the tympanum (tympanic membrane)

– Incus (2) – attaches the malleus to the inner bone (stapes)

– Stapes (2) – seated within the "oval window."

Hyoid Bone – U-shaped and hangs below the skull, suspended by ligaments from the styloid processes of the temporal bones, and serves as a base for muscles associated with the tongue and larynx.

Vertebral Column • Cervical vertebrae (7) – extend from the head to

the thorax • Thoracic vertebrae (12) – extend from the

cervical portion to the lumbar section • Lumbar vertebrae (5) – continues from the

thoracic vertebrae to the sacrum • Sacrum (1) – forms the posterior wall of the

pelvis • Coccyx (1) – is one mass of four to five small

coccygeal vertebrae that have fused into one, commonly called the tailbone

Thoracic Cage • True ribs (14) – consist of 7 pairs of bone that reaches

the anterior body wall. They are connected to the sternum by separate cartilaginous extensions (costal cartilages).

• False ribs (10) – consist of ribs 8-12 that do not attach directly to the sternum. The last two pairs are floating ribs because they have no connection with the sternum.

• Sternum (1) – has three parts in the adult. The manubrium articulates with the clavicles of the appendicular skeleton and with the cartilages of the first pair of ribs. The body, or gladiolus, ends at the xiphoid process.

Appendicular Skeleton

Pectoral Girdle Scapula (2) is commonly called the shoulder blade. It is supported and positioned by the skeletal muscles. The scapula has no bony or ligamentous bonds to the thoracic cage, but it is extremely important for muscle attachment. Clavicle (2) is commonly called the collarbone. It articulates with the manubrium of the sternum, and is the only direct connection between the pectoral girdle and the axial skeleton.

Upper LimbsHumerus (2) extends from the scapula to the elbow. Radius (2) lies along the lateral side (or thumb side) of the forearm. Ulna (2) forms the medial support of the forearm. Carpals (16) consist of 8 pairs of bones of the wrist and, composed of:

four proximal bones (scaphoid, lunate, triangular or triquetral, and pisiform); four distal bones (trapezium, trapezoid, capitate, and hamate).

Metacarpals (10) consist of 5 pairs of bones that articulate with the distal carpal bones forming the palm of the hand. Phalanges (28) consist of 14 pairs of finger bones. Four fingers contain three phalanges while the pollex (thumb) has only two.

Pelvic Girdle

Os coxae (2) is commonly called the hip bone. It is formed from a fusion of three bones (ilium, ischium, and pubis).

Lower LimbsFemur (2) is commonly called the thigh bone. It is the longest, strongest, and heaviest bone in the body. Distally, it articulates with the tibia at the knee joint. The head (epiphysis) articulates with the pelvis at the acetabulum. Tibia (2) is commonly called the shinbone. It is the large medial bone of the leg, attached to the patella by a ligament. Fibula (2) parallels the lateral border of the tibia. Patella (2) is the knee cap. Tarsals (14) consist of 7 pairs of bones (talus, calcaneus, navicular, cuboid, and the 1st, 2nd, and 3rd cuneiform bones). Only the talus articulates with the tibia and fibula. Metatarsals (10) support the sole of the foot and numbers I to V from medial to lateral with the distal ends forming the ball of the foot. Phalanges (28) have the same arrangement as with the fingers and thumb only with the toes and great toe (hallux)

Ossification

OssificationThe ossification process is divided into two main phases.

In the first stage of ossification, the cartilage is covered with a layer of cells called osteoblasts, which form other bone cells. Once this encasement of osteoblasts has formed, the cartilage is slowly eaten away and the bone cells replace the cartilage. These bone cells are arranged in concentric circles, which causes the bone to be very hard. The mature cells, called osteocytes, store the calcium of the body which can be released or extracted from the bloodstream as needed. After the bone completes its formation process, the mature bone is encased in a membrane of connective tissue called the periosteum.

Long Bone•This bone is much longer than it is wide.

•consists of a long shaft, the diaphysis, with two ends or extremities, the epiphyses.

•The outer part of a long bone is made of compact bone.

•medullary cavity is in the interior part of the long bone. This is the central cavity of bone shafts

where red bone marrow and yellow bone marrow, adipose tissue, is stored.

•The functions of the long bone include strength, structure, and mobility. They are very strong

dense bones.

Joint Articulation

•A joint is the location at which two or more bones make contact.

•There functions include movement and mechanical support.

•joints can also be classified functionally, by the degree of mobility they allow.

Joint Articulation

Examples of classificationsSynarthrosis - permits little or no

mobility. Example: Skull

Amphiarthrosis - permits slight mobility. Example vertebrae

Diarthrosis - permits a variety of movements. Example: shoulder, hip

knee, elbow.

Orthopaedic Surgery • Orthopaedics is a medical specialty that

deals with the musculoskeletal system and uses medical, physical, and surgical methods to restore function lost as a result of injury or disease. An orthopaedist, also called an orthopaedic surgeon, is a highly skilled physician trained in a variety of medical and surgical techniques that will be used during your surgery.

Osteoporosis

Over time, bone mass, and therefore bone strength, is decreased

Bones become fragile and break easily

“porous bones”

Types of Osteoporosis

Primary osteoporosis is from an acceleration of the normal aging process.

Secondary osteoporosis is caused by other disease processes or prolonged use of certain medications that result in bone loss.

Who is Affected?

Most often, older people and women after menopause are affected by osteoporosis.

Women are five times more likely than men to develop the disease.

Women have smaller, thinner bones than men and they lose bone mass more rapidly after menopause when they stop producing the bone-protecting hormone, estrogen

Symptoms of Osteoporosis

People cannot feel their bones getting weaker. They may not know that they have osteoporosis until they actually break a bone.

Women can lose up to 20% of their bone mass in the five to seven years after menopause, making them more susceptible to osteoporosis.

Treatments of Osteoporosis

There is no cure for osteoporosis, but there are medications to prevent or treat it

Fosamax® / Boniva® / Actonel®: Alendronate, Ibandronate and Risedronate are approved for the prevention and treatment of osteoporosis in postmenopausal women and for the treatment of osteoporosis in men.

Five Steps to Bone Health & Osteoporosis Prevention

Eat healthyGet your daily recommended amounts of Calcium and Vitamin D

ExerciseEngage in regular weight-bearing and muscle strengthening exercise.

Maintain a healthy lifestyleAvoid smoking and excessive alcohol consumption.

Talk to your healthcare providerTalk to your healthcare provider about bone health.

Get testedHave a bone density test and take medication when appropriate.

Enchondromas

Enchondromas

One type of benign cartilage tumor that appears on the inside of the bone

These tumors usually begin and grow in childhood, then stop growing but remain present throughout adulthood.

They are often found in patients between 10 and 20 years of age.

Enchondromas

These tumors are very common and often occur in the small bones of the hand and feet.

They are the most common tumor of the hand.

They also occur in the long bones of the upper arm and thigh.

Symptoms of Enchondromas

These tumors are usually painless. They are usually found during an X-ray evaluation of another problem in the same area.

When these tumors appear in the hands or feet, or in multiple lesions, they can deform the bone.

Symptoms: enlarged fingers, pathologic fracture, or deformities.

On an X-ray, they appear as a dark hole in the bone

Treatments of Enchondromas

Nonsurgical TreatmentMost enchondromas require no treatment at all

Some surgeons think that tumors without symptoms do not need to be removed

Surgical TreatmentWhen enchondromas are treated surgically, it is usually with scraping out and filling of the cavity with bone graft or other filling substances. Although they can come back, most of them will not

Osteomyelitis

OsteomyelitisOsteomyelitis is the medical term for an infection in a bone. Infections can reach a bone by traveling through your bloodstream or spreading from nearby tissue.

Infections can also begin in the bone itself if trauma exposes your bone to germs. Bone infections commonly affect the long bones of your body, such as your leg bones and upper arm bone, as well as your spine and pelvis.

OsteomyelitisOsteomyelitis is a serious condition, requiring aggressive treatment to prevent spread of your infection and to save the affected bone

Types of OsteomyelitisOsteomyelitis is divided into several types depending on

where an infection begins and where it occurs. Infections that travel through the bloodstream. Infections that travel through the bloodstream affect only a small portion of adults, but affect the majority of children with osteomyelitis. Infections may begin as a urinary tract infection, and spread through the blood to a bone.Infections that occur after injury or surgery. Bone infections can occur after trauma such as broken bones that break the skin or open wounds to the surrounding skin and muscles. Infections in people with poor circulation. Osteomyelitis that occurs in people with poor circulation, such as those with diabetes, usually begins with minor scrapes or cuts on the feet. Poor circulation impairs the body's response to infection. Infection in the bones of the spine. Osteomyelitis that occurs in the spine most commonly affects older adults and usually starts with an infection in the bloodstream, though it can also occur from trauma or surgery. A number of infections can cause vertebral osteomyelitis, including skin infections, respiratory tract infections, urinary tract infections, infections in the mouth, and infections in areas where you receive drug injections.

Symptoms of Osteomyelitis

Acute OsteomyelitisFever that may be abruptIrritability or lethargy in young childrenPain in the area of the infectionSwelling, warmth and redness over the area of the infection

Chronic OsteomyelitisWarmth, swelling and redness over the area of the infectionPain or tenderness in the affected areaChronic fatigueDrainage from an open wound near the area of the infectionFever, sometimes

Treatments of Osteomyelitis

SurgeryDrain the infected area. Remove diseased bone and tissue. Restore blood flow to the bone. In order to stabilize the affected bone and the new graft, you may need to have metal plates, rods or screws inserted into the bone.

Antibiotics If your doctor suspects you have chronic osteomyelitis, he or

she works to determine exactly what microorganism is causing the infection before prescribing antibiotics. Your doctor uses a bone biopsy or a piece of bone removed during surgical treatment to determine what's causing the infection.

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