HUMAN NECK ANATOMY

These are some facts about the human neck anatomy:

• Obviously, the neck is what connects our head to our torso, and the upper part of the spine is also located in the neck. The spine consist of 33 smaller bones known as vertebrae, and 7 of these vertebrae are in the neck. The area of the spine that is in the neck is known as the cervical curve.
• The hyoid bone is another bone that is located in the neck. This is the only bone that is not attached to any other bone in the human skeleton, and it's located just below the adams apple.
• Speaking of the adams apple, the adams apple(scientifically called the laryngeal prominence) is a lump much more prominent in males than in females. The adams apple is made up of thyroid cartilage surrounding the larynx(the voice box). During a males puberty the larynx grows, and thus the adams apple becomes larger.
• One of the main functions of the neck is to protect the nerves that are between our brain and the rest of the human body.

The main and very important function of clavicle is to keep scapula in proper position so that arm movement becomes free and thus having maximum range for its movement. It also provides attachment for many muscles as the scapula and girdle being the one responsible for movements; it is free for the movement because of the collar bone being connected with many other important muscles.

Another important thing to notice is that clavicle does not contain bone marrow cavity but is made of spongy bone. This bone is visible even from above the skin and just where the neck ends, one can notice this bone. Thus, shoulder should be kept in proper movement and exercise should be on the daily to-do lists. If proper care not taken, one may dislocate any of this shoulder bones which results into pain and swelling.

In this article, I'd like to give you some quick but important points about the human body and how they pertains to your figure drawing.

Of all the aspects of human anatomy, the muscles will undoubtedly have the most impact on how your drawings look, as it is at the very surface. One thing to remember about muscles is that they always pull; every movement that you make is the direct result of one or more muscles contracting and pulling on your bones. What this means is that when the figure you are drawing is engaged in dynamic action, you must pay attention to the muscles involved and depict them accordingly.

For example, if you are drawing a boxer who is throwing a right hook, you must ask yourself, "Which muscles are pulling in order to make this action possible?" Then you would draw those muscles as flexing. In this case, the flexing muscles would be the pectoralis major, the deltoid, and the biceps, to name a few. In most cases, a particular movement will involve multiple muscle groups and the more muscles you can depict, the more convincing your drawings will be. Without this, your drawings will look static and lifeless.

Your ability to recognize and draw these muscles will improve as your knowledge of anatomy increases. As a beginner, you might only be able to draw big muscles like the bicep or shoulder, but as you progress in your study of anatomy, you'll be able to add in finer details like the supinator longus and the anconeus. This will give your drawing an extra dimension of realism.

Just a light knowledge of anatomy can do wonders for your drawing. For example, there are many muscles in the neck but there is one particular muscle that artists should pay attention to. It is the sternocleidomastoid. It connects behind the ear and attaches to the collar bone. This muscle is very prominent and can be seen on almost everyone. Simply by adding this one muscle to your drawings of the neck, you can instantly make it ten times more realistic. This should show you how useful human anatomy is to the figure drawing artist.

We will start from the top to the bottom and I have to say that the head is filled with such places. First of all, the eyes represent one of the weakest points in the human body. It will sound cruel however in a life or death situation you must act. A direct blow with the fingers to the attackers eyes will leave him in extreme pain and complete incapacity. He will most likely run away or collapse from the pain. Also behind the ears there is a bone that in placed directly over the balance center of the body or the inner ear. A direct blow with your palm or elbow to that area will leave an attacker with limited or no balance, causing him to fall.

Another weak point the human body has is located directly under the nose. A cartilage is located there and if receiving a direct blow, that cartilage will send out extreme pain sensations to the brain and activate the tear glands of the eyes, thus the attacker will not see and will be temporarily incapacitated. Also a special spot which only men have is the Adam's apple in the neck. A straight punch to that are will leave a man without breath and can actually be fatal if delivered with too much power.

Moving down a bit on the body, we reach the liver. It is considered to be regenerating organ and filters all the impurities in your body. It is located in the lower right side of the abdominal cavity and when punched properly, can cause the attacker to collapse in extreme pain, have almost total lack of breath and even loss of consciousness.

The last weak point taught by self defence classes on the human body, is represented by the knee. It holds you leg together as a principle joint and is covered by a very hard cartilage known as the patella or the knee cap. Upon receiving a direct blow, this injury can cause an attacker to instantly drop and experience pain. All these techniques may seem cruel and unfair, however they must be used only in critical situations and are only for protection.

The spine consists of a column of bony blocks known as vertebrae standing one on top of the other. In the neck there are seven which are known as cervical vertebrae; there are twelve in the back of the chest - the dorsal or thoracic vertebrae; and five in the back - the lumbar vertebrae. The bottom or fifth lumbar vertebra (L5) is directly attached to the sacrum or tail bone. The sacrum is the back part of the pelvis, a ring of bone providing support for the spine and trunk.

All the vertebrae have similar basic structures but with considerable variations at each level, reflecting the different functions at each site. For example, the neck is remarkably flexible and only has to bear the weight of the skull. The cervical vertebrae are very lightly built and shaped so as to allow a considerable range of movement between them. In contrast the back has to bear the weight of the trunk and transmits forceful movements of the body. The lumbar vertebrae are much thicker and tougher structures with relatively limited movements allowed between them.

Each vertebra consists of a cylindrical part in front known as the vertebral body. This has flat upper and lower surfaces known as the vertebral end-plates. The vertebral body is convex in the front and flattened behind. This flattened area forms the front part of the canal down which the spinal cord and nerve roots pass. The vertebral arch surrounds the rest of the canal giving protection to the structures within. Each vertebra is joined to those above and below by joints between the vertebral bodies and between the arches.

The intervertebral disc lies between the vertebral end-plates. It is a cushion of tissue that normally provides a springy and movable connection between the bones. Three types of movement occur at this cushion - flattening under loads, bending, and twisting. However, unlike a cushion the disc has a very definite structure that is all-important when things go wrong. Basically the disc consists of two parts: a central area known as the nucleus pulposus and an outer ring, the annulus fibrosus.

In his drawings of the spine Vesalius showed the structure of the disc and realized that it was complex. He knew that the outermost layer is different from the inner material but he did not get the details absolutely right. The nucleus consists of jelly-like material containing a few tangled fibres and many large molecules known as proteoglycans. The nucleus has the property of all gelatinous materials, namely that it can be squashed and then alters in shape but its total volume will remain constant. The nucleus is kept in shape by the outer annular ring and the vertebral end-plates above and below.

This allows it to transmit the enormous loads that may be carried by the spine. It is the nature of the proteoglycans in the nucleus that they are constantly trying to suck in water and swell. This tendency is resisted by pressures produced by the weight of the body. When we sleep lying horizontally at night this swelling process is unimpeded. It is a fact that we are slightly taller when we first rise in the morning than at the end of the day. This process is carried to the extreme in spacemen who after several days of weightlessness may grow by a couple of inches. As their space suits are individually and very precisely designed this produced considerable difficulties and a lot of complaints from the spacemen before the cause was appreciated.

The annulus fibrosus which surrounds the nucleus has quite a different structure. It consists mainly of fibres of collagen. This is a fibrous protein which is uniquely designed for tensile or stretching strength. A collagen fibre is considerably stronger than a steel wire of the same dimensions. The collagen fibres of the annulus are attached around the edge of the vertebral end-plate and spiral obliquely upwards and downwards to the end-plates above and below. They cross over and interweave one another in a complex fashion so forming an extremely strong network that surrounds the nucleus. When vertical loads are placed on the spine the nucleus is squashed and slightly flattened and the annular ring will expand slightly, but nevertheless will not give way. Indeed, the annulus is so strong that under extreme load it is the vertebral end-plates that will fracture rather than the annulus itself. This criss-cross arrangement of annular fibres allows relatively easily the movements of bending forwards and backwards and to the side. However, twisting movements are more difficult. This is one of the reasons why back problems are more likely to arise with this type of activity.

At the back of the spine the vertebral arches are also joined to the arches above and below by the small facet joints. There is one joint on each side at each level so that connecting each pair of vertebrae are three joints: one between the vertebral bodies and two between the arches. The facet joints differ from the intervertebral disc in that they are synovial joints. The opposing joint surfaces are covered by cartilage or gristle and are connected to each other by a fibrous capsule lined by a layer of tissue known as the synovial membrane. Within the joint is a lubricant known as the synovial fluid which allows the joint surfaces to move against each other. This arrangement is very similar to that of the joints in the limbs, although the sizes and shapes of the various joints differ enormously. Any movement between a pair of vertebrae must involve all three joints; it is not possible for one of these joints to move to the exclusion of the others- It may seem trite to point this out but one often hears statements that one of these joints alone is stiff or that manipulation is applied to a single joint, ignoring the movements that must take place at the others.

The vertebrae are also joined to one another by a series of ligaments which ensheath the bodies and connect the arches. These ligaments are relatively flexible and yet have an important role in covering the bony and joint surfaces.

A pile of vertebrae one on top of the other is intrinsically unstable and one can readily imagine how bowing or slipping of the structure could occur. The spine is stabilized by very powerful muscles attached to the vertebrae, the pelvis, and the back of the chest wall. An interesting analogy is with the stays on a yacht which have a remarkably similar function in stiffening and stabilizing the mast. During any exertion these muscles contract so stiffening the spine and enabling it to bear the load.

The spinal cord emerges from the base of the brain and passes down through the vertebral canal behind the vertebral bodies and surrounded by the vertebral arches. During its passage downwards nerve roots separate off to emerge through the invertebral foramina between the vertebral arches at every level. The spinal cord itself finally ends at about the junction between the first and second lumbar vertebrae (Ll/2) and below that level there are only nerve roots in the vertebral canal. The roots emerge from the canal and pass on to their ultimate destinations, uniting and dividing in complex fashions to provide appropriate nerve supplies to all the structures of the human body.

The spinal cord and nerve roots are not in direct contact with the bony vertebral canal but are covered by several protective sheaths. The outermost is known as the dura mater and is a strong fibrous membrane which forms a wide tubular sheath around the spinal cord and the upper part of the nerve roots with tubular prolongations along the nerve roots themselves as they pass out through the intervertebral foramina. Inside the dura is the arachnoid which is a much more delicate membrane loosely investing the spinal cord and nerve roots. The innermost layer is known as the pia and is intimately adherent to the spinal cord and nerve roots. In the course of various back disorders these coverings may become inflammed and thickened with a lot of scar tissue. This is known as arachnoiditis and can be the cause of severe pain in the back and in the areas in the legs that the nerves supply.

The spine itself also has a nerve supply. Tiny branches from the nerve roots will supply the ligaments around the spine, the capsule or surroundings of the facet joints, the dura, arachnoid, and pia coats around the spinal cord and the blood vessels in the bone marrow. Surprisingly they do not occur in the substance of the intervertebral disc but only in the very outermost layers of the annulus fibrosus. As damage to a nerve fibre is a prerequisite to produce the sensation of pain, it is clear that most disorders of the disc alone will be painless. The presence of damage to a disc seen on X-rays does not mean that this has been the cause of back pain. It is only when a disc disorder produces damage to the surrounding structures that pain may develop.

Another point about the nerve supply to the spine is that the nerves from each level combine with one another in extremely complex fashions. This produces the phenomenon known as cross-innervation which means that any nerve may carry information about abnormalities arising at several different levels. For this reason it is often extremely difficult to localize the source of symptoms felt in the back. Pain felt at one site can be due to abnormalities at a quite different area. Considerable circumspection is required when trying to identify the source of the problem in the back pain subject.

Courses in anatomy and physiology help students better comprehend the intricate mechanisms at work within the human body. Having this understanding helps one to understand physicians, make good decisions that will improve their own health, and make important decisions down the road in health care for their family. Students planning a career in medicine will always have courses in anatomy and physiology as a base of study. Anatomy and physiology help is available online. These consist of diagrams, quizzes, tutorials, dictionaries, movies, and many more helps.

Anatomy is the branch of biology which studies the structure of living things within the human body. This study includes and leads to understanding the operations of organs, cells, tissues, bones, cartilages, muscles, blood, the brain, and the nervous system, to name a few. These large areas can also be sub-divided into smaller categories of study. These categories in anatomy and physiology help are almost endless. For simplicity in study, some group the areas of the body into these four main categories. Firstly, the regional groups, secondly, the major organ systems, thirdly, the superficial anatomy, and fourthly, the internal organs.

The regional group includes the neck and head, upper limb, thorax, abdomen, back, pelvis and perineum, and lower limb. The major organ systems include the circulatory, endocrine, digestive, immune, integumentary, nervous, respiratory, lymphatic, reproductive, and urinary. The superficial anatomy refers to the surface anatomy of bodily landmarks from which physicians can use as reference points to gauge the position of deeper structures. The internal organs comprise the last group. The physiology of anatomy helps one understand how all of these different structures work together! When you access anatomy and physiology help you will begin a fascinating journey of the human body.

Just as all humans have joints and physical features labeled as elbow, wrist, knuckles etc., there are common labels given to the various joints and features of canine anatomy. While some of these labels, such as thigh or knee, are the same as that of humans, it is important to remember that the thighs and knees of a canine are very much different from our own.

The withers is arguably one of the most important parts of canine anatomy, as it is used to measure the height of a dog. The withers is a ridge on the dog's back between its shoulder blades. The height of a dog is measured from the bottom of the paw up to the withers, and never includes the neck, head or ears of a dog in the measurement. Starting from the paws on a dog's forelegs, the paw is connected to the pastern by the wrist joint. There is no human equivalent to the pastern, but it is the shortest and lowest bone on a dog's forelegs excluding the paws and toes. The pastern is connected to the forearm by the pastern joint, and the forearm is connected to the upper arm by the elbow. These are only vaguely similar to forearms, elbows and upper arms found in humans. The upper arm is connected to the body by the shoulder.

A dog's hind legs are considerably different than its forelegs. Again starting from the paws, the hind paws are connected to the rear pastern. The rear pastern is connected to the secondary thigh, also known as the gaskin, by a pronounced joint known as the hock. The secondary thigh is connected to the upper thigh by the stifle, sometimes referred to as the knee joint. The upper thigh forms the hind-quarters and is connected to the body by the hip.

Along the back of the dog, there is the croup, loin, back, withers and crest. The croup is the rear-most portion of the dog's back, where the tail is connected. The crest lies along the neck-line of the dog. The loin, back and withers fall in between the two, in the order described. Along the underside, there is abdomen, brisket and forechest. The abdomen is rear-most portion of the dog's underside, starting where the rib-cage stops. The brisket forms the underside of the dog's chest, where the rib-cage is, and the forechest is the protrusion of chest past that forelegs.

The head of the dog includes characters common among most mammals such as eyes, nose, ears and tongue. The elongated portion of the dog's mouth and nose area is known as the muzzle. The point where the muzzle meets the remainder of the head is known as the stop, and is usually where the eyes are located.

While the various terms may seem initially daunting, they are not difficult to learn. Knowing the key parts of the German Shepherd anatomy will help ensure that you have the tools you need to make an intelligent, informed decision when purchasing a person protection dog, guard dog or security dog.