bone marrowThe filling of a bone, where blood cells are born. In an adult the red kind lies mainly in the ribs, the vertebrae, the breastbone and the bones of the pelvis. Yellow marrow, which stores fat, fills the rest.
cartilageA flexible tissue, softer than bone, found in joints. It has no blood vessels. Most bones first take shape as cartilage models, which then turn to bone.
femurThe single bone inside the thigh. It runs from the hip to the knee. No bone in the body is larger or thicker.
jointWhere one bone connects with the next. Most joints in an adult move freely. The sutures of the skull do not move at all.
ligamentWhat keeps the two bones of a joint from parting. It is a band of tough fiber. Tendons are made of the same stuff, collagen, but run from muscle to bone.
ribOne of the 24 bones that hoop the chest. They come in 12 pairs. Ribs shield the heart and the lungs, and they let the chest expand for a breath.
Show all 36 terms (30 more)
Bones and what joins them, continued
rib cageThe frame of bone that expands as the lungs fill. It is made of the ribs, the breastbone and the 12 vertebrae behind the chest.
skeletal systemThe body's frame: its bones and what connects them. Cartilage, ligaments and tendons belong to it as well as the bones. It is about 20 percent of body weight.
skullThe head's bone framework, a case for the brain. Cranium is another name. Its bones are locked together at seams called sutures.
spineThe body's central column, from skull to tailbone. It has 7 vertebrae in the neck, 12 behind the chest and 5 in the lower back, then the sacrum and the tailbone. Backbone is another name.
tendonA sinew: the rope a muscle uses to tug on bone. It passes the pull of the muscle on to the skeleton and has to stand up to being stretched.
vertebraOne link in the chain of bones down the back. The plural is vertebrae. Disks of cartilage sit between one and the next.
Joints and bone tissue 12
ball-and-socket jointA joint shaped like a knob sitting in a bowl. The hip and the shoulder are the best known. This kind of joint can move in many directions.
bone matrixThe hard material laid down between bone cells. Bone-forming cells deposit it around themselves until they are walled in.
compact boneThe dense, solid layer that forms a bone's outside. It is heavier and denser than spongy bone, and packed so tightly that it looks solid.
hematopoiesisThe making of blood cells, mostly in red marrow. The word joins the Greek for blood and to make. Red cells, white cells and platelets are all made this way.
hinge jointA joint that swings one way only, like a door. The elbow is one: it bends and straightens and does nothing else. The knee is another.
immovable jointA joint held fast by fibers, as between skull bones. Only a thin layer of fibrous tissue separates the bones. The sutures of the skull are the usual example.
joint capsuleThe sleeve of fiber that encloses a movable joint. Its outer layer is made of ligaments, which hold the bones together. Its lining makes the fluid that oils the joint.
joint cavityThe fluid-filled gap inside a movable joint. The fluid is synovial fluid, about as thick as egg white. It lets the cartilage of one bone glide over the cartilage of the next.
osteonOne of the tiny ringed columns that build hard bone. It is about a quarter of a millimeter across, with a canal for blood vessels down the middle. Compact bone is osteons packed side by side.
skeletal muscleMuscle that is anchored to bone and moves it. It is the kind of muscle a person moves at will. Tendons attach it to the bones, and bone and muscle together work as levers.
slightly movable jointA joint with a pad of cartilage that gives a little. The joints between the vertebrae are of this kind, and so are the ones that tie the ribs to the breastbone.
spongy boneThe honeycomb of bone found inside the hard layer. It is lighter than compact bone. Its plates and bars follow the lines of stress, like the braces of a building, and red marrow fills the gaps.
The skeleton and kinds of bone 12
appendicular skeletonThe bones of the limbs, shoulders and hips. It has 126 bones, and the two hands and two feet hold 106 of them.
axial skeletonThe skull, the spine and the rib cage taken together. It has 80 bones: 28 in the skull, 26 in the spinal column, 25 in the rib cage and the hyoid bone.
endoskeletonA skeleton on the inside, under skin and muscle. Every animal with a backbone has one. A skeleton worn on the outside, like a crab's, is an exoskeleton.
flat boneA thin, plate-like bone, such as a shoulder blade. The breastbone, the ribs and most of the cranium's bones are flat. They protect organs and give muscles broad surfaces to attach to.
floating ribA rib joined to the spine only, free at the front. The eleventh and twelfth pairs are floating ribs. They are joined only to the vertebrae behind.
irregular boneA bone whose odd shape fits no other class. The vertebrae are irregular bones, and so are some bones of the skull.
long boneA bone built as a shaft with a knob at each end. The humerus, radius and ulna of the arm and the femur, tibia and fibula of the leg are long bones. So are the small bones of the fingers: shape counts, not size.
pelvic girdleThe paired hip bones, where each leg is attached. With the sacrum and the tailbone it forms the pelvis. The top of each femur fits into a socket in a hip bone.
short boneA bone about as wide and thick as it is long. The carpals of the wrist and the tarsals of the ankle are short bones.
shoulder girdleThe two collarbones and two shoulder blades. Pectoral girdle is another name. The arms hang from it, and its only joints with the trunk are where the collarbones meet the breastbone.
stirrupThe smallest bone of all, deep inside the ear. Stapes is its Latin name, and it is shaped like the stirrup of a saddle. It passes sound vibrations on to the inner ear.
true ribA rib with its own cartilage link to the breastbone. The first seven pairs are true ribs. The next three pairs share one strip of cartilage to the breastbone.
How this list was compiled: Term list chosen for this site on 2026-10-12. Each meaning is written in our own words and was checked that day against the article on the term in the English Wikipedia (https://en.wikipedia.org/), whose text is under the Creative Commons Attribution-ShareAlike license: Human skeleton, Skeleton, Endoskeleton, Skull, Rib, Vertebra, Hip bone, Femur, Cartilage, Ligament, Tendon, Bone marrow, Elbow, Ball-and-socket joint, Synovial fluid, Collagen, Osteon, Haematopoiesis, Appendicular skeleton, Shoulder girdle, Long bone, Short bone, Flat bone, Irregular bone and Stapes. Rib cage, spine, hinge joint, ball-and-socket joint, true rib, floating rib, shoulder girdle, compact bone, spongy bone, osteon, hematopoiesis and skeletal muscle rest on their entries in Wiktionary, the free dictionary (https://en.wiktionary.org/). What the skeletal system is made of and does, calcium, red and yellow marrow, the bone matrix, compact and spongy bone, the four shapes of bone, the counts of the axial and the appendicular skeleton, and the immovable and the slightly movable joint, the joint capsule and the joint cavity were checked a second time against the Skeletal System pages of the SEER Training Modules of the National Cancer Institute (https://training.seer.cancer.gov/anatomy/skeletal/): Introduction, Structure of Bone Tissue, Bone Development and Growth, Classification of Bones, Axial Skeleton, Appendicular Skeleton and Articulations. The 106 bones of the hands and feet are added up from the list on its Appendicular Skeleton page. The fact after each meaning is from the same pages. Licence: own work
How it works
This skeletal system vocabulary worksheet prints skull, rib, spine, vertebra, femur, joint, cartilage, ligament, tendon and bone marrow, among twelve terms, to match to their meanings, with a key as the last page.
Read the full guide
Joints and bone tissue
Set opens on Bones and what joins them. The second set has hinge joint, ball-and-socket joint, immovable joint, slightly movable joint, joint capsule, joint cavity, compact bone, spongy bone, osteon, bone matrix, hematopoiesis and skeletal muscle.
The skeleton and kinds of bone
The third set has axial skeleton, appendicular skeleton, endoskeleton, shoulder girdle, pelvic girdle, long bone, short bone, flat bone, irregular bone, true rib, floating rib and stirrup.
Humerus, radius, ulna, tibia, fibula, carpals, tarsals and pelvis are named in the facts under the tool, not on the sheet.
Questions and answers
What are the functions of the skeletal system?
Support, protection, movement, storage and making blood cells. Bones hold the body up, shield soft organs, act as levers for the muscles, store calcium and, in their red marrow, produce blood cells.
Why do babies have more bones than adults?
Because some bones fuse as a child grows. A newborn has around 270, and an adult around 206.
What are bones made of?
A matrix rich in the protein collagen and hardened by calcium salts, chiefly calcium phosphate. Bone is living tissue: some of its cells build new bone while others break old bone down.
Can this be a vocabulary review worksheet for the skeletal system?
Yes. In Set, All of them draws twelve terms from all 36, so one printed sheet mixes bones, joints and kinds of bone.