Medical Terminology: Human Body Systems, Skeletal and Muscular Anatomy

Comprehensive vocabulary flashcards covering organ systems, long bone anatomy, bone markings, fracture and joint classifications, muscle physiology, contractions, actions, and anatomical body regions.

Lymphatic System

A body system consisting of lymphatic vessels, lymph nodes, spleen, tonsils, and thymus that controls fluid balance, absorbs fats, fights disease, and builds immunity.

Thymus

An endocrine and lymphatic organ responsible for the maturation of T-cells for cellular immunity; most active from childhood to puberty.

Axial Skeleton

A division of the skeletal system consisting of 80 bones—including the skull, vertebrae, ribs, sternum, and hyoid—that functions to protect internal organs such as the brain, spinal cord, heart, and lungs.

Appendicular Skeleton

A division of the skeletal system consisting of 126 bones—including the upper and lower limbs, pectoral girdle, and pelvic girdle—that functions in locomotion, reaching overhead, grasping, and manipulating objects.

Long Bones

Bones that are longer than their width, function as levers pulled by muscles, and support body weight; examples include the femur, tibia, fibula, radius, clavicle, and phalanges.

Short Bones

Bones whose length and width are nearly equal and are irregularly shaped; examples include carpals and tarsals.

Flat Bones

Bones made of two layers of bone divided by a narrow span that serve as a protective layer; examples include the cranium, scapula, ribs, and sternum.

Irregular Bones

Bones that do not fit into other classification groups and feature specialized surfaces for attachments; examples include vertebrae, the hyoid, and the ischium.

Sesamoid Bones

Bones that develop inside tendons that pass over long bones; examples include the patella and pisiform.

Diaphysis

The shaft or central part of a long bone.

Epiphysis

The end part of a long bone.

Epiphyseal Plate

The growth plate of a bone, serving as the specific area where longitudinal bone growth occurs.

Medullary Cavity

Also called the marrow cavity; the central cavity within a bone shaft where yellow and/or red bone marrow is stored.

Compact Bone

Also known as cortical bone; dense bone tissue used to form the outer part of all bones.

Spongy Bone

Also known as cancellous bone; lattice-like bone tissue forming the inner layer of all bones.

Articular Cartilage

Smooth, white hyaline tissue that covers the ends of bones where they come together to form a joint.

Periosteum

A membrane that covers the entire outer surface of all bones, with the exception of joint surfaces.

Parts of a Long Bone

Anatomical structures of a long bone, including the epiphysis, epiphyseal plates, diaphysis, medullary cavity, compact bone, spongy bone, periosteum, and bone marrow.

Process (Bone Marking)

A bone marking where part of a bone projects outward like a bridge.

Tuberosity

A surface feature of a bone characterized as a long bump that is difficult to see or feel.

Crest (Bone Marking)

A raised ridge located at the edge of a bone.

Condyle

A rounded knob located at the end of a bone.

Simple Fracture

A bone fracture where the bone is broken, but the overlying skin remains intact and unopened.

Compound Fracture

A bone fracture where the bone is broken, ends are angulated, and the broken bone ends may penetrate through the skin.

Comminuted Fracture

A fracture where the bone is shattered into pieces that lodge into surrounding tissues.

Greenstick Fracture

A fracture in which the bone bends and splits, producing an incomplete break.

Sprain

An injury caused by tearing of a ligament or joint capsule resulting in a loss of stability, classified into three grades of severity.

Dislocation

An injury where a joint exceeds its normal physiological limits and remains out of place.

Subluxation

A partial dislocation or incomplete separation of bones at a joint that goes back into place.

Fibrous Joints

Immovable joints where bones are joined by fibrous tissue; an example is the sutures of the cranium.

Cartilaginous Joints

Slightly movable joints; examples include vertebral discs, sacroiliac joints, and the symphysis pubis.

Synovial Joints

Freely movable joints characterized by fluid-filled joint cavities; examples include ball-and-socket, hinge, pivot, gliding, saddle, and condyloid joints.

Ligament

A tough band of fibrous connective tissue that holds bone to bone.

Tendon

A band of fibrous connective tissue that attaches muscle to bone, anchoring directly to the periosteum.

Lever

A rigid bar that moves on a fixed point called a fulcrum when a force is applied to it, operating as the mechanical basis for skeletal muscle movement.

Muscle Origin

The point of muscle attachment on a stationary bone, typically located closer to the midline of the body.

Muscle Insertion

The point of muscle attachment on the moving bone, typically located more distal to the midline of the body.

Muscle Attachment Points (Origin and Insertion)

The structural points of attachment showing muscle origin on a stationary bone and insertion on a movable bone crossing at least one joint to produce movement.

Myosin and Actin

Protein filaments within muscle fibers that slide over each other to generate tension and cause muscle contraction.

Isotonic Contraction

A type of muscle contraction where muscle tension remains constant while the muscle changes length, divided into concentric and eccentric contractions.

Concentric Contraction

An isotonic contraction where the muscle shortens and its ends move closer together (e.g., the biceps during a pull-up).

Eccentric Contraction

An isotonic contraction where the muscle lengthens under tension and its ends move further apart (e.g., the biceps when lowering from a pull-up).

Isometric Contraction

A muscle contraction where the muscle generates tension but stays the exact same length without joint movement (e.g., shoulder muscles during tug-of-war).

Isokinetic Contraction

A muscle contraction performed at a constant speed through a full range of motion.

Muscle Strain

Damage or injury to a muscle or tendon characterized by tenderness and swelling.

Tendonitis

Inflammation of a tendon or its lining sheath caused by repeated stress.

Gluteus Maximus

The largest muscle in the human body; acts primarily to pull the leg backward at the hip (hip extension).

Stapedius

The smallest muscle in the human body.

Sartorius

The longest muscle in the human body.

Muscle Actions and Anatomy Diagram

Anterior and posterior representations of primary skeletal muscles and their directional actions across anatomical planes.

Piloerection

The muscular and integumentary response that produces goosebumps in order to conserve body heat.

Peristalsis

Involuntary smooth muscle contractions of digestive tract organs that push food and drink through the alimentary canal.

Cervical Vertebrae

The group of 7 vertebrae ($C1$ to $C7$) in the neck that form the cervical curve.

Thoracic Vertebrae

The group of 12 vertebrae ($Th1$ to $Th12$) in the mid-back that form the curvature known as thoracic kyphosis.

Lumbar Vertebrae

The group of 5 vertebrae ($L1$ to $L5$) in the lower back that form the curvature known as lumbar lordosis.

Sacrum

A triangular bone at the base of the spine composed of 5 fused vertebrae that exhibits a convex curvature.

Pollex

The anatomical term designating the thumb.

Hallux

The anatomical term designating the great toe.

Brachial Region

The anatomical body region encompassing the upper arm.

Antebrachial Region

The anatomical body region encompassing the forearm.

Popliteal Region

The anatomical body region located on the posterior surface (back) of the knee.

Sural Region

The anatomical body region encompassing the posterior calf area of the leg.

Calcaneal Region

The anatomical body region encompassing the heel of the foot.

Inguinal Region

The groin area located at the junction between the lower abdomen/legs and the genitals.