Equine Distal Limb 3
227.205 Comparative Veterinary Anatomy
Thursday, July 25, 2013. 9a.m. SSLB3 1)
Cases Of The Day
Stay apparatus of the left forelimb, lateral view.
A. Tendon of serratus ventralis
B. Internal tendon of biceps brachii
C. Lacertus fibrosus
D. Extensor carpi radialis
E. Common digital extensor
F. Extensor branch of interosseus
G. Collateral ligament of elbow
H. Superficial digital flexor
I. Proximal check ligament (= accessory ligament of SDF)
J. Deep digital flexor
K. Distal check ligament (= accessory ligament of DDF)
L. Suspensory ligament or Interosseus 3)
Digital Extensor Tendons dorsal surface of forelimb
Interosseus▯S(uspensory Ligamentdeep to the SDF AND DDF
Digital Flexor Tendons-palmar aspect of forelimb.
- composed of SDF and DDF
DDFT- deeper to SDFT
distal check ligament from DDFT - from the palmar carpal ligament distal to the
carpus to the DDF middle of the cannon bone.
Proximal check ligament from SDFT for the forelimb only arises from proximal to
Proximal to the carpus/tarsus the SDF and DDF are fleshy. Muscle as a tissue is
relatively soft and easily torn if
stretched beyond its normal range of motion.
Check ligaments act like the chain on the bungee cord to the right, allowing a
muscle to move within ts normal range, but mechanically reventing over- stretchi
ng if a muscle
is pulled to a certain point.
checkligament givesstability to prevent the digital joints from overextension.
suspensory ligament insert onto the sesamoid bone.
The Digital Sheath
▯The DDFT (13) shares a synovial digital sheath (14) with the SDFT (18) at the lev
el of the fetlock joint.
The sheath begins a few centimetres proximal to the fetlock joint and ends
level with the middle of PII. It lubricates the passage of the tendons over the
It is a common site of Inflammation and, when distended, bulges most noticeably
proximal sesamoid bones.
Although the sheath is in close proximity to the fetlock, pastern & coffin joint
s and to the navicular bursa, these cavities do not commun ▯icate.
Applied Anatomy: Swollen Fetlock
DSW4 fig. 23-26, p. 607
the digital sheath extends a few centimetres above the fetlock joint and ends mi
dway at the level middle to p2
When there is a swallon fetlock. needle should be inserted into the palmar pouch
of the fetlock joint and not the digital sheath.
to diffrentiate these ,apply some local pressure on the palmar aspect of the fet
lock joint to the area that the needle is going to be inserted,
.Since the fetlock synovial pouch has a dorsal extension as well as a palmar ext
ension., when pressure is applied
on the palmar aspect this is shown as a bulging in the dorsal aspect. if the pre
ssure was applied on the digital sheath , there will
be no bulging on the dorsal surface.
Digital Extensor Tendons-dorsal aspect of limb
Interosseus▯S(uspensory Ligament- deep to SDFT AND DDFT
Digital Flexor Tendons- on palmar aspect of that forelimb
Extent of Digital Synovial Sheath- few centimetres above the fetlock joint and e
nds midway the level to p2
Carpal & Tarsal Synovial Structures
Right Hock: Dorsal View
DSW4 fig. 24-10, p. 633
1) long digital extensor
2) laterodorsal pouches of tarsocrural joint
3)mediodorsal pouches of the tarsocrural joint
Left Carpus: Lateral View
DSW4 fig. 23-16, p. 599
1)radiocarpal joint capsule
2)midcarpal joint capsule
3)carpometacarpal joint capsule
4)tendon sheath of extensor carpi radialis
5)tendon sheath of common digital extensor
6)tendon sheath of lateral digital extensor
7)tendon sheath of SDF and DDF
8)tendon sheath of ulnaris lateralis
9)lateral collateral ligament (goes obliduely over tendon sheath of the lateral digital extensor)
3 extensor retinaculum of the lateral digital extensor = proximal middle and dis
tal Foot= within the hoof?
Digit= from the fetlock and below.
The location and extent of the synovial structures of the digit,
including joint spaces and pouches, bursae, and tendon sheaths is essential know
Of particular clinical importance are:
(a) the location of the synovial sheath shared by the DDFT and SDFT (the digital
synovial sheaths are thing walled, double layered, fluid filled tubes enveloping
of tendons; they protect the tendonds where they are exposed to wear.
digital sheath serves both superficial and deep flexor tendon. extends from abov
e the fetlock joint to the middle of P2.
the deep flexor tendon is wholly enveloped. the palmar surface of the digita she
ath is covered by
the annular ligament of the fetlock joint and by the prox. and dist. digital li
(b) the location of the bursa (the navicular bursa) protecting the
DDFT from excessive friction against the navicular bone. located between the dee
p flexor tendon and t