Ch. 7.4 Skeletal System Key Terms
Forms the extremities (shoulders, arms, hips, and legs). The skeletal system is divided into the axial skeleton and the appendicular skeleton.
appendicular skeleton
The long shaft of a long bone.
diaphysis
foramina
Openings in bones that allow nerves and blood vessels to enter or leave the bone.
Medullary Canal
A cavity in the center of the diaphysis. It is filled with yellow marrow.
The outside of the bone. It is covered with a tough membrane, called the periosteum, which contains blood vessels, lymph vessels, and osteoblasts (special cells that form new bone tissue). It is necessary for bone growth, repair, and nutrition.
Periosteum
Forms the main trunk of the body. It is composed of the skull, spinal column, ribs, and breastbone. The skeletal system is divided into the axial skeleton and the appendicular skeleton.
Axial skeleton
The membrane that lines the medullary canal. It keeps the yellow marrow intact and produces some bone growth.
endosteum
fontanels
Areas made of membrane and cartilage, also called "soft spots". They allow for the enlargement of the skull as brain growth occurs. They are converted to solid bone by approximately 18 months of age.
Metacarpals
The five bones of the palm of the hand.
The bone that allows the lower arm to turn freely. It is the lower arm bone.
Radius
The wrist bones. There are 8 carpals.
Carpals
The two ends of a long bone.
epipphysis
Humerus
The upper arm bone.
Metatarsals
The five bones of the instep of the foot.
Phalanges
The bones that make up the fingers (3 on each finger, 2 on the thumb), and the toes (2 on the great toe and 3 on each of the other 4 toes).
Also called collarbones. They are part of the shoulder, or pectoral, girdle.
Clavicles
The largest bone in the body. It is the upper leg bone, or thigh.
femur
Joints
Areas where two or more bones join together. Connective tissue bands, called ligaments, help hold long bones together at joints.
Os coxae
The hip bones. The pelvic girdle is made of two os coxae (coral, or hip, bones).
There are 12 pairs . They attach to the thoracic vertebrae on the dorsal surface of the body. The first seven pairs are true (attach directly to the sternum), the next five pairs are false, and the last two pairs of false are called floating ___.
ribs
The dome-shaped structure that surrounds and protects the brain. It is composed of eight bones: one frontal, two parietal, two temporal, one occipital, one ethmoid, and one sphenoid.
Cranium
The smaller of the two lower leg bones. It attaches to the proximal end of the tibia.
fibula
Ligaments
Connective tissue bands that help hold long bones together at joints.
Patella
The kneecap.
Found in certain bones, such as the vertebrae, ribs, sternum, and cranium. It produces red blood cells (erythrocytes), platelets (thrombocytes), and some white blood cells (leukocytes).
Red Marrow