Locomotor system Organs and structures concerning with the animal movements Passive skeletal structure Bones (osteology) Joints (artherolog) Dr: Ahmed Saber Active skeletal structure Muscles (myology) Vet. Anat. 1. 2008 Osteology Def: it is the science deals with the bones Functions of bones 1. 2. 3. 4. 5. 6. give the body shape (through skeleton) Storage of minerals (calcium) Storage of lipids (yellow marrow) Blood cell production (red marrow) Protection Leverage (force of motion) Dr: Ahmed Saber Vet. Anat. 1. 2008 Classification of bones I- according to shape, position and function 1-long or tubular bones •Long, cylindrical with central cavity •have long body, proximal and distal extremities •Present in limbs as humerus, radius and femur •Act as supporting column and levers Dr: Ahmed Saber Vet. Anat. 1. 2008 1-long or tubular bones (cont) Reduced long bone: have very small central cavity as small metatarsal and metacarpal bone elongated bone: have no medullary cavity as ribs Rib Dr: Ahmed Saber Vet. Anat. 1. 2008 2- flat bones Is plate like give area for muscles attachments Protect underline vital organ Scapula, pelvic bone and skull 3- short bones Has similar dimensions diffuse and reduce concussion carpal and tarsal bone Dr: Ahmed Saber Carpal bones Vet. Anat. 1. 2008 4- Irregular bones irregular in shape single bone & median position As vertebrae vertebra 5- sesamoid bones Present between tendons and joint reduce the frictions between tendons and bones As proximal and distal sesamoid bones Dr: Ahmed Saber Vet. Anat. 1. 2008 6- pneumatic bone Have air spaces instead of central cavity As Para-nasal sinus of mammal the majority of birds skeleton Dr: Ahmed Saber Vet. Anat. 1. 2008 II- according to their structures 1- compact bone Forming the external dense shell of all bones Its thickness is differ – thick in the middle and thin at the extremities Medullary cavity Compact bone Periosteum Dr: Ahmed Saber Vet. Anat. 1. 2008 Haversian system or osteon: is the microscopical structure of bones Dr: Ahmed Saber Vet. Anat. 1. 2008 2- Spongy bones Delicates bony spicules and trabeculae have spongy appearance Its spaces is filled by bone marrow The spongy bone (trajectories) fill the short bones And fill the extremities of long bones Dr: Ahmed Saber Compact bone Spongy bone Marrow space Bony trabeculae Vet. Anat. 1. 2008 III- according to their development 1- endochondral bones: from hyaline cartilage All except skull and flat bone 2- intramembranous bones: From fibrous membranes Cranial and flat bones Dr: Ahmed Saber Vet. Anat. 1. 2008 IV- according to their position 1- Axial bones: unpaired, in medain line Skull, vertebrae, sternum 2- Appendicular bones: bone of limbs 3- Splanchnic or visceral bones: within soft tissues os cordis of ruminant, os penis of dog, os diaphragmatic of camel Dr: Ahmed Saber Vet. Anat. 1. 2008 Cross anatomical components of long bone Periosteum Endosteum Dr: Ahmed Saber Compact bone Medullary cavity Vet. Anat. 1. 2008 1-Periosteum (the outer connective tissue covering), it divided into – Outer protective layer (more fibers) – Inner cellular layer (osteogenic ) Its function – Isolate bone from surrounding tissues – route for circulatory and nervous supply – bone growth and repair Dr: Ahmed Saber Inner cellular layer Outer fibrous layer Vet. Anat. 1. 2008 2- Compact substance Thick at the shaft and thin at extremities 3- Spongy bone at the extremities 4- Medullary cavity contain the marrow 5- Bone marrow in the central cavity of long bones and within the spaces of spongy bone Dr: Ahmed Saber Vet. Anat. 1. 2008 types of bone marrow – Red marrow (mainly in young and rich in blood forming cells) – Yellow marrow( in adult, much amount of fat cells) – Gelatinous (degenerated yellow marrow in senile animal or badly nourished animal) 6- Endosteum – thin fibrous membrane – lined the central cavity and haversian canals of long bone. – covers the trabeculae of spongy bones Dr: Ahmed Saber Vet. Anat. 1. 2008 Gross anatomical regions of long bone 1.Middle body (shaft or diaphysis) 2.Proximal and distal extremities (epiphysis) 3.In young the growth zone (metaphysis) is located between epiphysis and diaphysis) 4. in adult metaphysis become ossify know as epiphyseal line Dr: Ahmed Saber Vet. Anat. 1. 2008 Articular cartilage Spongy bone Epiphysis Epiphyseal line or metaphysis in young Periosteum Compact bone Diaphysis Endosteum Medullary cavity Epiphyseal line or metaphysis in young Epiphysis Dr: Ahmed Saber Vet. Anat. 1. 2008 Gross structures of short, irregular and flat bones Periosteum Compact layer Spongy bone (trabeculae, spaces, endosteum and marrow Compact layer Periosteum In the skull the spongy bones is called diploe, contain diploic veins Dr: Ahmed Saber Vet. Anat. 1. 2008 Chemical composition of bones The bones are hard structures consists of 5% water and 95% solid materials, that divided into A-organic material (35%) cells, osteoid (ground sulfated mucopolysaccharides) and collagen fibers it provides toughness and elasticity B- inorganic materials (65%) mostly calcium and phosphorus it provides hardness to bones Dr: Ahmed Saber Vet. Anat. 1. 2008 Blood and nerve supply of bones 1- Arterial blood supply I. II. III. IV. medullary or nutrient artery periosteal arteries epiphseal arteries metaphyseal arteries Dr: Ahmed Saber Vet. Anat. 1. 2008 2- Venous drainage few accompany arteries but the majoirty not accompany the arteries, they emerge near the articular surfaces 3- Lymph vessels forming channels within periosteum and haversian canals larger lymphatic passes with the veins 4- Nerve supply vasomotor (autonomic) to vessels sensory fibers distributed mainly in the periosteum Dr: Ahmed Saber Vet. Anat. 1. 2008 Skeleton It is the framework of hard structures (bones & cartilages) which support the soft tissues, and is divided into 1- Exoskeleton from ectoderm shells, scales of fish, feather of birds, hair and hoofs of mammals 2- Endoskeleton from mesoderm (except notochord from endoderm) bones and cartilages of animal Dr: Ahmed Saber Vet. Anat. 1. 2008 Classification of mammalian skeleton 1- Axial skeleton skull, vertebrae, ribs and sternum 2- Appendicular skeleton bones of limbs 3- Splanchnic or visceral skeleton os penis of dog, os cordis of ruminant, os diaphragmaticus of camel Dr: Ahmed Saber Vet. Anat. 1. 2008