THE SKELETAL SYSTEM
The skeletal system consists of bones and joints as well as ligaments and cartilages that connect them. The skeletal system serves many important functions. It supports the body and protects vital organs in the skull, rib cage and pelvis. It allows bodily movement due to the combined actions of the bones and the muscles. Also, it provides the shape to our bodies. Bones provide the structure to which tissues and muscles are attached. All bones store minerals such as calcium and phosphorus, and certain bones produce blood cells.
Disorders of the skeletal system include fractures, postural deformities (kyphosis, lordosis, scoliosis) and many other skeletal conditions such as osteoporosis, arthritis, osteoarthritis, rickets, osteomalacia or bone tumors.
The skeleton
The skeleton is the bony framework of the body supporting the soft tissues and protecting the vital organs. The 206 bones comprise the adult human skeleton.
The human skeleton is divided into two parts: the axial skeleton and the appendicular skeleton. The axial skeleton consists of bones that form the axis of the body: the skull, the rib cage and the vertebral column. The appendicular skeleton is composed of bones that are outside the main axis: the upper and lower limbs, the shoulder girdle and the pelvic girdle.
The axial skeleton is designed for the support and protection and is quite rigid although the flexibility of the vertebral column allows it a certain degree of movement such as bending and some twisting.
The skull is made up of cranial bones and facial bones. The cranium containing and protecting the brain consists of 7 thin and flat bones united by immovable joints called sutures. The cranial bones include: the frontal bone, the two temporal bones, the two parietal bones the sphenoid bone and the occipital bone. The 14 facial bones include the mandible, which is the only freely movable joint in the head, the maxilla, the nasal bone and the two zygomatic bones (commonly called the cheekbones).
The rib cage contains 24 ribs arranged in 12 pairs. The rib bones are thin, flat and curved. The first seven pairs of ribs extend from the vertebral column to the sternum, commonly called the breast bone. These ribs are referred to as the true ribs. The next five pairs of rib bones are called the false ribs. These bones are shorter than the true ribs and are not attached directly to the sternum, but to the costal cartilage of the lowest true ribs. The last two pairs of ribs, called the floating ribs, are unattached in front. The function of the rib cage is to protect the heart and the lungs.
The vertebral column is composed of 33 irregularly shaped bones known as vertebrae. A single bone is called a vertebra. The 33 vertebrae are divided into 5 regions according to where they are found: the 7 cervical vertebrae located in the neck, 12 thoracic vertebrae contained at the back of the chest, 5 lumbar vertebrae found in the small of the back, and five sacral and four coccygeal vertebrae fused together to form the sacrum and the coccyx. The first cervical vertebra is called the atlas and the second cervical vertebra is called the axis. The intervertebral discs, which are found between the vertebrae, allow the spine to move.
The appendicular skeleton consists of the bones of the extremities as well as of the bones of the shoulders and hips which attach the bones of the limbs to the axial skeleton.
The shoulder girdle, also called the pectoral girdle, is composed of 2 bones, the clavicle and the scapula. The clavicle, commonly called the collarbone, is a thin S-shaped bone forming the front of the shoulder. It is attached medially to the sternum and laterally to the scapula. The scapula, or the shoulder blade, is a large, triangular, flat bone located on the back of the rib cage.
The upper extremity is made up of the bones of the arm, the forearm, the wrist and the hand. The arm consists of a single bone called the humerus. The humerus is the longest bone in the upper extremity. The forearm is composed of 2 bones, the radius and the ulna. The wrist consists of 8 carpal bones. The hand is made up of 19 bones. The 5 metacarpals of the palm articulate with the carpals and with the 14 finger bones referred to as phalanges. A single finger bone is called a phalanx. Each finger has three phalanges, except the thumb which has two phalanges.
The pelvic girdle is composed of the two large and irregularly shaped hip bones. Each hip bone consists of three fused bones: the ilium, the ischium and the pubis. They form the side and the front of the pelvic girdle, and the sacrum forms the back.
The lower extremity is made up of the bones of the thigh, leg, ankle, foot and the patella. The thigh contains one bone, the femur, which is the longest and the heaviest bone of the body. The patella, or kneecap, is a flat, triangular-shaped bone that covers and protects the knee joint. The leg is composed of 2 bones, the tibia and fibula. The ankle is composed of 7 tarsal bones which correspond to the carpals in the wrist. As in the hand, 19 bones form each foot. The 5 metatarsals of the foot articulate with the tarsals and the 14 toe bones, or phalanges. The toes have, like the fingers, three phalanges, except the big toe, which has two phalanges.
WORDLIST
appendicular skeleton – szkielet obwodowy
arthritis – zapalenie stawów
atlas – kręg szczytowy
axial skeleton – szkielet osiowy
axis – oś, kręg obrotowy
carpal bones – kości nadgarstka
cartilage – chrząstka
cervical vertebrae – kręgi szyjne
clavicle (collarbone) – obojczyk
coccygeal vertebrae – kręgi guziczne
coccyx – kość guziczna
costal cartilage – chrząstka żebrowa
cranial bones – kości mózgoczaszki
cranium – mózgoczaszka
facial bones – kości twarzoczaszki
false ribs – żebra rzekome
femur – kość udowa
fibula – kość strzałkowa
flexibility – elastyczność, giętkość
floating ribs – żebra wolne
framework – konstrukcja, struktura
frontal bone – kość czołowa
humerus – kość ramienna
ilium – kość biodrowa
intervertebral disc – krążek międzykręgowy
ischium – kość kulszowa
joint – staw
ligament – więzadło
lumbar vertebrae – kręgi lędźwiowe
mandible – żuchwa
maxilla – szczęka
metacarpal – kość śródręcza
metatarsal – kość śródstopia
occipital bone – kość potyliczna
osteoarthritis – zapalenie kości i stawów
osteomalacia – rozmięknienie kości, demineralizacja kości
osteoporosis – osteoporoza
parietal bone – kość ciemieniowa
patella (kneecap) – rzepka
phalanx (pl. phalanges) – paliczek
pubis – kość łonowa
radius – kość promieniowa
rib cage – klatka piersiowa
rickets – krzywica
rigid – sztywny
sacral vertebrae – kręgi krzyżowe
sacrum – kość krzyżowa
scapula (shoulder blade) – łopatka
sphenoid bone – kość klinowa
sternum (breast bone) – mostek
suture – szew
tarsal bone – kość stępu
temporal bone – kość skroniowa
thoracic vertebrae – kręgi piersiowe
tibia – kość piszczelowa
true ribs – żebra prawdziwe
ulna – kość łokciowa
vertebra (pl. vertebrae) – kręg
vertebral column – kręgosłup
zygomatic bone (cheekbone) – kość jarzmowa
EXERCISES
I. Answer the questions.
1. What is the function of the skeletal system?
2. What diseases affect the skeletal system?
3. What bones does the cranium contain?
4. What does the term ‘floating ribs’ mean? Which ribs are called floating?
5. What are vertebrae? How are they divided?
6. What does the appendicular skeleton consist of?
7. What is the shoulder girdle composed of?
8. What are phalanges? Where are they found?
II. Decide whether the following sentences are true or false.
1. The terms ‘appendicular’ and ‘axial’ are synonymous.
2. All the ribs extend from the vertebral column and are attached to the sternum.
3. Each finger and toe has three phalanges.
4. The clavicle is related medially to the sternum and laterally to the humerus.
5. The cheekbones are medically called the occipital bones.
6. The ankle is formed by the carpals, while the tarsals make up the wrist.
7. The sternum is commonly called the collar bone.
8. The cranium contains two parietal bones.
III. Choose the correct answer.
1. What makes up the skeletal system?
a) All the bones in the body c) All the body’s organs and tissues
b) All the muscles and tendons d) All the bones and the tissues that connect them
2. The bone which protects the brain is ……
a) calcium b) the cranium c) the cerebrum d) the cerebellum
3. How many bones are there in the average adult person’s body?
a) more than 260 b) 33 c) it varies by the individual d) 206
4. The longest and the heaviest bone of the body is ……….
a) the tibia b) the radius c) the femur d) the humerus
5. ……. is the only freely movable joint in the head.
a) the phalanx b) the mandible c) the maxilla d) the patella
IV. Complete the sentences.
1. The forearm is composed of the …………………..……… and the …………..……………
2. The bones of the foot comprise the……………...
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