| Term | Definition |
| Functions of the skeletal system | 1. Supports and gives shape to the body
2. Protects internal organs
3. Helps with movement (bones are pulled by muscles)
4. Stores calcium
5. Helps with Hematopoiesis |
| Hematopoiesis | Blood Cell Formation |
| Skeletal system is composed of: | -Joints
-Ligaments
-Cartilage
-Bones |
| Joints | Part of the body where two or more bones meet to allow movement. |
| Joints are classified into three categories | - Synarthroses - no movement
- Amphiarthroses - slight movement
- Diarthroses - free movement |
| Synarthroses | Immovable, connected with fibrous tissue |
| Amphiarthroses | Slightly moveable, connected by cartilaginous tissue |
| Diarthroses | Free movement aka as a synovial joint, lined by articular cartilage and lubricated with synovial fluid |
| Different Joints | Hinge joint - elbow joint
Pivot joint - dens of axis rotating against atlas
Saddle joint - Carpometacarpal joint of thumb
Condyloid joint - Atlantooccipital joint
Ball-and-socket joint - Shoulder, hip joint
Gliding - Articular process between vertbr |
| Ligaments | Bands of tough elastic tissue around your joints.
They connect bone to bone, give your joints support, and help limit their movement. |
| Cartilage | Can be found around joints, fibers are embedded in a gel-like substance as opposed to a calcified hard substance like bone, therefore cartilage has much more flexibility. |
| Cartilage can be classified into three categories! | A. Elastic Cartilage
B. Fibrocartilage
C. Hyaline Cartilage |
| Hyaline Cartilage | Articular cartilage when it covers the ends of bones at a joint, is the most abundant in the body. |
| Bones | Substance that forms the skeleton of the body |
| Ossification | Bone formation, begins during prenatal development andpersists throughout adulthood. |
| Bones of infants | Are softer than adults because it has not yet been ossified. |
| There are two ways osteogenesis or ossification occurs: | Intramembranous Ossification: Develops from mesenchymal cells replacing the cartilage
Endochondral Ossification: Develops from the cartilage that is already present |
| Words to Remember | Osteoblasts - Build bone
Osteoclasts - Chew bone
Osteocytes - Maintain bone
Osteogenic Cell - Stem Cells |
| Bone Tissue Structure | Typical bone has an out layer of hard or compact bone, inside this layer is spongy bone. In the middle of some bones is jelly-like bone marrow, where new cells are constantly being produced for the blood. |
| Red and Yellow Bone Marrow | Red - contains blood stem cells; can become red blood cells, white blood cells, or platelets.
Yellow - made mostly of fat; contains stem cells that can become cartilage, fat, or bone cells. |
| Bone Types | -Long
-Short
-Flat
-Irregular
-Sesamoid |
| Sesamoid | Usually short or irregular bones, imbedded in a tendon. It passes over a joint which serves to protect the tendon. |
| Examples of sesamoid bones | Patella (knee cap) - sits in the quadriceps tendon.
Pisiform (smallest of the Carpals) and two small bones at the base of the first Metatarsal. |
| Irregular | These are bones which do not fall into any category (due to non-uniform shape). Primarily consists of cancellous bone, aka spongy bone, with a thin outer layer of compact bone. |
| Examples of irregular bone | -Vertebrae
-Sacrum
-Mandible (lower jaw) |
| Flat | Strong flat plates of bone with main function of providing protection to the vital organs, and a base for muscular attachment.
Anterior and posterior surfaces are made of compact bone to provide protection with the center (spongy) bone and bone marrow. |
| Examples of flat bone | -Scapula
-Sternum
-Cranium
-Coxae
-Pelvis
-Ribs |
| Short | Being approximately as wide a they are long, have primary function of providing support and stability with movement. |
| Examples of short bone | Carpals and tarsals (wrist and foot bones)
Consist of only a thin layer of compact, hard bone with spongy bone on the inside along with relatively large amounts of bone marrow. |
| Long | Largest bones in the body, such as the Femur, Humerus and Tibia. Some of the smallest including the Metacarpals, Metatarsals and Phalanges. |
| Structure of long Bones | -Diaphysis (or shaft)
-Epiphysis (ends) |
| Articular Cartilage | Covers epiphysis and functions as a cushion9 |
| Structure of long bone (medullary cavity, etc) | Medullary Cavity - hollow area inside diaphysis of the bone that contains yellow marrow
Endosteum - membrane lining medullary cavity
Periosteum - strong membrane covering bone everywhere except at joint surfaces |
| Divisions of the Skeleton | Axial & Appendicular Skeleton |
| Appendicular Skeleton (126 total) | -Upper extremities, including shoulder (pectoral) girdle
-Lower extremities, including hip (pelvic) girdle |
| Axial Skeleton (80 total) | -Skull
-Spine (vertebral column)
-Thorax (ribs & sternum)
-Hyoid bone |
| Bones of the SKULL | Skull consists of:
-8 bones that form the cranium
-14 bones that form the face
-6 tiny bones in the middle ear |
| Middle Ear (bones) | The following assists with amplifying sound through vibration:
-Malleus (hammer)
-Incus (anvil)
-Stapes (stirrup) |
| Spinal Column | Consists of a series of separate bones called vertebrae that form a flexible curved rod
-The curves provide strength to support weight of the body & balance |
| Regions of the vertebral column: | 1. Cervical Vertebrae (7) *breakfast
2. Thoracic Vertebrae (12) *lunch
3. Lumbar Vertebrae (5) *supper
4. Sacrum (1)
5. Coccyx (1) |
| Thorax or Chest | Consists of 12 pairs of ribs, the sternum, and thoracic vertebrae. |
| Ribs | 12 pairs except for the lower 2 pairs are attached to the sterum by costal cartilage
8th, 9th, 10th ribs are attached to the 7th rib called "False Ribs"
Last 2 pairs of ribs are not attached to any costal cartilage calld "Floating Ribs" |
| Appendicular Skeleton | Upper and Lower extremities |
| Upper Extremities | Pectoral Girdle
-Scapula (shoulder blade)
-Clavicle (collarbone)
Humerus - long bone of the arm
Radius & Ulna - bones of the forearm
Carpals - wrist bones
Metacarpals - first section of finger bones
Phalanges - second & third sections of fingers |
| Sternoclavicular Joint | Connects the upper extremity to the axial skeleton |
| Lower Extremities | Femur - thigh bone (largest in the body)
Patella - knee cap
Tibia - inner lower leg bone
Fibula - outer lower leg bone |
| Lower Extremities continued | Tarsals - bones of the ankle area
Carpals - wrist bones
Metatarsals - first section of toe bones
Phalanges - second section of toe bones |
| Pelvic Girdle (male vs female) | Shape of pelvis
(male) deep and narrow
(female) broad and shallow
Size of pelvic inlet
(female) generally wider, normally wide for a baby's head to pass through
Pubic Angle
(female) angle between pubic bones generally wider |
