Anatomy

Directional Terms

Structures' locations in the body and the areas of other systems are described using directional terminology.

The hand is an extremity considered superior since it is located at the upper section of the body, above the trunk level.

An inferior extremity (the foot is away from the head).

A kneecap, for instance, is found on the anterior side of the leg (the anterior side of the leg is the kneecap's location).

Regardless of whether the body is on the front or the back, the shoulder blades are located on the posterior side.

The middle toe of the foot is located on the medial side, towards the body's midline.

Located on the lateral side of the foot, far from the body's center, the little toe is located on the side of the foot where it sits.

Toward or closest to the trunk or the point of origin of a portion (for instance, the femur unites with the pelvic bone at its proximal end).

The hand, for instance, is at the distal end of the forearm, which means it is the furthest away from the trunk.

The body's planes

Coronal Plane (Frontal Plane)

The frontal plane, also called the coronal plane. The anterior-posterior plane is a vertical division of the human body into the front and back halves (ventral and dorsal; anterior and posterior). The bone that makes up the forehead and a portion of the upper eye sockets inspired the plane's moniker.

(vertical) divides the body into dorsal and ventral (back and front, or ) portions.

Frontal plane movements can be described as abductions or adductions of the arms or legs. Abduction means moving away from the midline of the body, whereas adduction means moving toward it.

Internal body structures can also be described in their location on the frontal plane. The lungs, for instance, are found in the thoracic cavity, which is limited by the ribcage and is separated from the abdominal cavity by the diaphragm. The diaphragm is a flat, dome-shaped muscle that lies in the frontal plane and dome-side up to facilitate airflow to the lungs.

Sagittal Plane (Lateral Plane)

The lateral plane, often known as the sagittal plane (longitudinal, anteroposterior). Each half of the body is an exact reflection of the other along a vertical plane. The sagittal suture, the line of union between the two parietal bones of the skull, inspired the name of this plane.

A joint's bending, or flexion, is contrasted with straightening or extension. Flexion and extension of the limbs are examples of lateral plane movements. Because they entail the translation of anatomical structures along an imaginary line traversing the body from front to back, these motions take place in the lateral plane.

Structures inside the body can also be described using the lateral plane. The liver, for instance, is situated in the abdominal cavity, predominantly on the right side, and the heart, somewhat to the left of the midline.

Axial Plane (Transverse Plane)

The transverse plane, commonly known as the horizontal plane. The anatomical superior-inferior plane is a horizontal line that divides the human body into the upper and lower halves (cranial and caudal; or head and tail).

Head and trunk rotations are examples of movements in the transverse plane. In contrast to linear motion, rotation involves the change in the orientation of a bodily part relative to its axis.

The transverse plane can also describe the positions of anatomical structures inside the body. By illustration, the spinal cord is housed within the vertebral column in the transverse plane and is held together by intervertebral discs between each pair of vertebrae.

Median plane

Median planes, or midsagittal planes, are vertical anatomical planes that run through the center of the body and divide it in half. The sagittal suture, which connects the two parietal bones of the skull, is the inspiration for the name.

Position and motion of anatomical structures within the body as they pertain to the median plane. The ears, for instance, are laterally situated relative to the median plane, while the nose is centrally positioned.

The bending and stretching of the head and neck are examples of movements in the median plane. By bending the head and neck forward, one can bring one's chin closer to one's chest, while stretching the head and neck backward can cause one's head to be pushed farther from one's body.

Body Cavities

The viscera are located within the cavity or gap of the body. There is an essential difference between the ventral cavity and the dorsal cavity. The diaphragm divides the ventral cavity into smaller thoracic and abdominal spaces as a dome-shaped respiratory muscle.

The cardiovascular system, respiratory system, esophagus, major blood arteries, and nervous system are all housed in the thoracic cavitye (chest) or upper ventral cavity. Diaphragm and ribs form the caudal and lateral boundaries of the thoracic cavity, respectively.

Two distinct regions, the abdominal and pelvic regions, make up the lower ventral (abdominopelvic) cavity. The abdominal cavity houses most of the digestive system, including kidneys and adrenal glands. The diaphragm at the top, the body wall on the sides, and the pelvic cavity at the bottom form the boundaries of the abdominal cavity. Within the pelvic cavity, many organs are associated with the urogenital system, including the rectum. The abdominal cavity forms the posterior wall of the pelvic cavity, the sacrum forms the dorsal border, and the pelvis forms the lateral walls.

We refer to the smallest of the two primary cavities as the dorsal cavity. It houses the body's backward-most organs, as the name suggests. Moreover, the dorsal cavity has a bifurcation point. The vertebral canal in the bottom half of the body protects the spinal cord, while the cranial cavity in the top half protects the brain.