Skeletal System The skeleton is a framework of structures, made of bones and cartilage that support and protect the body. - The skeleton is a framework of structures, made of bones and cartilage that support and protect the body.

Axial Skeleton includes the skull, vertebrae, ribs, and sternum. -includes the skull, vertebrae, ribs, and sternum.

Skull Cervical Axis Thoracic Lumbar Atlas Coccygeal Sacral Axial Skeleton Ribs

Skull -many plates of bone fused together.

Skull The soft spot on top of the skull is called a fontanel The soft spot on top of the skull is called a fontanel.

Vertebrae Have five distinct regions: 1.Cervical 2.Thoracic 3.Lumbar 4.Sacral 5.Coccygeal

Cervical vertebrae of the neck regionvertebrae of the neck region

Cervical Atlas  the first cervical vertebra  called “C1”

Cervical Atlas

Cervical Atlas Forms the joint that lets you nod “yes” “yes”

Cervical Axis  the second cervical vertebra  called “C2”

Cervical Axis

Cervical Axis Forms the joint that lets you nod “no”

Cervical How many does a cow have?How many does a cow have? What about a horse?What about a horse? How about a dog?How about a dog? And a cat?And a cat? Any guesses on a giraffe?Any guesses on a giraffe?

Cervical There are seven cervical vertebrae in all mammals Even the giraffe!

Cervical

Thoracic - vertebrae of the body region

Thoracic - always have a rib attached and a spine on top.

Thoracic “True ribs”: directly attach to sternum with cartilage

Thoracic “True ribs”:

Thoracic “False ribs”: connect to each other with cartilage, not the sternum

Thoracic “False ribs”:

Thoracic “Floating ribs”: seen in the dog have cartilage on the tips but do not attach to anything.

Thoracic “Floating ribs”:

Lumbar vertebrae of the lower back

Lumbar Carnivores generally tend to have more perhaps to lend greater flexibility

Lumbar Herbivores need to have a short, strong back to support large digestive and reproductive organs

Sacral vertebrae of the pelvic region

Sacral Fused together on the ventral side.

Sacral Herbivores generally tend to have more to add strength and support to the back. Carnivores tend to have less for flexibility.

Coccygeal vertebrae of the tail region

Coccygeal Used for balance. Become smaller at the end of the tail

Appendicular Skeleton the fore and hind limbs

Appendicular Skeleton Scapula Ulna Radius Carpals Humerus Metacarpals Phalanges Olecranon Forelimb Sesamoids

Pelvis Tarsals Tibia Metatarsals Fibula Femur Sesamoids Phalanges Appendicular Skeleton Hind limb Patella

Forelimb Scapula “shoulder blade” attached with muscle

Clavicle Forelimb the cat is the only domestic animal with a clavicle!

Humerus forms the upper arm Forelimb

Ulna forms the elbow joint Forelimb

Ulna fused with the radius in herbivores Forelimb

Radius forms the forearm Forelimb

Carpus commonly called the “knee” in horses Forelimb

Carpus the “wrist” in dogs and humans Forelimb

Metacarpals commonly called the cannon region of the forelimb Forelimb

Metacarpals Humans:5 Number depends on species:

Metacarpals Horses: 1 plus 2 accessory metacarpals called “splint bones”

Metacarpals Splint Bones (II or IV Metacarpals) Cannon Bone (III Metacarpals)

Metacarpals Dogs and cats: 4 plus the dewclaw Number depends on species:

Metacarpals Cattle: 1 that splits at bottom into a cloven hoof and 2 dewclaws Number depends on species:

Metacarpals Pigs:4 (2 toes and 2 dewclaws) Number depends on species:

Phalanx Proximal phalanx (P1) (bones of the finger, hoof, and claw) Intermediate phalanx (P2) Distal phalanx (P3) (the coffin bone in horses)

Phalanx P1 P2 P3

Phalanx P1 P2 P3

Sesamoids Proximal sesamoids (tucked in behind P1) Distal sesamoid (tucked in underneath P3) called the navicular bone in horses

Sesamoids Proximal Distal

Sesamoids Navicular Bone

Hind Limb Pelvis

Pelvis Tuber coxae part of pelvis that forms the “point of hip”

Hind Limb Pelvis Ischiatic tuberosity part of pelvis that forms the “seat bones”

Pelvis Tuber coxae Ischiatic tuberosity

Femur Hind Limb

Patella

Patella -forms the “stifle” joint in horses -sometimes called the “knee” in dogs -equivalent to the human knee Hind Limb

Patella

Tibia main bone of the gaskin of the horse Hind Limb

Fibula fused with the tibia & considered vestigial in herbivores Hind Limb

Tarsus commonly called the “hock” Hind Limb

Tarsus equivalent to the human “ankle” Hind Limb

Metatarsal cannon region in the hind limb. Hind Limb

Metatarsal Number depends on species Hind Limb

Short Bone cube shaped cube shaped i.e. carpus and tarsus Classification of Bones

Flat Bone plate of bone i.e. scapula, rib, skull Classification of Bones

Irregular Bone complex shaped i.e. vertebrae Classification of Bones

Sesamoid small, seed-shaped bone i.e. proximal and distal sesamoids, patella Classification of Bones

Long Bone bone is longer that it is wide i.e. femur, tibia, humerus, etc. Classification of Bones

Bone Anatomy Diaphysis body of a long bone

Bone Anatomy Epiphysis enlarged ends of long bones

Bone Anatomy Metaphysis joining point of diaphysis and epiphysis

Bone Anatomy Periosteum thin outer protective layer of bone

Bone Anatomy Medullary Cavity space within bone filled with marrow

Bone Anatomy Endosteum thin inner protective layer lining the medullary cavity

Bone Anatomy Marrow

Bone Growth Occurs in the epiphysis of long bones.

Bone Growth Epiphyseal growth plates produce cartilage, which gradually turns into bone via a process called ossification

Fractures Major Categories Simple bone does not break skin

Fractures Major Categories Compound bone breaks through skin, much more serious

Fractures Major Categories Complete fracture goes completely across the bone

Fractures Major Categories Incomplete fracture does not go completely across bone

Classifying Fractures Fissure Fracture incomplete break, along the long axis of the bone

Classifying Fractures Greenstick Fracture incomplete break on one side of a bone, usually due to a bending force

Classifying Fractures Transverse Fracture break across the bone

Classifying Fractures Comminuted Fracture bone shatters into many pieces

Healing Fractures Bone cells lay down a material called fibrocartilage, which gradually turns into bone in a process called ossification.