BONES JOINTS AND
MUSCLES
DR. VINIT.K.ASHOK
ADJUNCT FACULTY
INTODUCTION/FUNCTION
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INTRODUCTION-BONES FORM THE SKELETAL SYSTEM ,BONES ARE
FORMED OF MANY TISSUES, CONTAIN NERVES AND BLOOD
VESSELS.BONES ARE ATTACHED TO EACH OTHER AT JOINTS.THE
COMBINATION OF BONES, JOINTS AND RELATED CONNECTIVE
TISSUE FORM THE SKELETAL SYSTEM.THERE ARE A TOTAL OF 206
BONES IN THE SKELETON
• FUNCTIONS –
-BONES GIVE SHAPE TO THE BODY AND FORM A FIRM FRMEWORK
TO SUPPOT THE WEIGHT OF THE BODY
-TO PROTECT DELICTE STRUCTURES( BRAIN, SPINAL CORD, LUNGS)
-WORK AS LEVERS, ALONG WITH THE ATTACHED MUSCLES BRING
ABOUT MOVEMENT
-STORE MINERALS LIKE CALCIUM AND PHOSPHATE. THESE ARE
RELEASED INTO THE BLOOD WHEN NEEDED
-SITE OF ERYTHROPOIESIS( RED BLOOD CELLFORMATION)
CLASSIFICATION OF BONES
ACCORDING TO THEIR SHAPE
• LONG BONES-LONGER THAN WIDER. EACH LONG BONE HAS A SHAFT,UPPER( PROXIMAL END)
AND A LOWER( DISTAL END)
-MOST OF THE BONES OF THE LIMBS ARE LONG BONES( HUMERUS,FEMUR)
-SHORT LONG BONES ARE PRESENT IN THE HAND AND FEET( PHALANGES)
• SHORT BONES-THESE BONES ARE CUBE SHAPED( CARPAL BONES OF THE WRIST)
-SESAMOID BONES ARE ANOTHER TYPE OF SHORT BONE, THEY ARE FORMED
WITHIN A TENDON( PATELLA)
• FLAT BONESTHIN FLAT AND CURVED BONES
-SKULL BONES, RIBS , STERNUM( BREAST BONE)
IRREGULAR BONESTHEY HAVE DIFFERENT SHAPES
EXAMPLES ARE VETEBRAE, HIP BONES
ANATOMY OF BONES
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COMPACT BONE-THIS IS HARD AND DENSE BONE,FORMS THE
OUTER LAYER OF BONES , FORMS THE SHAFT OFLONG BONES.THE
OSTEOCYTES IN THIS ARE IN RINGS AROUND A CANAL( HAVERSIAN
CANAL)
SPONGY BONE- THIS HAS MORE SPACES THAN COMPACT
BONES(HONEYCOMB).MADE UP OF A MESHWORK OF BONY PLATES
FILLED WITH RED MARROW AND IS FOUND AT THE END OF LONG
BONES AND THE CENTER OF OTHER BONES
* RED MARROW- IS THE SITE WHERE RED BLOOD CELLS ARE
FORMED
* YELLOW MARROW – WHERE NO RED BLOOD CELLS ARE FORMED.
FILLED WITH FAT
ANATOMY OF A LONG BONE
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DIAPHYSIS-THIS IS THE SHAFT OF THE BONE AND CONTAINS THE MARROW CAVITY
EPIPHYSIS- THE IRREGULAR ENDS OF THE LONG BONE
EPIPHYSEAL LINE- THIS IS PRESENT BETWEEN THE DIAPHYSIS AND EPIPHYSIS OF AN
ADULT LONG BONE
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EPIPHYSEAL PLATE- THIS IS A PLATE OF HAYLINE CARTILAGE PRESENT IN CHILDREN
BETWEEN THE EPIPHYSIS AND DIAPHYSIS( ALLOWS GROWTH OF THE BONE)
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ARTICULAR CARTILAGE- IT COVERS THE ENDS OF THE LONG BONES(EPIPHYSIS)
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PERIOSTEUM-BONES ARE COVERED ON THE OUTSIDE EXCEPT AT THE JOINT REGION
BY THIS MEMBRANE.
a) PROVIDES NOURISHMENT
b) ATTACHMENT FOR LIGAMENTS AND TENDONS
c) OSTEOGENESIS
-MEDULLARY CAVITY- IT IS IN THE DIAPHYSIS OF THE LONG BONES, AND THERE IS NO
BONE TISSUE. IT IS FILLED WITH YELLOW BONE MARROW
ENDOSTEUM- THE MEMBRANE THAT LINES THE INNER SURFACE OF THE BONE.HAS
OSTEOBLASTS( FORM NEW BONE), OSTEOCLASTS( BONE RESORPTION),NOURISHMENT
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ANATOMY OF SHORT
/IRREGULAR/FLAT BONES
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LOOK SIMILAR TO EACH OTHER HISTOLOGICALLY
PRESENCE OF PERIOSTEUM EXTERNALLY AND ENDOSTEUM
INTERNALLY
DO NOT HAVE DIAPHYSIS
HAVE NO MARROW CAVITY BUT HAVE BONE MARROW IN THE
SPACES INSIDE THE BONE
* IN THE FLAT BONES( SKULL) THE SPACES INSIDE ARE CALLED
DIPLOE AND THESE CONTAIN BONE MARROW
HISTOLOGY OF BONE
(OSSEOUS TISSUE)
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CONNECTIVE TISUE ,HAVING CELLS AND INTERCELLULAR
SUBSTANCE( MATRIX)
• CELLS ARE OSTEOBLASTS,OSTEOCYTES AND OSTEOCLASTS(
GIANT CELLS)
• MATRIX HAS COLLAGEN FIBRES AND HYDRXYAPATITES( MINERAL
SALTS CALCIUM AND PHOSPHATE)
• HISTOLOGICALLY COMPACT BONE LOOKS DIFFERENT FROM THE
SPONGY BONE
 OSSIFICATION---- FORMATION OF BONE TISSUE( 2ND -3RD MONTH OF
IUL)
HISTOLOGY OF COMPACT BONE
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HAVERSIAN SYSTEM( OSTEON)FORMS THE MAIN HISTOLOGICAL
COMPONENT
OSTEONS ARE PLACED ALONG THE LONG AXIS OF THE BONE
MICROSCOPICALLY AN OSTEON LOOKS LIKE A CROSS SECTION OF A
TREE TRUNK AND IT HAS CONCENTRIC CIRCLES( CONCENTRIC
LAMELLAE)
PRESENT IN THE MIDDLE OF EACH OSTEON IS A CANAL( HAVERSIAN
CANAL). IT IS LINED WITH ENDOSTEUM HAS HAS BLOOD VESSELS
AND NERVES WHICH SUPPLY THE BONE
OSTEOCYTES ARE THE MATURE BONE CELLS AND LOOK LIKE
SPIDERS AND ARE PRESENT IN A SPACE CALLED A LACUNA. THE
SPIDER LEGS OCCUPY THIN TUBES CALLED CANALICULI.( THESE
HELP IN DIFFUSION). THE MAIN FUNCTION OF THE OSTEOCYTE IS
TO MAINTAIN THE BONE MATRIX
HISTOLOGY OF SPONGY ( CANCELLOUS ) BONE
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PRESENCE OF BONY TRABACULAE
THEY ENCLSE THE MARROW SPACES
PERIPHERALLY THESE TRABACULAE MERGE WITH THIN SHELL OF
COMPACT BONE WHICH HAVE OSTEONS
WITHIN THE MARROW SPACES ARE THE BLOOD FORMING CELLS (
HEMOPOETIC) AND FAT CELLS ( ADIPOSE CELLS)
THERE ARE ALOS BLOOD VESSELS WITHIN THE MARROW SPACES
FORMATION OF
BONE(OSSIFICATION)
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THIS BEGINS IN THE EMBRYO AND GOES ON THROUGH CHILHOOD
AND ADOLESCENCE , AS THE SKELETON KEEPS GROWING AND
OCCURS AT A SLOWER RATE IN ADULTS( REMODELLING)
• THERE ARE 2 TYPES OF OSSIFICATION
a)Intramembranous ossificationb)Enchondral ossification-
OSSIFICATION
OSTEOBLASTS
FORM NEW BONE
MATRIX
OSTEOCLASTS
COLLAGEN
STERNGTH
MAINTAIN SHAPE
CALCIUM DEPOSITION
OSTEOCYTES
MAINTAIN BONE
INTRAMEMBRANOUS
OSSIFICATION
• MEMBRANE BONES DEVELOP LIKE THIS ( SKULL
BONES, CLAVICLE)
• DURING THE 8TH WEEK OF EMBRYONIC
DEVELOPMENT CERTAIN CELLS IN THE
MESENCHYMAL MEMBRANE BECOME
OSTEOBLASTS( BONE FORMING CELLS)
• THESE CELLS SECRETE OSTEOID( ORGANIC PART
OF THE BONE MATRIX), THIS GETS CALCIFIED AND
THE OSTEOBLASTS FORM THE MATURE
OSTEOCYTES.
ENCHONDRAL OSSIFICATION
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ALL THE REST OF THE BONES EXCEPT THE SKULL BONES AND THE
CLAVICLE DEVELOP LIKE THIS
FIRST A CARTILAGE MODEL IS FORMED WHICH IS THEN REPLACED
WITH BONE TISSUE
BEGINS IN THE 2ND MONTH OF THE EMBRYO, AND GOES ON TO
EARLY ADULHOOD
FORMATION OF A LONG BONE
CARTILAGE
OSSIFACTION AT THE CENTER
SHAFT
BONE FORMED AT THE ENDS
BY 20 YRS BONE GROWTH STOPS
REMODELING MAINTAINS SHAPE
VIT D ESSENTAIL
UV RADIATION
ACTS ON THE SKIN
DEFFICIENCY
RICKETS
OSTEOMALACIA
DIVISION OF THE SKELETON
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AXIAL/ APPENDICULAR
AXIAL---SKULL,VERTEBRAL
COLUMN ,THORACIC CAGE( 80
BONES)
APPENDICULAR –SHOULDER
GIRDLE,PELVIC GIRDLE AND LIMB
BONES( 126 BONES)
MUSCLES
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MUSCLES ATTACHED TO THE SKELETON ARE CALLED SKELETAL
MUSCLES AND THEY FORM THE BULK OF THE MUSCULATURE IN
THE HUMAN BODY
• FUNCTIONS-BRING ABOUT MOVEMENT IN THE BODY
-RESPONSIBLE FOR FACIAL EXPRESSIONS( FACIAL MUSCLES)
-GIVES SHAPE TO THE BODY
DIFFERENCES BETWEEN SKELETAL,SMOOTH
AND CARDIAC MUSCLES
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SKELETAL MUSCLES
VOLUNTARY MUSCLE
STRIATED
NOT BRANCHED
MULTINUCLEATED( NUCLEUS
PRESENT PERIPHERALLY)
NOT BRANCHED
CYLINDRICAL IN SHAPE
PRESENT INRELATION TO
BONES
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SMOOTH MUSCLES
-INVOLUNTARY MUSCLE
-NOT STRIATED
-SPINDLE SHAPED
-SINGLE CENTRAL NUCLEUS
-PRESENT IN RELATION TO ORGANS( GIT)
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CARDIAC MUSCLES
-INVOLUNTARY MUSCLE
-STRIATED
-BRANCHED
-SINGLE CENTRAL NUCLEUS
-CYLINDRICAL IN SHAPE
-PRESENT ONLY IN THE HEART
CLASSIFICATION OF SKELETAL
MUSCLES
BASED ON THE DIRECTION OF MUSCLE FIBRES.
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RECTUS-( STRAIGHT) – MUSCLE WHERE THE FIBRES ARE RUNNING
PARALLEL TO AN IMAGINARY LINE ALONG THE LONG AXIS OF A LIMB
BONE OR MIDLINE OF THE BODY( RECTUS ABDOMINIS)
• TRANVERSE- FIBRES RUNNING AT RT ANGLES TO AN IMAGINARY
LINE( TRANVERSUS ABDOMINIS)
• OBLIQUE-FIBRES RUN OBLIQUELY( EXTERNAL OBLIQUE)
BASED ON SIZE OF MUSCLE FIBRES.
MAXIMUS-LARGEST( GLUTEUS MAXIMUS)
MINIMUS –SMALLEST( GLUTEUS MINIMUS)
LONGUS-LONG( ADDUCTOR LONGUS)
BREVIS-SHORT( ADDUCTOR BREVIS)
CLASSIFICATION-2
• BASED ON THE LOCATION
-FRONTALIS( PRSENT IN THE FRONTAL REGION)
• BASED ON THE NUMBER OF ORIGINS
- BICEPS( 2 ORIGINS, 2 BELLIES)
- TRICEPS( 3 ORIGINS , 3 BELLIES)
- QUADRICEPS( 4 ORIGINS ,4 BELLIES)
BASED ON THE LOCATION OF ORIGIN AND INSERTION
-STRENOCLIEDOMASTOID.( ORIGIN ON THE STERNUM AND CLAVICLE
AND INSERTION ON THE MASTOID PROCESS)
- BASED ON SHAPE OF THE MUSCLE
- DELTOID( SHAPE OF A TRIANGLE)
- TRAPEZIUS( TRAPEZOID IN SHAPE)
- BASED ON ACTION OF THE MUSCLE
- EXTENSORS( CAUSE EXTENSION)
BONE MUSCLE RELATIONSHIP
LEVER SYSTEMS
• LEVER SYSTEM-CONSISTS OF A RIGID BAR ( LEVER) WHICH
MOVES ON A FIXED PONIT ( FULCRUM) WHEN A FORCE IS
APPLIED( EFFORT) TO MOVE A RESISTANCE( LOAD)
• THE BONES AND MUSCLES IN THE BODY ACT AS LEVER
SYSTEMS
 BONES—LEVERS
 JOINTS---FULCRUM
 MUCLES CONTRACTING ---EFFORT
 RESISTNCE(LOAD)-----BONE ITSELF + ALL RELATED
STRUCTURES
LEVER SYSTEM
TYPES OF LEVERS
• FIRST CLASS LEVERS-FULCRUM LIES BETWEEN THE EFFORT AND THE LOAD( SEESAW)
- EFFORT IS APPLIED AT ONE END AND LOAD LIES ON THE
OTHER END
- SECOND CLASS LEVERS
-LOAD LIES BETWEEN EFFORT AND FULCRUM( WHEELBARROW)
GREATER STRENGTH, LESS SPEED AND RANGE OF ACTION
THIRD CLASS LEVERS
- EFFORT LIES BETWEEN LOAD AND FUNCTIONFAST LARGE
MOVEMENTS WITH LITTLE EFFORT
- MOST SKELETAL MUSCLES ARE OF THIS TYPE
Second class levers
THIRD CLASS LEVERS
OPERATION OF SKELETAL
MUSCLES
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ORGIN VS INSERTION
MORE FIXED ATTACHMENT IS THE ORIGIN
THE LESS FIXED ATTACHMENT IS TH INSERTION
FUNCTION TYPES BASED ON ACTIONS
-PRIME MOVER ( AGONIST)- THE MUSCLE THAT IS RESPONSIBLE
FOR A SPECEFIC ACTION ( BICEPS FLEXES THE FOREARM AT THE
ELBOW)
 ANTAGONIST – MUSCLES THAT OPPSE A PARTICULAR ACTION(
RELXED WHEN AGONIST ARE ACTING( TRICEPS ARE RELAXED
WHEN BICEPS ACT)
 SYNERGISTS- THESE ACT ALONG WITH AGONISTS ADD A LITTLE
EXTRA FORCE TO THE ACTION
 FIXATORS- THEY HELP THE AGONIST BY HOLDING A BONE IN PLACE