Human Anatomy Vol 1

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epicondyles of the humerus; and in the flexed
elbow (Fig.2.19) the three bony points form an
equilateral triangle. These relations are disturbed
in dislocation of the elbow.
Fracture of the olecra,non is conunon and is caused
by a fall on the point of the elbow. Fracture of the
coronoid process is uncommon, and usually
accompanies dislocation of the elbow.
Madelung's deformity is dorsal subluxation
(displacement) of the lower end of the ulna, due
to retarded. growth of the lower end of the radius
(Fig.2.33).

BONES OF UPPER LIMB

line of union of metaphysis with the epiphysis. At the
end of the bone, besides the epiphyseal line is the
attachment of the capsule of the respective joints.
So infection in the joint may affect the metaphysis of
the bone if it is partly or completely inside the joint
capsule. As a corollary, the disease of the metaphysis if
inside a joint may affect the joint. So it is worthwhile to
know the intimate relation of the capsular attachment
and the epiphyseal line at the ends of humeral, radial
and ulnar bones as shor,rm in Table 2.2.

Relation of capsular attachments and epiphyseal
lines: If epiphyseal line, i.e. site of union of epiphysis
and metaphyseal end of diaphysis, is intracapsular,
the infections of the joints are likely to affect the
metaphysis, the actively growing part of the bone
especially in young age.

Ossificolion of Humerus, Rodius ond Ulno
Lawaf Ossificcffofl

In long bones possessing epiphyses at both their ends,
the epiphysis of that end which appears first is last to
join with the shaft. As a corollary, epiphysis which
appears last is first to join.
These ends of long bones which unite last with the
shaft are designated as growing end of the bone. Lr case
of long bones of the upper limb, growing ends are at
shoulder and wrist joints. This implies that, the upper
end of humerus aird lower ends of both radius and ulna
are growing ends; and each will, therefore, unite with
their shaft at a later period than their corresponding
other ends.
The direction of the nutrient foramen in these bones,
as a rule, is opposite to the growing end.
The time of appearance and fusion (either of various
parts at one end, or with the shaft) are given in Table 2.1.


Irnporfcnce of prulsr
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Metaphysis is the epiphyseal end of the diaphysis. It is
actively growing part of the bone with rich blood
supply. Infections in this part of the bone are most
common in the young age. The epiphyseal line is the

The carpus is (Greek Karpos, wrist) made up of^8 carpal
bones, which are arranged in two rows (Fig.2.34).
L The proximal row contains (from lateral to medial
side):
i. The scaphoid (Greek boat,wrist),
ii. The lunate (Latin moon shaped),
iii. The triquetral (Latin three cornered), and
iv. The pisiform (Greekpen)
2 The distal row contains in the same order:
i. The trapezlrn (Greekfour sided geometric figure),
ii. The trapezoid (Greek baby's shoe),
iii. The capitate (Latin hend), and
iv. The hamate (Latinhook).

ldentificotion
1 The scaphoid is boat-shaped and has a tubercle on its
lateral side.
2 The lunate is half-moon-shaped or crescentic.
3 The triquetral is pyramidal in shape and has an
isolated oval facet on the distal part of the palmar
surface.
4 Thepisiformispea-shaped and has only one oval facet
on the proximal part of its dorsal surface.
The trapezium is qtadrangular in shape, and has a
crest and a groove anteriorly. It has a sellar (conca-
voconvex) articular surface distally.
The trapezold resembles the shoe of a baby.
The capitate is the largest carpalbone, with a rounded
head.
The hamate is wedge-shaped with a hook near its base.

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