AP1 Skeletal System

Functions of the skeletal system

Movement, Protection, Calcium storage, Haematopoiesis

Hematopoiesis

blood cell formation

Divisions of the Skeletal System

axial skeleton and appendicular skeleton

axial skeleton

Portion of the skeletal system that consists of the skull, rib cage, and vertebral column

appendicular skeleton

bones of the shoulder, pelvis, and upper and lower extremities

Fontanels

Gaps between a baby's skull that slowly close up during the first 2-24 months. Allow passage through birth canal and allow the brain to grow.

Foramina

a passage or opening; a hole in a bone through which blood vessels or nerves pass

nasal septum

a wall of cartilage that divides the nose into two equal sections

Turbinates

create turbulence to warm air in nose before going to lungs

hard palate

roof of the mouth, genetic defect can produce cleft palate

Sections of the vertebral column

cervical, thoracic, lumbar, sacrum, coccyx

How many vertebrae make up the cervical spine?

7

How many vertebrae make up the thoracic spine?

12

How many vertebrae make up the lumbar spine?

5

How many bones make up the sacrum of the spine?

1

How many bones make up the coccyx of the spine?

1

Spina Bifida

A birth defect in which a developing baby's spinal cord fails to develop properly. It occurs when a developing baby's spinal cord fails to develop or close properly while in the womb.

Spina Bifida Occulta

most common and least severe form of spina bifida without protrusion of the spinal cord or meninges

spina bifida cystica

more severe type of spina bifida that involves protrusion of the meninges, spinal cord, or both

intervertebral discs

a layer of tough cartilage w/pulp center separating adjacent vertebrae in the spine.

Herniated disc

protrusion of a fragmented intervertebral disc in the intervertebral foramen, may be painful if due to pinched nerve

annular tear

degenerative changes to the intervertebral disc that weakens the disc's outer layers called the annulus

Kyphosis

normal curve of the thoracic spine back/ posterior

Hyperkyphosis

An exaggerated outward/posterior curvature of the thoracic spine resulting in a rounded, “humpback”.

Hypokyphosis

decrease in natural thoracic curvature, spine is too straight

Lordosis

Normal curve of lumbar spine forwards/anterior

Hyperlordosis

exaggerated anterior lumbar curvature (swayback)

Hypolordosis

Decreased secondary curve, base of spine is too straight

Scoliosis

a spinal curve more than 20 degrees

true ribs

1-7; attach directly to sternum

false ribs

8-12; attach indirectly to sternum

floating ribs

13-14; no anterior attachment to sternum

female pelvis traits

shallow, wide, oval, pubic arch \>90 degrees

Male Pelvis Traits

tall, narrow, heart-shaped, pubic arch

Sesamoid bones

Formed within tendons (e.g. patella)

perineum

genital region, from genital region to anus

Fibrous joints

fibrous connective tissue holds bones together. immoveable (e.g. skull, teeth)

Cartillagenous Joint

cartilage pad between bones, slightly moveable (e.g. intervertebral discs

Synovial Joints

created where two bones articulate to allow free movement within range of motion (e.g. knee, elbow, ankle)

temperomandibular joint (TMJ)

the point where the upper skull forms a joint with the lower jaw that is inferior to the zygomatic arch, and just anterior to the ear

glenohumeral joint (GH)

The synovial ball-and-socket joint of the shoulder

acromioclavicular joint (AC)

the joint formed by the acromion of the scapula and the clavicle

joint dislocation

displacement of a bone from its joint. only happens to synovial joints (GH or fingers, usually due to hyperextension)

Joint separation

the connective tissue between two bones tears (acromioclavicular joint due to outstretched arms)

Sprains

ligaments and/or cartilage reinforcing a joint are stretched or torn (2-3 months to heal d/t poor circulation)

Fractures (Fx)

broken bone (6-8 weeks to heal, good circulation)

Strains

muscle tear (10 days-2 weeks to heal, rich circulation)

Tendonitis

inflammation of a tendon due to injury or over use

Bursitis

inflammation of a bursa due to injury or overuse

bursa

a synovial bag of fluid between tendons and joints to reduce friction

rheumatoid arthritis (RA)

chronic joint condition where inflammation erodes joint tissue and deviates bone; caused by an autoimmune reaction. most common in middle aged women

Osteoarthritis (OA)

aka Degenerative Joint Disease (DJD) or "wear and tear Arthritis" caused trauma, repetitive overuse, or immobilization after injury wearing down the cartilage cushion covering bones in a joint; most common in bearing weight joints like hips, knees, neck, and lower back; results in bone rubbing against bone and crepitus (creaky joints). Seen mainly in elderly. Bone spurs grow in and try to freeze the damaged joint.

Gout

metabolic disease caused by the accumulation of uric acid crystals in the blood that erode bone and produce inflation

Fracture haematoma

Occurs in the reactive phase of fracture repair, and is where a mass of blood pools around the site of the fracture.

Procallus (cartilage)

Semi-rigid union of cartilage matrix and granulation tissue splinting bones together. replaces haematoma.

Callus (bone)

forms as a bulging deposit around the area of the break as a bone heals. Replaces procallus. complete by 6-8 weeks

remodeled bone

callus works almost like new

Incomplete Fracture

Bone is partially cracked, but still attached

Complete/Nondisplaced Fracture

Bone is cracked all the way across, but still in place

Complete/Displaced Fracture

Bone is cracked all the way across and separated

Open or Compound Fracture

Bone fragment tears through skin

Communicated Fracture

Bone is shattered into more than 2 pieces

stress fracture

inflamed periosteum, possible hairline fractures, tiny cracks

flat bones,short bones and irregular bones

Bones that may be flat like skull bones and sternum, stubby like wrist and ankle bones, and odd-shaped like facial bones and vertebrae. The interiors of all these are entirely honeycombed

Long Bones

columnar-shaped bones as in the arms, hands, legs, and feet, that have shollow shank and a honeycombed structure of bone at each end

Diaphysis

The center of a long bone

Epiphysis

Ends of long bone that articulate with other bones. Longitudinal growth plates here

Periosteum

Connective tissue tunic that produces circumferential growth or thickness of bone. Pain fibers. Outer layer of bone

compact bone

dense, hard layers of bone tissue that lie underneath the periosteum

medullary cavity

cavity within the shaft of the long bones filled with bone marrow

yellow marrow

fat that fills medullary cavity; energy source

spongy bone

honeycombed structures within the ends of bone or throughout all other types

Red Marrow

Myeloid Tissue: Hematopoiesis. Tissue within red bone marrow that produces the blood cells

Chondroblasts

cartilage forming cells. lay down a matrix of Chondroitin Sulphate; light, rigid but slightly bendable

Chondrocytes

mature blasts that maintain the life of cartilage when formed

hyaline cartilage

the most common type of cartilage used by cartilaginous joints, in the body- found in all synovial joints, shiny and slick

Osteoblasts

bone forming cells. lay down a matrix of Hydroxyapatite; hard, heavy and strong

Osteocytes

mature blasts that maintain life of bone when formed

Osteoclasts

Bone-destroying cells. macrophages that consume or erode bone matrix

Results of the battle between Osteoblasts and Osteoclasts

Compact bone, Spongy bone, Medullary Cavity (only in long bone)

Intramembranous Formation

Osteoblasts form bone within fibrous connective tissue, few examples, e.g. skull, mandible, clavicle

Endochondral Formation

All other bones. Osteoblasts form bone within a cartilaginous precursor, i.e. a bone-shaped model of hyaline cartilage

How do bones with no medullary cavity (e.g. flat bones, irregular) ossify?

The periosteum expands the overall size and thickness of the bone

Ossification

Replacement of cartilage cells and matrix with bone cells and matrix

Diaphyseal ossification

periosteum expands circumference or thickness of long bones

Epiphyseal ossification

epiphyseal plate (Longitudinal Growth plate) increases length of long bones. Plate begins as cartilage. Chondrocytes are highly active and continue to proliferate and lay down cartilage until the genetic length of the bone is achieved. Plate slowly converted to bone. Invading osteoblasts convert the cartilage matrix to bone matrix

Why do bones thicken?

Osteoblasts respond to use, that is, forces operating on bone, such as weight-bearing activities of any kind and exercise

Why do bones get thin?

Osteoclasts respond to disuse, that is, reduced forces on bone, when one ages, becomes sedentary, or is injured/ill (e.g. leg in cast or bedridden). Also, postmenopausal females lose hormonal protection against osteoclastic activity. Since women start with less bone than men, they have less bone to lose after menopause

Osteoporosis

a condition in which the bones lose density and become fragile and break easily. most common in elderly (disuse),post-injury (disuse), females (esp. Caucasians)

Parathormone

secreted by the parathyroid glands; increases blood calcium levels by stimulating osteoclastic activity (eroding bones)

Calcitonin

secreted by the thyroid glands; lowers blood calcium levels by stimulating osteoblastic activity (incorporating blood calcium into bones)

Gigantism

abnormal growth of the entire body that is caused by excessive secretion of growth hormone before epiphyseal plates close at puberty. Affects height and causes enlargement of hands, feet, head and facial deformities

acromegaly

growth hormone secretion becomes excessive and causes bone growth when adult. Causes enlargement of hands, feet, head and facial deformities, but does not affect height

What is a Suture joint? How moveable is it?

The suture joints are immovable or fixed joints consisting of a thin layer of dense fibrous connective tissue, which are found between all the bones of the skull except the mandible

What heals faster: a fracture or a sprain?

Fractures (6-8weeks vs 2-3months)

List the three types of Arthridities listed in your lecture

Rheumatoid Arthritis, Osteoarthritis, Gout

What are the stages of healing a fracture?

Fracture hematoma, procallus, callus, remodeled

What is ossification?

Replacement of cartilage cells and matrix with bone cells and matrix; the hardening of cartilage into bone

What is the key difference between the 2 types of bone formation?

In intramembranous formation, the osteoblasts form within fibrous CT. In endochondral formation, the osteoblasts form within a cartilage precursor.

Distinguish between epiphyseal and diaphyseal ossification.

In diaphyseal ossification, periosteum expands circumference of the bone whereas in epiphyseal ossification the epiphyseal plate increases length of long bones.