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Key Concepts addressed

Specific Objectives

  • To be able to define the axial and appendicular divisions of the skeleton and identify the main bones of each division.
  • To be able to describe the main features of long bones and indicate the function of each feature. • To be able to indicate the main features of fibrous, fibrocartilaginous and synovial joint types and give examples of each.
  • To be able to describe movements at selected joints and indicate how joint shape, ligaments, and muscles influence the range of possible movements.
  • To be able to identify bones of the body in radiographs.
  • To be able to identify some of the major muscles acting across the elbow, wrist, and knee, indicating their action about the relevant joint.

Notes

Refer to Wikipedia and use prac book to find out what to identify (words in bold)

  • Skeleton has an axial component (midline) and an appendicular component
  • Axial:
    • Skull, mandible
    • Vertebral column:
      • Cervical (C1-C7)
      • Thoracic (T1-T12… each on a rib)
      • Lumbar (L1-L5… straight under thoracic)
      • Sacral (5 bones, fuse into 1 bone)
      • Coccygeal (1,2,3… variable)
    • Hyoid (for tongue and larynx)
    • Ribs (12 pairs)
    • Sternum:
      • Manubrium (top)
      • Body
      • Xiphoid process (bottom bit)
  • Appendicular:
    • Shoulder girdle (stable attachment for bones to connect):
      • Clavicle
      • Scapular
      • Humerus
      • Ulna (pinky side)
      • Radius (thumb side)
      • Carpals (8)
      • Metacarpals (5 – 1 for each finger)
      • Phalanges
        • Thumb – proximal and distal phalanges (2)
        • Others: Proximal, middle and distal phalanges (3)
    • Pelvic girdle:
      • Pubus
      • Ileum
      • Ischium
      • Acetabulum (hip socket)
      • Femur
      • Tibia
      • Patella (these 3 are the knee) (patella is a sesamoid bone, embedded in a tendon to change the direction of pull)
      • Fibula (articulates with the patella and tibia in 1 joint)
      • Tarsals form joint with the leg at the talus (7 tarsals)
      • Heel = calcaneus (a tarsal)
      • Metatarsals (5)
      • Phalanges
        • Big toe: proximal and distal
        • The rest have 3 (proximal, middle, distal)
  • Most of skeleton = long bone
    • Ends = epiphyses
    • Shaft = diaphysis
    • Compact bone on outside (cortex)
    • Spongey bone on inside (honeycomb… aka cancellous)
      • Spicules are orientated along lines of force transition
      • Some parts of bone are hollow
        • Filled with red and yellow marrow
        • Red – produce blood cells
        • Yellow – fat store
    • Greater trochanter
    • Hyaline cartilage covers smooth areas
      • Synovial joints
      • Arthritis – cartilage wears out
      • Smooth surface for articulation
    • Elevated regions – rough = muscle attachment
    • Periosteum
      • Sensitive to pain
      • Covers surface of bone
      • Nerves and blood vessels
    • Epiphyseal plates
      • Separates metaphysis from epiphysis in children
      • Growth plate
      • Dark lines at ends of growing bones
      • Zones of cartilage and growth of bone
      • Disappear as people mature (then we can see a line which represents the fusion of the epiphyseal plate)
      • Young – gaps in the x-ray (epiphyseal plate of cartilage is there as we are still growing)
      • Middle of long bones = medullary cavity (produces a dark x-ray)
      • The borders of long bones are very white (due to compact/cortical bone)
      • Dark space observed between bones is synovial fluid
  • Joints (where ≥2 bones meet)
    • Fibrous
      • Sutures of skull (Initially allow movement in childbirth… e.g. coneheads coming out of vagina)
      • Sutures zigzag
      • Barely any movement
      • Interdigitation
      • Gomphosis – attach teeth in mandible
      • Epiphyseal plates fuse earlier in females
        • Growth spurt
        • Oestrogen
    • Fibrocartilagenous joints
      • Intervertebral joints (have an IV disc)
      • Pubic symphysis – girls need it for when babies come out
      • Limited movement (want a little bit)
    • Synovial joint
      • Lots of movement
      • Membrane produces fluid to lubricate the join
      • E.g. knee
      • Bone surfaces are covered with hyaline cartilage
      • Joint cavity
      • May see ligaments within join
      • Knee: menisci – improve conformation of joint surfaces to each other in mobile joints
        • In anatomy, a meniscus (from Greek μηνίσκος meniskos, "crescent"[1]) is a crescent-shaped fibrocartilaginous structure that, in contrast to articular disks, only partly divides a joint cavity.[2] In humans it is present in the knee, acromioclavicular, sternoclavicular, andtemporomandibular joints;[3] in other organisms they may be present in other joints (e.g. between the forearm bones of birds). A small meniscus also occurs in the radio-carpal joint.
        • It usually refers to either of two specific parts of cartilage of the knee: The lateral and medial menisci. Both are cartilaginous tissues that provide structural integrity to the knee when it undergoes tension and torsion. The menisci are also known as 'semi-lunar' cartilages — referring to their half-moon "C" shape — a term which has been largely dropped by the medical profession, but which led to the menisci being called knee 'cartilages' by the lay public.
      • A bursa (plural bursae) is a small fluid-filled sac lined by synovial membrane with an inner capillary layer of slimy fluid (similar in consistency to that of a raw egg white). It provides a cushion between bones and tendons and/or muscles around a joint. This helps to reduce friction between the bones and allows free movement. Bursae are filled with synovial fluid and are found around most major joints of the body.
    • Range of movement depends on:
      • the shape of the bones/joint (e.g. femur has ridge to prevent it moving too far/twisting in the knee joint)
      • ligaments and musculature surrounding it
  • Hyaline cartilage has no blood supply
    • Can’t heal
    • If damaged, you need to chop a little bit off (eg. Torn meniscus)
    • If near a blood vessel, then the cartilage can repair a little bit (crutches for 6 months)
  • Flexion – bending at joint (decreasing the angle between the two bones)
  • Extension – straightening at joint (increasing the angle between the two bones)
  • Abduction: moving away from the midline e.g. take arm away from body
  • Adduction: moving closer to the midline e.g. take arm toward body
  • Medial rotation: e.g. bend forearm, turn inward
  • Lateral rotation: e.g. bend forearm, turn outward
  • Pronation: rotate forearm so that palm is down
  • Supination: rotate forearm so that palm is up
  • Both of the above 2 movements involve the radius rotating around the ulna
  • Shoulder joint = glenohumeral joint
  • Hinge joint
    • Elbow joint
    • Movement in 1 plane (flexion and extension)
  • Ellipsoidal joint
    • Wrist
    • Flexion, extension, abduction, adduction
  • Saddle joint
    • Thumb (carpometacarple joint)
    • Flexion, extension, abduction, adduction, limited rotation
  • Condyloid joint
    • First knuckles
    • Flexion, extension, abduction, adduction
    • (Second knuckles are hinge joints)
  • Bicondylar joint
    • Knee
    • Flexion, extension, a little bit of rotation (rotates slightly and then the knee locks into place)
  • Tibiotalar joint has specific terms:
    • Plantar flexion (plantar = bottom) and dorsi flexion (dorsi = top)
    • Inversion and eversion (turning left and right… inversion = in)
  • Interphalangeal joints: flexion and extension
  • Metacarpophalangeal joints: flexion and extension, adduction and abduction

Muscle

Shoulder/arm

  • Flexor and extensor muscles
  • Muscle can produce active movement only through shortening
  • Biceps brachii
    • Arises above shoulder joint and inserts below elbow so it may produce movement at both joints
    • 2 heads
  • Brachialis
    • Along with the biceps bracii, results in flexion at the elbow joint
  • Triceps brachii
    • 3 heads
    • extensor of elbow
  • There are superficial and deep flexors in the forearm (pianists can see extensors on the top of their forearm)
  • Top of forearm is the extensor compartment, for extending the fingers
  • Deltoid over shoulder
  • Triceps on back of arm

Thigh

  • Quadriceps femorus
    • Vastus medialis
    • Vastus lateralis
    • Vastus intermedius
    • Rectus femoris
  • Hamstrings – cause flexion at the knee and extension at the hip.
    • Biceps femoris
    • Semitendinosus (long tendon)
    • Semimembranosus (long membrane)
  • NB: vastus muscles are the only extensors at the knee
    • rectus femoris also crosses the hip so it can cause flexion at the hip

Musculoskeletal system

  • Tendon: attachment between muscle and bone (named according to muscle)
  • Ligament: bone-bone
    • Bone and bone
    • Protect and stabilise joint
    • Usually named by the bones they’re attached to (keep this in mind for BGD)
  • In organs:
    • Stop organs flopping around
  • Muscles are usually named by attachments
  • Origin = proximal attachment.
  • Insertion = distal attachment
  • Biceps brachii has its origin at the shoulder and its insertion at the forearm.
  • Fibula doesn’t articulate (unlike with the radius/ulna, where both articulate)