Bones of the Upper Limb

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Bones of the Upper Limb

• Tanvaa Tansatit
• Department of Anatomy
• Medicine, Chulalongkorn university

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UL consists of four segments

• Pectoral girdle
• Formed by scapula, clavicle
• Arm
• Containing humerus
• Forearm
• Containing ulna, radius
• Hand
• Containing carpus, metacarpus, phalanges

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Clavicle
dt
tl
sg
ctcl
ct

• Double curved long bone
• Medial two-thirds are convex anteriorly, lateral
  third is concave anteriorly
• Sternal end
• is enlarged and triangular, articulates with
  manubrium of sternum at sternoclavicular joint
• Acromial end
• is flat, articulates with acromion at
  acromioclavicular joint

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Clavicle
dt
tl
sg
ctcl
ct

• Superior surface is smooth
• Deltoid tubercle indicating attachment of deltoid
  
• Inferior surface is rough
• Conoid tubercle gives attachment to conoid
  ligament of coracoclavicular ligament
• Subclavian groove is attached by subclavius
• Impression for costoclavicular ligament which
  binds to first rib
• Trapezoid line to which trapezoid ligament of
  coracoclavicular ligament attaches

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Fracture of clavicle

• Results from impacts to outstretched hand during
  a fall or falls directly onto shoulder itself
• Weakest part is junction of middle and lateral
  thirds
• Sternocleidomastoid elevates medial fragment
• Shoulder drops because of weight of upper limb
• Lateral fragment is pulled medially by pectoralis
  major

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Scapula

• Triangular flat bone
• medial, lateral and superior borders
• Concave costal surface forms subscapular fossa
• Convex posterior surface is divided by spine into
  supraspinous fossa and infraspinous fossa
• Spine continues laterally as acromion
• Lateral border forms glenoid cavity of shoulder
  joint
• Coracoid process is superior to glenoid cavity
  projects anterolaterally
• Suprascapular notch on superior border

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Humerus

• Head articulates with glenoid cavity
• Anatomical neck separates head from greater
  tubercle laterally and lesser tubercle anteriorly
• Intertubercular groove separates tubercles
• Body has deltoid tuberosity laterally and radial
  groove posteriorly
• Inferior end widens as sharp medial and lateral
  supracondylar ridges form and end distally in
  medial and lateral epicondyles

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Humerus

• Condyle has two articular surface capitulum for
  head of radius and trochlea for trochlear notch
  of ulna
• Superior to trochlea is coronoid fossa
• Superior to capitulum is radial fossa
• Olecranon fossa is posteriorly

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Fracture of humerus

• Stable impacted fracture of surgical neck results
  from fall on elderlys hand
• Avulsion fractures of greater tubercle result
  from fall on acromion or abducting arm,
  subscapularis pulls into medial rotation of
  humerus
• Transverse fractures of body result from direct
  blow to arm, deltoid pull proximal fragment
  laterally
• Intercondylar fractures results from fall on
  flexed elbow

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Ulna

• stabilizing medial bone of forearm
• Olecranon projects proximally from posterior
  aspect
• Coronoid process projects anteriorly
• Trochlear notch articulates with trochlea
• Radial notch articulates with head of radius
• Tuberosity of ulna is attached by tendon of
  brachialis
• Supinator crest and fossa is attached by
  supinator laterally
• Narrow distal end form head and styliod process

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Radius

• Head is covered with articular surface and
  concave for capitulum
• Rdial tuberosity is attached by tendon of biceps
  brachii
• Distal end enlarges and is rectangular when
  sectioned
• Radial styloid process extends from lateral
  aspect
• Ulnar notch accommodates head of ulna
• Dorsal tubercle projects dorsally

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Fracture of radius and ulna

• Results from severe injury
• Transverse fractures at same level in middle
  third
• Fracture of one bone of forearm is associated
  with dislocation of nearest joint
• Colles fracture of distal end of radius in
  elderly women produces dinner fork deformity

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Bones of hand

• Carpus is composed of eight carpal bones
• Proximal row
• Boat-shaped scaphoid
• Moon-shaped lunate
• Pyramidal three-cornered triquetrum
• Pea-shaped pisiform

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Bones of hand

• Distal row
• Four-sided trapezium
• Wedge-shaped trapezoid
• Rounded head capitate
• Wedge-shaped hamate and hook

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Bones of hand

• Metacarpus is composed of five metacarpal bones
• Head articulates with proximal phalanges
• Base articulates with carpal bones

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Bones of hand

• Each digit has three phalanges except the first
• Each phalanx has a base proximally, head
  distally, body between both ends
• Distal phalanges expanded at distal ends to form
  nailbed

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Fracture of bones of hand

• Avascular necrosis of scaphoid causes pain on
  lateral side of wrist
• Hamate fracture may injure ulnar nerve
• Fracture of 1st and 2nd metacarpals are referred
  as boxers fractures
• Crushing injuries of distal phalanges are common
  and extremely painful
• Hyperextension injuries of proximal or middle
  phalanges must be carefully realigned to restore
  function

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