Posterior or dorsal - back example, the shoulder blades are located on the posterior side of the body. Medial - toward the midline of the body example, the middle toe is located at the medial side of the foot. Lateral - away from the midline of the body example, the little toe is located at the lateral side of the foot. Proximal - toward or nearest the trunk or the point of origin of a part example, the proximal end of the femur joins with the pelvic bone.
Distal - away from or farthest from the trunk or the point or origin of a part example, the hand is located at the distal end of the forearm. Coronal Plane Frontal Plane - A vertical plane running from side to side; divides the body or any of its parts into anterior and posterior portions. Sagittal Plane Lateral Plane - A vertical plane running from front to back; divides the body or any of its parts into right and left sides.
Axial Plane Transverse Plane - A horizontal plane; divides the body or any of its parts into upper and lower parts. Median plane - Sagittal plane through the midline of the body; divides the body or any of its parts into right and left halves. The cavities, or spaces, of the body contain the internal organs, or viscera. Inferior or caudal describes a position below or lower than another part of the body proper; near or toward the tail in humans, the coccyx, or lowest part of the spinal column.
The pelvis is inferior to the abdomen. Lateral describes the side or direction toward the side of the body. The thumb pollex is lateral to the digits. Medial describes the middle or direction toward the middle of the body. The hallux is the medial toe. Proximal describes a position in a limb that is nearer to the point of attachment or the trunk of the body. The brachium is proximal to the antebrachium. Distal describes a position in a limb that is farther from the point of attachment or the trunk of the body.
The crus is distal to the femur. Superficial describes a position closer to the surface of the body. The skin is superficial to the bones. Deep describes a position farther from the surface of the body. The brain is deep to the skull. Body Planes A section is a two-dimensional surface of a three-dimensional structure that has been cut.
The sagittal plane divides the body or an organ vertically into right and left sides. If this vertical plane runs directly down the middle of the body, it is called the midsagittal or median plane. If it divides the body into unequal right and left sides, it is called a parasagittal plane or less commonly a longitudinal section. The frontal plane divides the body or an organ into an anterior front portion and a posterior rear portion.
The frontal plane is often referred to as a coronal plane. Transverse planes produce images referred to as cross sections. Body Cavities The body maintains its internal organization by means of membranes, sheaths, and other structures that separate compartments. Chapter Review Ancient Greek and Latin words are used to build anatomical terms.
The upper limbs are held out to each side, and the palms of the hands face forward as illustrated in Figure 1. Using this standard position reduces confusion. It does not matter how the body being described is oriented, the terms are used as if it is in anatomical position. A body that is lying down is described as either prone or supine. Prone describes a face-down orientation, and supine describes a face up orientation.
These terms are sometimes used in describing the position of the body during specific physical examinations or surgical procedures. Certain directional anatomical terms appear throughout this and any other anatomy textbook Figure 1. These terms are essential for describing the relative locations of different body structures.
Commit these terms to memory to avoid confusion when you are studying or describing the locations of particular body parts. A section is a two-dimensional surface of a three-dimensional structure that has been cut. We call these scans. Body sections and scans can be correctly interpreted, however, only if the viewer understands the plane along which the section was made.
A plane is an imaginary two-dimensional surface that passes through the body. There are three planes commonly referred to in anatomy and medicine, as illustrated in Figure 1.
The body maintains its internal organization by means of membranes, sheaths, and other structures that separate compartments. The dorsal posterior cavity and the ventral anterior cavity are the largest body compartments Figure 1. These cavities contain and protect delicate internal organs, and the ventral cavity allows for significant changes in the size and shape of the organs as they perform their functions.
The lungs, heart, stomach, and intestines, for example, can expand and contract without distorting other tissues or disrupting the activity of nearby organs. The posterior dorsal and anterior ventral cavities are each subdivided into smaller cavities.
In the posterior dorsal cavity, the cranial cavity houses the brain, and the spinal cavity or vertebral cavity encloses the spinal cord. Just as the brain and spinal cord make up a continuous, uninterrupted structure, the cranial and spinal cavities that house them are also continuous. The brain and spinal cord are protected by the bones of the skull and vertebral column and by cerebrospinal fluid, a colorless fluid produced by the brain, which cushions the brain and spinal cord within the posterior dorsal cavity.
The anterior ventral cavity has two main subdivisions: the thoracic cavity and the abdominopelvic cavity see Figure 1. The thoracic cavity is the more superior subdivision of the anterior cavity, and it is enclosed by the rib cage. The thoracic cavity contains the lungs and the heart, which is located in the mediastinum. The diaphragm forms the floor of the thoracic cavity and separates it from the more inferior abdominopelvic cavity.
The abdominopelvic cavity is the largest cavity in the body. Although no membrane physically divides the abdominopelvic cavity, it can be useful to distinguish between the abdominal cavity, the division that houses the digestive organs, and the pelvic cavity, the division that houses the organs of reproduction. The more detailed regional approach subdivides the cavity with one horizontal line immediately inferior to the ribs and one immediately superior to the pelvis, and two vertical lines drawn as if dropped from the midpoint of each clavicle collarbone.
There are nine resulting regions. A s erous membrane also referred to a serosa is one of the thin membranes that cover the walls and organs in the thoracic and abdominopelvic cavities. The parietal layers of the membranes line the walls of the body cavity pariet- refers to a cavity wall.
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