Lesson One Basic Ecorche

Activity 1: Building Simple Clay Versions of the Ribcage, Skull and Pelvis

 Points about the Ribcage, Skull and Pelvis 


This diagram is adapted from the 19th century text "Artistic Anatomy" by Paul Richer

1. Total height about 8 heads

2. Shoulders about 2 heads wide, which means an overall ratio of about 4:1 in front view

3. Symphysis pubis is at about half the total height, which lines up with the greater trochanter of the femur and about half way up the buttocks

4. Knee joint is at about 1/4 or 2 heads up

5. There is about half a head from the pit of the neck (top of the sternum) to the chin

6.  The angles of the shoulders trend upwards slightly, giving about 1/3 head from chin to shoulder line in relaxed posture, depending on the individual.

 

 

 

 

 

 

 

 

 

 

 

 


7. The pelvis and ribcage taper away from each other when seen from the front.  Notice also that the femur and shoulder girdle project out from their respective masses, thus inverting the visible taper, as seen in the small diagram at top left.

 

8. The ribcage and pelvis are approximately the same width in a male body, as shown in the diagram, while in the female body the ribcage is generally smaller relative to the pelvis.  Overall this causes the size of the pelvic mass and the upper body mass to be more similar in the female body, though in both sexes the upper body dominates.

 

9. In a neutral posture seen from the side, the pelvis tilts forward while the ribcage tilts back, and the neck projects forward

 

10. The skull is widest at the Parietal eminences in front view.

 

11. The skull has a taper in the cranium from back towards front. 


1. The shoulder girdles are wider than the waist, so there is an angle inwards from shoulders to waist, often following the line of the Latissimus dorsi muscles.

2.  The greater trochanters are wider than the iliac crests, so there is an angle outwards from the waist

3. There is a space from the narrowest point of the waist (where the ribcage mass disappears into the External obliques) to the iliac crests.  This “midrif” region is very important and will vary dramatically depending on the pose.

4. In a neutral posture seen from the side, the back of the shoulders is about in line with the buttocks, while the abdominals continue the line of the ribcage in a central sweep towards the symphysis pubis

5.  Also from the side: the bulk of the pelvis sweeps outwards from the iliac crests, with the anterior superior iliac spines (the front points) approximately vertically aligned with the symphysis pubis

6. The female torso is essentially the same pattern as the described in the notes above.  It varies from the male torso most obviously in terms of the proportion of the ribcage to the pelvis masses, with the upper mass being more similar to the pelvis mass in size.  This is due to three main factors: 1. A relatively smaller, narrower ribcage 2. Relatively lighter musculature on the upper body/ shoulder girdle and 3. the greater adipose tissue on the upper thigh and pelvis, which also contributes to the tapering shape of the characteristic female thigh.  Note that relatively lighter latisimus dorsi muscles make the sweep from the waist to the iliac crests more dramatic, when viewed from the front.


Below left: Basic figure set-up, including the simplified bucket form of pelvis developed by Gottfired Bammes

Below right: A development of the ribcage and pelvis based on some of the ideas of Gottried Bammes


Overview of Activity 1

1. Build each of the simplified torso masses (1.), at correct scale relative to each other

2. We will build them separately and then skewer them onto the vertical spike provided in the course  in correct orientation to each other for a neutral posture 

3. Add the connecting tubes of vertebral column, as per the diagrams below. Notice how the tube of the vertebral column flows into each of the masses, parallel to the sacrum and ribcage at their connection.  On the other hand, the cervical(neck) vertebrae tube strikes the base of the skull more perpendicularly, inserting just behind the jaw. (2.)

The purpose is not perfect models but rather to go through a process that will bring understanding about the main torso masses.


Click the image to view the page with rotatable 3D models of the 5 levels of simplification

Click the image to view the page with rotatable 3D models of the 5 levels of simplification

Ribcage

-Taper towards top, both from side and front, like a gently flattened egg

-Taper towards front from back

-Angle of first rib angles down toward the front

-Angles inwards to vertebrae on back face of ribcage

- Butterfly pattern

- Conceive of ribs as bucket handles

- Ribs 1-7 True Ribs, attaching by cartilage directly onto the sternum

- Ribs 8-12 False ribs (not attached to Sternum directly) 

- Of the False Ribs, the cartilage of Ribs 8, 9 and 10 each attach to that of the rib above.  Ribs 11 and 12 are Floating ribs (not a attached by cartilage to the ribs above). 


Profile and Profile views of the simplified levels of the ribcage


Perspective views of the Ribcage simplification


Pelvis

-General bucket-like form

-Tilt of pelvis bucket is parallel to sacrum angle i.e. sacrum is on the back surface of the bucket

- Notice how the iliac crests are like two hands cupped around the abdomen from the back, while the ischial tuberosities reverse this pattern - smaller hands cupping from the front, below the symphysis pubis


This pelvis "Fold it" shows an exploded view of the pelvis, illustrating how the iliac crests and upper half of the pelvis are offset to the ischial tuberosities (The third point above)

This pelvis "Fold it" shows an exploded view of the pelvis, illustrating how the iliac crests and upper half of the pelvis are offset to the ischial tuberosities (The third point above)




Skull

Click the image to view all models of the Skull in 3D

Click the image to view all models of the Skull in 3D

-Cervical spine attaches to skull surprisingly far in under the cranium - towards the back of the jaw 

-Obtuse angle between facial line and axis of cranium

-Taper from widest part of cranium at lower rear towards the front and towards the chin

-Relatively square region of forehead and cheek bones against triangular region of lower face 

-general curve of front of face that is still separated from the side of the head by the cheek plane break

-Jaw finishes approx half way back on the skull

-Base of nose approx in line with base of cranium

Head 3D models


Profile and Profile views of the simplified levels of the ribcage


Perspective views of the levels of simplification of the skull


Visualisations based on an alternative conception of the Skull by Gottfried Bammes