Page 46 - Adams and Stashak's Lameness in Horses, 7th Edition

12 Chapter 1

VetBooks.ir Proximal phalanx

1 Deep Complementary
digital fibrocartilage
Collateral flexor
sesamoidean tendon Middle phalanx
ligament
2 2
Secondary
3 attachment
of DDFT
Cartilage of distal Navicular bone 4
phalanx (sectioned)
Navicular bursa
5

Distal phalanx Primary attachment
of DDFT

Figure 1.12. Attachments of deep digital flexor tendon and distal interphalangeal joint, (4) attachment of CSL to cartilage of the
collateral sesamoidean ligaments (CSLs). (1) Attachment of CSL to distal phalanx, and (5) attachment of medial and lateral CSLs to
proximal phalanx, (2) attachment of CSL to middle phalanx, (3) navicular bone.
abaxial outpocketings of palmar pouch of the synovial cavity of the

Flexor surface feature. Its dermal base gives origin to the two distally
diverging ligaments of the ergot. Deep to the skin and
superficial fascia, the palmar annular ligament of the
fetlock encircles the digital flexor tendons and their digi­
tal synovial sheath, binding them in the groove between
the proximal sesamoid bones. Distally, the palmar annu­
lar ligament of the fetlock blends with the proximal
digital annular ligament.
The fetlock joint is formed by the distal end of the
A 1 Articular surface third metacarpal bone (the cannon bone), the proximal
end of the proximal phalanx, the two proximal sesa­
moid bones, and the extensive fibrocartilaginous palmar
Facet for articulation ligament that the proximal sesamoids are embedded.
with distal phalanx The articular surface on the third metacarpal bone, its
trochlea, is sharply divided by a sagittal ridge, and this
ridge fits into a complementary sagittal groove in the
articular surface of the proximal phalanx.
Collateral ligaments of the fetlock joint extend distad
from the eminence and depression on each side of the
distal cannon bone. The superficial part of each liga­
B 2 ment attaches to the edge of the articular surface of the
proximal phalanx; the shorter, stouter deep part of the
Figure 1.13. Distal sesamoid (navicular) bone. (A) Proximal ligament attaches to the abaxial surface of the adjacent
view. (B) Distal view. (1) Foramina and (2) fossae. proximal sesamoid and the proximal phalanx.
The smooth depression between the proximal sesa­
straight sesamoidean ligament. These taut overlying moid bones through which the digital flexor tendons
structures subdivide the capsule into medial and lateral pass is formed by the fibrocartilage of the palmar liga­
pouches that are accessible for arthrocentesis. ment that covers the flexor surfaces of the proximal sesa­
moid bones. Immediately distal to the canal formed by
Fetlock the encircling annular ligament and the groove between
the proximal sesamoids, the DDFT perforates through a
The fetlock of the thoracic limb is the region around ringlike opening in the SDFT, the manica flexoria.
the metacarpophalangeal (fetlock) joint. On the palmar The common and lateral digital extensor tendons pass
aspect of the fetlock, the ergot is a prominent cutaneous over the dorsal aspect of the fetlock joint where a bursa