Skeleton

At present we are preparing for our classes in Anatomy. As medical students we must have deep knowledge on this subject. I am reading the chapter considering the structure and functions of skeletal system. My fellow-student is making notes of the material on the bone shape and bone ossification. The following material must help us to prepare for our classes in Anatomy.

There are 206 bones in the average adult skeleton, although the actual number varies from person to person and decreases with the age as some bones become fused.

The skeleton is divided into the skull, vertebral (spinal) column, thoracic cage, upper and lower limbs and the girdles that attach the limbs to the body.

The skull is composed of 28 bones. These bones are organized into cranial vault, facial bones, and auditory ossicles.

The vertebral column usually consists of 33-34 bones. They are divided into five regions. There are 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, 5 sacral vertebrae, and 4-5 coccygeal vertebrae. The vertebral column performs some major functions: it supports the weight of the head and trunk, it protects the spinal cord, it provides a site for muscle attachment, and it permits movement of the head and trunk.

The thoracic cage, or rib cage, protects the internal organs within the thorax. It consists of the thoracic vertebrae, the ribs with their associated costal (rib) cartilages, and the sternum (breastbone). Each rib consists of the head, the neck, and the body. Twelve pairs of ribs attach to the thoracic vertebrae. The sternum, or breastbone, is composed of the manubrium, the body, and the xiphoid process.

The human upper limb is capable of a wide range of movements, including lifting, grasping, and touching. The arm (the portion of the upper limb from the shoulder to the elbow) contains only one bone, the humerus. Between the arm and forearm there is a cubital (elbow) joint. The forearm has 2 bones, the ulna on the medial side of the forearm and the radius on the lateral side of the forearm. The wrist is a relatively short region between the forearm and hand and is composed of 8 carpal bones. The hand consists of five metacarpal bones. The pectoral, or shoulder, girdle attaches the upper limb to the body. It consists of two bones: the scapula, or shoulder blade, and the clavicle, or collar bone.

The lower limb is very similar to that of the upper limb, except the pelvic girdle. It is attached much more firmly the body than is the pectoral girdle. The bones in general are thicker, heavier, and longer than those of the upper limb. The pelvic girdle supports the weight of the body and protects internal organs. The male pelvis usually is more massive than the female pelvis as a result of the greater weight and size of the male. Pelvic girdle is formed by the sacrum and paired bones, called the coxae, or hip bones. The thigh contains a single bone, the femur, which has a prominent rounded head. The femur articulates with the coxa, the tibia, and the patella. The knee joint is a joint located between the femur and the tibia. The leg (the portion of the lower limb between the knee and the ankle) consists of the two bones, the tibia and the fibula. The tibia supports most of the weight of the leg. The fibula doesn't articulate with the femur but has a small proximal head where it articulates with the tibia. The ankle consists of seven tarsal bones. The ankle is relatively much larger than the wrist. The foot consists of five metatarsal bones.

Ex. 18. Translate the following words and word-combinations into English:

З’єднувати; сполучати, шарнірно; палець; фаланга; плечова кістка; відрізнятися; ключиця; дозволяти, давати можливість; реберний; великогомілкова кістка; наколінок; сіднична кістка; малогомілкова кістка; кульша; хребець; шийний; грудина; ребро.

Human Skeleton

Ex. 19. Translate the text "Skeleton" into Ukrainian.

Ex. 20. Complete the following sentences:

1. Approximately 206 bones _ in the adult skeleton. 2. The _ is divided into the skull, vertebral (spinal) column, thoracic cage, upper and lower limbs and the girdles. 3. The skull _ of 28 bones. 4. They are divided into _, facial bones and auditory ossicles. 5. The bones of vertebral column are cervical vertebrae, thoracic vertebrae, _ vertebrae, sacral bone, and coccygeal bone. 6. The vertebral column _ the weight of the head and trunk, protects the spinal cord, and _ movement of the head and trunk. 7. The thoracic cage protects the _ organs. 8. It consists of the thoracic vertebrae, the ribs, and the _. 9. The upper limb consists of the humerus, _ joint, the ulna, and the radius. 10. The five _ of each hand include one thumb and four fingers. 11. Each digit consists of small long bones called _. 12. Each finger has 3 phalanges, and the thumb _ two ones. 13. The pelvic _ supports the weight of the body. 14. The thigh contains the _. 15. The knee is the _ located between the femur and the tibia. 16. The leg consists of the _ and the fibula. 17. The ankle consists of _ bones. 18. Each _ is formed by the fusion of the ilium, the ischium, and the pubis. 19. The toes of lower limb have three phalanges each except for the big _, which has two phalanges.

Ex. 21. Answer the following questions:

1. What parts is the skeleton divided into? 2. What portions does the skull consist of? 3. What is the vertebral column composed of? 4. What are the functions of the vertebral column? 5. What is the major function of the thoracic cage? 6. What does the thoracic cage consist of? 7. What is the upper limb capable of? 8. What bones are in the upper limb? 9. What are the bones of the lower limb?

Ex. 22. Using the data of the table speak on the anatomy of the skeleton:

Vertebral column	cervical vertebrae; thoracic vertebrae; lumbar vertebrae; sacral bone; coccygeal bone
Thoracic cage	thoracic vertebrae; costal cartilages; sternum (breastbone); manubrium; xiphoid process; ribs
Upper limb	pectoral girdle; humerus; cubital joint; ulna; radius; carpal bones; metacarpal bones
Lower limb	pelvic girdle; femur; tibia; patella; fibula; tarsal bones; metatarsal bones

Ex. 23. Read the following abstract and retell it:

The skeleton consists of the skull, the spine, the ribs, the sternum (breastbone), two limb girdles (the shoulders and pelvis) and their attached limb bones. There are only minor differences between the skeletons of the male and the female: the men's bones tend to be larger and heavier than corresponding women's bones and the women's pelvic cavity is wider to accommodate childbirth. The skeleton plays an important part in movement. It also supports and protects the internal body organs. The skeleton is not just a movable frame, however; it is an efficient factory, which produces red blood cells from the bone marrow of certain bones and white cells from the marrow of other bones to destroy harmful bacteria. The bones are also a storehouse for minerals – calcium, for example – which can be supplied to other parts of the body. Babies are born with 270 soft bones – about 64 more than an adult; and many of these will fuse together by the age of twenty or twenty-five into the 206 hard, permanent bones.

Ex. 24. Translate the following sentences into English:

1. Скелет дорослої людини складається приблизно з 206 кісток. 2. Скелет складається з черепа, хребетного стовпа, грудної клітки та верхніх і нижніх кінцівок. 3. Склепіння черепа, лицьові кістки та слухові кісточки є кістками черепа. 4. Хребет складається з шийних, грудних, поперекових, крижових хребців та крижової кістки. 5. Хребетний стовп захищає спинний мозок. 6. Грудна клітка підтримує та захищає внутрішні органи. 7. Грудна клітка складається з грудних хребців, ребер, реберних хрящів та грудини. 8. Основна частина грудної кліткии складається з ребер. 9. Кожне ребро має голівку, шийку та тіло. 10. Грудина – це довгаста кістка всередині грудної клітини. 11. Як правило, хребець складається з тіла, дуги та відростка. 12. Верхня кінцівка складається з плечової кістки, ліктьового суглоба, ліктьової кістки та променевої кістки. 13. Зап'ясток складається з зап’ясткових кісток. 14. Кисть складається з п’яти п’ясткових кісток. 15. Тазовий пояс підтримує вагу тіла та захищає внутрішні органи від пошкоджень. 16. Коліно – це суглоб, розташований між стегном та великою гомілковою кісткою. 17. Гомілка складається з великої гомілкової кістки та малогомілкової кістки.

Ex. 25. Speak on:

The vertebral column;

The thoracic cage;

The bones of upper limb;

The bones of lower limb.

Ex. 26. Read the following words and try to memorize them:

Epiphysis [e'pIfIsIs] епіфіз; epiphyseal line [epI'fIzIql] епіфізарна лінія; cartilage ['ka:tIlIG] хрящ; compact bone ['kOmpxkt 'boun] компактна кісткова тканина; cancellous bone ['kxnsqlqs] сітчаста кістка, губчаста кісткова речовина; spongy bone ['spAnGI] губчаста кісткова речовина; matrix ['meItrIks] матрикс, основа, міжклітинний матеріал; сavity ['kxvItI] порожнина; rigid ['rIGId] жорсткий, негнучкий, твердий; medullary [me'dAlqrI] медулярний, мозковий; серцевинний; maintain [meIn'teIn] підтримувати, утримувати, зберігати; support [sq'pO:t] підтримка; sinus ['saInqs] пазуха; fill with [fIl] наповнювати(ся); band [bxnd] зв'язка; approximately [q'prOksImItlI] близько, приблизно; marrow ['mxrqu] кістковий мозок; broad [brO:d] широкий; periosteum ["perI'OstIqm] окістя, надкісниця; fit [fIt] підходити, відповідати; dense [dens] щільний, густий; diaphysis [daI'xfIsIs] діафіз, середня частина трубчастої кістки.

Ex. 27. Read the following text:

BONE'S STRUCTURE

The skeletal system consists of bones, cartilages, tendons, and ligaments. Because bone is very rigid, it is well adapted to help maintain the shape of the body and protect internal organs. Cartilages, which are somewhat rigid but more flexible than bones, also provide support. Tendons and ligaments are strong bands of fibrous connective tissue. Tendons attach muscles to the bones, and ligaments attach bones to bones.

Individual bones can be classified according to their shape as long, short, flat, or irregular. Most of the bones of the upper and lower limbs are long bones. These bones are very strong. They are broad at the ends where they join with other bones, and have large surface areas for muscle attachment. Short bones are approximately as broad as they long. They are nearly cube shaped or round. They are in the wrist and ankle. Flat bones have a relatively thin, flattened shape. The examples of flat bones are some skull bones, ribs, pelvic bones, and the breastbone (sternum). Irregular bones are ones such as the vertebrae and facial bones with shapes that do not fit into three categories.

Each long bone consists of three major components: the diaphysis; an epiphysis; and the epiphyseal line (or epiphyseal plate in each growing long bone). The diaphysis is long middle region of a long bone composed of compact bone, which is bone matrix. Each end of a long bone is called an epiphysis. The epiphyses consisting of cancellous bone (sometimes called spongy bone), has many small spaces or cavities within the bone matrix. The outer surface of the epiphyses consists of a layer of compact bone. In addition to the small spaces within cancellous bone and compact bone, some bones contain large cavities. The diaphyses of long bones have a large medullary cavity (some of the skull bones have spaces called sinuses). The medullary cavity and the cavities of the cancellous bone are filled with marrow. Medullary cavity contains yellow bone marrow and spaces in cancellous bone contain red bone marrow. Yellow bone marrow is mostly composed of adipose tissue. Red bone marrow is the site of blood formation. In general, yellow marrow is associated with the long bones of the limbs, and red marrow is associated with the rest of the skeleton. The outer surface of bones consists of a periosteum. The periosteum is a strong, fibrous, vascular membrane that covers the surface of a long bone, except at the ends of the epiphyses. The inner layer consists mostly of a single layer of osteoblasts with a few osteoclasts. Osteoblasts are bone producing cells, and osteoclasts are cells breaking down bone.

Flat bones usually have no diaphyses or epiphyses. They contain an interior framework of cancellous bone sandwiched between two layers of compact bone. Short and irregular bones have a composition similar to the epiphyses of long bones. They have compact bone surfaces surrounding a cancellous bone center with small spaces that usually filled with marrow. Short and irregular bones have no diaphyses. However, certain regions of these bones (e.g., the processes of irregular bones) have epiphyseal growth plates and therefore have small epiphyses.

Ex. 28. Answer the following questions:

1. What does the skeletal system consist of? 2. What is the major function of the bone? 3. What does the cartilage provide? 4. What are ligaments and tendons? 5. What are their functions? 6. What types of bones do you know? 7. What components does every long bone consist of? 8. What is diaphysis composed of? 9. What does the epiphysis consist of? 10. What is compact bone? 11. What is osteoblast? 12. What is osteoclast? 13. What do the flat bones contain? 14. What are short and irregular bones composed of?

Structure of Bone

Ex. 29. Match the following terms with their definitions:

1. Cartilage	1. noncellular substance surrounding the cells of connective tissue.
2. Ligament	2. dense plate of bone in a bone that is no longer growing, indicating the former site of the epiphyseal plate.
3. Tendon	3. similar molecules binding to the same carrier molecule or receptor site.
4. Compact bone	4. band of dense connective tissue connecting a muscle to a bone or other structure.
5. Epiphyseal line	5. portion of a bone developed from a secondary ossification center and separated from the remainder of the bone by the epiphyseal plate.
6. Epiphysis	6. band of dense connective tissue connecting two or more bones, cartilages, or other structures.
7. Matrix	7. firm, smooth, nonvascular connective tissue.

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