2 Anatomy: Equine Fl Joints

Front 1

fx of cannon bone

Back 1

fx sesamoids of cannon bone:
1. proximal sesamoids: cry first, fracture frequently
2. distal sesamoids: no direct articulation with the proximal (1st) phalanx
3. cannon and carpal bones also fx frequently

Front 2

fetlock jt capsule

Back 2

fetlock jt capsule:
- palmar, large, thick
- projects proximally between the cannon bone and interosseus m on palmar surface
- injected medially or laterally
- galls, articular windgalls or windpuffs: pathological distention

Front 3

distal sesamoidean ligaments

Back 3

distal sesamoidean ligaments:
- fetlock
- thought to be distal continuations of interosseus m
1. supeficial (straight) sl
2. intersesamoidean l
3. collateral sesamoidean ll

Front 4

superficial (straight) sesamoidean ligament

Back 4

superficial (straight) sesamoidean ligament:
- a distal sesamoidean l (fetlock)
- extends from sesamoid bones and intersesamoidean l to fibrocartilage lip on palmar aspect of proximal end of middle (2nd) phalanx
- straight, long fibers

Front 5

sesamoidean ligaments fxn

Back 5

sesamoidean ligaments fxn:
1. support fetlock
2. prevent over-extension (dorsal flexion) of the joint when foot on ground
3. dorsal branch: limits flexion of jt, prevents DF tendon from flexing joint as a result of tension when limb is on ground and jt extended

Front 6

intersesamoidean ligament

Back 6

intersesamoidean ligament:
- a distal sesamoidean ligament (fetlock)
- fibrocartilage
- extends between two proximal sesamoid bones

Front 7

collateral sesamoidean ligaments

Back 7

collateral sesamoidean ligaments:
- a distal sesamoidean l (fetlock)
- medial and lateral
- attach sides of the proximal sesamoid bones to the metacarpal condyles and proximal tubercles of 1st phalanx

Front 8

middle (oblique) sesamoidean ligament

Back 8

middle (oblique) sesamoidean ligament:
- fetlock
- extends from bases of sesamoids to palmar surface of proximal phalanx

Front 9

deep (cruciate) sesamoidean ligament

Back 9

deep (cruciate) sesamoidean ligament:
- fetlock
- two bands of fibers, crossing each other
- from bases of sesamoids to opposite emminence on proximal end of first phalanx

Front 10

short sesamoidean ligament

Back 10

short sesamoidean ligament:
- fetlock
- two ligaments running from axial side of the bases of sesamoid bone to the abaxial side of the eminence of the proximal phalanx

Front 11

collateral ligaments

Back 11

collateral ligaments:
- fetlock
- medial and lateral
- each divided into 2 layers:
1. deep: shorter and stronger
2. superficial: covers deep

Front 12

assists interosseus m in support of fetlock

Back 12

assists interosseus m in support of fetlock?
- distal sesamoidean ligaments

Front 13

prevents over-extension of pastern

Back 13

prevents over-extension (buckling forward) of pastern jt when foot hits ground:
1. oblique sesamoidean l
2. SDF tendon

Front 14

pastern ( prox interphalangeal) jt

Back 14

pastern (prox interphalangeal) jt:
- fx plane jt: little movement
- prox part of palmar surface of middle phalanx extended by complementary fibrocartilage
- fibrocartilage enlarges the jt cavity, helps support jt
- capsule extends considerably prox on both dorsal and palmar surfaces

Front 15

coffin (distal interphalangeal) jt bones

Back 15

coffin (distal interphalangeal) jt bones:
1. distal end of middle and prox end of distal phalanx
2. distal sesamoid/ navicular bone
3. cartilages of distal phalanx: med, lat, hyaline in young and fibrocartilage in adult

Front 16

pastern ligaments

Back 16

pastern ligaments:
1. med and lat collateral: straight, vertically oriented
2. palmar ligaments: medial (axial) and lateral (abaxial), from distal end of first phalanx to complementary fibrocartilage of middle phalanx
- mostly flexion and extension

Front 17

coffin jt capsule

Back 17

coffin jt capsule:
- extends prox on dorsal and palmar surfaces, forming pouches:
1. mid 2nd phalangeal region -and-
2. below navicular bone
- joint vulnerable at these pouches

Front 18

stay apparatus fx

Back 18

stay appartus fx:
1. standing w/ min muscular effort
2. FL and HL involved
3. FL bears more weight 55:45

Front 19

facies serrata

Back 19

facies serrata:
- attaches to scapula
- body wt transmission to FL via serratus ventralis m
- middle, vertical line drops ca to shoulder jt, through elbow jt, but cr to distal jts
- limb requires support to avoid collapse on flexion of shoulder and elbow jts, plus overextension of distal jts

Front 20

stay apparatus at pastern jt

Back 20

stay apparatus at pastern jt:
- prevents overextension
1. palmar ligaments: short and tensed
-and-
2. superficial (straight) sesamoidean ligament

Front 21

stay apparatus at fetlock jt

Back 21

stay apparatus at fetlock jt:
- prevent overextension by formidable support of
1. interosseus tendon
2. proximal sesamoid bones
3. sesamoidean ligaments
4. digital flexor tendons and accessory ligament

Front 22

stay appartus at carpal jt

Back 22

stay apparatus at carpal jt:
- prevents overextension
1. flat nature of articular surfaces of radicarpal (antebrachiocarpal) and mid-carpal jts
2. palmar carpal ligament: holding composite bones together

Front 23

stay apparatus at shoulder

Back 23

stay apparatus at shoulder jt:
- prevents flexion
1. biceps brachii m: tendinous
2. extensor carpi radialis m: tendinous
3. lacertus fibrosus: tendinous, unites 1&2 preventing collapse of jt
- biceps tensed: biceps distal attachment and that of ext carpi radialis are fixed by body wt

Front 24

sesamoidean ligaments of fetlock

Back 24

sesamoidean ligaments of fetlock:
- interosseus m: formerly suspensory lig, sup sesamoidean lig
- homolog of canine interosseus m: little m in foal, entirely tendinous in adult
- well-formed

Front 25

FL lameness

Back 25

FL lameness:
- bears 55-60% weight
- 95% lameness problems below carpus

Front 26

shoulder bones

Back 26

shoulder bones:
- synovial, simple, ball and socket but fxn as ginglymus
1. distal scapula: glenoid cavity, no acromion process or head of deltoideus
- labrum glenoidum: like that of acetabulum
2. head of humerus: larger than glenoid cavity, affording gliding movement

Front 27

shoulder jt capsule

Back 27

shoulder jt capsule:
- thin, capacious
- intertubercular bursa: b/w fibrocartilagenous tendon of origin of biceps and joint capsule

Front 28

shoulder jt ligaments

Back 28

shoulder jt ligaments:
- none
- tendons of supraspinatus, infraspinatus, subscapularis, teres minor and biceps brachii: active ligaments, stabilize as pass over, attach close

Front 29

shoulder jt ligaments

Back 29

shoulder jt ligaments:
- flexion, extension
- some abduction, adduction, rotation
- normally partially flexed (115 deg): concussion absorption

Front 30

cubital bones

Back 30

cubital bones:
- synovial, ginglymus
1. distal end of humerus (condyle)
2. fovea capitis of head of radius
3. trochlear notch of ulna

Front 31

cubital jt capsule

Back 31

cubital jt capsule:
- loose
- attaches on edges of articular surfaces

Front 32

collateral cubital ligaments

Back 32

collateral cubital ligaments:
- from epicondyles of humerus to corresponding tuberosities of radial
1. medial: branched
a. sup, long: ending on radius, distal to antebrachial interosseus space
b. deep, short: inserts on med tuberosity of radius
2. lateral: not branched

Front 33

cubital jt movements

Back 33

cubital jt movements:
- flexion, extension
- rotation, abduction, adduction hardly permitted

Front 34

cubital jt inj

Back 34

cubital jt inj:
- cr and ca to lateral collateral ligament

Front 35

carpus jt gen

Back 35

carpus jt:
- synovial, compound, ginglymus
- simpler than tarsus
- simpler than in dog

Front 36

carpus bones

Back 36

carpus bones:
- distal end of radio-ulnar segment, ulna not participating
1. prox row: radial intermediate, ulnar, accessory carpals
2. distal row: 1 (missing or small)- 4
3. prox ends of metacarpal bones

Front 37

carpus jts

Back 37

carpus jts:
1. antebrachiocarpal/ radiocarpal
2. middle carpal
3. carpometacarpal
4. intercarpal: between carpal bones of each row

Front 38

carpus jt capsule

Back 38

carpus jt capsule:
- fibrous layer
- common capsule: radius proximally to metarcarpal bones distally
- attaches to composite bones as passes over
- thickened on dorsal and palmar surfaces

Front 39

palmar part of carpus jt capsule

Back 39

palmar part of carpus jt capsule:
- smooth, may be cartilagenous
- carpal canal: w/ accesory carpal bone and flexor retinaculum, DFs pass through
- middle or distal end extends into accessory ligament: attached to DDF tendon

Front 40

carpus synovial sacs

Back 40

carpus synovial sacs:
1. antebrachiocarpal: largest, includes jt formed by accessory carpal and between proximal intercarpal sacs
2. middle: communicates with carpometacarpal sac between 3rd and 4th carpals
3. carpometacarpal sac: very small

Front 41

collateral ligaments of carpus

Back 41

collateral ligaments of carpus:
- medial and lateral
- long, extends between radius and metacarpals
- unites bones of carpus on each side

Front 42

ligaments of carpus

Back 42

ligaments of carpus:
1. collateral
2. accesory carpal bone
3. short ligaments uniting adjacent carpal bones

Front 43

accessory carpal bones

Back 43

accessory carpal bones:
- proximal, middle and distal ll of accessory carpal bone, joining bone the bone to:
1. ulnar carpal: AU/acessoriulnar l
2. 4th carpal: AQ/ acessorioquartal l
3. lateral splint (1V): AM/ accesorimetacarpal l

Front 44

carpus movements

Back 44

carpus movements:
- composite: concussion absorbing
- flexion and ext (up to 90 deg)
- mainly in antebrachiocarpal and middle carpal
- carpometacarpal: little movement, bound down by ligaments

Front 45

carpus clin

Back 45

carpus clin:
- flexion: 2 prox jt cavities open wide
- grooves overlying them can be palpated
1. damage when animal falls on flexed carpus
2. inj easily performed

Front 46

jts of distal TL

Back 46

jts of distal TL:
1. fetlock: most freq damaged, stressed
- synovial, hinge
2. coffin: 2nd most freq damaged

Front 47

bones of fetlock

Back 47

bones of fetlock:
1. distal end of cannon bone
2. proximal end of 1st phalanx: very important component
3. proximal sesamoids: very important components
- ligaments act as a sling, support

Front 48

divisions of interosseus m

Back 48

division of interosseus m:
- at distal 1/4 cannon bone
- each div
1. inserts on abaxial surface of prox sesamoid
2. detaches an oblique, dorsal branch (extensor slip) to common digital extensor tendon over dorsal surface of prox phalanx

Front 49

fetlock clinical

Back 49

fetlock clinical:
1, jt capsule : prox extension palmarly ( articular windgalls) can be inj b/w cannon and interosseus tendon
2. fx of prox sesamoid, esp distal 1/2 = cry
3. sxn of interosseus: fetlock sinks
4. sxn of SDF tendon: fetlock sinks slightly, not grounded
5. sxn of DFs and interosseus: complete grounding (collapse) of fetlock

Front 50

ligaments of coffin jt

Back 50

ligaments of coffin jt:
1. from phalanges to cartilages of distal phalanx
2. collateral of coffin jt
3. collateral of navicular bone
4. distal sesamoidean (navicular) impar

Front 51

distal sesamoidean (navicular) impar ligament

Back 51

distal sesamoidean (navicular) impar ligament:
- short
- from distal border of navicular bone to palmar surface of distal phalanx

Front 52

ligaments from phalanges to cartilages of distal phalanx

Back 52

ligaments from phalanges to cartilages of distal phalanx (med/ lat):
1. chondrocompedal(ia): from prox phalanc to cartilage
2. chondrocoronal(ia): from middle phalanx to cartilage
3. chondroungular(ia): from distal phalanx to ligament

Front 53

collateral l of coffin and navicular

Back 53

1. collateral ligaments of coffin jt:
med/lat, straight, vertically oriented
2. collateral ligaments of navicular bone:
suspensory ligaments

Front 54

stay appartus

Back 54

stay appartus:
- bear body weight in normal and appropriate stance for prolonged periods with little muscular action or effort
- operates when foot placed on ground and bearing body wt

Front 55

stay apparatus cubital jt

Back 55

stay apparatus cubital jt:
- fixed by BW, acting through the radius, distalward
- tonic activity of triceps brachii (radial n damages this) prevents collapse
- collateral l eccentric: ca to axis of rotation, tensed in normal standing, must be stretched to permit flexion
- flexor mm (SDF, FCU and UL): ca to axis of rotation, tensed in normal standing
- joint close-packed