Bones of the UE

1
Bones of the UE

• UE ones may be divided into two groups
• Pectoral girdle
• Clavicle
• Scapula
• Free upper limb
• Humerus
• Radius
• Ulna
• Carpals
• Metacarpals
• Phalanges

• Figure 6.1 Moore Dalley, Clinically Oriented
  Anatomy 5th edition.

2
Clavicle

• Connects UE appendicular skeleton to axial
  skeleton
• Sternal end joins manubrium at sternoclavicular
  joint
• Lateral end joins acromion of the scapula at the
  acromioclavicular joint

Fig. 1.1 p. 75
3
Clavicle

• The clavicle serves to suspend the upper limb
  laterally from the body to allow freedom of
  motion.
• Strong ligaments attach the proximal clavicle to
  the 1st rib and the distal conoid tubercle to the
  coracoid process of the scapula

4
Clavicle

• This is the only joint holding the UE to the
  axial skeleton

• Fig. 6.3 p729

5
Clavicle-Clinical Notes

• Manual laborers have more robust and curvaceous
  clavicles
• The right clavicle is stronger than the left
• Clavicular fractures usually occur between the
  middle and lateral thirds (the weakest point)
• Fracture fragments are often displaced by the
  action of gravity and unopposed muscle action.
• Classic clinical presentation, usually caused by
  a fall on the outstretched hand or direct trauma

• Fig. B6.1 p. 730

6
Clavicle-Clinical Notes
7
Scapula

• Triangular shaped flat bone
• Posterior surface divided into infra- supra-
  spinous fossae by the scapular spine
• Subscapular fossa on the anterior surface
• Lateral spine flattens to form the acromion
• Greater scapular notch formed by lateral
  extension of the acromion
• Deltoid tubercle
• Glenoid cavity- shallow, concave oval fossa for
  articulation of the humeral head
• Coracoid process a stout beak-like process
  superior to the glenoid fossa
• Medial (vertebral), lateral (axillary) and
  superior borers
• Superior, lateral inferior angles
• Thickened lateral angle supports the scapular
  head which supports the glenoid fossa
• Scapular notch on the superior border

• Fig. 6.4 p 731

8
Humerus

• The largest bone of the UE
• Articulates at
• Glenohumeral joint (scapula)
• Elbow joint (radius ulna)
• Proximal end
• Spherical head allows maximum ROM
• Anatomical neck separated from head by a groove
  (?)
• Greater lesser tubercles at the junction of the
  neck and shaft
• Interturbercular groove for the tendon of the
  long head of the biceps
• Surgical neck the narrowest part, common fracture
  site

9
Humerus

• Shaft with 2 prominent features
• Deltoid tuberoses
• Radial (spiral) groove for the radial nerve and
  artery
• Humerus - Nerve relationships
• Surgical neck axillary nerve
• Radial groove radial nerve
• Distal humerus median nerve
• Medial epicondyle ulnar nerve

10
Humerus
Fig. 6.5 p 732

• Distal humerus
• Trochlea articulates with the ulna
• Capitulum articulates with the radius
• Olecranon fossa accommodates olecranon of the
  ulna (full extension)
• Radial fossa accommodates the head of the radius
  (full flexion)
• Coronoid fossa accommodates the coronoid process
  of the ulna (full flexion)
• Supracondylar ridge- medial lateral
• Epicondyles- medial lateral

11
Humerus Fractures

• Fractures
• Proximal fractures occur at the surgical neck
  they are frequently impacted (mechanism), stable
  and may cause little pain.
• Transverse fractures of the shaft may have
  significant proximal distal fragment
  displacement due to unopposed muscle action, the
  can result in shortening and internal rotation of
  the limb.

Fig. B6.2 p 733
12
Bones of the Forearm Radius, Ulna, Interosseeous
Membrane

• Radius
• 1. Thin proximally the head articulates with the
  capitulum and radial notch of the proximal ulna.
• 2. The shaft enlarges distally where the ulnar
  notch accommodates the ulnar head.
• 3. The radial styloid process is larger and
  longer than the ulnar styloid.
• 4. Only the distal radius articulates with the
  carpal bones

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14
Bones of the Forearm Radius, Ulna, Interosseeous
Membrane

• Ulna
• 1. Stabilizing bone of the forearm, massive
  proximal end articulates with the trochlea and
  head of the radius
• 2. Olecranon serves as a short, stout lever arm
  for extortion.
• 3. Coronnoid process
• 4. 2. 3. form the trochlear notch
• 5. Tuberosity of the ulna for attachment of the
  bachialis muscle
• 6. The shaft tapers distally to the head and
  styloid process

15
Bones of the Forearm Radius, Ulna, Interosseous
Membrane

• Interosseous membrane
• Traverses the space between the radius and ulna.
  The fibers run infero-medially from the radius to
  the ulna. It acts to transmit force from the
  hand to the humerus
• Hand? (wrist)? radius? (interosseous
  membrane)?ulna? (elbow)? humerus

16
Fracture of the Radius
Fig. B6.3 p 736

• Middle third of both is the most common site
• Colles fracture (transverse facture of the
  distal radius)
• Usually from forced dorsiflexion of the hand
• Usually an associated ulnar styloid avulsion
  fracture
• Dinner fork deformity from dorsal displacement
  of the distal fragments

17
Bones of the hand

• Carpal Bones two rows of four yields remarkable
  freedom of motion

• Scaphoid - largest proximal
• Trapezium
• Lunate moon shaped
• Trapezoid
• Triquetrum
• Capitate largest carpal bone
• Pisiform pea like on the palmer surface
• Hamate anteriorly directed hook
• The scaphoid lunate articulate with the radius.
• The triquetrum articulates with the disc of the
  radioulnar joint.

18
Carpal Bones
Fig. 6.8 p. 737
19
Carpal Bones

• Modify diagram

20
Bones of the hand

• Metacarpals form the palm dorsum of the hand
• Base articulates with the carpal bones, stout
  shaft and head articulates with phalanges
• Phalanges
• 1 has 2
• 2, 3, 4, 5 have 3

21
Fracture of the Carpal Bones

• Scaphoid fracture - most commonly associated from
  a fall on an open palm and occurs across the
  waist. It is difficult to visualize
  radiographically in the acute setting, repeat
  X-ray 2 weeks later may show bone growth.
  Avascular necrosis is a risk.
• Hamate fractures may be associated with injury to
  the distal ulnar nerve artery