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The Complete Bridgman Part 2
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THE HUMAN HEAD
At first the study of heads should be in the abstract, that is, we should forget everything that distinguishes one head from another and think of the masses common to all heads. Heads are about the same size. Each is architecturally conceived, constructed and balanced; each is a monumental structure.
By first mentally conceiving of a head as a cube, rather than as an oval or egg-shaped form, we are able to make simple, definite calculations.
The cube of the head measures about six inches wide, eight inches high and seven and a half inches from front to back. These measurements are obtained by squaring a skull on its six sides: face, back, two sides or cheeks, top and base or lower border, which is partly hidden by the neck but is exposed under the chin and jaw, and again at the back where it is seen as the lower border of the skull. Therefore the base of this cube is about seven and a half inches deep and six inches wide, and on this “ground plan” as on that of a square, any form may be constructed. This cube may be tilted to any angle, also foreshortened, and it may be placed in perspective.
The skeleton of the head, like the cube, has six surfaces: top, base, two sides or cheeks, front and back. Its bony framework is immovable, except the lower jaw, which articulates.
There are twenty-two bones in the head. Eight of these bones compose the brain case and fourteen bones compose the face. The brain case is bounded in front by the frontal bone or forehead, which extends from the root of the nose to the crown of the head and laterally to the sides of the temples. The two malar bones, or cheek bones, are facial bones, each united to four other bones forming a part of the zygomatic arch which spans the space from cheek to ear. Above, the malar or cheek bone joins the forehead at its outer angle; below, it joins the superior maxillary or upper jawbones. The two superior maxillary bones constitute the upper jaw and cylinder that hold the upper row of teeth. They are attached above to the cheek bones and eye cavities. The nasal bones form the bridge of the nose.
The inferior maxillary or lower jawbone is the lower border of the face. It is shaped like a horseshoe, its extremities ascending to fit into the temporal portion of the ear. It is a mandible, working on the principle of a hinge moving down or up as the mouth opens or closes, but with a certain amount of play, sideways and forward, so that when worked by the masseter muscles the food is not simply hammered or flattened, but ground by the molar or grinding teeth. The masseter muscle extends from under the span of the zygomatic arch to the lower edge and ascending angle of the lower jaw. It is the large muscle raising the lower jaw, used in mastication. It fills out the side of the face, marking the plane which extends from the cheek bone to the angle of the jaw.
Drawing the Head
|Begin by drawing with straight lines the general outline of the head.|
|Then draw the general direction of the neck from its center, just above the Adam’s apple, to the pit, at the junction of the collar bones. Now outline the neck, comparing its width and length with the head.|
|Draw a straight line through the length of the face, passing it through the root of the nose, which is between the eyes, and through the base of the nose where the nose centers in the upper lip.|
|Draw another line from the base of the ear at a right angle to the one you have just drawn.|
|On the line passing through the center of the face, measure off the position of the eyes, mouth and chin. A line drawn through these will parallel a line drawn from ear to ear, intersecting, at right angles, the line drawn through the vertical center of the face.|
|With straight lines, draw the boundaries of the forehead, its top and sides, and the upper border of the eye sockets. Then draw a line from each cheek bone at its widest part, to the chin, on the corresponding side, at its highest and widest part. If the head you are drawing is on a level with your eyes, the lines you have just drawn will intersect at right angles at the base of the nose and if both ears are visible and the line from the ear extended across the head, it will touch the base of both ears.|
Consider the head as a cube, the ears opposite each other on its sides or cheeks and the line from ear to ear as a spit or skewer running through rather than around the head.
If the head is above the eye level, or tilted backward, the base of the nose will be above this line from ear to ear. Or should the head be below the eye level or tilted forward, the base of the nose will be below the line from ear to ear. In either case, the head will be foreshortened upward or downward as the case may be and the greater the distance the head is above or below the eye level the greater the distance between the line from ear to ear and the base of the nose.
You now have the boundaries of the face and the front plane of the cube. The features may now be drawn in.
Perspective of the Head
Perspective refers to the effect of distance upon the appearance of objects and planes. There are to be considered parallel perspective, angular perspective and oblique perspective.
Parallel lines which do not retreat do not appear to converge. Retreating lines, whether they are above or below the eye, take a direction toward the level of the eye and meet at a point. This point is called the center of vision, and it is also the vanishing point in parallel perspective. In parallel perspective, all proportions, measurements and locations are made on the plane that faces you. So in drawing a square, a cube or a head, draw the nearest side first.
When an object is turned to right or left, so that the lines do not run to the center of vision, then the center of vision is not their vanishing point and the object is said to be in angular perspective.
When an object, such as a cube, is tilted or turned from the horizontal it is said to be in the oblique perspective.
Take a circle for an illustration. Draw a horizontal line through its center, then a line at right angles. Where they intersect place a point of sight. Should a head be placed directly in the center of this circle the center of the face would correspond to the root of the nose, on a line level with the lower border of the eyes. The horizontal line is called the horizon and is at eye level at the height of the eye. The features will parallel the horizontal line.
If the head remains in the same position and the observer steps to one side, the side of the head comes within the range of vision and the relative positions of the head and features are perspectively changed, but not the proportions. The distance away is the same.
Looking directly toward the corner of a head at close range, it would be necessary to change the point of sight. The lines that were parallel with the horizon are no longer parallel, but drop or rise to meet the horizon at some point to form vanishing points.
Unless a head is at eye level it must necessarily be in perspective. When a head is above the spectator, obviously he is looking up. Not only is the head in perspective, but every feature of the face; eyes, nose, mouth, ears. Like the barnacles on the hull of a ship, the features follow the lift. In the same manner they follow the upward trend, or its reverse. Everything to that is secondary. The features must travel with the mass of the head.
Perspective must have some concrete shape, form or mass as a basis. A cube or a head seen directly in front will be bordered by parallel lines; two vertical and two horizontal. These lines do not retreat, and therefore, in appearance remain parallel. As soon however, as they are placed so that they are seen from beneath, on top or from either side, they appear to converge. This convergence causes the further side of the object to appear smaller than the nearer side.
The rules are:
- First—Retreating lines whether above or below the eye tend toward the level of the eye.
- Second—Parallel retreating lines meet at the level of the eye. The point where parallel retreating lines meet is called the vanishing point.
As objects retire or recede they appear smaller. It is the first rule of perspective—on this, the science of perspective is built.
Distribution of Masses of the Head
Four distinct forms compose the masses of the face. They are:
- The forehead, square and passing into the cranium at the top.
- The cheek-bone region which is flat.
- An erect, cylindrical form on which are placed the base of the nose and the mouth.
- The triangular form of the lower jaw.
From forehead to chin a face that is not flat either protrudes or recedes, curving outward or inward, alternating as to curves and squares of varied forms. In this respect a face in profile resembles architectural mouldings.
Construction of the Head
First draw an outline of the head, then check to see that it will take but four lines. Number one line is to be drawn first, number two line next, three and four to follow numerically. Number one line is drawn down the face touching the root and base of the nose. Number two line from the base of the ear at a right angle to number one, with no relation to the face as to where this line crosses. Number three line is drawn from the cheek bone at its greatest width to the outer border of the chin. Where two and three intersect, start the fourth line and carry it to the base of the nose. Whether the head is seen from above or below, the features will follow the number four line.
Planes of the Head
In considering the distribution of the masses of the head, the thought of the masses must come first; that of planes, second. Planes are the front, top and sides of the masses.
It is the placing and locking of these planes or forms that gives solidity and structural symmetry to the face, and it is their relative proportion as well as the degree to which each tilts forward or backward, protrudes or recedes, that makes the more obvious differences in faces.
Heads in general should be neither too round nor too square. All heads, round or oval or square, would be without contrast in form.
In drawing, one must look for or suspect that there is more than is casually seen. The difference in drawing is in what you sense, not what you see. There is other than that which lies on the surface.
The front of a face is the front plane. The ear side is another plane. Spectacles are hinged to conform to the front and sides of a face.
The square or triangular forehead must have a front and two sides, making three planes.
The face turns at a line from each cheek bone downward to the outer side of the chin. There is also a triangular plane on each side of the nose; its base from tip to wings forms another triangular plane. There is also the square or rounded chin with planes running back from each side.
Border lines separate the front and sides of the forehead above, and cheek bones and chin below. Across from ear to cheek bone is a ridge separating two more planes which slope upward toward the forehead and downward to the chin.
Considering the masses of the head, the thought of the masses comes first, then the planes; after that the rounded parts of the head. There are four rounded forms on the skull. One on the forehead, two on the sides of the head, just above each ear, and one on the front of the face, extending from nose to chin. On each side, at the upper part of the forehead, are two rounded elevations termed the frontal eminences. These eminences often merge into one and are referred to as the frontal eminence.
The plane of the forehead slopes upward and backward to become the cranium; and the sides turn sharply to the plane of the temples.
The plane of the face, divided by the nose, is broken on each side by a line from the outer corner of the cheek bone to the center of the upper lip, making two smaller planes.
The outer of these turns to become the plane of the jaw, which also is again divided by a line marking the edge of the masseter muscle, running from the outer border of the cheek bone to the corner of the jaw, and again making two secondary planes, one toward the cheek and one toward the ear.
The relations of these masses and planes is to the moulding of a head what architecture is to a house. They vary in proportion with each individual, and must be carefully compared with a mental standard.
The Head in Profile
In profile the masses of the head are the same—the cranium, the skeleton of the face, and the jaw. The front border of the temple is seen to be a long curve, almost parallel to the curve of the cranium. The top of the cheek bone is seen to be prolonged backward toward the ear as a ridge (zygoma or yoke) which also marks the base of the temple. It slopes slightly down in front. From cheek bone and zygoma, where they meet, a lesser ridge is seen rising between the temple and the orbit, marking the back of the orbit and the first part of the long line of the temple. Assume a profile view of a head measures eight by eight inches.
Directly in front or from the back, the relative proportions would be six by eight. At three-quarters view it would be somewhere between the two measurements.
Above Eye Level
When a cube is tilted upward in such a way that the spectator is seeing it from beneath, it is above the horizon or height of the eye. If more of one side of the cube is seen than the other, the broader side will be less in perspective than the narrower side. The narrowest side of a cube presents the more acute angle and will have its vanishing point nearest.
When an object is above eye level, the lines of perspective are coming down to the level of the eye and the vanishing points will be near or far apart according to the angles. The nearer the object the nearer together are the vanishing points.
When a head is to be drawn in profile it is well to first determine whether the head is above or below eye level. This can be done by holding a pencil or rule at arm’s length at a right angle to the face from the base of the ear. If the base of the nose shows below the ruler, then you are looking up underneath the head; therefore the head is above eye level or tilted backward. If the head is three-quarters view or front, the line from ear to ear will cut below the nose as in profile when seen from beneath.
Below Eye Level
In looking down on an object you will see more or less the top of the object. If the object is a head, you will see the top of the head. The higher above the head you are, the more top you see, the lower you are, the less you see.
The top is nearest the level of the eye and the lower part further away. In profile at eye level the center of an adult’s head will be a little below where the hook of a pair of spectacles curl around the top of the ears. If this line were continuous, it would pass through the eye, dividing the head into two parts. The base of the ear is on a level with the base of the nose. A line passing around the head from ear to ear would parallel the spectacles.
When the view is below eye level you are looking down and therefore see a portion of the top. This means the head, top, bottom and sides are rising to the level of the eye.
From the lower corners of the forehead, the cheek bones mark the beginning of a plane descending downward in a long curve to the widest part of the chin. This curve marks the corner of the two great planes of the face, front and side. Here the spectacles turn in perspective as well as the line passing from ear to ear.
Round Forms of the Head
The skull is rounded on both sides of the head directly on a line above the two ears. Part of this formation is the parietal bone, a thick spongy shock absorber at the side of the head, at its widest and most exposed portion.
Below this, cylindrical in shape, comes the rounded portion of the face. This rounded portion corresponds to the lower portion of the face inasmuch as it has front and receding sides. The upper portion, known as the superior maxillary, is irregular in shape and descends from the base of the eye socket to the mouth. The lower portion, known as the lower or inferior maxillary, takes the same curve as the mouth and is part of the angular jaw bone.
The nose lies on the center of this cylindrical formation.
Below the nose, the lips follow the contour of this part of the rounded form, which as a covering, takes the shape of the teeth.
It is in reality, plane against plane, adjusted at different angles, which forms the shape of the head. There is no exact mathematical proportion, but in perspective or from any angle, we are forced to balance truly one side with the other.
Round and Square Forms of the Head
A square line naturally is the outline of a square form. A round line is the outline of a round form. The classic beauty of all drawing is a happy combination or contrast of both these forms. A partially rounded square form or a partially square rounded form adjacent to each other do not produce power or style.
When a head is built on a cube there is a sense of mass, a basis of measurement and comparison. The eye has a fixed point upon which to rest. A vertical line divides the head into two parts. These are equal, opposite, and balanced. Each side is an exact duplicate of the other. A horizontal line drawn through the lower eyelids divides the head in half. The lower portion again divided in the middle gives the base of the nose. The mouth is placed two-thirds up from the chin. Built on the form of a cube, the head has a sense of bulk and solidity that easily lends itself to foreshortening and perspective.
When heads are built on an oval, the basic idea is that the shape is rather like an egg. The main line passes through the features from top of head to chin. This is divided into three parts. The cranium and forehead of the adult occupy the top half, the lower half divided again in the middle gives the base of the nose. The mouth is placed two-thirds the distance up from chin to nose. When the head is tilted or turned, the main axis that is drawn down the face follows the oval. The divisions follow the divisions as before mentioned.
In the oval construction the eye and ear are taken as the medium line. Above this line is the top of the head, while below is the face.
A line drawn at a right angle to the line already drawn, gives another median or facial line. On this the features are marked off to give their relative positions. The carriage of the head rests upon its placing or poise upon the neck. When the head tips or leans forward, back or toward the sides, the head and neck must be in relation one to the other both in movement and rhythm.
The Head in Light and Shade
There is light and shade on any object on which light falls. There are light, shade, and cast shadows. The light blends into half light which again blends into a halftone, which again blends into a shadow. A cast shadow is the shadow of some object falling on some other object or form and bears a resemblance to the object from which it is cast.
In the parlance of Art the variations of light and shade are in a sense numbered, catalogued and called values. Light, halftone and shade, making three values, are said to be all that one can keep track of. The grading, passing, and mingling of these, through or into one another, gives the suggestion of other values, but they become more subtle and less definable.
There are many methods, mannerisms and approaches to handling light and shade. One is that form is built by light and shade, that the outline does not exist; the edges of the object are given prominence by light and shade. Another approach is that an outline drawing is solidified by light and shade, that the outline itself should suggest depth, volume and bulk with only enough shade to give it solidity.
Values are comparative and depend upon their surroundings.
Comparative Measurements of the Head
In an adult, from the extreme top to the bottom, the eyes, roughly speaking, are in the middle. The head and face of an infant may be divided in three parts, the eyes placed on the line marking the upper third, from the chin up. In all heads the base of the nose is placed half way between the eyes and chin; the mouth two-thirds the distance from chin to nose. Ages between these two necessarily range somewhere between.
There is also a marked difference in the formation of the head with varying ages. The forehead of an adult recedes, the cheek bones become more prominent, the jaw bone more angular, the whole head in fact more square. In infancy the head is more elongated and somewhat oval in form. The forehead is full, it recedes down and back toward the brows; the jaw bones and other bones of the face are diminutive; the neck is small compared to the head. In youth the face is lengthened and is less round than in the infant. The head above the brows however, is not enlarged in proportion to the increase of the lower part of the face.
The Child’s Head
The cranium of a child’s head differs from an adult in shape, solely as a means of protection. The head is of an elongated and oval form, its greatest length being in the direction from forehead to the back of the head; its widest portion lies just above the ears. The forehead is full, and protrudes to a marked degree, receding and flattening at the eyebrows. The bones of the face, as well as the jaw bones, are small. The neck is thin and short as compared with the size of the head. The lumps at the widest part of the head are lower than in the adult as a protection for the temporal region and the ears. The peculiar projection at the back (occiput) is for the same reason, protection, and so is the protruding forehead.
A child’s skull is thin and elastic; it will bear blows which would be fatal later on in life. The narrow shoulders and the almost useless arms make a necessity of a bulging forehead to protect the face from the front; the other prominent bulges protect the sides and back of the head. From infancy to adolescence great changes take place in the upper as well as the lower portion of the face. Above, the face lengthens; the nose and cheek bones become more prominent. The teeth add width and depth at the lower part of the face. Jaw bones become more angular and pointed, the masseter muscles are more in evidence, and a squareness of the chin is noticeable.
Muscles of the Face
The variable expressions of the human face, like the varied tones of the voice, are sensed and ever changeable. Expression is not always caused by the contraction of certain muscles, but rather from the combined action of many muscles as well as the relaxation of their opposing muscles. The same group act, for example, in both the expression of smiling and laughter, in a lesser or greater degree.
The eyes and mouth are surrounded by muscles of circular form. These muscles function primarily to close either mouth or eye. The fibrous ring that surrounds the eye is attached to the inner angle of the orbit. The fibres of the outer rim blend or mingle with the bordering muscles of the face. Another muscle of circular form surrounds the mouth. The inner fibres operate on the lips, while the outer borders blend with the free ends of the surrounding facial muscles.
The muscles which encircle the eye and mouth are operated by two distinct classes, those which control and those which oppose. If the mouth is stretched laterally and the muscles of the cheek are raised to the lower eyelid a smile is produced. By muscular action, a paroxysm of laughter affects not only the face, but the body as well. The breath is drawn in, the chest, a diaphragm, is convulsed and agitated.
The lips, the depression of the angles of the mouth disclosing the teeth and the corrugation of the brows denote despair, fear and anger, rage and other combinations of which the human face is capable.
Below the cleft of the chin, the chin itself protrudes. Its breadth at the base is marked by two lines which, prolonged, would meet at the septum of the nose, making a triangle that wedges upward into the base of the lower lip. It is bordered on each side by two planes which reach to the angle of the jaw.
Variations in chins present the following comparisons: high or low; pointed or ball; flat, furrowed or dimpled; elongated, double, etc.
Movements of the Lower Jaw
Above the eye socket, or orbit, the frontal bone is buttressed and of double thickness. The cheek bones beneath are reinforced and the entire bony structure surrounding the eye is designed to protect this vulnerable and expressive feature of the face.
The eye, cushioned in fat, rests in this socket. In shape, the eyeball is somewhat round. Its exposed portion consists of pupil, iris, cornea and the “white of the eye.” Due to the transparent covering, or cornea, which fits over the iris, much as a watch crystal fits over a watch, making a part of a smaller sphere laid over a larger one, the eye is slightly projected in front.
It is the upper lid which moves. Its curtain, when closed, is drawn smoothly over the eye; when open, its lower part follows the curve of the eyeball, like the roll top of a desk, folding in beneath the upper part and leaving a wrinkle to mark the fold. The transparent cornea of the eye, raised perceptibly and always partly covered by the upper lid, makes this lid bulge. This bulge on the lid travels with the eyeball as it moves, whether opened or closed.
The lower lid is quite stable. It may be wrinkled and slightly lifted inward, bulging below the inner end of the lid. The lashes which fringe the upper and lower lids from their outer margin, shade the eye and serve as delicate feelers to protect it, the upper lid instinctively closing when they are touched.
The ear, irregular in form, is placed on the side of the head. The line of the ear toward the face is on a line with the upper angle of the lower jaw. The ear, in man, has lost practically all movement. It is shaped like half of a bowl with a rim turned out, and below is appended a piece of fatty tissue called a lobe. Its muscles which in primitive times, no doubt, could move it to catch faint sounds, now serve only to draw it into wrinkles, which, though varying widely, have certain definite forms. There is an outer rim often bearing the remains of a tip, an inner elevation in front of which is the hollow of the ear with the canal’s opening protected in front by a flap and behind and below by smaller flaps.
The ear has three planes divided by lines radiating from the canal, up and back and down and back. The first line marks a depressed angle between its planes. The second marks a raised angle.
Cartilages of the Ear
Planes of the Ear
The nose is in the center of the front plane of the face. Its shape is wedgelike, its root in the forehead and its base at the center of the upper lip. As it descends from the forehead it becomes larger in width and bulk, and at its base it is held up in the middle and braced from the sides by cartilages.
The bony part of the nose descends only half way from its root and is composed of two nasal bones. The lower part is composed of cartilages, five in all: two upper, two lower laterals and one dividing the nasal cavities.
Two wedges meet on the nose, a little above the center at a point called the bridge of the nose. The direction of one is toward the base of the forehead between the eyes; that of the other toward the end of the nose, diminishing in width as it enters the bulbous portion at the tip.
Cartilages of the Nose
This bulb rises as two sheets of cartilage from the middle of the upper lip (septum of the nose), expands into the bulbous tip, flows over the sides, and flares out to form the alae or wings of the nostrils.
The cartilaginous portion is quite movable. The wings are raised in laughter, dilated in heavy breathing, narrowed in distaste, and wings and tip are raised in scorn, wrinkling the skin over the nose.
Average variations in noses divide them into classes.
- They may be small, large, or very large; concave or convex; humped, Roman or straight.
- At the tips they may be elevated, horizontal, or depressed; flattened, tapering or twisted.
- The wings may be delicate or puffy, round or flat, triangular, square or almond-shaped.
That part of the jaws in which the teeth are set is cylindrical in shape and controls the shape of the mouth. If the cylinder is flat in front, the lips will be thin and the mouth a slit. The greater the curve of this cylinder, the fuller and more bow-shaped will be the mouth and lips.
From the base of the nose to the upper red lip, this curtainous portion of the mouth has a central vertical groove and pillars on either side which blend into broad, drooping wings, ending at the corners of the mouth in fleshy eminences called the pillars of the mouth.
The upper red lip has a central wedge-shaped body, indented at the top by the wedge of the groove above, and two long, slender wings disappearing under the pillars of the mouth. The lower red lip has a central groove with a lateral lobe on either side. It has three surfaces: the largest depressed in the middle at the groove, a smaller one on either side diminishing in thickness, curving outward, and not so long as those of the upper red lip.
Below the lower red lip, the curtainous portion of the mouth slopes inward and ends at the cleft in the chin. It has a small, linear central ridge and two large, lateral lobes, bounded by the pillars of the mouth.
The oval cavity of the mouth is surrounded by a circular muscle (orbicularis oris) whose fibres, overlapping at the corners, raise the skin into the folds or the pillars of the mouth.
Its outer margin is usually marked by a crease in the skin running from the wings of the nose out and down to varying distances, paralleling the pillars. Its lower end may blend into the cleft of the chin. From this muscle radiate various facial muscles of expression.
Average variations in lips present the following comparisons: thick or thin, prominent, protruding or receding. Each may be compared with the other in these respects: straight, curved or bowed, rosebud, pouting or compressed.
The neck is cylindrical in shape, following the curve of the spinal column; even when the head is thrown back the neck curves slightly forward.
In front, it is rooted at the chest and canopied above by the chin. In back it is somewhat flattened and the back of the head overhangs it. The neck is buttressed on each side by the shoulders. From behind each ear a muscle descends inward to the root of the neck. These muscles almost meet each other, making a point at the pit. They form, in fact, on the front plane of the neck, the sides of an inverted triangle whose base is the canopy of the chin. The two muscles referred to are called bonnet strings.
Into this triangle are set three prominent forms: a box-shaped cartilage called the larynx or voice-box; just below it a ring of cartilage called the cricoid cartilage; and beneath these a gland called the thyroid gland. In men, the voice-box or larynx is larger; in women, the thyroid gland is more prominent. The whole is known as the Adam’s apple. The neck has the following action: up and down, from side to side, and rotary.
Front of the Neck
Back of the Neck
From the sloping platform of the shoulders the neck rises. It is buttressed on the sides by the trapezius (table) muscle. The table shape of this muscle appears only from the back, a diamond with lower apex well down the back. Its lateral corners arise from the shoulder girdle opposite the deltoid. Rising diagonally upward it braces the back of the head.
The strength of the neck is therefore at the back, which is somewhat flat and overhung by the base of the skull.
Muscles of the Neck
- Sterno-cleido-mastoid: From top of sternum and sternal end of clavicle to mastoid process (back of ear). Action: Together, pull head forward; separately, rotates to opposite side, depresses head.
- Levator Scapulae: From upper cervical vertebrae to upper angle of shoulder blade. Action: Raises angle of shoulder blade.
- Trapezius: From occipital bone, nape ligament and spine as far as twelfth dorsal, to clavicle, acromion and ridge of shoulder blade. Action: Extends head, elevates shoulder and rotates shoulder blade.
- Platysma Myoides: A sheathing from chest and shoulder to masseter and corner of mouth. Action: Wrinkles skin of neck, draws down corner of mouth.
- Digastric (double-bellied muscle): Anterior belly, from maxilla, behind chin; posterior belly, from mastoid process; fastened by loop to hyoid bone. Action: Raises hyoid and tongue.
- Mylo-hyoid: Forms floor of mouth and canopy of chin in front.
- Stylo-hyoid: From hyoid to styloid process. Action: Draws back hyoid and tongue.
- Sterno-hyoid: From sternum to hyoid bone. Action: Depresses hyoid and Adam’s apple.
- Omo-hyoid: From hyoid bone to shoulder, upper border of scapula. Action: Draws hyoid down and to one side.
Tongue Bone and Larynx
Movements of the Neck
In the neck are seven vertebrae, each moving a little. When the neck is turned to one side, that side of each vertebra moves back as far as the perpendicular and then the opposite sides move forward, lengthening the neck as they do so. This motion is much freer at the second joint from the skull, which turns on a pivot. The joint of the skull itself moves only in nodding, in which the rest of the neck may be quite stationary.
1. For safety as well as to see and to hear, the head and shoulders must be able to turn in all directions.
2. The head is a lever of the first order.
3. The muscles that move the atlas.