Introduction to Anatomy

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Introduction to Anatomy
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Basic Anatomy

• Anatomy is the science of the structure and
  function of the body that can be seen grossly
  (without the aid of magnification) and
  microscopically (with the aid of magnification).
• Typically, when used by itself, the term
  'anatomy' tends to mean gross or macroscopic
  anatomy
• Clinical anatomy is the study of the macroscopic
  structure and function of the body as it relates
  to the practice of medicine and other health
  sciences.
• Basic anatomy is the study of the minimal amount
  of anatomy consistent with the understanding of
  the overall structure and function of the body.
• Physiology the study of the function of the
  bodys structural machinery

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Gross Anatomy

• Regional all structures in one part of the body
  (such as the abdomen or leg)
• Systemic gross anatomy of the body studied by
  system
• Surface study of internal structures as they
  relate to the overlying skin

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Microscopic Anatomy

• Cytology study of the cell
• Histology study of tissues

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Developmental Anatomy

• Traces structural changes throughout life
• Embryology study of developmental changes of
  the body before birth

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Specialized Branches of Anatomy

• Pathological anatomy study of structural
  changes caused by disease
• Radiographic anatomy study of internal
  structures visualized by X ray
• Molecular biology study of anatomical
  structures at a sub-cellular level

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Descriptive 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

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Terms Related to Position
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Terms Related to Position

• All descriptions of the human body are based on
  the assumption that the person is standing erect,
  with the upper limbs by the sides and the face
  and palms of the hands directed forward
• This is the so-called anatomical position. The
  various parts of the body are then described in
  relation to certain imaginary planes.

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Anatomical Position

• Body erect
• Feet slightly apart
• Palms facing forward
• Thumbs point away from body

Figure 1.7a
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Median Sagittal Plane

• This is a vertical plane passing through the
  center of the body, dividing it into equal right
  and left halves
• Planes situated to one or the other side of the
  median plane and parallel to it are termed
  paramedian
• A structure situated nearer to the median plane
  of the body than another is said to be medial to
  the other
• Similarly, a structure that lies farther away
  from the median plane than another is said to be
  lateral to the other.

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Terms Related to Position

• Coronal Planes
• These planes are imaginary vertical planes at
  right angles to the median plane
• Horizontal, or Transverse, Planes
• These planes are at right angles to both the
  median and the coronal planes

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Body Planes
Figure 1.8
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Terms Related to Position

• The terms anterior and posterior are used to
  indicate the front and back of the body,
  respectively
• 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
• In describing the hand, the terms palmar and
  dorsal surfaces are used in place of anterior and
  posterior

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Terms Related to Position

• in describing the foot, the terms plantar and
  dorsal surfaces are used instead of lower and
  upper surfaces
• The terms proximal and distal describe the
  relative distances from the roots of the limbs
• for example, the arm is proximal to the forearm
  and the hand is distal to the forearm.

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Terms Related to Position

• The terms superficial and deep denote the
  relative distances of structures from the surface
  of the body,
• and the terms superior and inferior denote
  levels relatively high or low with reference to
  the upper and lower ends of the body.
• The terms internal and external are used to
  describe the relative distance of a structure
  from the center of an organ or cavity
• for example, the internal carotid artery is found
  inside the cranial cavity and the external
  carotid artery is found outside the cranial
  cavity.

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Directional Terms
Table 1.1
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Directional Terms
Table 1.1
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Terms Related to Position

• The term ipsilateral refers to the same side of
  the body Contralateral refers to opposite sides
  of the body
• for example, the left hand and left foot are
  ipsilateral
• The supine position of the body is lying on the
  back. The prone position is lying face downward.

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Terms Related to Movement
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Terms Related to Movement

• A joint is a site where two or more bones come
  together is known as a joint
• Some joints have no movement (sutures of the
  skull),
• some have only slight movement (superior
  tibiofibular joint)
• and some are freely movable (shoulder joint).

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Terms Related to Movement

• Flexion is a movement that takes place in a
  sagittal plane
• For example, flexion of the elbow joint
  approximates the anterior surface of the forearm
  to the anterior surface of the arm
• It is usually an anterior movement, but it is
  occasionally posterior, as in the case of the
  knee joint
• Extension means straightening the joint and
  usually takes place in a posterior direction

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Terms Related to Movement

• Abduction is a movement of a limb away from the
  midline of the body in the coronal plane
• Adduction is a movement of a limb toward the body
  in the coronal plane

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Terms Related to Movement

• In the fingers and toes, abduction is applied to
  the spreading of these structures
• adduction is applied to the drawing together of
  these structures
• The movements of the thumb are a little more
  complicated

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Terms Related to Movement

• Rotation is the term applied to the movement of a
  part of the body around its long axis
• Medial rotation is the movement that results in
  the anterior surface of the part facing medially
• Lateral rotation is the movement that results in
  the anterior surface of the part facing laterally

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Terms Related to Movement

• Circumduction is the combination in sequence of
  the movements of flexion, extension, abduction,
  and adduction

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Terms Related to Movement

• Lateral flexion is a movement of the trunk in the
  coronal plane

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Terms Related to Movement

• Pronation of the forearm is a medial rotation of
  the forearm in such a manner that the palm of the
  hand faces posteriorly
• Supination of the forearm is a lateral rotation
  of the forearm from the pronated position so that
  the palm of the hand comes to face anteriorly

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Terms Related to Movement

• Inversion is the movement of the foot so that the
  sole faces in a medial direction
• Eversion is the opposite movement of the foot so
  that the sole faces in a lateral direction

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Terms Related to Movement
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Terms Related to Movement
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Regional Terms
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Regional Terms Anterior View

• Axial head, neck, and trunk
• Appendicular appendages or limbs
• Specific regional terminology

Figure 1.7a
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Regional Terms Posterior View
Figure 1.7b
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Body Cavities
Figure 1.9a
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Body Cavities

• Dorsal cavity protects the nervous system, and is
  divided into two subdivisions
• Cranial cavity is within the skull and encases
  the brain
• Vertebral cavity runs within the vertebral column
  and encases the spinal cord
• Ventral cavity houses the internal organs
  (viscera), and is divided into two subdivisions
  - Thoracic and Abdominopelvic cavities

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Body Cavities
Figure 1.9b
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Bones and Muscles
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Bone

• Bone is a living tissue capable of changing its
  structure as the result of the stresses to which
  it is subjected
• Like other connective tissues, bone consists of
  cells, fibers, and matrix
• It is hard because of the calcification of its
  extracellular matrix and possesses a degree of
  elasticity because of the presence of organic
  fibers

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Skeleton
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Functions

• 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
• an important storage area for calcium salts
• It houses and protects within its cavities the
  delicate blood-forming bone marrow.

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• Bone exists in two forms compact and cancellous
• Compact bone appears as a solid mass
• cancellous bone consists of a branching network
  of trabeculae
• The trabeculae are arranged in such a manner as
  to resist the stresses and strains to which the
  bone is exposed.

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Surface Markings of Bones

• The surfaces of bones show various markings or
  irregularities
• Where bands of fascia, ligaments, tendons, or
  aponeuroses are attached to bone
• These roughenings are not present at birth
• They appear at puberty and become progressively
  more obvious during adult life
• In certain situations, the surface markings are
  large and are given special names

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Classification of Bones

• Bones may be classified regionally or according
  to their general shape
• Bones are grouped as follows based on their
  general shape long bones, short bones, flat
  bones, irregular bones, and sesamoid bones.

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Long Bones

• Long bones are found in the limbs (e.g., the
  humerus, femur, metacarpals, metatarsals, and
  phalanges).
• Their length is greater than their breadth
• The ends of long bones are composed of cancellous
  bone surrounded by a thin layer of compact bone
• The articular surfaces of the ends of the bones
  are covered by hyaline cartilage.

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Short Bones

• Short bones are found in the hand and foot (e.g.,
  the scaphoid, lunate, talus, and calcaneum).
• They are roughly cuboidal in shape
• composed of cancellous bone surrounded by a thin
  layer of compact bone
• Short bones are covered with periosteum, and the
  articular surfaces are covered by hyaline
  cartilage.

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Flat Bones

• Flat bones are found in the vault of the skull
  (e.g., the frontal and parietal bones).
• The sternum and scapulae, although irregular, are
  included in this group.

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Irregular Bones

• Irregular bones include those not assigned to the
  previous groups (e.g., the bones of the skull,
  the vertebrae, and the pelvic bones).
• They are composed of a thin shell of compact bone
  with an interior made up of cancellous bone.

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Sesamoid Bones

• Sesamoid bones are small nodules of bone that are
  found in certain tendons.
• The greater part of a sesamoid bone is buried in
  the tendon, and the free surface is covered with
  cartilage
• The largest sesamoid bone is the patella, which
  is located in the tendon of the quadriceps
  femoris
• The function of a sesamoid bone is to reduce
  friction on the tendon

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Regional Classification of Bones

• Axial skeleton
• Appendicular skeleton

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Axial skeleton (num. of bones)

• Skull
•     Cranium 8
•   Face 14
•  
• Auditory ossicles 6
• Hyoid 1
• Vertebrae (including sacrum and coccyx) 26
•  Sternum 1
•  Ribs 24
• Subtotal 80

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Appendicular skeleton

•  Shoulder girdles
• Clavicle 2         Scapula 2
• Upper extremities
•  Humerus 2     Radius 2     Ulna 2    
•  Carpals 16     Metacarpals 10     Phalanges
  28
• Pelvic girdle    
•  Hip bone 2
• Lower extremities    
•  Femur 2     Patella 2     Fibula 2     Tibia 2
      Tarsals 14    
•  Metatarsals 10     Phalanges 28
• Subtotal 126
• Total 206

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Upper Limb
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Bones of Upper Limb
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Bones of the Shoulder Girdle

• The shoulder girdle consists of the clavicle and
  the scapula
• which articulate with one another at the
  acromioclavicular joint.

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Clavicle

• The clavicle is a long, slender bone that lies
  horizontally across the root of the neck just
  beneath the skin
• It articulates with the sternum and first costal
  cartilage medially and with the acromion process
  of the scapula laterally
• The clavicle acts as a strut that holds the arm
  away from the trunk
• The medial two thirds of the clavicle is convex
  forward and its lateral third is concave forward

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Scapula

• The scapula is a flat triangular bone
• lies on the posterior chest wall between the
  second and the seventh ribs
• On its posterior surface, the spine of the
  scapula projects backward
• The posterior surface of the scapula is divided
  by the spine into the supraspinous fossa above
  and an infraspinous fossa below

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• The superolateral angle of the scapula forms the
  pear-shaped glenoid cavity, or fossa
• articulates with the head of the humerus at the
  shoulder joint
• The coracoid process projects upward and forward
  above the glenoid cavity and provides attachment
  for muscles and ligaments
• Medial to the base of the coracoid process is the
  suprascapular notch

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• The lateral end of the spine is free and forms
  the acromion, which articulates with the clavicle
• The anterior surface of the scapula is concave
  and forms the shallow subscapular fossa
• The inferior angle of the scapula can be palpated
  easily and marks the level of the seventh rib

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Humerus

• The humerus articulates with the scapula at the
  shoulder joint and with the radius and ulna at
  the elbow joint
• The upper end of the humerus has a head
• forms about one third of a sphere and articulates
  with the glenoid cavity of the scapula
• Immediately below the head is the anatomic neck

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• Below the neck are the greater and lesser
  tuberosities, separated from each other by the
  bicipital groove
• Where the upper end of the humerus joins the
  shaft is a narrow surgical neck
• About halfway down the lateral aspect of the
  shaft is a roughened elevation called the deltoid
  tuberosity
• Behind and below the tuberosity is a spiral
  groove, which accommodates the radial nerve

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• The lower end of the humerus possesses the medial
  and lateral epicondyles for the attachment of
  muscles and ligaments
• the rounded capitulum for articulation with the
  head of the radius
• the pulley-shaped trochlea for articulation with
  the trochlear notch of the ulna
• Above the capitulum is the radial fossa, which
  receives the head of the radius
• Above the trochlea anteriorly is the coronoid
  fossa
• Above the trochlea posteriorly is the olecranon
  fossa

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Radius

• The radius is the lateral bone of the forearm
• Its proximal end articulates with the humerus at
  the elbow joint and with the ulna at the proximal
  radioulnar joint
• At the proximal end of the radius is the small
  circular head
• The upper surface of the head is concave and
  articulates with the convex capitulum of the
  humerus
• The circumference of the head articulates with
  the radial notch of the ulna
• Below the head the bone is constricted to form
  the neck
• Below the neck is the bicipital tuberosity for
  the insertion of the biceps muscle

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• The shaft of the radius is wider below than above
  
• It has a sharp interosseous border medially
• for the attachment of the interosseous membrane
  that binds the radius and ulna together
• The pronator tubercle, for the insertion of the
  pronator teres muscle, lies halfway down on its
  lateral side

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• At the distal end of the radius is the styloid
  process
• On the medial surface is the ulnar notch, which
  articulates with the round head of the ulna
• The inferior articular surface articulates with
  the scaphoid and lunate bones
• On the posterior aspect of the distal end is a
  small tubercle, the dorsal tubercle

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Ulna

• The ulna is the medial bone of the forearm
• The proximal end of the ulna is large and is
  known as the olecranon process
• forms the prominence of the elbow
• It has a notch on its anterior surface, the
  trochlear notch
• Below the trochlear notch is the triangular
  coronoid process
• has on its lateral surface the radial notch

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• The shaft of the ulna tapers from above down
• It has a sharp interosseous border laterally for
  the attachment of the interosseous membrane
• The posterior border is rounded and subcutaneous
  and can be easily palpated
• Below the radial notch is the supinator crest
  that gives origin to the supinator muscle.

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• At the distal end of the ulna is the small
  rounded head
• which has projecting from its medial aspect the
  styloid process

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Bones of the Hand

• There are eight carpal bones, made up of two rows
  of four
• The proximal row consists of (from lateral to
  medial)
• the scaphoid, lunate, triquetral, and pisiform
  bones.
• The distal row consists of (from lateral to
  medial)
• the trapezium, trapezoid, capitate, and hamate
  bones
• The bones of the hand are cartilaginous at birth

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The Metacarpals and Phalanges

• There are five metacarpal bones, each of which
  has a base, a shaft, and a head
• The first metacarpal bone of the thumb is the
  shortest and most mobile
• The bases of the metacarpal bones articulate with
  the distal row of the carpal bones
• the heads, which form the knuckles, articulate
  with the proximal phalanges
• There are three phalanges for each of the fingers
  but only two for the thumb.