Skeletal System
     Part B
Skeletal System
     Part B
   Extends from the skull to the pelvis and
    protects the spinal cord.
   It is composed of a vertebrae separated by
    intervertebral disk.
   An infant has 33 vertebral bones and an
    adult has 26
   The vertebral bones have 4 curvatures-
    Cervical, thoracic, lumbar, and pelvic.
   A Typical Vertebra
   All vertebrae have a
    common structural
    pattern. Each
    vertebra consists of a
    body, vertebral arch,
    vertebral foramen and
    vertebral canal.
   Cervical Vertebrae (7)
   C1 and C2 are the smallest and are
    unusual. Often called the atlas and the
   They have no intervertebral disc
    between them and are highly modified.
   The dens of the axis (2nd vertebra)
    provides a pivot for the atlas when the
    head is turned from side to side.
   C1 has no spinous process nor body.
   Cervical Vertebrae
   The remaining cervical
    vertebra help to make
    up the neck.
   Thoracic Vertebrae
   Larger than the
   Slope downward and
    faces the sides of
    bodies articulate with
    the ribs
              Lumbar Vertebrae
              Large and strong
   Starts as 5 bones but
    fuses together
    between 18-30
   Triangular structure that
    bears rows of dorsal
    sacral foramina
   United with coxal bones
    at the sacroiliac joints.
   Provides a guide for
    determining the size of
    the pelvis.                      Sacrum
              Composed of 4 bones
               that fuse together by
               age 25
              Forms the lowest part
               of the vertebral
              Acts a shock absorber
               when a person sits.

          Includes the ribs,
           thoracic vertebrae,
           sternum, and costal
          It supports the
           shoulder girdle and
           upper limbs, protects
           viscera, and functions
           in breathing.
          RIBS
          12 pairs of ribs are attached
           to the 12 thoracic vertebrae
          First 7 rib pairs are called
           true ribs, join the sternum
           directly by their costal
          Remain 5 pairs called false
           ribs, their cartilages do NOT
           reach the sternum directly.
            THORACIC CAGE

   RIBS
   In fact the first 3 of the false ribs join the
    cartilage of the 7th true rib.
   The remain two ribs are called floating ribs,
    because they have no attachment to any
    Typical rib has a shaft, head, and tubercle
    that articulate with the vertebrae.
              THORACIC CAGE
   Sternum is a flat
    elongated bone that
    develops in three
    parts- an upper
    Manubrium, a
    middle body, and a
    lower xiphoid
   Articulates with costal
    cartilages and
                PECTORAL GIRDLE
   Composed of 2 clavicles
    (collar bone) and 2
    scapulae (shoulder
   It forms an incomplete
    ring that supports the
    upper limbs and provides
    attachments for muscles
    that move the upper
               PECTORAL GIRDLE
   Rodlike bones that run horizontally between the
    sternum and shoulders.
   Hold shoulders in place and provide attachments
    for muscles.
   Has a medial (sternal) end and a lateral (acromial
                 PECTORAL GIRDLE
   Broad, triangular bones
   Articulate with the humerus of each limb and provides
    attachment for muscles of the upper limbs and chest.
   Has a Acromion process that forms the tip of the shoulder
   A Coracoid process that curves anteriorly and inferiorly to
    the clavicle.
   Has a Glenoid cavity, it articulates with the head of the
    arm bone (humerus).

 Providethe frameworks and
 attachments of muscles, and
 function in levers that move the
 limb and its parts.
             UPPER LIMBS
   Humerus-extends from scapula to
   Radius-Located on thumb side of the
    forearm between elbow and wrist
   Ulna-Longer than radius and overlaps the
    humerus posteriorly.
   Hand- Has a wrist, palm, and 5 fingers
   8 carpals that form a carpus, 5
    metacarpals, and 14 phalanges.
   Its upper end has a smooth round head that fits
    into the glenoid cavity.
   Below the head are two processes a greater
    tubercle on the lateral side and a lesser
    tubercle on the anterior side.
   Near the middle of the bony shaft on the lateral
    side is a rough V-shaped area called the deltoid
   On the bottom section of the humerous are
    Epicondyles which provide attachments for
    muscles and ligaments of the elbow. (medial
    and lateral)
   Radius-Located on thumb side of the forearm
    between elbow and wrist.
   Shorter than the ulna
   A thick-disklike head at the upper end
   On the radial shaft just below the head is a
    process called the radial tuberosity. An
    attachment for muscles.
   At the distal end of the radius, a lateral styloid
    process provides attachments for ligaments of
    the wrist.

   Longer than radius and overlaps the
    humerus posteriorly.
   A Medial Styloid process at the distal
    end of the ulna proves attachemnts for
    ligaments of the wrist.
   The Ulna also has a head…on the
    opposite side as the radius
                       Styloid Process

   Remember….when thinking of
    medial/lateral processes…you must put
    your arms in the correct anatomical
    position! 
Radius and Ulna
               Wrist and Hand

   The wrist joint is at the junction of the
    forearm and the hand. The skeleton of
    the wrist consists of 8 small carpal bones
    that are firmly bound in two rows of four
    bones each. The resulting compact mass
    is called a carpus.
                 Wrist and Hand

•   Hand- Has a palm, and 5 fingers.
•   Five metacarpals bones, one in line with each
    finger, form the framework of the palm. These
    bones are cylindrical, with rounded distal ends
    that form the knuckles of clench fist. These
    bones are numbered 1-5 beginning with the
    metacarpal of the thumb.
               Wrist and Hand

•   Hand- Has a palm, and 5 fingers.
•   Phalanges are the finger bones. There are
    three in each finger. A proximal, a
    middle, and a distal phalanx and two in
    the thumb.
Wrist and Hand
                PELVIC GIRDLE

   The PG consists of 2
    coxal bones (hipbones)
    that articulate with each
    other anteriorly and with
    the sacrum posteriorly.
    Along with sacrum and
    coccyx they form the
   Provides support for the
    weight, and attachments
    for muscles, and protects
    visceral organs.
            PELVIC GIRDLE

   Each coxae (hipbone) develops from three
    key parts. An ilium, an ischium, and a
   These parts fuse in the region of a cup-
    shaped cavity called acetabulum.
   This depression, on the lateral surface of
    the hipbone receives the rounded head of
    the femur.
            PELVIC GIRDLE

 Illium-     largest portion of the coxal bone,
    flares outward, forming the prominence of
    the hip.
   The margin of the prominence is called
    the Iliac Crest.
   Joins the sacrum at sacroiliac joint

          Ischium- Lowest
           portion of the coxa
          L-shaped.
                    PELVIC GIRDLE
   Pubis- constitutes the
    anterior portion of the
   The two pubic bones
    come together at the
    midline to form a joint
    called the smyphysis
   The angle these bones
    form below the
    symphysis is the pubic
    Greater and Lesser Pelvis

 Below   the pelvic brim; greater
  pelvis is above it
 Lesser pelvis functions as a birth
  canal; Greater pelvis helps
  support abdominal organs.
                   PELVIC GIRDLE
               Difference: Male/Female

   Female: Tilted forward, adapted for childbearing,
    cavity of the true pelvis is broad, shallow, and has
    a greater capacity.
   Bones are lighter, thinner, and smoother
   The acetabula are smaller and farther apart
   The pubic arch is broader and more rounded.
   The sacrum are wider, shorter, sacral curvature is
   The coccyx more movable and much straighter.
                  PELVIC GIRDLE
              Difference: Male/Female
   Male: Tilted less far forward, adapted for support
    of a male’s heavier build and stonger muscles;
    cavity of the true pelvis is narrow and deep.
   Bones are heavier and thicker; and markings are
    more prominent
   The acetabula are larger and closer together.
   The pubic arch is more acute.
   The sacrum is narrow; longer;
   The coccyx less movable and curves ventrally.
            LOWER LIMBS

 Providethe frameworks of
 the thigh, leg, and foot.

   FEMUR- Extends from
    the hip to knee;
    Longest bone in the
   A large, rounded
    head at its proximal
    end which projects
    medially into the
    acetabulum of the
    coxal bone

   Just below the head are a
    constriction, or neck and
    two large processes.
   A greater trochanter and
    a lesser trochanter.
   These processes provide
    attachments for muscles of
    the lower limbs and

•   At the distal end of the femur are two rounded
    processes, the lateral and medial condyles,
    articulate with the tibia of the leg.
•   On the medial surface at its distal end is a
    prominent medial epicondyle, and on the
    lateral surface is a lateral epicondyle. These
    projections provide attachments for muscles and

   Flat seasamoid bone located in a tendon
    that passes anteriorly over the knee.
   Controls the angel of this tendon and
    functions in lever actions associated with
    lower limbs movement.

   AKA- Shin Bone,
    Larger of the two leg
   Located on the medial
    side of the leg
   Its proximal end is expanded into medial and
    lateral condyles.
   Below the condyles on the anterior surface is a
    process called the tibial tuberosity.
   At its distal end, the tibia expands to form a
    prominence on the inner ankle called the
    medial malleolus, which is an attachment for
    ligaments. (Its lateral cousin is on the fibula).

A  long slender bone located on
  the lateral side of the tibia.
 Ends are slightly larger, with a
  proximal head and a distal
  lateral maleolus.
   The foot is an
    amazing and
    intricate structure.
                            Ankle and Foot
    The bones in your
    feet make up about
    one-fourth of all the
    bones in your body.
   Each foot contains
    26 bones. It takes
    33 joints, 107
    ligaments, 19
    muscles and
    numerous tendons
    to hold the bones in
    place and to move in
    a variety of ways.
             Ankle and Foot

   In addition, each
    foot has about
    125,000 sweat
    glands that excrete
    as much as a half a
    pint of moisture
    each day.
                 Ankle and Foot
   Consists of an tarus, a
    metatarsus, and five
   The tarsus is
    composed of seven
    tarsal bones. These
    bones are arranged
    so that one of them,
    the talus, can move
             Ankle and Foot

   The largest of the tarsals, the calcaneus or
    heel bone. It helps to support the weight
    of the body and provides an attachment
    for muscles that move the foot.
                Ankle and Foot
   The metatarsus
    consists of five
    elongated metatarsal
   They are numbered
    1-5, beginning on the
    medial side.
                    Ankle and Foot

   The phalanges of the toes
    are shorter, but otherwise
    similar to those of the
    fingers, and align, and
    articulate with the
   Each toe has three
    phalanges, a proximal, a
    middle, and distal
    phalanx- except the big
    toe which only has the
    first two.
   How well can
    you do?
   On a scrape
    piece of
    paper take
    this mini-quiz!
   How did you

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