Anatomical Terminology

fracture

a break, especially the breaking of a bone or cartilage

Types of Bone Tissue

1. Cortical bone is solid and extremely strong, allowing it to form a protective outer shell for most bones in the body. 85% of Bone Mass 2. Cancellous Bone is a spongy type of bone in which the lamellae are arranged in plates or bars termed trabeculae that branch and unite to form an irregular meshwork filled with bone marrow

3 types of Bone Cells

1. Osteoblasts: responsible for bone formation. 2. Osteoclasts: responsible for bone resorption. 3. Osteocytes: are mature osteoblasts embedded in the bone that helps maintain the tissue by balancing the activity of Osteoblasts and Osteoclasts

Anatomical Planes

1. Sagittal Plane: passes through center of body. Also called midline. 2. Transverse Plane: cuts the body into an upper and lower half. Also called axial plane. 3. Coronal Plane: cuts vertically through the body, creating front and back half. Also called frontal plane.

4 key overall principles of fracture care

1. fracture reduction and fixation to restore anatomic relationships 2. fracture fixation providing absolute or relative stability as the "personality" of fracture, the patient, and the injury requires: -absolute stability does not allow movement at the fracture site -relative stability allows movement at the fracture site 3. preservation of the blood supply to soft tissues and bone by gentle reduction techniques and careful handling 4. early and safe mobilization and rehabilitation of the injured part and the patient as a whole

The goals of fracture fixation

1. to maintain the reduction 2. to create adequate stability, which allows early and optimal function of the injured limb and minimizes pain

Wolff's Law

A bone grows or remodels in response to forces or demands placed upon it

Anatomic Orientation

Anterior: Toward the Front Also called Ventral Posterior: Toward the back Also known as Dorsal

Distal

Away from the center of the body EX: Hand is Distal to the Wrist

Understanding Plates

In addition to the wide variation in design seen in Figure 2.2, plates can vary in: thickness hole-to-hole distance hole diameter

Locking Plating System

In contrast, when using a locking plate with a locking screw, the plate does not have to be precisely adapted to the bone. Once the screw locks within the threaded plate hole, it cannot pull the bone upward. As a result, reduction is not lost as the screw is tightened, ie, a primary loss of reduction is avoided. In addition, because the plate is not pressed onto that area of bone, potential interference with blood supply to the underlying bone is reduced Another advantage of locking plating systems is that the screws rarely loosen since they are locked to the plate. This increases the stability of the fixation, reducing the risk of a secondary loss of reduction. In fact, loosening is unlikely even if the screw is inserted into a gap in the fracture or into a bone graft. Increased stability can possibly decrease the incidence of inflammatory complications due to loosening.

Anatomic Orientation

Lateral: Away to the side Medial : Towards the Middle

Proximal

Refers to body part that is closer to the center of the body than another part EX: Knee is proximal to the Toes

Understanding Screws

Screws differ in their characteristics, including: -dimension, ie, their major (outer) and minor (inner) diameters and their thread depth -type, ie, whether insertion requires drilling of a preliminary pilot hole -drive mechanisms, ie, a cross-drive or center-drive screw head design Another characteristic that varies among screw is length. As a result, screws are also classified as: -bicortical screws, which extend from the near cortex (on the side of the insertion) to the far cortex -monocortical screws, which do not extend to the far cortex Titanium binds to bone well over time and reduces risk of screw loosening

Anatomic Orientation

Superior: Above Inferior: Below

Stages of Bone Healing

The normal bone healing process includes the following stages: 1. hematoma formation, which is caused by damage to blood vessels in the area and creates the initial framework for healing 2. formation of a fibrocartilage soft callus (woven bone), a granulation tissue that acts to close the gap in the broken bone 3. replacement of fibrocartilage callus by a hard bony callus 4. remodeling, which forms a strong, permanent patch at the fracture site

Requirements for Bone Formation

The process of bone healing requires the interaction of 3 key ingredients: 1. Competent bone- forming cells 2. A suitable matrix/scaffold 3. Presence of biological stimulants

Cephalad

Toward the head Ex: Neck is Cephalad to the lower back

Caudad

Towards the tail or feet Spinal Cord is Caudad to the Brain

Bone Fracture

When a force is applied that exceeds the strength of the bone.

Conventional Plating System

With a conventional plating system, tightening of the screws presses the plate against the bone. This creates the needed stability of the reduction. However, because of the design of this system, it is essential to contour the plate precisely to the bone surface before it is secured to the bone. If there is a gap between the plate and the bone, the tightening of the screws will pull the bone upward towards the plate. This can result in a primary loss of the fracture reduction. In addition, this produces a larger area of contact between the plate and the bone, which can increase the amount of disruption to the periosteal blood supply.

tissue

a collection of similar cells and the intercellular substances surrounding them

remodeling

a cyclic process by which bone maintains a dynamic steady state through sequential resorption and formation of a small amount of bone at the same site; as a result, the size and shape of remodeled bone remain unchanged

callus

a granulation tissue (ie, a vascular connective tissue on the surface of inflamed tissue) that is formed during bone healing

basic multicellular units (BMUs)

a group of cells that participate in bone remodeling in a concerted and coordinated fashion

bones

a hard connective tissue consisting of cells embedded in a matrix of mineralized ground substance (a gelatinous material) and collagen fibers

marrow

a highly cellular hemopoietic connective tissue filling the medullary cavities and spongy epiphyses (ends) of long bones

hematoma

a localized mass of extravasated blood that is relatively or completely confined within an organ or tissue, a space, or a potential space

bone mass

a measure of the density of bone, which relates to the quantity of bone

hydroxyapatite

a naturally occurring mineral that the crystal lattice of bones and teeth (ie, amorphous hydroxyapatite) closely resemble

lacunae

a space in hardened bone matrix that contains an osteocyte

trabecular bone

a type of bone in which the lamellae are arranged in plates or bars termed trabeculae that branch and unite to form an irregular meshwork filled with bone marrow; also known as cancellous or spongy bone

cancellous bone

a type of bone in which the lamellae are arranged in plates or bars termed trabeculae that branch and unite to form an irregular meshwork filled with bone marrow; also known as trabecular or spongy bone

osteoblasts

bone-forming cells that synthesize an osseous matrix in which they become enclosed as osteocytes

osteocytes

cells of osseous (bone) tissue that occupy a lacuna and have cytoplasmic processes that extend into canaliculi and contact the processes of other osteocytes

osteons

central canals containing blood capillaries and the concentric osseous lamellae around them occurring in compact bone; also called haversian systems

haversian systems

central canals containing blood capillaries and the concentric osseous lamellae around them occurring in compact bone; also called osteons

lamellae

concentric layers of bone matrix

osteotomy

cutting a bone, usually by means of a saw or osteotome

Purpose of Rigid Fixation

f fracture fragments are displaced, bone healing generally must begin with a process called reduction. In this process, the broken bone ends are realigned to their normal position. There are several methods of reduction, including: closed manipulation, which moves the bone ends back into place without opening the skin application of traction, which pulls the bone ends into proper alignment open reduction, which uses a surgical approach to expose the fracture site and allow the bone fragments to be brought together under direct visualization After reduction, proper alignment must be maintained. In some cases, splints and casts are used to immobilize the fracture site, thus holding the reduction in alignment. In cases that use open reduction, immobilization can be maintained by placement of devices such as screws, plates, nails, or wire into the bone fragments. This process is called internal fixation.

Mature Bone

is a highly organized structure. Cells are interconnected by channels.

Woven Bone

is disorganized tissue found in tumors, new fracture sites, and regions of growing bone

Supine Position

is lying on the back.

Lateral Recumbent Position

is lying on the side.

Prone

is lying on the stomach with face down

Lamellar Bone

is organized bone characterized by a linear orientation of collagen

osteoclasts

large multinucleated cells functioning in the absorption and removal of osseous (bone) tissue

osteoid

newly formed organic bone matrix before calcification

Bone Remodeling

ongoing replacement of old bone tissue by new bone tissue

craniomaxillofacial (CMF)

pertaining to the cranium (the bones of the head), the jaws, and the face

osteoporosis

reduction in the quantity of bone or atrophy of skeletal tissue; an age-related disorder characterized by decreased bone mass and loss of normal skeletal microarchitecture, leading to increased susceptibility to fractures

vertebral

relating to one of the segments of the vertebral column, ie, the spine

canaliculi

small channels in bone that connect the lacunae to each other and to the haversian canal; each canaliculus encloses a small extension from the osteocyte contained in the lacuna

tensile strength

the ability of a material to hold itself together; the maximum tensile stress or load that a material is capable of sustaining; usually expressed in pounds per square inch

skull

the cranium, ie, the bones of the head collectively

matrix

the extracellular substance of bone tissue consisting of collagen fibers and ground substance, before the deposition of inorganic bone salts

collagen

the major protein of the white fibers of connective tissue, cartilage, and bone; gives bone its tensile strength (the ability to hold itself together

cortical bone

the noncancellous portion of bone that consists largely of concentric lamellar osteons and interstitial lamellae; the superficial thin layer of compact bone

resorption

the removal of osseous tissue by osteoclasts; can be part of the normal balance of bone resorption and deposition or part of a pathologic process

reduction

the restoration, by surgical or manipulative procedures, of a part to its normal anatomic relation

homeostasis

the state of equilibrium (balance between opposing pressures) in the body with respect to various functions and to the chemical compositions of the fluids and tissues

periosteum

the thick, fibrous membrane covering the entire surface of a bone except its articular cartilage and the areas where it attaches to tendons and ligaments

thorax

the upper part of the trunk between the neck and the abdomen; formed by the 12 thoracic vertebrae, the 12 pairs of ribs, the sternum, and the muscles and fasciae attached to these; below, it is separated from the abdomen by the diaphragm; it contains the chief organs of the circulatory and respiratory systems

Rigid fixation

the use of screws and plates to secure a fracture in proper alignment so that healing can occur.

Volkmann canals

vascular canals in compact bone that perforate the lamellae of the haversian system, and connect the canals of that system