Anatomy Basics Quiz

Study Notes

Anatomical position is characterized by palms facing forward, thumbs pointing laterally, face pointing anteriorly, and body standing upright.
Failure to meet any of these conditions alters the anatomical position.

A vertical plane dividing the body into right and left halves is termed a midsagittal plane.

The skeletal system consists of bones, cartilage, and joints joining them.
Bones are living tissue responding to injury by growing and repairing.
Bone hardness comes from calcification of the extracellular bone matrix.
Bones form the body's framework, act as attachment points for muscles, facilitating movement, and protect internal organs.

Bones also store calcium and phosphorus and create blood cells in the bone marrow.

The adult skeleton, consisting of 206 bones, is classified by position and shape.

Axial skeleton: Includes bones forming the central axis, e.g., skull, vertebrae, ribs.
Appendicular skeleton: Includes bones of the appendages (limbs), e.g., arms, legs, shoulder girdle, pelvic girdle.

Long bones (e.g., femur, humerus) are characterized by a shaft, two ends, and a medullary cavity. Subcategories include typical long bones, modified long bones (no medullary cavity in the shaft – e.g. clavicle), and miniature long bones.
Short bones (e.g., carpals, tarsals) are roughly cube-shaped.
Flat bones (e.g., ribs, scapulae, skull) are thin and flattened.
Irregular bones (e.g., vertebrae, hip bones) have complex shapes.
Sesamoid bones (e.g., patella) are small, round bones embedded in tendons.
Pneumatic bones (e.g., some skull bones) contain air-filled spaces.

Joints are sites where two or more bones meet.
Joints are classified by the tissue type between the bones:
- Fibrous joints: Have fibrous tissue connecting the bones; typically immovable (e.g., sutures of the skull).
- Cartilaginous joints: Connected by cartilage; have little movement (e.g., joints between ribs and sternum, intervertebral joints).
- Synovial joints: Have a joint cavity lined with a synovial membrane, often allowing free movement (e.g., shoulder, hip, knee). Synovial joints consist of a joint capsule, synovial membrane, and synovial fluid. Cartilage is present between the bones to ease movement.

The vertebral column consists of cervical, thoracic, lumbar, sacral, and coccygeal vertebrae.
Cervical, 7 vertebrae, 8 nerves.
Thoracic, 12 vertebrae.
Lumbar, 5 vertebrae.
Sacral, 5 fused vertebrae.
Coccygeal, 1 fused vertebra.