To accurately describe and locate the body’s various parts, scientists and healthcare professionals rely on a standardized system of regional anatomy. This mapping system provides a universal language, ensuring that a description of a structure’s location remains precise, regardless of a patient’s actual position. By dividing the body into specific, named areas, anatomists avoid the ambiguity of everyday language. This common terminology is crucial for diagnosis, surgery, research, and clear communication across all medical disciplines.
The Foundation: Axial and Appendicular Divisions
The entire human form is first separated into two overarching classifications: the axial and the appendicular divisions. The axial division forms the main vertical axis of the body, encompassing the central core structures. This includes the head, the neck, and the trunk, which together protect the brain, spinal cord, heart, and lungs.
The appendicular division consists of the structures that attach to this central axis, functioning as appendages or limbs. These structures include the upper and lower extremities, along with the pectoral (shoulder) and pelvic girdles that anchor them. This division provides the body with its mobility, allowing for movements such as walking, lifting, and carrying objects.
Regional Terminology of the Trunk and Head
The axial body contains the most extensive set of regional names. The entire head is referred to as the cephalic region, which further subdivides into the cranial region (skull) and the facial region. Below the head, the neck is designated as the cervical region, connecting the head to the main trunk.
The torso, or trunk, is divided into large anterior regions, starting with the chest, known as the thoracic region. Beneath the chest is the abdominal region, which gives way to the lower pelvic and pubic areas. The abdominal area is often partitioned into smaller regions to precisely locate pain or internal organs, such as the umbilical region surrounding the navel.
On the posterior aspect of the trunk, the upper back is called the dorsal region, while the lower back is termed the lumbar region. Inferior to the lumbar area is the sacral region, located near the base of the spine. The buttocks are collectively referred to as the gluteal region, and the posterior shoulder blade area is the scapular region.
Regional Terminology of the Upper and Lower Limbs
For the upper limbs, the shoulder area is the acromial or deltoid region, which connects to the arm, known as the brachial region. The forearm is termed the antebrachial region, separated from the arm by the elbow, or cubital area. The lower limbs begin with the thigh, designated as the femoral region.
Moving distally, the wrist is the carpal region, which transitions into the hand, or manual region. The palm side of the hand is called the palmar region, and the fingers are the digital or phalangeal regions.
The area between the knee and the ankle is referred to as the leg, or crural region. The knee itself is the patellar region on the anterior side, while the posterior side is the popliteal region. The ankle is the tarsal region, leading to the foot, or pedal region, with the sole being the plantar surface.
Describing Position: Anatomical Planes and Directional Vocabulary
To ensure consistent descriptions, all anatomical references are based on the standard anatomical position. In this posture, the body stands upright, facing forward, with the arms at the sides and the palms facing forward, providing a fixed reference point even when the body is lying down or in motion.
Directional terms describe the location of one structure relative to another. Superior refers toward the head, and inferior refers toward the feet. Anterior (or ventral) refers to the front of the body, while posterior (or dorsal) refers to the back. Medial describes a position closer to the midline, and lateral describes a position farther away from the midline.
When describing the limbs, the terms proximal and distal are used. Proximal means nearer to the point of attachment to the trunk, and distal means farther away.
These relationships are visualized using three main imaginary planes that section the body. The sagittal plane divides the body into right and left portions, and the frontal (or coronal) plane separates the body into anterior and posterior portions. The transverse (or horizontal) plane divides the body into upper and lower sections.