Exam 3 Thoracic Limb Week 8 Flashcards
stratum basale cellls must remain attached to ________ that rests on the dermis (corium)
basement membrane
Primary epidermal laminae slide past stationary (non-keratinized) cells of the secondary epidermal laminae how?
by breaking and reforming desmosomes between cells of primary laminae and stationary cells of secondary epidermal laminae
what is the white zone
junction between sole and wall
what does the white zone include
innermost part of stratum medium
distal ends of primary laminae of stratum internum
pigemented horn produced by stratumbasale over terminal papillae located at distal end of laminar dermis (dermal laminae)
stratum basale produces _____ to fill in between the primary epidermal laminae (of the stratum internum)
tubular and intertubular horn
what attaches dermis to bone, hoof cartilages, and tendons
subcutis (hypodermis)
subcutis is thickened in what two areas
coronary cushion and digital cushion
coronary cushion
deep to coronary dermis
coronary dermis is highly _____
elastic
coronary dermis and cushion fill the _____
coronary groove of hoof
coronary cushion contains ____
venous plexus
digital cushion
subcutis deep to palmar part of hoof capsule
digital cushion is composed of
CCT, elastic fibers, and adpiose tissue
bulbs of cushion underly what
bulbs of heel
digital cushion contains what
modified sweat glands and the fat-rich secretions help keep frog pliable
the duct pass through the ______
dermis of the frog
digital cushion assists with
shock absorption and venous return
blood supply to the equine hoof is from branches of
the medial and lateral digital arteries
the medial and lateral digital arteries supply what
all regions of dermis and coronary and digital cushions
do veins parallel the arteries in the foot
no
veins form interconnected networks especially in the
coronary band (coronary plexus), laminar dermis (dorsal plexus), and palmar aspect of the hoof (palmar plexus)
when the hoof impacts the ground, musch of concussive force dissipated due to
hoof flexibility
Load on PIII goes to
interdigitating epidermal and dermal laminae then to hoof wall
heels of hoof spread
apart
force on navicular bone preses into
deep digital flexor m. tendon
frog and digital cushion are
compressed
frog presses on ____ to help spread heels
bars and sole
pressure on foot compresses
venous plexuses and pumps blood from plexuses on both sides of collateral cartilages into medial and lateral palmar digital veins, which have valves
what occurs to the hoof commonly with aging
progressive calcification; called “sidebone”; causes lameness
more weight is born on the _____ limbs
thoracic (55-66%)
therefore, thoraic limb hoof is a little _____ and more rounded in outline
wider
laminitis
epidermlaminae separate from dermal laminae, which are attached to the distal phalanx
breakdown of the ______ occurs in laminitis
basement membrane and hemidesmosomes of stratum basale associated with basement membrane
tension from the deep digital flexor displaces _______ such that it can peneterate through the sole of the hoof capsule
distal phalanx
_____ supports cranial end of body at medial surface of the scapula
serratus ventralis m.
force passes what
caudal to shoulder
through elbow joint
through (or cranial to) carpus
cranial to fetlock and pastern
without support what happens to shoulder
shoulder and elbow would flex
when horses rest while standing, weight is carried by
tendons, ligaments, and deep fascia that constitue the passive stay apparatus; thus reducing energy expenditure in the standing horse
tendon of _______ keeps shoulder joint from flexing (supraglenoid tubercle to radial tuberosity)
biceps brachii m. (internal)
intermediate tubercle may help do what
lock the shoulder joint
force transmited via ________ to the _______ which attachs to the proximal end of metacarpal III
lacertus fibrosus; extensor carpi radialis m.
in passive stay apparatus, elbow joint is prevented from ____
flexing
weight of trunk rests on the
nearly vertical radius
axis of rotation of elbow joint is next to the _____ of the elbow which are eccentrically placed; making the elbow joint a _____ joint
collateral ligaments; snap
passive tendsion of tendons of
digital flexors and carpal flexors
what muscles may also help appose flexion of the elbow joint
medial head of triceps m. and anconeus
flexion of carpus prevented by
force from biceps brachii m. transmitted via lacertus fibrosus to the extensor carpi radialis m.
overextension at the carpus is prevented by
palmar carpal ligament and close packing of the carpal bones
suspensory apparatus of the fetlock joint keeps the fetlock from
overextension
tension in ______ also helps prevent fetlcok overextension
accessory check ligaments; distal parts of both flexor tendons
overextension is opposed by
straight sesamoidean ligament
palmar ligaments of the pastern joint
deep digital flexor tendon
flexion is prevented by
pull of superficial digital flexor m. tendon (attaching on distal P1 and proximal PIII)
Tension of the deep digital flexor m. tendon on PIII tends to flex the
coffin jiont
what counteracts pull of deep digital flexor m. tendon and allows the hoof to stay level
extensor branches of the interosseus m.
suprascapular nerve innervates
supraspinatus and infraspinatus
suprascapular paralysis
aka sweeny or sholder slip; may cause lateral deviation of the shoulder joint; chronic muscle atrophy resulting in proinent spine of scapula
radial nerve proximal to the elbow jint innerates
triceps brachi m. all heads; tensor fasciae antebrachii m. and anconeus m.
deep branch of radial nerve innervates
extensor muscles of all joints distal to the shoulder (and ulnaris lateralis)
high radial nerve paralysis damage occurs where
proximal to innervation of triceps brachii
clincial signs of high radial nerve paralysis
unable to support weight onthe affeced limb; dropped elbow; hoof rests on its dorsal aspect; can be caused by damage to brachial plexus
low radial nerve paralysis damage occurs distal to
innervation of triceps brachii m.; may reult during lateral recumbency during surgery or trauma
clinical signs of low radial paralysis
dorsal surface of hoof may rest on the ground; horse is able to bear weight if hoof is placed in its normal position; horse will likely have difficulty walking on uneven ground, but may compensate on even ground
median nerve runs with
brachial artery
median innervates
flexor carpi radialis m. and deep digital flexor m. (with ulnar n.);
end branches of median nerve in the horse are
medial and lateral palmar nerves
median nerve becomes sensory after
muscular branches are given off
ulnar nerve innervates
flexor carpi ulnaris m.
digital flexors
sensory at caudal margin of the limb
above carpus, ulnar nerve divides into
dorsal and palmar branches
ulnar nerve palmar branch combines with
fibers with lateral palmar nerve from median nerve
distal to carpus, lateral palmar nerve gives off
deep branch that innervates inteosseous and gives rise to medial and lateral palmar metacarpal nn.
medial and lateral palmar metacarpal nn. supply
interosseus m. and palmar pouch of fetlock joint
medial and lateral palmar nerves run medial ad lateral to
flexor tendons
communicating branch connects
meidal and lateral palmar nn.
just above the fetlock, the palmar nerves continue as
medial and lateral palmar digital nerves;
palmar digital nerves give offf
1+ dorsal branches to dorsum of digit; pass deep to ligament of the ergot
disappear into the hoof capsule
nerves on the dorsal aspect of the distal limb include
cutaneous antebrachial nerevs; dorsal branch of ulnar nerves; dorsal branches of digital nerves
AZ for musculocutaneous
cranial (dorsal) metacarpal bone
AZ median
from fetlock joint down
ulnar nerve AZ
from caudal antebrachium to lateral metacarpal
radial nerve AZ
lateral and cranial antebrachium
a horse that is lame will become ______ when the area with lesion is desensitzed
temporarily sound
intrasynovial injection
anesthetize specific synovial structures with injection into the structure
perineural nerve block
localized anesthetic injected around a specific nerve; start distally and inject sequentially; work proximally to desiensitize larger areas of the limb to rule out specific region s of thelimb
palmar digital nerve blocks (medial and lateral_
inject 1 cm proximal to collateral cartilage of hoof distal to dorsal branch
palmar digital nerve block anesthetizes what area
mos of foot inside the hoof except dorsal part of the laminar dermis and coronary band
abaxial sesamoidean blocks
inject at level of proximal sesamoid bones; block medial and lateral palmar nerves proximal to dorsal branches;
all structures blocked by digital nerve block plus rest of structures of the foot and pastern joint
low 4 point block
inject at level of distal end of splint bones (buttons); block medial and lateral palmar nerves; block medial and lateral metacarpal nerves;
all previous structures blocked PLUS fetlock joint sesamoid bones, distal supsensory ligament, distal flexor tendons and pastern jiont
high 4 point nerve block
medial and lateral palmar nerves; medial and lateral palmar metacarpal nerves in the proximal metacarpus;
all structures blocked by previous block plus interosseous m. flexor tendons
modifiied high for point nerve block (also called lateral palmar nerve block)
block the lateral palmar nerve before it branches off the deep branch; block lateral palmar nerve as it runs medial to accessory carpal bone; +/- medial palmar nerve; blocks structures o metacarpuus, especially the origin of the interosseous
dorsal aspect of distal nerve supply of ruminants
superficial branch of radial nerve and dorsal branch of ulnar nerve
dorsal branch of ulnar nerve goes to
dorsal common digital abaxial digital;
palmar apsect of distal nerve supply of the ruminant
median n. ; palmar branch of ulnar n. plalmar common digital nerves and palmar axial and abaxial digital nerves
intravenous local anesthesia tourniquet applied to
distal to carpus
anesthetic injected via
Intravenously into superficial veins
nerve blocks of ruminants
middle of metacarpus; block ranial n. ulnar ne. an dorsal polimb
BLOOD VESSES
d
____ HOOF BEARS MORE WEIGHT IN THE THORACIC LIMB
LATERAL
ground surfacce of ruminant hoof consists of
wall, sole, and part of bulb
dermal regions include
perioplic, coronary, laminar (with termina lpapillae) sole, bulb
what is the main weight bearing part of the ruminant hoof
bulb
angle at toe
50
does ruminant hoof have secondary laminae
no
