BY Dr Farooq Khan Aman Ullah khan

Transcription

1 Lecture 01 General Anatomy & Classification of Bone BY Dr Farooq Khan Aman Ullah khan Dated:

2 Skeleton The hard, supporting framework of the body is called the skeleton. Skeleton includes bones and cartilages. It forms the main supporting framework of the body, and is primarily designed for a more effective production of the movements by the attached muscles.

3 Skeleton Human skeleton is bilaterally symmetrical with typical vertebrate pattern of an axis, divided into segments for flexibility and of movement. Two pairs of limbs, pectoral and pelvic, also divided into jointed parts for grasping and locomotion etc. 3 9/28/2014

4 Skeleton The skull is the expanded and modified cranial end of the axis Osteo-cartilaginous sesamoid bones develop in some tendons and ligaments All these elements are collectively called the Skeleton 4

5 Skeleton Human Skeleton, like other vertebrates is ENDOSKELETON in contrast to the EXOSKELETON of many invertebrates 5

6 The skeletal system may be divided into two functional parts: Skeletal system The Axial skeleton, that consists of the bones of the head (cranium of skull), neck (hyoid bone and cervical vertebrae) and trunk (ribs, sternum, vertebrae, and sacrum). The Appendicular skeleton consists of the bones of the limbs, including those forming the pectoral (shoulder) and pelvic girdles. 6

7 Bones A living tissue is highly specialized hard form of connective tissue that makes up most of the skeleton. The average adult skeleton has 206 bones. Although this is the traditional number, the actual number of bones varies from person to person and decreases with age as some bones become fused. 7

8 Bones Bones can be categorized as paired or unpaired. A paired bone is two bones of the same type located on the right and left sides of the body, whereas an unpaired bone is a bone located on the midline of the body. There are 86 paired and 34 unpaired bones 8

9 Bones of the adult skeleton provide: Support for the body and its vital cavities. It is the chief supporting tissue of the body. Protection for vital structures e.g. heart and lungs. The mechanical basis for the movement ( leverage) Storage of salts e.g. calcium A continuous supply of new blood cells ( produced by the marrow in the medullary cavity of many bones). 9

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11 Classification of Bones A. Developmental classification B. Regional classification C. Classification on the basis of shape D. Structural classification 11

12 A: Developmental classification Membran0us bones: They are Ossified in membranes, e.g. Bones of skull Cartilaginous bones: They ossify in cartilage. e.g. bones of limbs Membrano-cartilaginous bones: They Ossify partly in membrane and partly in cartilage, e.g. clavicle, mandible 12

13 B: Regional classification AXIAL BONES: This group consists of the head and trunk which includes : Skull bones Vertebrae Ribs and Sternum APPENDICULAR BONES: This group consists of the upper and lower limbs : Upper Limb (with shoulder girdle) Lower Limb (with pelvic girdle) 13

14 C: Classification of Bones based on shape The long bones are those that are longer than they are wide. Has two types. Typical long bones Miniature long bones. 1. LONG BONES: They grow primarily by elongation of the diaphysis, with an epiphysis at each end of the growing bone. The ends of epiphyses are covered with hyaline cartilage ("articular cartilage"). Bone growth in length is stimulated by the production of growth hormone (GH). 14

15 C: Classification of Bones based on shape 2. SHORT BONES: Short bones are designated as those bones that are as wide as they are long. Their primary function is to provide support and stability with little to no movement. Examples: 15

16 C: Classification of Bones based on shape 3. FLAT BONES: Flat bones are bones whose principal function is either extensive protection or the provision of broad surfaces for muscular attachment. These bones are expanded into broad, flat plates, as in the cranium (skull), the ilium (pelvis), sternum and the rib cage. The flat bones are: the occipital, parietal, frontal, nasal, lacrimal, hip bone (coxal bone), sternum, ribs, and scapulae. 16

17 C: Classification of Bones based on shape 4. IRREGULAR BONES: The irregular bones are bones which, from their peculiar form, cannot be grouped as long, short, flat or sesamoid bones. The spine is the place in the human body where the most irregular bones can be found. There are, in all, 33 irregular bones found here. The irregular bones are: the vertebrae, sacrum, coccyx, temporal, sphenoid, ethmoid, zygomatic, maxilla, mandible and hyoid 17

18 C: Classification of Bones based on shape 5. PNEUMATIC BONES: Skeletal pneumaticity is the presence of air spaces within bones. It is generally produced during development by excavation of bone by pneumatic diverticula (air sacs) from an air-filled space such as the lungs or nasal cavity. Pneumatic Bones have air spaces within them which makes them lighter than more solid bone. They are only found in the skull. 18

19 6. SESAMOID BONES C: Classification of Bones based on shape The sesamoid is a small nodular bone most often present embedded in tendons in the region of the thumb. Calcification of sesamoid bone is one of the important features of pubertal growth spurt, which is earlier in females than in males. Absence of sesamoid bone indicates delay in reaching puberty. 19

20 C: Classification of Bones based on shape 7. WORMIAN / SUTURAL BONES /accessory bones Accessory bones of the skull go by many names including Wormian bones, intrasutural bones or sutural bones. Accessory bones of the skull are formed from additional and separate centres of ossification of the cranium. They are located near or in the cranial sutures that lead to extra isolated bone segments in the cranium. These small accessory bones tend to vary in size and also tend to be irregular in shape. 20

21 21 C: Classification of Bones based on shape

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23 23 D: Structural classification

24 D: Structural classification Two types of bone tissue are found in the human body: 1. SPONGY 2. COMPACT This is based upon the relative amount of solid matter and the number and size of spaces in each of them. All bones have a complete outer shell of compact bone around a central mass of cancellous bone, except where the later is replaced by a medullary cavity or an air space e.g. paranasal sinuses. 24

25 A. Spongy bones Consists of slender, irregular trabeculae or bars of compact bone which branch and anastomose with one another to form intercommunicating spaces that are filled with bone marrow. The trabeculae of spongy bones are arranged in lines of pressure or tension In radiograph these pressure lines are seen to pass across the joints from bone to bone 25

26 Compact bones Appears solid except for microscopic spaces It s crystalline structure gives it rigidity and hardness and makes it radiopaque to X-rays 26

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28 Microscopically Lamellar bone Woven bone 28 9/28/2014

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30 "The difference between a successful person and others is not a lack of strength, not a lack of knowledge, but rather in a lack of will." Vincent T. Lombardi Thank You. Thank You.