Anatomy Basics Quiz

Anatomical Position

• 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.

Planes of the Body

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

Directional Terms

• The elbow is proximal to the wrist.

• The heart is medial to the lungs.

Skeletal System

• 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.

Bone Functions

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

Classification of Bones

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

Types of Bones based on Position

• 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.

Types of Bones based on Shape

• 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

• 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.

Vertebral Column

• 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.