INTRODUCTION TO ANATOMYTERMINOLOGY IN ANATOMY

BONES & JOINTS, GENERAL CONSIDERATIONS

Kaan Yücel M.D.,Ph.D.24.November.2011 Thursday

Yeditepe UniversityMedical School

Department of Anatomy

INTRODUCTION TO ANATOMY

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“anatomia, anatome” Latin and Ancient Greek origin.

ana-= up temnein, tome=to cut

Anatomy means “cutting up, cutting through”.

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The term human anatomy comprises a consideration of the various structures which make up the human organism.

Human anatomy deals with the structure of the human body at the gross, cellular, and subcellular levels.

It also deals with the way in which development and growth alter structure and with relationships between structure and function.

HistologyEmbryology

A knowledge of these topics is essential for anyone who wishes to become a clinical practitioner and especially for those whose practice is likely to be of a surgical nature.

Impossible to:Understand the effects of diseases and their clinical manifestations without an understanding of healthy structure and function

To intervene effectively and safely with surgical procedures without a good working knowledge of the anatomy of the relevant part of the body.

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Types of anatomyThe three main approaches to studying anatomy are regional, systemic, and clinical (or applied), reflecting the body's organization and the priorities and purposes for studying it.

In systematic anatomy, various structures may be separately considered.The organs and tissues may be studied in relation to one another in topographical or regional anatomy.

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Regional anatomy (Topographical anatomy)

Considers the organization of the human body as major parts or segments: a main body, consisting of the head, neck, and trunk (subdivided into thorax, abdomen, back, and pelvis/perineum), and paired upper limbs and lower limbs.

All the major parts may be further subdivided into areas and region.

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Surface anatomy

An essential part of the study of regional anatomy.

Provides knowledge of what lies under the skin and what structures are perceptible to touch (palpable) in the living body at rest and in action.

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Systematic AnatomyThe various systems of which the human body:Osteology—the bony system or skeleton. Syndesmology—the articulations or joints.Myology—the muscles. Angiology—the vascular system, comprising the heart, blood vessels, lymphatic vessels, and lymph glands.Neurology—the nervous system. The organs of sense may be included in this system.Splanchnology—the visceral system.

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Topographically the viscera form two groups, viz., the thoracic viscera and the abdomino-pelvic viscera.

The heart, a thoracic viscus, is best considered with the vascular system.

The rest of the viscera may be grouped according to their functions: (a) the respiratory apparatus; (b) the digestive apparatus; and (c) the urogenital apparatus.

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History of dentistry and anatomy in dentistry The field of Human Anatomy has a prestigious history, and is

considered to be the most prominent of the biological sciences of the 19th and early 20th centuries.

Methods have also improved dramatically, advancing from examination of animals through dissection of cadavers to technologically complex techniques developed in the 20th century.

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It is believed that the oldest civilization that knew something of dentistry was Egypt.

The earliest indication of such knowledge is found in the Edwin Smith Surgical Papyrus.

The first known dentist was an Egyptian named Hesi-Re (3000 B.C.). He was the chief toothist to the Pharaohs. He was also a physician, indicating an association between medicine and dentistry.

During the 1500s, advances in anatomy, microbiology, and other areas laid the foundations for specialized treatises on dentistry and for a theoretical—not just mechanical and empirical—approach to oral health.

These advances included detailed anatomical descriptions of teeth and related structures.

Andreas Vesalius

In 1771, John Hunter published "The natural history of human teeth" giving a scientific basis to dental anatomy.

By the 21st century, the availability of interactive computer programs and changing public sentiment led to renewed debate on the use of cadavers in medical education.

The Peninsula College of Medicine and Dentistry in the UK, founded in 2000, became the first modern medical school to carry out its anatomy education without dissection, though most medical schools continue to see experience with actual cadavers as preferable to entirely computer-based education.

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All anatomical descriptions are expressed in relation to one consistent position, ensuring that descriptions are not ambiguous.

One must visualize this position in the mind when describing patients (or cadavers), whether they are lying on their sides, supine (recumbent, lying on the back, face upward), or prone (lying on the abdomen, face downward).

Anatomical position

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The anatomical position refers to the body position as if the person were standing upright with the:

Head, eyes, and toes directed anteriorly (forward) Arms adjacent to the sides with the palms facing anteriorly Lower limbs close together with the feet parallel.

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Anatomical descriptions are based on four imaginary planes (median, sagittal, frontal-coronal, and transverse-axial) that intersect the body in the anatomical position.

Sagittal= New Latin sagittālis < sagitta (“arrow”)

Coronal= L. corona "crown, garland»

Axial = "pertaining to an axis,«

Anatomical planes

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The median plane, the vertical plane passing longitudinally through the body, divides the body into right and left halves.

Sagittal planes are vertical planes passing through the body parallel to the median plane.

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Frontal (coronal) planes are vertical planes passing through the body at right angles to the median plane, dividing the body into anterior (front) and posterior (back) parts.

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Transverse planes are horizontal planes passing through the body at right angles to the median and frontal planes, dividing the body into superior (upper) and inferior (lower) parts. Radiologists refer to transverse planes as transaxial, which is commonly shortened to axial planes.

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Anatomy books describe (initially, at least) the structure of the body as it is usually observed in people—that is, the most common pattern.

However, occasionally a particular structure demonstrates so much variation within the normal range that the most common pattern is found less than half the time!

Variations in topographic position of the appendix.

Anatomical variations

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Terminology in anatomy

It is important for medical personnel to have a sound knowledge and understanding of the basic anatomic terms.

The accurate use of anatomic terms by medical personnel enables them to communicate with their colleagues both nationally and internationally.

Without anatomic terms, one cannot accurately discuss or record the abnormal functions of joints, the actions of muscles, the alteration of position of organs, or the exact location of swellings or tumors.

Anatomical terms are descriptive terms standardized in an international reference guide, Terminologia Anatomica (TA).

TA- International Anatomical Terminology

Created by the Federative Committee on Anatomical Terminology and approved by the International Federation of Associations of Anatomists, the most recent (6th) edition was published in 1998.

Many anatomical terms have both Latin and Greek equivalents.

Thus the tongue is lingua (L.) and glossa (Gk), and these are the basis of such terms as lingual artery and glossopharyngeal nerve.

Various adjectives, arranged as pairs of opposites, describe the relationship of parts of the body or compare the position of two structures relative to each other.

Anatomical directional terms are based on the body in the anatomical position

Four anatomical planes divide the body, and sections divide the planes into visually useful and descriptive parts.

Medial is used to indicate that a structure is nearer to the median plane of the body. For example, the 5th digit of the hand (little finger) is medial to the other digits.

Lateral stipulates that a structure is farther away from the median plane. The 1st digit of the hand (thumb) is lateral to the other digits.

Dorsum usually refers to the superior aspect of any part that protrudes anteriorly from the body, such as the dorsum of the tongue, nose, penis, or foot

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Anatomical terms are specific for comparisons made in the anatomical position, or with reference to the anatomical planes:

• Superior refers to a structure that is nearer the vertex, the topmost point of the cranium (Mediev. L., skull).

• Inferior refers to a structure that is situated nearer the sole of the foot.

• Cranial relates to the cranium and is a useful directional term, meaning toward the head or cranium.

• Caudal (L. cauda, tail) is a useful directional term that means toward the feet or tail region, represented in humans by the coccyx (tail bone), the small bone at the inferior (caudal) end of the vertebral column.

• Posterior (dorsal) denotes the back surface of the body or nearer to the back.

• Anterior (ventral) denotes the front surface of the body.

• Rostral is often used instead of anterior when describing parts of the brain; it means toward the rostrum (L. for beak).

To describe the relationship of two structures, one is said to be anterior or posterior to the other insofar as it is closer to the anterior or posterior body surface.

• Combined terms describe intermediate positional arrangements: inferomedial means nearer to the feet and median plane—for example, superolateral means nearer to the head and farther from the median plane.

Other terms of relationship and comparisons are independent of the anatomical position or the anatomical planes, relating primarily to the body's surface or its central core:

Superficial, intermediate, and deep (Lat. Profundus, profunda) describe the position of structures relative to the surface of the body or the relationship of one structure to another underlying or overlying structure.

External means outside of or farther from the center of an organ or cavity, while internal means inside or closer to the center, independent of direction.

Other terms of relationship and comparisons are independent of the anatomical position or the anatomical planes, relating primarily to the body's surface or its central core:

External means outside of or farther from the center of an organ or cavity, while internal means inside or closer to the center, independent of direction.

Proximal and distal are used when contrasting positions nearer to or farther from the attachment of a limb or the central aspect of a linear structure (origin in general), respectively. For example, the arm is proximal to the forearm and the hand is distal to the forearm.

Terms of Laterality

Paired structures having right and left members (e.g., the kidneys) are bilateral, whereas those occurring on one side only (e.g., the spleen) are unilateral.

Something occurring on the same side of the body as another structure is ipsilateral.

Contralateral means occurring on the opposite side of the body relative to another structure.

Terms of Movement

Various terms describe movements of the limbs and other parts of the body.

Most movements are defined in relationship to the anatomical position, with movements occurring within, and around axes aligned with, specific anatomical planes.

While most movements occur at joints where two or more bones or cartilages articulate with one another, several non-skeletal structures exhibit movement (e.g., tongue, lips, eyelids).

Terms of movement may also be considered in pairs of oppositing movements:

Flexion and extension movements generally occur in sagittal planes around a transverse axis.

Flexion indicates bending or decreasing the angle between the bones or parts of the body. For most joints (e.g., elbow), flexion involves movement in an anterior direction, but it is occasionally posterior, as in the case of the knee joint. Lateral flexion is a movement of the trunk in the coronal plane.

Extension indicates straightening or increasing the angle between the bones or parts of the body. Extension usually occurs in a posterior direction.

The knee joint, rotated 180° to other joints, is exceptional in that flexion of the knee involves posterior movement and extension involves anterior movement.

• Abduction is to draw away from the median plane, while adduction is to move towards the median plane.

• Circumduction is a combination of abduction, adduction, flexion and extension, e.g., circumduction can take place in joints like wrist, shoulder.

• To protrude or protract is to move forwards.

• To retrude or retract is to move backwards.

• Elevation raises or moves a part superiorly, as in elevating the shoulders when shrugging, the upper eyelid when opening the eye, or the tongue when pushing it up against the palate (roof of mouth).

• Depression lowers or moves a part inferiorly, as in depressing the shoulders when standing at ease, the upper eyelid when closing the eye, or pulling the tongue away from the palate.

Positions of the body

The supine position of the body is lying on the back.

The prone position is lying face downward.

OSTEOLOGYBONES

Osteology (Gk, osteon, bone, logos, science) is the branch of medicine concerned with the development and diseases of bone tissue.

The human skeleton 206 bones in adults

The skeletal system may be divided into 2 functional parts:The axial skeleton • head (cranium or skull)• neck (hyoid bone and cervical vertebrae) • trunk (ribs, sternum, vertebrae, and sacrum)The appendicular skeleton • Limbs including those forming the shoulde & pelvic girdles

Bone is one of the hardest structures of the animal body, because of the calcification of its extracellular matrix.

Living bones have some elasticity (results from the organic matter) and great rigidity (results from their lamellous structures and tubes of inorganic calcium phosphate).

Its color, in a fresh state, is pinkish-white externally, and deep red within.

Cartilage and Bones

The skeleton is composed of cartilages and bones.

Cartilage is a resilient, semirigid form of connective tissue that forms parts of the skeleton where more flexibility is required—for example, where the costal cartilages attach the ribs to the sternum.

Also, the articulating surfaces (bearing surfaces) of bones participating in a synovial joint are capped with articular cartilage that provides smooth, low-friction, gliding surfaces for free movement.

Blood vessels do not enter cartilage (i.e., it is avascular); consequently, its cells obtain oxygen and nutrients by diffusion.

The proportion of bone and cartilage in the skeleton changes as the body grows; the younger a person is, the more cartilage he or she has.

The bones of a newborn are soft and flexible because they are mostly composed of cartilage.

Bone has a protective function; the skull and vertebral column, for example, protect the brain and spinal cord from injury; the sternum and ribs protect the thoracic and upper abdominal viscera.

It serves as a lever, as seen in the long bones of the limbs, and as an important storage area for calcium salts.

It houses and protects within its cavities the delicate blood-forming bone marrow.

Classification of Bones Bones are classified according to their shape.1) Long bones 2) Short bones3) Flat bones 4) Irregular bones 5) Sesamoid bones

Classification of Bones Long bones are tubular (e.g., the humerus in the arm).

Classification of Bones Short bones are cuboidal and are found only in the tarsus (ankle) and carpus (wrist).

Classification of Bones Flat bones usually serve protective functions (e.g., the flat bones of the cranium protect the brain).

Classification of Bones Irregular bones have various shapes other than long, short, or flat (e.g., bones of the face).

Classification of Bones Sesamoid bones (e.g., the patella or knee cap) develop in certain tendons and are found where tendons cross the ends of long bones in the limbs; they protect the tendons from excessive wear and often change the angle of the tendons as they pass to their attachments.

There are two types of bones according to histological features: compact bone and spongy (trabecular) bone.

They are distinguished by the relative amount of solid matter and by the number and size of the spaces they contain.

All bones have a superficial thin layer of compact bone around a central mass of spongy bone, except where the latter is replaced by a medullary (marrow) cavity.

Spongy bone is found at the expanded heads of long bones and fills most irregular bones.

Compact bone forms the outer shell of all bones and also the shafts in long bones.

Bone Markings and Formations

Bone markings appear wherever tendons, ligaments, and fascias are attached or where arteries lie adjacent to or enter bones.

Other formations occur in relation to the passage of a tendon (often to direct the tendon or improve its leverage) or to control the type of movement occurring at a joint.

Bone Markings and Formations

Surfaces of the bones are not smooth.

Bones display elevations, depressions and holes.

The surface features on the bones are given names to distinguish and define them.

Vasculature and Innervation of Bones

Bones are richly supplied with blood vessels.

Veins accompany arteries.

Nerves accompany blood vessels supplying bones.

GENERAL CONSIDERATIONS ON JOINTS

Joints (articulations) are unions or junctions between two or more bones or rigid parts of the skeleton.

Joints exhibit a variety of forms and functions. It is the fact that, whether or not movement occurs between them, it is still called a joint.

Some joints have no movement, others allow only slight movement, and some are freely movable

Classification of Joints

Joints are classified according to the tissues that lie between the bones:

1) Fibrous joints

2) Cartilaginous joints

3) Synovial joints

Fibrous joints The bones are united by fibrous tissue.

The amount of movement occurring at a fibrous joint depends in most cases on the length of the fibers uniting the articulating bones.

The sutures of the cranium are examples of fibrous joints.

A syndesmosis type of fibrous joint unites the bones with a sheet of fibrous tissue, either a ligament or a fibrous membrane.

Consequently, this type of joint is partially movable.

The interosseous membrane in the forearm is a sheet of fibrous tissue that joins the radius and ulna in a syndesmosis.

A dentoalveolar syndesmosis (gomphosis or socket) is a fibrous joint in which a peglike process fits into a socket articulation between the root of the tooth and the alveolar process of the jaw.

Mobility of this joint (a loose tooth) indicates a pathological state affecting the supporting tissues of the tooth.

Gomphosis is a joint that binds the teeth to bony sockets (dental alveoli) in the maxillary bone and mandible.

The fibrous connection between a tooth and its socket is a periodontal ligament.

Specifically, the connection is made between the maxillary or mandible to the cementum of the tooth.

Small quantity of fibrous tissue holds the bones together.

No movement is possible at such peg-and-socket joints.

Gomphosis- Gk, gomphos, gomphoein; boltSydesmosis- It comes from the Greek σύν, syn (meaning "with") and δεσμός, desmos (meaning "a band).

Cartilaginous joints

The bones are united by hyaline cartilage or fibrocartilage. In primary cartilaginous joints, or synchondroses, the bones are united by hyaline cartilage, which permits slight bending during early life.

Secondary cartilaginous joints, or symphyses, are strong, slightly movable joints united by fibrocartilage.

The fibrocartilaginous intervertebral discs between the vertebrae consist of binding connective tissue that joins the vertebrae together.

Synovial joints

The bones are united by a joint (articular) capsule (composed of an outer fibrous layer lined by a serous synovial membrane) spanning and enclosing an articular cavity.

Synovial joints are the most common type of joints and provide free movement between the bones they join.

They are joints of locomotion, typical of nearly all limb joints.

This type of joints has three common features:Joint cavity: The joint cavity of a synovial joint, like the knee, is a potential space that contains a small amount of lubricating synovial fluid, secreted by the synovial membrane.Articular cartilage: The articular surfaces are covered by hyaline cartilage

Articular capsule: This structure surrounds the joint and formed of two layers. Inside the capsule, articular cartilage covers the articulating surfaces of the bones; all other internal surfaces are covered by synovial membrane.1. Fibrous capsule2. Synovial membrane

Some synovial joints have other distinguishing features, such as a fibrocartilaginous articular disc or meniscus, which are present when the articulating surfaces of the bones are incongruous.

Ligaments

A ligament is a cord or band of connective tissue uniting two structures.

Articular capsules are usually strengthened by articular ligaments.

These are from dense connective tissue and they connect the articulating bones to each other.

Articular ligaments limit the undesired and/or excessive movements of the joints.

Articular disc: Help to hold the bones together.

Labrum: A fibrocartilaginous ring which deepens the articular surface for one of the bones.

Bursa

Bursae are flattened sacs that contain synovial fluid to reduce friction.

Its walls are separated by a film of viscous fluid.

Bursae are found wherever tendons rub against bones, ligaments, or other tendons.

Types of synovial jointsThe six major types of synovial joints are classified according to the shape of the articulating surfaces and/or the type of movement they permit:1.Plane joints (gliding joints) gliding or sliding movements 2.Hinge joints flexion and extension only3.Saddle joints abduction and adduction as well as flexion & extension4.Condyloid joints flexion & extension as well as abduction & adduction 5. Ball and socket joints circumduction 6. Pivot joints rotation around a central axis.

Stability of Jointsdepends on four main factors:

1) Negative pressure within the joint cavity

2) Shape, size, and arrangement of the articular surfaces

3) Ligaments

4) Tone of the muscles around the joint

Joint vasculature and innvervation

Joints receive blood from articular arteries that arise from the vessels around the joint.

Articular veins are communicating veins that accompany arteries (L. venae comitantes) and, like the arteries, are located in the joint capsule, mostly in the synovial membrane.

Joints have a rich nerve supply provided by articular nerves with sensory nerve endings in the joint capsule.