BONES JOINTS AND MUSCLES

DR. VINIT.K.ASHOK

ADJUNCT FACULTY

INTODUCTION/FUNCTION• 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 FRMEWORKTO 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 BONESACCORDING 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 BONES-

THIN FLAT AND CURVED BONES

-SKULL BONES, RIBS , STERNUM( BREAST BONE)

IRREGULAR BONES-

THEY HAVE DIFFERENT SHAPES

EXAMPLES ARE VETEBRAE, HIP BONES

ANATOMY OF BONES

• 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• 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• EPIPHYSEAL PLATE- THIS IS A PLATE OF HAYLINE CARTILAGE PRESENT IN CHILDREN

BETWEEN THE EPIPHYSIS AND DIAPHYSIS( ALLOWS GROWTH OF THE BONE)• ARTICULAR CARTILAGE- IT COVERS THE ENDS OF THE LONG BONES(EPIPHYSIS)• PERIOSTEUM-BONES ARE COVERED ON THE OUTSIDE EXCEPT AT THE JOINT REGION

BY THIS MEMBRANE.a) PROVIDES NOURISHMENTb) ATTACHMENT FOR LIGAMENTS AND TENDONSc) OSTEOGENESIS-MEDULLARY CAVITY- IT IS IN THE DIAPHYSIS OF THE LONG BONES, AND THERE IS NO

BONE TISSUE. IT IS FILLED WITH YELLOW BONE MARROWENDOSTEUM- THE MEMBRANE THAT LINES THE INNER SURFACE OF THE BONE.HAS

OSTEOBLASTS( FORM NEW BONE), OSTEOCLASTS( BONE RESORPTION),NOURISHMENT `

ANATOMY OF SHORT /IRREGULAR/FLAT BONES

• 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)

• 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

• 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

• 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)

• 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 ossification-

b)Enchondral ossification-

OSSIFICATION

OSTEOBLASTSFORM NEW BONE

MATRIX

COLLAGENSTERNGTH

CALCIUM DEPOSITION

OSTEOCYTES

MAINTAIN BONE

OSTEOCLASTS

MAINTAIN SHAPE

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

• 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 CENTERSHAFT

BONE FORMED AT THE ENDS

BY 20 YRS BONE GROWTH STOPS

REMODELING MAINTAINS SHAPE

VIT D ESSENTAIL

UV RADIATIONACTS ON THE SKIN

DEFFICIENCY

RICKETSOSTEOMALACIA

DIVISION OF THE SKELETON• AXIAL/ APPENDICULAR• AXIAL---SKULL,VERTEBRAL

COLUMN ,THORACIC CAGE( 80 BONES)

• APPENDICULAR –SHOULDER GIRDLE,PELVIC GIRDLE AND LIMB BONES( 126 BONES)

MUSCLES

• 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

• SKELETAL MUSCLES

- VOLUNTARY MUSCLE

- STRIATED

- NOT BRANCHED

- MULTINUCLEATED( NUCLEUS PRESENT PERIPHERALLY)

- NOT BRANCHED

- CYLINDRICAL IN SHAPE

- PRESENT INRELATION TO BONES

• SMOOTH MUSCLES

-INVOLUNTARY MUSCLE

-NOT STRIATED

-SPINDLE SHAPED

-SINGLE CENTRAL NUCLEUS

-PRESENT IN RELATION TO ORGANS( GIT)

• 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.

• 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 RELATIONSHIPLEVER 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( SEE-SAW)

- 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

• 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