Anatomical position and body cavities

 

Anatomical Position

What is an Anatomical Position?

The body is erect with the feet parallel and the arms hanging at the sides with the palms facing forward. (It’s important to note throughout this course, most terminology refers to this position regardless of the position the body happens to be in at the time).

This include:

• Standing erect
• Feet parallel
• Arms hanging at the sides
• Palms facing forward

Directional terms

• Superior (cranial or cephalad) –toward the head end or upper part of a structure or body; above
• Inferior (caudal) – away from the head end or toward the lower part of a structure or body; below
• Anterior (ventral) – toward or at the front of the body; in front of
• Posterior (dorsal) – toward or at the backside of the body; behind
• Medial – toward or at the midline of the body; on the inner side of
• Lateral – away from the midline of the body; on the outer side of
• Proximal – close to the origin of the body part or the point of attachment of a limb to the body trunk.
• Distal – farther from the origin of a body or the point of attachment of a limb to the body trunk.
• Superficial (external) – toward or at the body surface.
• Deep (internal) – away from the body surface; more internal.

Examples:

• The navel is inferior to the breastbone
• The heart is posterior to the breastbone
• The arms are lateral to the chest
• The elbow is proximal to the wrist
• The skin is superficial to the skeleton
• The forehead is superior to the nose
• The breastbone is anterior to the spine
• The heart is medial to the arm
• The armpit is intermediate between the breastbone and the shoulder
• The knee is distal to the thigh
• The lungs are deep to the rib cage

Body planes and sections 

Body Planes is imaginary lines that intersect the body in anatomical position.

 A section is a cut made along a plane

• Sagittal – cut made along the lengthwise or longitudinal plane of the body dividing it into left and right part
• Midsagittal (median) plane – right and left parts are of equal size
• Frontal (coronal) plane – cut made along a lengthwise plane that divides the body into anterior and posterior parts/
• Transverse plane (cross-section) – cut made along a horizontal plane dividing the body or organ into superior and inferior parts

Body Cavities 

is any fluid-filled space in a multicellular organism, However, the term usually refers to the space, located between an animal's outer covering(epidermis) and the outer lining of the gut cavity where internal organs develop. normal body cavity in humans is called the ventral body cavity because it is by far the largest one in volume. 

There are two sets of internal body cavities called the dorsal and ventral body cavities. These cavities are closed to the outside.

 1. Dorsal Body Cavity

this is located near the posterior surface of the body and Made up of two smaller cavities

•  Cranial Cavity – holds and protects the brain
• Spinal Cavity – (vertebra canal) and column which runs through the vertebra and protects the spinal cord

The cranial cavity, in the skull, encases the brain. The vertebral, or spinal, cavity, which runs within the bony vertebral column, encloses the delicate spinal cord. The cranial and spinal cavities are continuous with one another

2. Ventral Body Cavity

this is located near the anterior surface of the body and has been divided into two smaller cavities

•  Abdominopelvic – lower torso (holds digestive and reproductive organs) which is separated by the diaphragm consists of two cavities that are:

 abdominal and pelvic cavity.

The abdominal cavity is the superior part located between the diaphragm superiorly and the brim of the pelvis inferiorly. and pelvis cavity located between the pelvic brim superiorly and the body wall inferiorly that contains hip bones.

• Thoracic – chest area (holds  heart, lungs, and diaphragm)

the thoracic cavity is a space enclosed by the ribs, sternum, and vertebral column

the thoracic cavity is separated from the abdominal cavity by the diaphragm. This cavity contains three small cavities that are:

two pleural cavities, the pericardial cavity, and mediastinum.

Two pleural cavities are the potential space enclosed between the visceral and parietal pleurae. normally contains a very thin layer of serous fluid, as a result, the surface of the lung is covered by visceral pleurae and parietal pleurae attached to the wall.

The pericardial located surrounds the heart. that protect the heart well.

The mediastinum is a broad central partition that separates two laterally placed pleural cavities. it extends from the sternum to the bodies of the vertebrae and from the superior thoracic aperture to the diaphragm.

This saves the passageway of the thoracic duct, esophagus, and other components of the nervous system as they traverse the thorax on their way to the abdomen. the organ located here is the heart, thymus, trachea, esophagus, pleural cavities, and bronchi.

The structure within the thoracic are:

• cardiovascular system
• respiratory system
• digestive system
• nervous system

Abdominopelvic Regions and Quadrants  

 Because the abdominopelvic cavity is large and contains several organs, it helps to divide it into smaller areas for study. 

One division method, used primarily by anatomists, uses two transverse and two parasagittal planes. These planes, divide the cavity into these regions :

• The umbilical region is the centermost region deep to and surrounding the umbilicus (navel)
• The epigastric region is located superior to the umbilical region (epi = upon, above; gastric = belly)
• The hypogastric (pubic) region is located inferior to the umbilical region (hypo = below)
• The right and left iliac, or inguinal, regions are located lateral to the hypogastric region (iliac = superior part of the hip bone)
• The right and left lumbar regions lie lateral to the umbilical region (lumbus = loin).
• The right and left hypochondriac regions flank the epigastric region laterally ( cartilage)
• The epigastric region is located superior to the umbilical region (epi = upon, above; gastric = belly)
• The hypogastric (pubic) region is located inferior to the umbilical region (hypo = below)
• The right and left iliac, or inguinal, regions are located lateral to the hypogastric region (iliac = superior part of the hip bone)
• The right and left lumbar regions lie lateral to the umbilical region (lumbus = loin).
• The right and left hypochondriac regions flank the epigastric region laterally ( cartilage).

A simpler scheme to localize the abdominopelvic cavity organs is to imagine one transverse and one median sagittal plane passing through the umbilicus at right angles. The resulting quadrants are named according to their positions from the subject’s point of view:

Body Quadrants

• Right Upper Quadrant (RUQ)
• Left Upper Quadrant (LUQ)
• Right Lower Quadrant (RLQ)
• Left Lower Quadrant (LLQ)