Forensic Pathology for Police - Brainshare Public Online Library

92 6 Overview of Anatomy and Physiology
have no postmortem laboratory test available to make a diagnosis. Determining the
cause of death in these cases requires knowing the medical history of the person (for
example, knowing that the person had a history of epilepsy) and then ruling out all
other causes of death.
Body Regions and Compartments
From an anatomic standpoint, the human body can be divided into various regions,
each of which contains structural supporting elements (bone, cartilage, and connective
tissue), muscles, joints and ligaments that allow for movement, and blood
vessels that supply oxygen and nutrition. The head region includes the intracranial
cavity, within which the brain resides, as well as the sinuses, the nasal cavity, the
oral cavity, and the pharynx (the back of the throat, where nasal and oral cavities
merge). The neck contains numerous structures, including blood vessels, structures
that are part of the gastrointestinal system and the respiratory system, and a portion
of the vertebral column and spinal cord. The remainder of the body can be divided
into the extremities (two upper extremities or arms; two lower extremities or legs)
and the trunk region.
The trunk includes everything other than the head and neck and the extremities.
There are four body cavities contained within the trunk (Disc Images 6.1 and 6.2).
The dome-shaped diaphragm muscle separates the chest cavities above from the
abdominal, or peritoneal, cavity below. The chest cavities include two pleural, or
thoracic, cavities, within which the lungs reside, and the pericardial cavity (the heart
sac), within which the heart resides. The peritoneal (abdominal) cavity contains
most of the remainder of the trunk organs, including the liver, spleen, stomach, and
a large portion of the intestines. The lowermost portion of the peritoneal cavity is
referred to as the pelvis region.
Not all of the organs within the trunk region actually reside within the body
cavities. Some, in fact, are behind the actual cavities themselves. Within the chest,
the “mediastinum” is an area above the pericardial sac and medial (towards the
middle) to the pleural cavities. The mediastinum contains the aorta, pulmonary arteries,
trachea, mainstem bronchi, thymus, and a portion of the esophagus. Within the
abdomen and pelvis, the kidneys, adrenal glands, most of the pancreas, portions of
the intestines, and the aorta and inferior vena cava are actually behind the peritoneal
cavity, in what is considered the “retroperitoneum” (which literally means behind
the peritoneum).
Specific Organ Systems
Integumentary System (Skin)
Although it may seem a bit unusual to consider the skin (the integument) as an
organ, the skin can certainly be considered an organ, since it represents a specific
grouping of cells and tissues that exists in a specific location and performs specific