More Related Content
What's hot (18)
Similar to Bones anatomy (20)
Recently uploaded (20)
Bones anatomy
- 1. BONES (By Dr Muzammil and Dr Amna saleem ) Define bone ?and its causes of hardness and elasticity? Bone :it is living tissue capable of changing its structure when subjected to stresses o Like other connective tissues ,bones consist of fibers ,cells and matrix o It is hard because of calcification of its extracellular matrix o It also possess a degree of elasticity because of the presence of organic fibers Functions of bones Protective function for example SKULL Protects brain and Vertebral coloumn protects spinal cord from injury It also serves as lever as seen in long bones of limbs and as an important storage areas for calcium salts Internally bone houses and protects the delicate blood forming bone marrow
- 2. Periosteum A thick layer of fibrous tissues called the periosteum covers all the bones surfaces other than articulating surfaces Periosteum has an abundant vascular supply and the cells on its deeper surfaces are osteogenic Periosteum is well united to bone at sites where muscles tendons and ligaments are attached to bones and it recieves a rich nerve supply and is very sensitive to trauma Sharpeys fiber Bundle of collagen fibers which extend from periosteum into an underlying bone are called Sharpeys fibers Bone exist in two forms Compact bone Cancellous bone Compact bone apears as solid mass Cancellous bone consist of branching network of trabecule Trabeculae are arranged so as to provide resistance against mechanical stresses and strains
- 3. Bones classification Bones can be classified according to regions and shapes According to regional classification bones are organizaed into two main groups Axial skeleton Appendicular skelton According to shapes bones are of four main types LONG SHORT FLAT IRREGULAR SEASAMOID AXIAL SKELETON Consist of the elements forming the central axis of body APPENDICULAR SKELETON Consists bones forming upper and lower limb girdles and extremeties Bones division in Axial =80 . Appendicular=126 Skull=28 . clavicle =2 Cranium=8 . scapula =2 Face=14. humerus=2 Auditory ossicles =6. Radius=2 Hyoid=1 . Ulna=2 Vertebrae =26 . carpals=16 Sternum=1 . metacarpals=10 Ribs=24 . phalanges =28 os coxae =2 femur =2 patella =2 fibula=2 tibia=2 Tarsal=14 metatarsals=10 phalanges
- 4. LONG BONES Their lentgh is greater than their breadth They have tubular shaft ,diaphysis ,and usually an epiphysis at each end During the growing phase diaphysis is seperated from the epiphysis by and epiphyseal cartilage is called the metaphysis Shaft: has a central cavity containing bone marrow The outer part of shaft is composed of compact bone that is covered by periosteum The ends of long bones are composed of cancellous bone surrounded by thin layer of compact bone The articular surfaces of the ends of bones are covered by Hyaline cartilage Long bones are found in the limbs (humerus ,femur ,metacarpals ,metatarsals,phalanges) SHORT BONES They are roughly cuboidal in shape and are composed of cancellous bone surrounded by thin layer of compact bone Short bones are covered by periosteum Articular surfaces are covered by hyaline cartilage They are found in hand and foots(scaphoid ,lunate,talus,calcaneum) FLAT BONES they are composed of thin inner and outer layer of compact bone , The tables seperated by a layer of cancellous bone,the Diploe Flat bones are are found in vault of the Skull (the frontal and parietel bone ) Scapulae although irregular in shape are included in this group
- 5. IRREGULAR BONES They are composed of thin shell of compact bone with an anterior made up of cancellous bone Irregular bones include those not assigned to the previous groups (the bones of skull , the vertebrae , pelvic bone ) SESAMOID BONES A sesamoid bone is one formed within a tendon where tendon passes over the joint The greater part of sesamoid bone is buried in the tendon and free surface is covered with cartilage The largest sesamoid bone is patella which is located in the tendon of quadriceps femoris Other examples include tendons of flexor pollices brevis and flexor hallucis brevis (thumb and toe) Function of sesamoid bone is to reduce friction on the tendon It can also alter the direction of pull of a tendon BONE SURFACE MARKINGS The surfaces of bones typically show various surface markings or irregular features The surface is roughened or raised where bands of fascia ,ligaments ,tendons,aponeurosis are attached to bone. these roughenings re not pressent at birth . These roughenings apear at puberty and become progressively more obvious during adult life The pull of these fibrous structures causes the periosteum to elevate and new bone to be deposited beneath In certain cases the surface markings are large and are given a special names Bone markings are of several types LINEAR ELEVATION ROUNDED ELEVATION SHARP ELEVATION EXPANDED ENDS FOR ARTICULATION SMALL FLAT AREA FOR ARTICULATION DEPRESSIONS OPENINGS
- 6. BONE MARROW Bone marrow occupies the marrow cavity in long and short bones and the interstices of cancellous bones in flat and irregular bones The marrow of all the bones is red and hematopoetic at birth The blood forming activity gradually lessens with age and red marrow is replaced with yellow marrow Yellow marrow begins to apears in distal bones of the limbs at about age of 7 years This replacement of marrow gradually moves proximally When person becomes adult red marrow is restricted to bones of skull ,the vertebral coloumn ,the thoracic cage ,the head of humerus and the femur What is diaphysis :the centre of bone formation found in the shaft of bone is the diaphysis What is epiphysis : the centre at the end of bone are epiphysis The plate of cartilage at each end lying between the epiphysis and diaphysis is called EPIPHYSEAL PLATE METAPHYSIS : it is part of diaphysis that abuts of onto the epiphyseal plate BONE DEVELOPMENT two processes Membranous and endochondral formation in Membranous formation bone develops directlly from connective tissue membrane Bones of vault of skull develops rapidly by membranous formation in the embryo and this serves to protect the underlying developing brain At birth small areas of membrane persist between the bones This is important clinically because it allows the bones a certain amount of mobility so that skull can undergo molding during its descent through the female genital passages In ENDOCHONDRAL FORMATION a cartilagenous model is first laid down and Later replaced by bone The long bones of limbs develop by endochondral ossification or formation in a slow process that is not completed untill age 18 to 20 years or even later .
- 7. Thank you ! Recite Darood paak once