OSTEOLOGY Boneafide THE BARE BONES OF IT n

OSTEOLOGY Bone-a-fide

THE BARE BONES OF IT n n n STRUCTURE FUNCTION TYPES IDENTIFICATION GROWTH, DEVELOPMENT & HEALING

THE BONE CELL n n n The osteocyte is surrounded by matrix 35% protein collagen for hardness and flexibility 65% mineral salts – mostly Calcium and Phosphorus Precursor – cells that manufacture the bone cells – Osteoblasts Cells that erode the bone matrix – Osteoclasts – these constantly remodel the bones according to the force of muscles. Outer covering is a thin membrane called Periosteum - encloses the bone - fibrous connective tissue - contains blood vessels

OSSEOUS/BONY TISSUE COMPACT BONE n Usually found on the outside where there is more stress n They are parallel cylinders called Osteons, which are concentric tubes of matrix, with a central canal that carries blood vessels. n Tiny spaces within this contain isolated osteocytes SPONGY or CANCELLOUS bone n It has a honeycomb structure and bony struts with spaces called trabeculae n Jelly like yellow marrow that stores fat n Red marrow that produces blood cells

OSSIFICATION n n In embryonic development the bones arise from the mesoderm. They are usually either Fibrous connective tissue or Cartilage. The fibrous tissue ossification is called INTRAMEMBRANOUS The cartilaginous ossification is called ENDOCHONDRAL.

Bone Ossification Skeleton begins as cartilage in prenatal development n At fetal age 2 months: - osteoblasts begin to deposit calcium (ossification) - first begins in the center of the long bones - called primary ossification points - ossification extends along the shaft at birth, shaft is fully ossified n Postnatal bone growth occurs at secondary ossification points called "epiphyseal plates" or "growth plates" The epiphyseal plate has four layers : n 1) Zone of resting cells - serves as reservoir for future growth n 2) Proliferative zone - cartilage cells increase in size n 3) Hypertrophic zone - cartilage cells arrange themselves in vertical columns n 4) Calcified cartilage zone - cartilage cells erode and bone is deposited by osteoblasts n Ossification of short bones ossify from the center outward At birth, about 400 ossification centers exist. After birth, another 400 more develop. After puberty, growth plates ossify and bone stops growth –there is evidence that excessive stress can cause premature ossification. Bone is constantly being broken down (osteoclasts) - rebuilt again by osteoblasts - else, we could not recover from a broken bone. n

GROWTH PATTERN OF BONES n n n GROWTH – our bones are growing all the time. Maximum growth happens within 18 yrs. Then mainly reshuffling esp of face, vertebrae, ribs and hips. LONG bones grow most and skull bones least. Growth in long bones takes place at the Epiphysis, at the ends.

FUNCTION Strong, lightweight frame work, dynamic and flexible. n SUPPORT n SHAPING BODY n ANCHORAGE OF SKELETAL MUSCLES n SURROUNDS AND PROTECTS INTERNAL ORGANS n MOVEMENT n STORES FAT n PRODUCES Red Blood Cells n STORES CALCIUM

THE TYPES OF BONES TYPES LONG FLAT SHORT IRREGULAR

LONG BONES LIMBS n ACT as LEVERS – responsible for movement. n Weight Bearing n LENGTH IS MORE THAN WIDTH – The Diaphysis or shaft is longer than the Epiphysis or end, which is usually rounded and expanded. Epiphysis - expanded portion at the end - made of spongy bone mostly with compact bone at the end Diaphysis - between the epiphysis's - made of compact bone Medullary Cavity - cavity in center of the bone - contains the yellow marrow Articular Cartilage - connection between bones

SHORT BONES n n n Cube like shape Form connective bridge Limited movement Stability is essential- predominantly in hands in feet Facilitate movement by elasticity, shock absorpbtion The CARPALS & TARSALS

FLAT n n n Usually thin, flattened and slightly curved Mostly protective in function Includes STERNUM, RIBS, SCAPULAE & CRANIAL bones

IRREGULAR n n Those that don’t have a symmetrical shapes or those which don’t fall into any other category Includes the FACIAL bones, PELVIS & VERTEBRAE

IDENTIFICATION n n n Bones are identified by shape, position in body, function and in relation to its surrounding structures. WHY DO WE NEED TO KNOW THIS ? When there is an injury/trauma to any bone structure, we must know what else could have been affected – muscle, ligament, tendon, artery, vein or nerve. We need to assess short term and long term damage along with choosing right remedies to promote healing. Specific bone diseases including Arthritis, Rheumatism, etc Also to predict healing patterns in case of fracture.

HEALING n n n Bones heal by producing extra osteocytes that occupy deficient area. Then the dead tissue trapped within is either completely re-absorbed or turned into a fibrous scar over which the bone unites. Long bones require to be set if healing needs to take place. The ability to produce RBC is usually lost or diminished in the area of the healing. Remedies like Symphytum, Ruta, Calc Phos aid in the healing by speeding up the process. Complete immobility of the area is essential.

AXIAL SKELETON It consists of The Skull – 22 bones – 8 Cranial and 14 Facial The Vertebrae – 24 The Ribs – 12 The Sternum

THE SKULL The skull has cavities – CRANIAL , NASAL , ORBITAL, ear. It also has foramina- for blood vessels and nerves, the biggest being foramen magnum – for the spinal cord. It develops intramembranously and ossification is complete at 1. 5 yrs when the fontanells disappear. Remedies for fontanelle ossification – Calc Carb, Calc Phos, Sil

Bones of Face and Skull n n n Bones not in diagram – Ethmoid (behind nasal) Lacrimal (part of orbit), Palatine (rear of hard palate), inferior nasal concha, Vomer (nasal septum) Other Facial Bonesn mandible n hyoid bone n Middle ear bones – malleus , incus stapes

The Vertebrae This surrounds and protects the spinal cord. The structure is a short pillar like body – centrum with projections called spinous and transverse processes, which attach to ligaments and back muscles. The body and the neural arch make the vertebral foramen. Between each vertebrea- are intervertebral discs- cartilage pads with jelly like filling.

Ribs and Sternum n n n The ribs are attached to vetrebrae at the back and to cartilage in front, which is then attached to the sternum. They are called costo-chondral cartilages. The last 2 ribs are called floating ribs as they are not attached to anything in the front. The sternum is held up by the cartilages, its ends are attached to muscles of the neck and abdomen. Occasionally an extra cervical rib is present, hampering neck movement. The sternum is fused from 3 parts (body, manubrium, and xyphoid process)

APPENDICULAR SKELETON n n n It consists of PECTORAL GIRDLE –SCAPULA + CLAVICLE and the Upper Limbs PELVIC GIRDLE – ILLIUM, Ischium, Sacrum, Pubis and the Lower Limbs

THE PELVIS n THE MALE Thick and heavy Deep Narrow and deep Heart shaped Smaller Narrow n Round n Large n n n n Structure n P major n n Shallow Wide and shallow Oval/round Larger Wide n Oval n Small n P minor P inlet P outlet -P arch + suprapubic angle -Obturator Foramen -Acetabulum THE FEMALE Thin and light n n

The Hip Bones n n Illium Ischium Sacrum Pubis

n n LOWER LIMBS THE FEMUR Articulates with the Illium via the obturator foramen proximally and to the Tibia and Patella via the condyles distally (at the bottom) Most common injury is fracture at the neck which is mostly in the elderly and a hip replacement surgery is performed where the head is replaced. If break anywhere else – then usually associated with major muscle damage and blood loss – which can be fatal if the femoral artery is cut.

TIBIA & FIBULA The head of the fibula fits just under the lateral condyle of the Tibia. The inner edges of the distal ends of the bones articulate with each other, The Tibia articulates with the Femoral condyles and Patella proximally- forming the Knee Jt and the Calcaneous bone distally to form the Ankle Jt.

THE PECTORAL GIRDLE n n n THE SCAPULA The Glenoid fossa articulates with the head of the Humerous The Acromion process articulates with the clavicle absorbs shock of shoulder impact,

THE CLAVICLE n n Acromial end- is flat and has a small facet for articulation with the acromion; Sternal end- has a large facet for articulation with the manubrium, and first costal cartilage; Conoid tubercle- conoid ligament of the coracoclavicular ligament attaches here; Trapezoid line- trapezoid portion of the coracoclavicular ligament attaches here.

THE HUMEROUS n n It is part of the shoulder joint or rotator cuff. Attached by the head to the scapula at the proximal end and to the Radius at the Capitulum-head of radius- and the Radial fossa in flexion Ulna- Coronoid fossa in flexion and Olecrenon fossa in extension Most common injury to the bone is fracture at the surgical neck.

RADIUS & ULNA They are the most commonly fractured bones. Called Colles #, the other being Barton’s #. n The trochlear notch is the point where the humerous articulates with the ulna and the radial notch is the point where the ulna articulates with the head of the radius n The styloid process of the radius forms the medial margin of the wrist while the styloid process of the ulna forms the lateral margin of the wrist. n

The Hand n n Attachments – to various muscles of the forearm and ligaments that hold all these small bones together. Carpals articulate with metacarpals which in turn articulate with the fingers or phalanges. Special movement – opposable thumb Other movementsholding, tearing, pincer action

The Foot n n n Attachments – to various muscles of the ankle and ligaments that hold all these small bones together. Tarsals articulate with metatarsals which in turn articulate with the fingers or phalangesproximal, intermediate and distal. Special movementsbalance of entire body weight across the arch/bones

Stretch Up… Dr Anjali Hariharan