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Transcript of THE APPENDICULAR SKELETON - Biology Building · PDF file The Appendicular Skeleton 2 pairs of...

  • The Appendicular Skeleton

  • THE SKELETAL SYSTEM The Appendicular Skeleton

     2 pairs of limbs and 2 girdles  Pectoral (shoulder) girdle attaches upper limbs  Pelvic (hip) girdle secures lower limbs  3-Segmented limbs

     Upper = arm  Arm  Forearm  Hand

     Lower = leg  Thigh  Leg  Foot

  • Pectoral Girdle (Shoulder Girdle)

     Clavicle – anterior: collar bone Sternal end attaches to the manubrium

    medially Acromial end articulates with the scapula

    laterally  Scapula – posterior: shoulder blade

  • Scapulae: triangular, paired, but don’t connect in back (adds thoracic flexibility)

  • Scapula

     Glenoid cavity articulates with the humerus

     Acromium articulates with clavicle

     Coracoid process projects anteriorly

  • Upper extremity

     Arm or Brachium = upper arm  Between shoulder

    and elbow (humerus)  Forearm or

    Antebrachium  Radius & ulna

     Hand includes:  Wrist (carpus)  Palm (metacarpus)  Fingers (phalanges)

  • Arm  Humerus is the only

    bone  Head of humerus fits

    into glenoid cavity of scapula

     Distal & medially, trochlea articulates with the ulna

     Distal & laterally capitulum articulates with the radius

     Medial & lateral epicondyles

  • Right humerus, anterior view

  • Right humerus, posterior view

  • Forearm

     2 bones: articulate with each other proximally and distally

     Interosseous membrane between them

     Ulna  Olecranon hinges with the

    humerus forming elbow  Styloid process distally

     Radius  Contributes to wrist joint  Styloid process anchors a

    ligament to wrist (thumb side)

    Radius is thinner proximally, like a spool of thread, and wide distally; ulna is slightly longer and looks like a monkey wrench (supposedly!)

  • Right forearm bones, anterior view

  • Right forearm bones, posterior view

  • In the anatomical position, the radius is lateral (thumb side); with pronation the palm faces posteriorly and the bones cross

    Left forearm

    Prone: body lying face down Suppine: body lying face up (you can remember prone if you think

    about how you would fall forward onto your face if you passed out)

    Anatomical position

    prone

    pronation moves the forearm into the prone position and supination moves it back to the anatomical position

  • proximal ulna

    Proximal and distal joints of the forearm

  • Hand  Proximal is “wrist” – 8 carpal bones  Palm of hand - 5 metacarpals  Fingers (or digits) consist of miniature long bones called

    phalanges: thumb (“pollex”) has 2; fingers have 3: proximal, middle, distal

    Right hand, 2 views:

  • Pelvic Girdle (Hip Girdle)

     Strongly attached to axial skeleton (sacrum)  Deep sockets  More stable than pectoral (shoulder) girdle  Less freedom of movement  Made up of the paired hip bones “Bony pelvis” is basin-like structure: hip bones

    plus the axial sacrum and coccyx

  • Hip bone (os coxae): 3 separate bones in childhood which fuse

     Ilium

     Ischium

     Pubis

  • Ilium  Iliac crest  Anterior

    superior iliac spine

     Greater sciatic notch

     Forms part of “acetabulum”

    (hip socket) which receives ball-shaped head of femur

    ilium

    ilium

  • Ischium

     Body  Ramus  Ischial spine  Ischial

    tuberosity  Part of socket

    ischium

    ischium

  • Pubis  Joins

    medially in pubic symphysis

     Forms “obturator foramen” (large hole) with ischium

     Part of socket

    pubis

    pubis

  • Hip bones with labels

  • Ligaments

    False (greater) and true (lesser) pelvis

  • Pelvis and childbearing  Male/female differences

     Large & heavy vs light & delicate  Heart shaped pelvic inlet vs oval  Narrow deep true pelvis vs wide & shallow  Narrow outlet vs wide  Less than 90 degree pubic arch vs more than 90

    degree  Birth canal changes shape as baby descends:

    head turns ¼  Higher: pelvic inlet (brim) - side to side largest  Lower: pelvic outlet - largest in AP direction

  • Lower limb

     Thigh: femur

     Leg (lower leg) Tibia Fibula

     Foot

  • Thigh

     Femur is largest, longest and strongest bone in the body

     Head fits in socket (acetabulum) of pelvis

     Neck is weakest  Greater trochanter  Distal: lateral & medial

    condyles and epicondyles  Patella: sesmoid bone

  • Right femur, anterior view

  • Right femur, posterior view

  • Leg  Tibia: shin bone

    Medial and lateral condyles

     Tibial tuberosity  Distal medial malleolus

    (medial ankle)  Fibula

     Distal lateral malleolus (lateral ankle)

     Interosseous membrane

  • Right lower leg, anterior view

  • Foot  Tarsus: 7 tarsal bones

     Talus: articulates with tibia and fibula anteriorly and calcaneus posteriorly

     Calcaneus: heel bone  Smaller cuboid,

    navicular, and 3 cunieforms (medial, intermediate and lateral)

     5 metatarsals  14 phalanges

    Great toe is hallux

  • Right foot, superior (dorsal) view and inferior (plantar) view

  • Right foot, lateral and medial views

  • Arches

    The Appendicular Skeleton THE SKELETAL SYSTEM�The Appendicular Skeleton Pectoral Girdle�(Shoulder Girdle) Scapulae: triangular, paired, but don’t connect in back (adds thoracic flexibility) Scapula Upper extremity Arm Right humerus, anterior view Right humerus, posterior view Forearm Slide Number 11 Slide Number 12 Slide Number 13 Slide Number 14 Hand Slide Number 16 Slide Number 17 Pelvic Girdle �(Hip Girdle) Hip bone (os coxae): 3 separate bones in childhood which fuse Ilium Ischium Pubis Slide Number 23 Slide Number 24 Pelvis and childbearing Lower limb Thigh Right femur, anterior view Right femur, posterior view Leg Right lower leg, anterior view Slide Number 32 Foot Right foot, superior (dorsal) view and inferior (plantar) view Slide Number 35 Slide Number 36