Wound Geography and Tissue Types: Part 2

  • Heather Hettrick, PT, PhD, CWS, CLT, CLWT
  • Volume 06 - Issue 4


This article (and the accompanying video course available at www.woundeducationpartners.com/ woundgeography) will introduce you to pictures and ask you to identify the correct answer as information is shared.

Intact Tissue

Let’s begin by looking at intact tissue. Figure 1 shows three different pictures of intact tissue that have some noticeable changes. One picture is representative of immature scar tissue. Another picture is indicative of hemosiderin staining, and a third photo represents macules of repigmentation.


FIGURE1           Photos copyright Gordian Medical Inc, dba American Medical Tecnologies


Picture 1 is representative of hemosiderin staining, also known as a “biological tattoo.” Venous hypertension leads to regurgitation and backflow of blood.

This, combined with insufficient venous valves, leads to a pooling of blood that leaks into the interstitial tissues. Blood outside the vessels begins to break down, and the hemoglobin releases iron, inducing a staining effect on the tissues that presents clinically as hemosiderin staining. This is irreversible but a telltale sign of chronic venous insufficiency.

Picture 2 is representative of immature scar tissue, which tends to present with what we call the three Rs: red, raised, and rigid. This is different than mature scar tissue, which is represented as the three Ps: pale, planar, and pliable. Scar tissue can take several months to two years to become mature.

While scar tissue is actively maturing, there are numerous interventions we can do to help hasten the maturation process. Some interventions include scar mobilization, ultrasound, silicone sheeting, scar massage, pressure or compression, and splinting. It is important to remember that scar modification techniques are effective only while the scar is immature. Once scar tissue is mature, we can no longer modify it or change it.

Scar tissue is never as strong as uninjured tissue. As scar tissue matures, it approaches 80% tensile strength of normal, uninjured tissue but will never regain normal tensile strength. During the maturation process, it is important to protect the area and realize it is always at risk for further breakdown.


Picture 3 is representative of macules of repigmentation. Over time, these macules enlarge and spread, ultimately “resurfacing” the area with near-normal pigmentation. During this process, the area may be slightly hyper- or hypopigmented. Patients with darker skin tones are often concerned about the pink or light color of the tissue, so it is important to educate them about the repigmentation process and reassure them that it will likely normalize over time. However, this process may take several months.

Figure 2 shows two different types of eschar. One is considered stable eschar, and the other is considered unstable eschar. What is the difference?

Stable eschar is noted by intact edges as shown in Picture A. This is a nonfluctuant tissue, which means when you push on it or touch it, it does not yield. 

Additionally, there is no evidence of drainage or separation at the wound edge. Stable eschar should be monitored as it acts as the body’s biological dressing. Aggressive wound care, debridement, and moist wound healing are not warranted when stable eschar is present. At times, the tissue beneath the stable eschar re- epithelializes. If this occurs, the eschar often sloughs off once epithelialization is complete.


FIGURE2Photos copyright Gordian Medical Inc, dba American Medical Technologies


If the eschar begins to demarcate or separate, if the tissue feels boggy or squishy, or if drainage becomes evident as in Picture B, then the eschar is considered unstable and should be managed according to the patient’s clinical presentation. An appropriate form of debridement should be selected or performed, and moist wound healing principles should be employed.

Wound Edge

Figure 3 shows pictures of the wound edge. Focus on the area of the wound where the wound base meets the wound margin. One photo is representative of a diffuse or irregular wound edge. Another photo depicts epiboly or invagination, and the third photo presents a wound edge with dyschromia or a form of erythema.

Picture 1 is representative of epiboly or invagination. The epithelial cells were unable to migrate across the wound surface, so in turn, they rolled over the edge, essentially “sealing” the edge. Re-epithelialization cannot occur from a wound edge with epiboly. Sharp debridement of the epiboly, cauterization of the edge with silver nitrate, or roughening the edges must be initiated to help jump-start the wound- resurfacing process.


Picture 2 shows a wound edge that is diffuse or irregular. It is quite difficult to ascertain where the wound edge is located.

Wound edges that appear rugged and diffuse are often being subjected to excess friction and shear. Such forces may be iatrogenic or patient-induced if they have cognitive impairments that can disrupt their ability to offload the wounded tissue. Interventions should focus on how to protect the wound from pressure, shear, and friction to allow the wound and wound edge to stabilize.

Picture 3 is indicative of dyschromia. Dyschromia is a darkening of a patient’s natural skin tone, and it is how erythema presents on non-Caucasian skin.


FIGURE3Photos copyright Gordian Medical Inc, dba American Medical Technologies


Typically erythema is a normal aspect of the inflammatory phase and is confined to the wound margin or perimeter. If it starts to extend beyond the wound edge and well into or beyond the periwound, then we might be dealing with something different, such as an underlying infection.

Picture 3 is a classic presentation of dyschromia in a non- Caucasian patient. It is important to visually look for a darkening of the natural skin tone in lieu of erythema, as it is often very subtle. If needed, you can use a penlight or a flashlight to help you visualize the area.

Periwound Tissue

The next seven photographs focus on the periwound area. The periwound is generally 3-4 cm extending out or away from the wound edge. The wound base, wound edge, and periwound are analogous to an archery target. The center is the wound base, the next area out is the wound edge or margin, followed by the periwound area, which surrounds the bull’s-eye. This is often where we need to affix dressings, so it is important to appreciate the quality and integrity of the periwound tissue.

For the following seven pictures, focus on the periwound area, and describe what you see occurring at this location. In Figure 4, is the periwound indurated or hard? Is it macerated or supersaturated? Or is it intact? The answer is the periwound is intact. This is actually a healthy-looking periwound with no overt problems, meaning this periwound is being adequately protected as it is not subject to excessive moisture, nor does it appear denuded or irritated.

Figure 5 has the periwound outlined in black. Is this tissue indurated or hard, macerated or supersaturated, erythematous or all of the above? If you said all of the above, you are correct. Note the shiny firmlike appearance of the periwound. This denotes induration or a hardening of the tissues. If you were to palpate the tissue, it would feel firm, sometimes even a little waxy in presentation. You can also appreciate some wet-looking tissue or white tissue at the three-o’clock location. This denotes maceration on the right side of the wound. Additionally, the tissue appears red and irritated, indicating a more extensive erythema beyond the wound margin. Collectively, these findings may be indicative of an underlying infection, so further examination would be warranted.


FIGURE4Photos copyright Gordian Medical Inc, dba American Medical Technologies



FIGURE5Photos copyright Gordian Medical Inc, dba American Medical Technologies



FIGURE6Photos copyright Gordian Medical Inc, dba American Medical Technologies



FIGURE7Photos copyright Gordian Medical Inc, dba American Medical Technologies


In Figure 6, would you describe this periwound as hypopigmented, macerated, intact, or erythematous? Look closely as there are actually two answers. This periwound is hypopigmented, but it is also somewhat 

macerated. This can be difficult to see in a picture. it is important to be able to discriminate between these two presentations, however, particularly in patients with darker skin tones. Maceration can make tissue appear white or lighter in color, especially in non- Caucasian patients. This can be managed with more absorptive dressings. For the hypopigmented tissue, it is important to educate and reassure patients about the repigmentation process to adequately manage their expectations.

Figure 7 also outlines the periwound area with a black line. You may have noticed many of these wounds occur at the sacral area. This is a common location for pressure ulcers as 36% of all pressure ulcers occur at the sacrococcygeal area. This is also a common location for moisture- associated skin damage (MASD) due to incontinence. What do you see in this periwound area — MASD, inflammation, or excoriation?

The answer is B. What you’re seeing in the periwound area is really an excessive amount of inflammation and erythema. This wound is due to moisture-associated skin damage, which renders the skin-barrier function disrupted. MASD can predispose an area to further injury and often, pressure ulcers develop concurrently. Note that a pressure ulcer is a different etiology than MASD.

Moisture-Associated Skin Damage Versus Pressure Ulcers

MASD and pressure ulcers are two different etiologies. Pressure ulcers are typically due to shear forces and take on the shape of the pressure-causing agent, whether it’s a bone or the patient is laying on something.

MASD is due to moisture where there’s presence of excessive moisture on the tissues, and it disrupts the skin-barrier function. The skin has a tipping point as to how much moisture it can be subjected to at any given time. It is not uncommon, especially at the sacral area, to see MASD due to urinary or fecal incontinence. An area with MASD is more likely to develop a pressure ulcer because the skin-barrier function has been disrupted and lacks integrity.

In Figure 8, note the appearance of the periwound area. Take note of the extensive erythema. How would you describe this clinical presentation?

The answer is overt signs of infection. Upon inspection, you can see that the erythema extends beyond the periwound. Linear streaking (lymphangitis) is present and extending away from the periwound. The tissue is red and “angry” in appearance. If you were to palpate the periwound, it may feel hot to touch, and the patient may report higher levels of pain or that their pain level has changed. This is representative of an active infection. Topical and possibly systemic interventions should be implemented to address the infection and associated symptoms.


FIGURE8Photos copyright Gordian Medical Inc, dba American Medical Technologies


An area with MASD is more likely to develop a pressure ulcer because the skin-barrier function has been disrupted and lacks integrity.
In Figure 9, which term here best describes the linear marks at the periwound? Look closely at the arrows pointing to the linear marks. Are those marks due to moisture- associated skin damage? Is it inflammation in erythema? Is it excoriated tissue? Or are these skin tears? The answer is excoriation. For thorough documentation, you want to include additional descriptions of how this periwound is presenting. Excoriation is evident by the liner scratch marks. This periwound area, however, is also accompanied with MASD and erythema. It is not uncommon for patients to have an associated pruritus when they’re dealing with tissue disruption, especially from moisture. Linear scratch marks, by definition, are considered excoriation. This is different from denudement, which is a diffuse loss of the epidermis.

Photos copyright Gordian Medical Inc, dba American Medical Technologies


In the last photograph of the periwound, Figure 10, what do you see? How would you describe this clinical presentation? This is MASD compounded with fungal involvement as indicated by the white, “cheesy” film present on the skin. Take note how this presentation compares to a pressure ulcer. Pressure ulcers typically take on the shape of the pressure-causing agent, whether it be bone or a foreign object. MASD is more diffuse and poorly demarcated. Because MASD disrupts the skin-barrier function, it renders the tissues more susceptible to shear, friction, and pressure forces, and patients may often present with both MASD and a pressure ulcer. Both should be described and documented as separate wound entities.


FIGURE10Photos copyright Gordian Medical Inc, dba American Medical Technologies


Now we are going to shift gears and review skin histology. In looking at Figure 11, focus on the purple fingerlike projections. Can you recall the name of these structures and their significance? These are rete ridges or rete pegs, which anchor the dermis to the epidermis to allow the layers to move together as one, mitigating the effects of shear and friction. These structures help to provide skin integrity under stress, strain, and torsion. As we age, our rete ridges reduce in size, adding to age-related skin changes. The skin becomes more fragile and susceptible to minor traumas that can lead to skin tears, senile purpura, and other skin conditions we commonly see in aging skin.


FIGURE11Photo courtesy of Bragg et al., Pityriasis rubra pilaris, type IV. Dermatol Online J. 2005; 11(4):14.



FIGURE12Photo courtesy of https://cyhsanatomy1.wikispaces.com/dermis


Skin begins to change and age in the third decade of life; however, significant age-related changes become more readily apparent in the sixth decade of life. It is important to be extra-vigilant about skin assessment and skin checks because patients in their 60s and beyond are very prone to minor skin problems that can become major issues, in part due to the reduction in size of the rete ridges. Instead of the epidermis and dermis moving together as one unit, they slip and slide over one another. This can lead to skin tears, friction blisters, purpura, and other trauma from a seemingly minor injury.

In the next histology photo, Figure 12, you will see an area highlighted in orange. I refer to this area as the skin’s continental divide. This line represents the two layers of the dermis. The papillary layer is the first layer directly below rete ridges and basement membrane. Trauma into the papillary layer manifests as a partial thickness injury because it is partially through the dermis. Partial thickness injuries do not present with necrotic tissue, and such wounds heal with epithelial resurfacing and no scar tissue. The second layer of the dermis, the reticular layer, is where all the adnexal structures or epidermal appendages reside: hair follicles, sweat glands, sebaceous glands, blood vessels, lymph capillaries, etc. Once permanently damaged, these structures cannot be replaced. Damage into and through the reticular layer results in full thickness wounds. Such wounds heal with granulation tissue formation (raw scar tissue), followed by resurfacing and contraction, creating scar tissue. Unlike partial thickness wounds, full thickness wounds can present with necrotic tissue (slough or eschar).

Clinically, when assessing a wound, it can be difficult to ascertain the level of tissue depth. Typically, partial thickness injuries present with pink or red nongranularand smooth tissue. Full thickness wounds can present with beefy red granulation, hyper- or hypogranulation, and even subcutaneous/adipose tissue or deep tissue structures. It is important to note the difference between partial and full thickness wound healing as interventions, and time to full wound closure (resolution) will be different.


Appreciating wound geography, where the wound is located  and how the wound is presenting can assist you with differential diagnosis and clinical decision making. This is analogous to a wound scene investigator. Paying attention to the clues at the wound base, wound edge/margin and the periwound area can help direct your plan of care and selection of interventions, improving patient outcomes and quality of life.



Join us for the CEU video course that complements this article. Details for the video course can be found at www.WoundEducationPartners.com.



About the Author


HEATHER HETTRICK, PT, PHD, CWS, CLT, CLWT, is an associate professor in the physical therapy program at Nova Southeastern University in Ft. Lauderdale, Florida. As a physical therapist, her expertise is in integumentary dysfunction with clinical specialties in wound, burn and lymphedema management. Her certifications include Certified Wound Specialist by the American Board of Wound Management, Certified Lymphedema Therapist by the Academy of Lymphatic Studies, and dual international certifications as a Certified Lymphedema and Wound Therapist through the International Lymphedema Wound Training Institute.

Dr. Hettrick’s work experience includes assistant professor and director of clinical education at the University of New Mexico; vice president of Academic Affairs and Education for Gordian Medical, Inc. (dba American Medical Technologies); clinical assistant professor in the department of physical therapy at New York University; adjunct professor at Drexel University; program coordinator for Burn Rehabilitation Research at the William Randolph Hearst Burn Center at NY Presbyterian Hospita; and a master clinician at the Hospital for Joint Diseases at the Diabetic Foot and Ankle Center.

A past president of the American Board of Wound Management, Dr. Hettrick is currently on the executive committee of the Association for the Advancement of Wound Care. She is program director at Hospital St. Croix in Leogane, Haiti, where she oversees and manages a lymphatic filariasis clinic. She is actively involved in numerous professional organizations, conducts research, and publishes, presents and teaches, nationally and internationally, on integumentary related issues.



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