Anatomical Landmarks, Body Cavities, and Orientation: Study Notes for Anatomy & Physiology

Anatomical Body Landmarks

Anterior Body Landmarks and Their Definitions

Anterior (front) body landmarks are specific regions on the front of the body used to describe locations and orientations in anatomy.

• Abdominal: The region of the abdomen.

• Acromial: The point of the shoulder.

• Antecubital: The anterior surface of the elbow.

• Axillary: The armpit area.

• Brachial: The arm (upper portion).

• Buccal: The cheek area.

• Carpal: The wrist.

• Cephalic: The head.

• Cervical: The neck region.

• Coxal: The hip.

• Crural: The leg (lower portion).

• Digital: The fingers or toes.

• Femoral: The thigh.

• Fibular (Peroneal): The side of the leg.

• Frontal: The forehead.

• Hallux: The great toe.

• Inguinal: The groin area.

• Mammary: The breast region.

• Manus: The hand.

• Mental: The chin.

• Nasal: The nose area.

• Oral: The mouth.

• Orbital: The eye area.

• Palmar: The palm of the hand.

• Patellar: The anterior knee (kneecap).

• Pedal: The foot.

• Pelvic: The pelvis region.

• Pollex: The thumb.

• Pubic: The genital region.

• Sternal: The region of the breastbone.

• Tarsal: The ankle.

• Thoracic: The chest.

• Umbilical: The navel (belly button).

Posterior Body Landmarks and Their Definitions

Posterior (back) body landmarks are used to describe locations on the back side of the body.

• Acromial: The point of the shoulder.

• Brachial: The arm.

• Calcaneal: The heel of the foot.

• Dorsum: The back.

• Femoral: The thigh.

• Gluteal: The buttock.

• Lumbar: The lower back between the ribs and pelvis.

• Occipital: The back of the head or base of the skull.

• Olecranal: The posterior surface of the elbow.

• Otic: The ear.

• Perineal: The region between the anus and external genitalia.

• Plantar: The sole of the foot.

• Popliteal: The back of the knee.

• Sacral: The area between the hips at the base of the spine.

• Scapular: The shoulder blade area.

• Sural: The calf (posterior surface of the leg).

• Vertebral: The area of the spinal column.

Body Direction and Orientation

Anatomical Position

The anatomical position is the standard reference position for the body in the study of anatomy. In this position, the body stands upright, facing forward, with feet parallel and arms at the sides with palms facing forward.

Directional Terms

Directional terms are used to describe the location of one body part relative to another or to the body as a whole.

• Axial/Appendicular: Axial refers to the head, neck, and trunk; appendicular refers to the limbs.

• Superior/Inferior: Superior means above; inferior means below.

• Cranial (cephalic)/Caudal: Cranial means toward the head; caudal means toward the tail (or lower part of the body).

• Anterior (ventral)/Posterior (dorsal): Anterior (ventral) means toward the front; posterior (dorsal) means toward the back.

• Medial/Lateral: Medial means toward the midline; lateral means away from the midline.

• Proximal/Distal: Proximal means closer to the point of attachment; distal means farther from the point of attachment.

• Superficial (external)/Deep (internal): Superficial means toward or at the body surface; deep means away from the body surface, more internal.

Body Planes and Sections

Body planes are imaginary lines drawn through the body to separate it into sections. These are used to describe views or cuts through the body or its organs.

• Sagittal plane: Divides the body into right and left parts.

  • Midsagittal (median): Divides the body into equal right and left halves.

  • Parasagittal: Divides the body into unequal right and left parts.

• Frontal (coronal) plane: Divides the body into anterior (front) and posterior (back) parts.

• Transverse (horizontal) plane: Divides the body into superior (upper) and inferior (lower) parts; also called a cross section.

• Oblique (diagonal) plane: Cuts made diagonally between the horizontal and vertical planes.

Body Cavities

Body cavities are spaces within the body that contain and protect internal organs.

Dorsal Body Cavity

• Vertebral (spinal) cavity: Contains the spinal cord.

• Cranial cavity: Contains the brain.

Ventral Body Cavity

• Thoracic cavity: Contains the heart and lungs.

  • Mediastinum: Central compartment of the thoracic cavity.

  • Pericardial cavity: Contains the heart.

  • Pleural cavities: Each contains a lung.

• Abdominopelvic cavity: Contains digestive, urinary, and reproductive organs.

  • Abdominal cavity: Contains stomach, intestines, spleen, liver, and other organs.

  • Pelvic cavity: Contains urinary bladder, reproductive organs, and rectum.

Serous Membranes of the Ventral Body Cavity

Serous membranes (serosa) line the ventral body cavity and cover the organs within it. They have two layers: parietal (lines the cavity wall) and visceral (covers the organ surface).

	PARIETAL	VISCERAL
Pleura (lung)	Parietal pleura (lines the cavity wall)	Visceral pleura (lines the organ surface)
Pericardium (heart)	Parietal pericardium	Visceral pericardium
Peritoneum (abdominal)	Parietal peritoneum	Visceral peritoneum

Abdominopelvic Quadrants and Regions

Quadrants

The abdominopelvic cavity is divided into four quadrants for clinical and anatomical reference:

• Right Upper Quadrant (RUQ)

• Left Upper Quadrant (LUQ)

• Right Lower Quadrant (RLQ)

• Left Lower Quadrant (LLQ)

Each quadrant contains specific organs. For example, the RUQ contains the liver and gallbladder, while the LUQ contains the stomach and spleen.

Regions

The abdominopelvic cavity can also be divided into nine regions for more precise localization:

Right	Center	Left
Right hypochondriac region	Epigastric region	Left hypochondriac region
Right lumbar region	Umbilical region	Left lumbar region
Right iliac (inguinal) region	Hypogastric (pubic) region	Left iliac (inguinal) region

Each region contains specific organs. For example, the umbilical region contains the small intestine, and the hypogastric region contains the urinary bladder.

Other Body Cavities

There are several smaller body cavities, mostly associated with the head, and open to the exterior of the body (except for synovial cavities).

• Oral cavity: Mouth

• Nasal cavity: Nose

• Orbital cavities: Eyes

• Middle ear cavities: Middle ear

• Synovial cavities: Joints (enclosed within fibrous capsules)

Organ Systems

The human body is organized into organ systems, each with specific functions. Major organ systems include:

• Integumentary System: Skin, hair, nails; protects the body.

• Skeletal System: Bones, joints; supports and protects organs.

• Muscular System: Muscles; allows movement.

• Nervous System: Brain, spinal cord, nerves; controls body activities.

• Endocrine System: Glands; secretes hormones.

• Cardiovascular System: Heart, blood vessels; transports blood.

• Lymphatic System: Lymph nodes, lymphatic vessels; defends against infection.

• Respiratory System: Lungs, airways; gas exchange.

• Digestive System: Stomach, intestines; processes food.

• Urinary System: Kidneys, bladder; eliminates waste.

• Reproductive System: Ovaries, testes; produces offspring.

Example:

The cardiovascular system includes the heart and blood vessels, which work together to transport oxygen, nutrients, and waste products throughout the body.