Alec Droussiotis

Skeletal System Overview of System Parts and Functions

The Skeletal System serves many valuable and important functions. It provides the shape and form for our bodies. It supports, protects, allows bodily movement, produces blood for the body, and stores minerals. The Skeletal System is perhaps one of the most important systems that is used in our bodies.

The skeleton is framework for the body which supports softer tissues and provides points to attach the majority of skeletal muscles. The skeleton provides mechanical protection for many of the body’s internal organs; this reduces the risk of injury. The skeletal muscles are attached to bones so when muscles contract they move the bones. Bone tissues store several minerals including Phosphorous and calcium. Bones also release minerals into the blood when required to facilitate the balance of minerals in the body. In larger bones there is a red bone marrow which produces blood cells. Red Blood Cells, White Blood Cells, and Platelets are produced in bone.

The Skeletal System is made up of many types of bones. There are axial and appendicular bones, usually in the arms and legs. There are 22 bones in the head which provide protection to the important nerves in the brain. There are 33 bones in the spine which includes: 7 cervix(neck), 12 thorax, 5 lumbar, 5 sacral, and 4 coccyx. All these bones in the spinal column will allow impulses from the brain to flow through the body. The pelvic girdle is fused to the sacrum at the sacro-illiac joint. The thorax(chest) consists of 12 pairs of ribs which includes: 7 pairs ‘true’ ribs(joined directly to the sternum(breast bone)), 3 pairs ‘false’ ribs(joined to the sternum by cartilage), and 2 pairs ‘floating’ ribs(not connected to the sternum at all, connected to the diaphragm).

There are 5 main categories of bones which make up the Skeletal System. These categories are the Long bones, Short bones, Flat bones, Irregular bones, Sesamoid bones, and the Sutural bones.

Skeletal System Parts and Function Outline

Alec Droussiotis

Axial Skeleton = 80 bones
I. Head Region (29 bones)

A. Skull

Cranium (Cranial Bones) = 8 bones

· Frontal (forehead)
· Parietal (topsides of the cranium)
· Temporal (lower side of the skull)
· Occipital ( back & base of the skull)
· Sphenoid (mid-portion of the cranial floor)
· Ethmoid (front portion of the cranial floor)
Face (Facial bones) = 14 bones

· Maxillae (upper jaw bone)
· Mandible (lower jaw bone)
· Zygomatic (cheek bones)
· Nasal (bridge of the nose)
· Lacrimal (medial wall of the orbit)
· Palatine (back part of the hard palate)
· Inferior Nasal Conchae (lateral wall of the nasal cavity)
· Vomer (back & lower part of the nasal septum)
B. Ear Ossicles (6 bones)

- Vibrate in response to sound waves that strike the eardrum and have a key role in hearing

· Hammer (Malleus)
· Anvil (Incus)
· Stirrup (Stapes)
C. Hyoid Bone

II. Trunk Region (51 bones)

A. Vertebrae (Backbones) = 26 bones

· Cervical vertebrae (neck)
· Thoracic vertebrae (upper back)
· Lumbar vertebrae (lower back)
· Sacrum (back of the pelvis)
· Coccyx (tail bone)

B. Bones of the Chest / Thorax = 25 bones

· Sternum (breast bone)
· Ribs (12 pairs)
o True Ribs (1st – 7th pairs of ribs)

o False Ribs (8th – 10th pairs of ribs)

o Floating Ribs (11th- 12th pairs of ribs)

Appendicular Skeleton = 126 bones
I. Upper Extremity (64 bones)

A. Shoulder Girdle / Pectoral Girdle = 4 bones

· Clavicle (collar bone)
· Scapula (shoulder blade)
B. Humerus (arm bone)
C. Radius (lateral forearm bone)
D. Ulna (medial forearm bone)
E. Carpals (bones of the wrist)
F. Metacarpals (framework of the palm)
G. Phalanges (finger bones)
(2 for thumb and 3 for other fingers)

· Proximal phalanges
· Middle phalanges
· Distal phalanges
II. Lower Extremity (62 bones)

A. Pelvic Girdle

· Hip bones / os coxae / innominate bones
B. Femur (thigh bone)
C. Patella (knee cap)
D. Tibia (shin bone, medial leg bone)
E. Fibula (splint bone, lateral leg bone)
F. Tarsals (ankle bones)
G. Metatarsals (bones of the instep / sole)
H. Phalanges (finger bones)
(2 for big toe and 3 for other fingers)

· Proximal phalanges
· Middle phalanges
· Distal phalanges

=Other Systems Related to the Skeletal System=

Lymphatic System

The Skeletal System relates to the Lymphatic System in a few ways. In the Skeletal System, as we know, is a series of 206 bones. These bones all produce White Blood Cells and these White Blood Cells are the soldiers that fight off infection and diseases. In connection to the Lymphatic System, the White Blood Cells fight the foreign objects that may be present inside the human body.

Immune System

The Skeletal System relates to the Immune System in ways that are similar to the Lymphatic System. The bones in the Skeletal System produce the White Blood Cells that will fight off diseases, illnesses, and infection that could be life threatening to the human body. The White Blood Cells are the cells that figure out how to fight the infection or illness and destroy it. Without the Skeletal System helping both the Immune and Lymphatic systems then there will be no White Blood Cells to fight off life threatening situations.

Muscular System

The Skeletal System relates to the Muscular System in many ways. The bones in the Skeletal System have pits that allow the tendons and muscles to latch onto. The Muscular System is the force that moves the bones and the bones is the structure that allows us to engage in physical activity.

Skeletal System Pictures and Diagrams

Skeletal System Blank Diagram

Skeletal System Informational Videos

Skeletal System Vocabulary

Structure and Function Vocabulary

1. Spine – the spinal or vertebral column; backbone
2. Cranium – the part of the skull that encloses the brain
3. White Blood Cells - any of various nearly colorless cells of the immune system that circulate mainly in the blood and lymph and participate in reactions to invading microorganisms or foreign particles, comprising the B cells, T cells, macrophages, monocytes, and granulocytes.
4. Bone marrow – The soft, fatty, vascular tissue that fills most bone cavities and is the source of red blood cells and many white blood cells.
5. Pelvis - the basinlike cavity in the lower part of the trunk of many vertebrates, formed in humans by the innominate bones, sacrum, etc.
6. Rib Cage – the enclosure formed by the ribs and their connecting bones.
7. Femur - a bone in the human leg extending from the pelvis to the knee, that is the longest, largest, and strongest in the body; thighbone.
8. Ulna – the bone of the forearm on the side opposite to the thumb.
9. Radius – the bone of the forearm on the thumb side.
10. Humerus - the long bone in the arm of humans extending from the shoulder to the elbow.

Diseases and Disorders

1. Osteoporosis- a disorder in which the bones become increasingly porous, brittle, and subject to fracture, owing to loss of calcium and other mineral components, sometimes resulting in pain, decreased height, and skeletal deformities: common in older persons, primarily postmenopausal women, but also associated with long-term steroid therapy and certain endocrine disorders.
2. Arthritis-acute or chronic inflammation of a joint, often accompanied by pain and structural changes and having diverse causes, as infection, crystal deposition, or injury.
3.Scoliosis-an abnormal lateral curvature of the spine.

4.Fracture-the breaking of a bone, cartilage, or the like, or the resulting condition
5.Osteomyelitis- an inflammation of the bone and bone marrow, usually caused by bacterial infection.

6. Cartilage-a firm, elastic, flexible type of connective tissue of a translucent whitish or yellowish color; gristle.
Infection-an act or fact of infecting; state of being infected.
8. Pain-physical suffering or distress, as due to injury, illness

9. Antibiotics-any of a large group of chemical substances, as penicillin or streptomycin, produced by various microorganisms and fungi, having the capacity in dilute solutions to inhibit the growth of or to destroy bacteria and other microorganisms, used chiefly in the treatment of infectious diseases.
10. Surgery-the art, practice, or work of treating diseases, injuries, or deformities by manual or operative procedures

Sudden Illness and Fist Aid

  1. Radiation Therapy-treatment of disease by means of x-rays or of radioactive substances.
  2. Calcium- A mineral found mainly in the hard part of bones, where it is stored
  3. Cavity- any fluid filled space in a multicellular organism.
  4. Barium- soft, white and is used to view the alimentary system in X-rays.
  5. Sprain- an injury to a ligament or to the tissue that covers a joint. Most sprains result from a sudden wrench that stretches or tears the tissues of the ligaments. A sprain is usually extremely painful. The injured part often swells and turns black and blue
  6. Tendinitis- a disorder involving stiffness or pain in the muscles or joints. It is often called rheumatism.
  7. Kyphosis- also called hunchback is a forward bending of the spine. Kyphosis is caused by any condition that deforms the bones of the upper part of the spine so that the person is bent forward. Diseases that cause kyphosis include tuberculosis, syphilis, and rheumatoid arthritis
  8. Poliomyelitis- is a serious infection caused by a virus. A polio virus may attack the nerve cells of the brain and spinal cord, causing paralysis. Some patients show only mild symptoms, such as fever, headache, sore throat, and vomiting. Symptoms may disappear after about a day
  9. Chemotherapy- a number of drugs have proven to be effective in treating bone and soft tissue sarcomas. The dosages required to provide a good chance for cure often produce significant side effects. Effective single agents may include doxorubicin (Adriamycin), cyclophosphamide, high-dose methotrexate (with leucovorin rescue), ifosfamide, dacarbazine, vincristine, dactinomycin (Actinomycin D), etoposide and investigational agents. Combinations of these drugs are often used.
  10. Biphosphonates- are drugs that can be used to reduce bone pain and slow down bone damage in people who have cancer that has spread to their bones

Hyperlinks for Structure and Function

Skeletal System PowerPoint

=Skeletal System - Structure and Function Quia QUIZ

Skeletal System JEOPARDY