Anatomy I for Veterinary Technicians - Skeletal System (part 1)

diaphysis

shaft of long bone

epiphysis

enlarged proximal and distal extremities of long bone

metaphysis

the joining point of the diaphysis and epiphysis in growing bone, the part of the epiphyseal cartilage being replaced by bone

nutrient foramen

opening through which nutrient artery passes

innervated

nerves come in and put end plates on bone or tissue

articular surface

smooth layer of hyaline cartilage covering the epiphysis, joint formation

endosteum

tissue lining the medullary cavity

periosteum

connective tissue surrounding the bone that is not covered by articular cartilage. Necessary for bone growth, repair, attachment of ligaments/tendons

endosteum

the fibrous membrane that lines the hollow interiors of bones

Wolff's Law

law according to which biologic systems such as hard and soft tissues become distorted in direct correlation to the amount of stress imposed upon them."use it or lose it"

medullary cavity

space in diaphysis containing marrow

cancellous bone

Cancellous bone: Spongy bone. A form of bone composed of a seemingly random spongelike to the naked eye. Found in the ends (epiphysis) of long bones and the interiors of short bones, flat bones, and irregular bones.

Compact bone

Heavy dense bone, made up of tiny, tightly compacted, laminated cylinders of bone called haversian systems; makes up the shafts (diaphyses) of long bones and othe outer surfaces of all bones.

cartilage

an opaque, dense connective tissue composed of a relatively small number of cells that are contained in a a non-living matrix. Cartilage is not innervated or vascularized, which makes it resistant to pain but also to healing

articulation (joints)

formed were on bone connects another

fibrous joints

minimal to no movement, main purpose is to hold bones together, along flat bones of cranium

cartilaginous joints

permit only limited movement, mainly stretching or compression, found in pelvic symphysis between vetrebral bodies

synovial joints

"true joint" permit a relatively wide range of motion, motion can be in a single plane (ie: elbow), motion can be in multiple directions (ie: hip)
Components: 2 bones, hyaline cartilage

articular cartilage

the thin layer of hyaline cartilage that cover the articular surfaces of long bones in synovial joints. It form as a smooth layer over the joint surfaces of the bones, which decreases friction and allows free joint movement

joint capsule

the membrane that encloses the ends of the bones in a synovial joint; consists of an outer fibrous membrane and an inner synovial membrane that produces viscous synovial fluid that lubricates the joint surfaces

synovial fluid

provides lubrication for the joints movements, provides a route for diffusion of oxygen and nutrients to, and removal of waste products from the joints cartilage

joint cavity

the fluid-filled potential space between the joint surfaces of a synovial joint; the joint cavity is normally filled by the viscous, lubricating fluid produced by the synovial membrane lining of the joint capsule (synovial fluid); also known as the joint space

Osteochondritis dissecans (OCD)

commonly occurring disease, a dissecting or abrading injury to articular cartilage produces pain and lameness, surgical intervention required, most common site for this lesion in the dog is the shoulder, but elbow, hock, stifle and femoral head may also be affected.

ossification

process of replacing other tissues with bone, mineralization or hardening of bone

ligaments

avascular; in most cases distinct thick collagenous bands passing in a proximal to distal direction along the joint; in some instances, ligaments are poorly distinguished from the joint capsule, injury to a ligament more serious than injury to bone

dewclaw

digit that does not bear weight

Cribriform plate

the sievelike area of the ethmoid bone through which the many branches of the olfactory nerves pass from the upper portion of the nasal cavity to the olfactory bulbs of the brain.

External acoustic meatus

the bony canal in the temporal bone that leads into the middle and inner ear cavities of the bone. In the living animal, it contains the external ear canal

Foramen magnum

the large hole in the occipital bone through which the spinal cord exits the skull

Frontal sinus

the large paranasal sinus in the frontal bone of the skull

Lacrimal sac

a small sac that receives tears from the lacrimal puncta and sends them down into the nasalacrimal duct

lower arcade

in reference to teeth, it means the teeth in the mandible, or lower set of teeth in the mouth

Pituitary fossa

a joint that allows only a rotary motion. The only true pivot joint in most animals is the atlantoaxial joint between the first and second cervical vertebrae; also called a trochoid joint

Upper incisor teeth

form the gnawing mechanism of rodets

Upper cheek teeth

Where does the parotid gland opens inside of?

Ball-and-socket joint

allows you to swing limb freely in a circle; found in shoulders and hips

Gliding joint

allows one bone to slide over another; found in wrist and ankles

Hinge joint

a joint allowing movement in one plane only

Pivot joint

a freely moving joint in which movement is limited to rotation

upper arcade

in reference to teeth, it means the teeth in the maxilla, or upper set of teeth in the mouth

Phalanges - proximal

digits, "long pastern" in a horse, cow

Phalanges - middle

digits, "short pastern" in a horse, cow

Phalanges - distal

digits, "coffin bone" in horse, cow,"pedal bone" in horse

fetlock joint

metacarpalphalangeal (+ prox sesamoid bone)

pastern joint

proximal interphalangeal joint

coffin joint

distal interphalangeal joint (+ distal sesamoid bone {navicular bone})

proximal sesamoid bones

dog, horse, cow, 2 per metatcarpal bone

distal seasmoid bones

horse, cow, 1 per digit not found in carnivore, navicular bone

dorsal sesamoid bones

only found in carnivores, 1 per digit

intervertebral articulations

fibrocartilaginous joints between vertebral bodies (intervertebral disc); 1. anulus thicker ventrally than dorsally, cocentric fibrous rings 2. Nucleus pulposus - semi fluid, under pressure - will escape if afforded the opportunity in direction of cord which will increase pressure on spinal cord - herniated disc (consequences: pain, hindlimb paresis(weakness)/ataxia(inability to coordinate muscle activity for smooth movements) and inability to stand unaided

muscular suspension of the thorax between the forelimbs(dog)

deep pectoral, serratus ventralis muscles act as a "sling" and transmit weight of head, neck and cranial trunk to forelimbs, also, rhomboideus, trapezius

arthrocentesis

aspiration of fluid from a joint performed by needle puncture. Joint tap.
Shoulder joint tap- Acromion and greater tubercle are landmarks, placing needle midway between

humerus

the long bone of the brachium or upper arm

radius

one of two bones that form the antebrahcium, or forearm. The radius is usually the main weight bearing bone.

ulna

one of two bones that form the antebrahcium, or forearm. The ulna forms a major portion of the elbow joint with the distal end of the humerus

antebrachiocarpal joint

between radius and ulna and proximal row of carpal bones, most movement

middle carpal joint

between proximal and distal row of carpal bones, most movement

carpometacarpal joints

between distal row and carpal bones and metacarpal bones, very little movement

sacroilliac joint

between the sacrum and the wing of the ilium, small range of motion. This flexibility allows the joint to absorb the shock transmitted when the pelvic limb contacts the ground

coxofemoral (hip) joint

ball and socket joint, wide range of movement, bones contributing to hip joint are the acetabulum of the os coxae and head of the femur

hip dysplasia

literally means an abnormality in the development of the hip joint. Characterized by a shallow acetabulum (the "cup" of the hip joint) and changes in the shape of the femoral head (the "ball" of the hip joint) These changes may occur due to excessive laxity in the hip joint. Hip dysplasia can exist without clinical signs. It may or may not be bilatreal (affecting both right & left sides) When dogs exhibit clinical signs of this problem they are usually are lame on one or both rear limbs. Severe arthritis can result of the malfomation of the hip joint and this results in pain as the disease progresses.

stifle (knee) joint

considered a hinge joint, motion is limited to flexion and extension. Bones -femur, patella, tibia and fibula contribute to stifle joint. Three mobile subjoints are formed among these 4 bones: a) femorotibial joint - formed by femoral condyles and tibial condyles, provides flexion/extension motion and weight-bearing function of stifle joint. b) femoropatellar joint - formed by the patella and femoral trochlea, this articulation protects the quadriceps femoris muscle by providing a wider bearing surface area for its tendon, thus distributing pressure over a wider area and reducing wear c) proximal tibiofibula joint - caudolateral surface to the fibular head, no movement

menisici

medial and lateral menisci and "C" shaped fibrocartilages interposed between the femur and tibia to improve the fit between these incongruous bones. On proximal surface of the tibia that help support the condyles of the femur

Long bones

-cylindrical, levers, i.e. humerus, femur

Centers of ossification:

-develop in specific regions of a bone
-each center closes/fuses at a specific age

Skeleton

consists of bones and other connective
tissue structures (cartilage, ligaments, and joints)

Two types of Ossification:
Intramembranous Ossification & Endochondral Ossification

1. Intramembranous Ossification-
bone develops frommesenchyme or
fibrous connective tissue.
--skull, sesamoid bones
--long bones
2. Endochondral Ossification-
bone replacesan existing cartilage model.
--long bones