9 Techniques of Somatometry & Somatoscopy

Dr. P. Venkatramana

Contents:

1. Introduction

2. Anthropometry

3. Somatometry

3.1 Instruments used in Somatometry

3.2 Guidelines for measurements of Somatometric parameters

3.2.1. Anatomical landmarks

3.2.2. List of Landmarks and their description

3.2.3. List of Somatometric parameters and instruments used

3.2.4. Indices

4. Somatoscopy

4.1. Somatoscopic parameters

4.1.2. Importance of ear in medical practice and forensic application

5. Summary

Introduction

Physical Anthropologists employ various tools to study human biological variation such as anthropometry, serology, dermatoglyphics, mitochondrial haplotypes, single nucleotide polymorphisms, gene and genome sequencing. Anthropologists used anthropometry and morphological traits (hair, skin, ear lobe etc.,) in earlier research studies to classify humans in to races but still reported in research journals as tools to study population variation in nutritional status assessment and in association with disease conditions.

Anthropometry

Anthropometry refers to the measurements of the human body. Anthropometry is categorized into three groups for convenience. They are somatometry (measurement on living human body), osteometry (measurement on skeletal long and short bones) and craniometry (measurement on the skull).

Somatometry

Measurements on the living human is made using well defined anatomical landmarks. Somatometry is useful to compare different populations, designing aircrafts, space ships, furniture and uniforms to defense and paramilitary personnel; assessment of nutritional status; to study the effect of interventions; developing non-invasive markers for diagnosis; to formulate policy and; to understand micro-evolutionary process as they are reflected in genetic and morphological traits in human populations (Bhasin, 2006). Variations in human body dimensions are hypothesized to be due to interaction of environment with biological, nutritional, economic and cultural factors (Bhasin, 2006). Somatometric studies in India have shown that on an average Indians have medium height (163.06 cm), mesocephalic (Cephalic index: 76.06); mesorrhine (nasal index:75.53) and mesoprosopic (facial index:86.34); (Bhasin,2006).

3.1 Instruments used in somatometry

Anthropometer: This instrument consists of four calibrated segments. First segment is called Rod Compass. All segments when combined show the scale of 200cm. It has two sleeves i.e. upper fixed sleeve and a movable sleeve. Cross bars are inserted through the sleeves and the measurements are made (Figure1).

Figure1: Anthropometer Source: http://www.seritex.com/gpm-anthropometer-100/

Spreading Caliper: This instrument is available in two sizes i.e 25 cm and 60 cm. The spreading calipers are made with blunt or rounded ends and sharp or pointed ends. The spreading caliper with rounded or blunted ends is used to make measurements on living human being, whereas, the spreading caliper with sharp or pointed end is employed to record measurements on skeletons (Figure 2 and 3).

Sliding caliper: The slider caliper is used for measuring breadths of short distance. The fixed and sliding arm have both sharp and blunted ends. The sharp ends and blunted are for measurements on skeleton and living human being, respectively (Figure 4).

Skinfold caliper: The caliper is used for measuring thickness of skin fold at various sites of the body and provide information about the amount of subcutaneous fat at each measurable site. A pressure of 10gm/mm2 is used at the contact surface of the arms ranging from 20-40mm2 (Figure 5).

Tape: It has a width of 1 cm and graduations in mm. The tape is made up of steel. All girth measurements are made using the tape.

Goniometer: This instrument has round upper shape and bottom straight base. On the round shape graduations are given in mm. It has a movable needle. A protractor is attached to the base. The Presence of slot with spring and screws allows the attachment with instruments like sliding or spreading calipers (Figure 6).

3.2.Guidelines for measurements of somatometric parameters: Measurements are recorded in standing position with minimal clothing without shoes and head should be in ear-eye plane (Frankfurt plane). Measurements are generally made on the right side of the body unless there is evidence of extra musculature in which case, measurements should be made on left side. In case of infants or children, measurements can be made by advising them to sit on a stool of 40 cm height. The allowed personal errors for various measurements are of the following: head measurement (0.5-1.0mm); head height (2.0 mm); most of the body measurements (3.0-5.0mm), weight (0.1kg); stature, arm span (10.0 mm) and skinfold thickness (1mm). It should be ensured that zero is set while taking measurements on weighing scale and skinfold caliper.

3.2.1. Anatomical landmarks: It may be defined as any anatomic feature such as fold, prominence, duct, vessel consistently present in a tissue that serves to indicate a specific structure or position (Medical dictionary). These anatomical landmarks are used to make measurements of somatometric parameters. There are several landmarks used in Somatometry. Some of the landmarks are given below:

Landmarks are given in Figures 7.

Using the somatometric measurements, a number of indices can be calculated. Some of the important indices are specified below:

Somatoscopy

Somatoscopy is the observation and description of morphological features of individuals (Singhai, 2014). Somatoscopic observations earlier were used to classify humans in to races and to study variations among human populations. Somatoscopic observations are human traits which cannot be presented in numbers and but can be described using standard charts and models developed by pioneers like Brown, Steindamm, Ackermann, Martin, Saller, Erhardt, Schultz, Ziegelmayer, Weninger, Topinard. Morphological triats have forensic application such as identification of suspected person; clinical applications like reconstruction of deformed body parts and identification of abnormalities for example Edward’s cleft lip/cleft palate syndrome (Singh and Purkait, 2009). Morphological methods are useful to study the correlation of structure and function of human body (Singh and Bhasin, 1989). For studying the morphological traits among human populations, close-up photographs are taken and humans are classified.

Human beings can be classified into different groups based on somatoscopic variables like body postures, upper and lower extremities with hand and foot, fingers, foot, toes, skin colour, hair, head and face, eyes, nose, lips, etc.

4.1. List of Somatoscopic parameters

Skin Colour: To study the skin colour on human subjects, the observable body parts are forehead, cheeks, chest, abdomen above the navel, shoulder blades, axis of the upper arm, inner side of the upper arm, palm and inner side of thigh and sole. If for some cultural reasons the above body parts are not allowed to be seen by the researchers, the investigator can make observations at least on forehead and inner side of the upper arm. Human skin colour differs from dark in Africans to very light or weight in Celtics. Various factors influence the skin colour such as melanin, hemoglobin, the level of blood oxygenation, chromophores, oils, soaps, presence of wrinkles, larger growth of hair, disease, malnutrition and change of climate has been shown to affect skin colour(Singh and Bhasin,1989; Treesirichod et al., 2014). Skin colour of the subject can be determined by matching with shades in chart developed by Taylor, Luschan, Broca, Fritsch, Hintz and Schultz. Skin colour can also be determined spectrophotometrically (Minolta chromameter and Mexa meter) (Treesirichod et al., 2014) and also using photographs. In Felix von Luschan skin color chart, the skin colour ranges from 1 to 36. (Figure 8).

The skin sites evaluated for skin colur include midpoint between the elbow and the wrist on the medial aspect of the volar regions and the medial aspect of the dorsal regions of both forearm (Treesirichod et al., 2014). The codes used for skin colur in this chart include (1, 2: Yellowish White; 3: Carmine White; 4,5: Yellowish; 6: Light Brown;7,8: Fawn White;9-11:Carmine White; 12,13: Pinkish White;14-29: Light Brown to Brown;30,31: Dark Brown;32: Reddish Brown; 33,34:Dark Brown;35:Greyish Black and 36: Black) (Singh and Bhasin, 1989).

Hair: Form, colour, texture, quantity and presence of whorls in hair can be used to classify human subjects. The body parts where hair can be observed includes hair on head, beard, genitals, eye lashes, eye-brow ridges, face. If for some cultural reasons, subjects may not be allow certains parts of the body too be seen by the investigator then the research can make observations on head and face.

Hair Colour: Several researchers have proposed hair colour charts such as Fischer and Saller, Tisserand and Fischer and Schultz. According Fischer and Saller hair colour table there are 30 different shades of natural hair colour. Factors like hair oil, perfumes, dyes, malnutrition,light, air and sea water have been observed to influence the hair colour.

Fischer and Saller hair colour classification (Figure 9)

Hair Form: There are three hair forms like straight or sleek, wavy and Frizzly.Water, soap and artificial curling have been shown to influence hair form

(a)Staight (Thicker) or Sleek (thinner) (Lissortrichous)

(b)Wavy(Cymatotrichous): Flat or Broad or Narrow waved or curly

(c) Frizzly(Ulotrichous): Closer or Wider knit or Pepper-corn or Spiral Hair Texture : It is of three types i.e Coarse or Medium or Fine

Quantity: Based on quantity, humans can be classified as Thin or Medium or Normal or Thick or Dense.

Presence of hair whorls: Presence of hair whorls can be categorized based on quantity or direction

(a) Quantitity: Single or Double or Multiple

(b) Direction: Clockwise or Anticlockwise

Head and Face: Human beings can be classified in to different somatscopic groups based on vertex, occiput, total face and forehead features in head and face.

(1) Vertex

(a) Curve: Flat or Slight or Medium or Well-arched

(b) Shape: Ovoid or Pentagonoid or Elliptical or Sphenoid

(2) Occiput :

(a) Projection: Flat or Moderate bulging or Strong bulging

(b) Shape: Barrel or Gable shape

(3) Total Face:

(a) Height: Long or Medium or Short

(b) Diameter: Narrow or Medium or Broad or Very Broad

(d) Frontal Outline of the Face: Eliptical or Oval or Round or Square or Quadrangular or Rhomboid or Trapezoid or Pentagonoid (Figure 10)

Eyes: Human beings can be classified based eye opening axis, direction and folds of the eye.

(a) Eye Opening Axis: Horizontal or Slanting or Oblique

(b) Direction: Outwards or Inwards

(c) Eye folds: Slight or Heavy or Deckfalte or Mongoloid or Epicanthous (Figure 11)

Nose: There are seven observable variables in nose structure such as nasal root, nasal bridge, tip of the nose, nasal wings or alae, nasal septum, nasal cavity or surface of nasal cavity (Figure 12).
1. Nasal Root:

(a) Height above Inner Angle of Eye: High or Medium or Low

(b) Depth from Glabella: High or Medium or Deep

(c ) Breadth: Broad or Medium Broad or Narrow

( d) Shape: Quite Flat or Flat or Medium or High or Very High

2. Nasal Bridge:

(a) Projection: Upwards or Downwards

(b) Shape from Profile: Concave or Verticle or Convex

(c ) Nasal Bridge Profile: Continuous or Wavy or Angular

3. Tip of Nose:

(a) Projection: Upwards or Downwards

(b) Profile of Tip: Rounded at point or Fully Rounded or Flat

4. Nasal Wings or Alae:

(a) Thickness: Thick or Medium or Thin

(b) Height: Height or Low

(c ) Bulge: Slight Flat or Slight or Strongly Bulging

5. Nasal Septum:

(a) Size: Long or Medium or Short

(b) Breadth: Narrow or Broad

(c ) Direction: Upwards or Downwards or Horizontal

( d) Profile: Septum Visibible or Not

6. Nasal Cavity:

(a) Shape and Size: Very Narrow or Narrow or Long Oval or Short Oval or Round or Broad or Very Broad

(b ) Size and Length: Small or Big

7. Surface of Nasal Cavity: Horizontal or Projecting Downwards or Upwards

Lips: For classification of human beings, both upper and lower lip are studied separately. Within each lip, three features namely form, mebral lip and mentolabial fold are observed. The meaning of integumentary meaning is pertaining to or composed of skin.

(1) Integumental Upper Lip:

(a) Form: Straight or Convex or Concave

(b) Membral Lip: Thin or Medium or Thick or Puffed-up

(2) Integumental Lower Lip:

(a) Form: Straight or Bulging Downwards

(b) Membral Lip: Thin or Medium or Thick or Puffed

(1) Prognathism (Figure 13) ( https://www.youtube.com/watch?v=-iCbxbgzsuE):

(a) Type: Alveolar or Facial

(b) Size: Slight or Medium or Marked

External Ear (Figure 14):

(1) Ear Lobe:

(a) Presence: Present or Absent

(b) Size: Long or Medium or Short

(d) Thickness: Thick or Medium or Thin

(e) Attachment: Free or Attached

(f) If Attached: One quarter or Half or One Third or Two Third or Three Quarters or Fully Attached

(2) Darwin’s Tubercle: Present or Absent

(3) Antihelix Curvature: Strong or Medium or Weak

(4) Antitragus: Strong or Weak or Angularly Developed

(5) Helix and Antihelix: Equal to each other or Narrower or Broader

(6) Tragus and Antitragus:

(a) Size: Small or Weak or Medium

(b) Shape: Long or Round or Knob-shaped

(7) Scaphoid:

(a) Size: Broad or Middle or Narrow

(b) Shape: Flat or Medium or Deep

4.1.2. Importance of ear in medical practice and forensic application:

Low set ears defined as upper edge of the auricle is below the exocanthion level and lower edge below the chelion level. Low set ears are used for diagnosis of congenital anomalies like Patau syndrome and Edward syndrome. Ear provide the supplementary information about the person’s identity and also serve as biometric triat to strengthen the primary biometric system. The famous sandalwood smuggler Veerappan’s dead body, was confirmed by observation of ear available in the ante and post-mortem photographs by forensic people. It was reported that Veerappan had unique ear characteristic such as a flat tragus contiguous with the curved portion of the helix and enlarged and squarish lobule, which served as marker to identify him (Singh and Purkait, 2009).

Summary

Physical anthropology is a study of human biology within the frame work of evolution. Physical anthropologists study human variation to obtain clues about how humans adapted to the environment over time. Various tools are employed by physical anthropologists to understand variation like anthropometry, serology, dermatoglyphics, mitochondrial haplotypes, single nucleotide polymorphisms, gene and genome sequencing. Physical anthropologists used anthropometry earlier to classify human beings into races. Physical anthropologist employ somatometric and somatoscopic approaches to study human variation.

Somatometry is defined as measurement on living human body and somatoscopy is the description of visible morphological traits.

Measurements on the living human is made using well defined anatomical landmarks.

For somatometric measurements, various instruments are used and they include anthropometer, head height needle, spreading caliper, sliding caliper, skinfold caliper, tape and goniometer etc., Measurements are made on standing position with minimal clothing without shoes and head should be in ear-eye plane (Frankfurt plane). Measurements are generally made on the right side of the body

In human body, 55 landmarks are well defined starting from acromion to zygion.

One hundred twenty six somatometric parameters are reported on living human body.

Fifty indices are reported using somatometric parameters to classify human beings into different groups.

Somatoscopic observations are visible morphological traits which can be confirmed by using models and charts. The somotoscopic traits have clinical applications for describing congenital anomalies and forensic applications. The list of somatoscopic traits includes skin colour, hair, head and face, cheeks, eyes, nose, lips, mouth, teeth, lip etc.,

you can view video on Techniques of Somatometry & Somatoscopy