Section 8.1: Pre-Embalming Prep & Feature Setting

Pre-Embalming Preparation and Feature Setting

Successful embalming and restoration begin with thorough pre-embalming preparation and feature setting. These foundational tasks sanitize the remains, establish the physical positioning, and set the facial expressions before the arterial injection of formaldehyde fixes the tissues in place. The embalmer must have a deep understanding of post-mortem physical and chemical changes to adapt their preparation protocols accordingly.

Post-Mortem Physical and Chemical Changes

Following somatic death, the body undergoes a series of changes. It is critical for the national board exam to distinguish between physical changes (which do not alter the chemical composition of the body tissues) and chemical changes (which result from chemical reactions and create new substances).

1. Algor Mortis (Physical Change)

Algor mortis is the post-mortem cooling of the body to the ambient temperature.

• Mechanism: Once blood circulation stops, the body loses its ability to thermoregulate. The body cools via radiation, conduction, convection, and evaporation.
• Factors Affecting Cooling Rate: The rate of cooling is influenced by intrinsic factors (such as body mass, ratio of surface area to mass, fat thickness, age, and temperature at death) and extrinsic factors (such as clothing, ambient temperature, humidity, and air currents).
• Embalming Implications: Cool bodies retard bacterial growth and delay decomposition. However, cooling increases blood viscosity, causing blood to coagulate and settle in dependent areas, which can create blockages in the vascular system. This high viscosity increases resistance and slows down the distribution and drainage of the arterial preservative.

2. Livor Mortis (Physical Change)

Also known as post-mortem lividity or cadaveric lividity, livor mortis is a reddish-purple intravascular discoloration resulting from the gravitational settling of blood into the dependent capillaries and venules.

• Mechanism: As blood flow stops, gravity pulls red blood cells down to the lowest points of the body (hypostasis), pooling within the blood vessels.
• Onset and Peak: Livor mortis typically begins 30 minutes to 2 hours after death and becomes fixed or reaches maximum intensity within 6 to 10 hours.
• The Blanching Test: The crucial diagnostic test for the embalmer is applying digital pressure (pressing a finger) to the discolored area. If the skin clears or blanches, the discoloration is intravascular (livor mortis). If it does not blanch, it is extravascular (post-mortem stain), indicating that hemolysis has occurred, and hemoglobin has broken down, leaking out of the vascular system and staining the surrounding tissues.
• Embalming Implications: Because livor mortis is intravascular, it can be cleared or washed out during arterial injection and drainage. Elevating the head and shoulders helps drain blood from the face and neck, and pre-injection fluids containing anticoagulants can assist in flushing the vascular channels.

3. Rigor Mortis (Chemical Change)

Rigor mortis is the temporary post-mortem stiffening of the body muscles.

• Mechanism: Muscle contraction and relaxation are active physiological processes dependent on Adenosine Triphosphate (ATP). After death, aerobic respiration ceases, and the body uses anaerobic glycolysis to produce ATP. Once ATP reserves are completely depleted, actin and myosin filaments within the muscle fibers lock together, forming an irreversible gel that causes rigidity.
• Onset and Progression (Nysten's Law): Rigor mortis typically starts in the involuntary muscles of the heart and eyes, spreads to the jaw, face, and neck, and then moves downward to the thoracic cavity, upper extremities, abdomen, and lower extremities. It resolves in the same order as autolytic enzymes break down the muscle proteins (a process known as secondary flaccidity). The typical onset is 2 to 4 hours, peaking at 12 to 24 hours, and resolving in 36 to 72 hours.
• Relieving Rigor Mortis: Rigor mortis must be physically relieved before arterial injection. The embalmer achieves this through passive manipulation: flexing, extending, and rotating the joints, and firmly massaging the muscle groups.
• Embalming Implications: Unrelieved rigor mortis causes several complications. The stiffened muscles compress the capillaries and extravascular tissues, creating high resistance to fluid flow, which leads to poor distribution and uneven preservation. Furthermore, the accumulation of lactic acid during anaerobic glycolysis drops the tissue pH from a normal 7.4 to an acidic 5.5 to 6.0. Formaldehyde binds most effectively to muscle proteins in a slightly alkaline environment (~7.2 to 7.4). Relieving rigor and utilizing buffering agents in the primary dilution helps restore the optimal pH.

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Pre-Embalming Prep Tasks

Before feature setting or vessel selection begins, the embalmer must perform the following standardized sanitization and preparation steps:

1. Primary Disinfection: Spray the entire body with a topical disinfectant, paying close attention to natural orifices (nose, mouth, ears, anus, genitals).
2. Washing and Grooming: Wash the body with warm water and germicidal soap. Clean and style the hair. Scrub under the fingernails and remove any dirt. Shave facial hair if requested or authorized by the family.
3. Body Positioning: Place the deceased on the embalming table. Align the head, shoulders, and chest. The head should be elevated higher than the chest, and the chest elevated higher than the abdomen. This prevents post-mortem hypostasis and swelling of the facial tissues during injection.
4. Relieving Rigor: Perform passive range-of-motion exercises on the limbs and massage the muscles.
5. Orifice Cleanliness and Packing: Clean the nasal and oral cavities. Pack them with cotton saturated with disinfectant or cavity fluid to prevent purge (the post-mortem evacuation of gas or fluids from the stomach, lungs, or brain through natural orifices).

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Feature Setting Techniques

Feature setting involves positioning the eyes and mouth to create a natural, peaceful appearance. This must generally be done prior to arterial injection because formaldehyde fixes the tissues, making adjustments extremely difficult afterward.

1. Eye Closure

The line of eye closure is in the lower one-third of the orbit. The eyelids should meet in a gentle curve; they must never overlap. The upper eyelid is longer and covers the top two-thirds of the eye, while the lower lid covers the bottom third.

• Eye Caps: Perforated plastic or cardboard domes placed directly over the eyeball under the eyelids. The tiny projections (teeth) on the outer surface grip the underside of the eyelid, preventing blinking, shifting, or separation. They also restore the natural curvature of the eye when the eyeball has collapsed or dehydrated.
• Adhesives: A thin layer of stay cream, massage cream, or eye cement is applied to the edges of the eyelids to seal them and prevent dehydration.

2. Mouth Closure and Jaw Stabilization

The line of mouth closure is the weather line of the lips, which is the transition line between the moist internal mucous membrane and the dry external skin of the lip. The upper lip should meet the lower lip without puckering, and the corners of the mouth should be slightly elevated to simulate a natural, relaxed expression.

• Mouth Formers: Curved plastic inserts placed over the gums or teeth. They support the lips and restore the natural contour of the mouth, which is especially important for edentulous (toothless) cases where the family did not provide dentures.

Methods of Jaw Closure

There are two primary methods for securing the mandible (lower jaw) to the maxilla (upper jaw):

Types of Suture Closure:

• Musculature Suture: The needle passes through the mentalis muscle of the chin, goes up in front of the mandible, enters the nasal cavity through the septum, and loops back down. A major drawback is the potential for visible puckering of the chin or nasal septum if the ligature is tied too tightly.
• Mandibular Suture: The needle is inserted through the floor of the mouth, behind the mandible, exits beneath the chin, re-enters the same hole, passes in front of the mandible, goes up into the nasal cavity, and loops through the nasal septum. This is the most secure suture method because it anchors the ligature directly around the mandible bone.
• Dental Tie: If natural teeth are present in both the upper and lower jaws, a ligature is tied around a tooth in each jaw and secured. This avoids puncturing muscle or bone but requires sound, stable dentition.