Download Practical anatomy equine muscles 2016

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MUSCLE
MUSCLE
FOUND
FOUND
ORIGIN
ORIGIN
INSERTION
INSERTION
ACTION
ACTION
DYSFUNCTION
DYSFUNCTION
MASSETER
Cheeks of the
lower jaw
Ventral border
of rostral half of
zygomatic arch
Ventrolateral
surface of
mandible and
ventral margin
of the masseteric
fossa of the
mandible
Raises mandible
when closing mouth
May be one sided if
there are problems with
chewing (teeth issues
or temperomandibular
joint issue for example).
This would create more
tension on the favoured
side.
Raises the mandible
Tension. May be
one sided if there
are problems with
chewing (teeth issues
or temperomandibular
joint issue for example).
This would create
tension on the favoured
side
Rotation of atlas on
axis
Restricted rotation of
head to opposite side,
posterior misalignment
of atlas.
Can be palpated
properly only if weight
of horse’s head is held,
otherwise is contracted
to hold head
TEMPORALIS
Over the temples
(above the upper
jaw)
Parietal, temporal,
frontal and
occipital bones
Medial surface
of the condyle
of the mandible
just ventral to its
articular surface
CRANIAL OBLIQUES
Covers the bulk
of the wing of the
atlas
Spinous and
articular process
of axis
Wing of atlas
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MUSCLE
FOUND
ORIGIN
INSERTION
ACTION
DYSFUNCTION
STERNOCEPHALICUS
Underside of
neck, between
the lower jaw
and breast bone.
Manubrium (front
end) of sternum,
and sternum
cartilage
Deep muscle
along top of
neck, from the
back of the skull
to the withers
and top of the
shoulder blade.
Occiput (under
front of poll),
attached to nuchal
and supraspinous
ligament from C2
to approx T10.
Mandible and
ramus (back ridge
of jaw)
Brings head
downwards and
forwards.
Can be over developed
in horses with a
high head carriage,
especially those who
pull. Can feel tight
at origin. May be
associated with horses
who trip
Lifts the shoulder:
protraction and
retraction, and
stabilises. In the
stance phase helps
extend neck and
spine
If tight; unable to
stretch and can cause
loss of co-ordination in
forelimbs. Palpation
causes twitching over
withers if tight
Lifts shoulder by
drawing the scapular
(shoulder blade) up
and forward, or up
and back. In the
stance phase helps
extend neck and
spine
If tight; decreased
shoulder and neck
flexibility. Can be
affected buy rug rubs.
Palpation causes
twitching over withers
if tight
RHOMBOIDEUS
Upper scapular
cartilage medial
(inner) surface.
TRAPEZIUS (CERVICAL AND THORACIC)
Triangle from 2/3
down the neck
to the shoulder
blade, and
another triangle
over the withers
Dorsal midline
and supraspinous
ligament above
C3 to T10
Cervical: on
spine of scapula.
Thoracic: on top
part of spine of
scapula
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MUSCLE
FOUND
ORIGIN
INSERTION
ACTION
DYSFUNCTION
SERRATUS VENTRALIS CERVICIS
Medial surface of
scapula
If neck fixed, draws
scapular forward.
If scapula fixed,
extends or laterally
flexes the neck
Prone to overwork in
horses who are on the
forehand or fixed too
high in neck posture,
as nuchal ligament
becomes too slack to
take the strain, so this
muscle has to take its
place. Often causes
twitching over withers
on palpation
T4 – T6 (T5/6 is
approx highest
point of wither)
Nuchal crest
(poll), mastoid
process, transverse
processes C3 –
C5
Turns and lifts head
and neck to the side
If tight, turning the neck
is difficult
Mastoid process
(behind TMJ),
temporal bone
(above TMJ), nuchal
crest (just behind
ear
Humerus deltoid
tuberosity (below
front point of
shoulder) and fascia
of the shoulder
Moves the head
If tight; short choppy
sideways or brings the
stride and resistance to
foreleg and shoulder
go forward
forward
Between scapula
and lower
cervicals
Transverse
processes C3 – 7
Side of neck,
from the back
of the head and
down the first
half of the neck
vertebrae to cover
the withers
Lower side of neck
over vertebrae,
From the back
of the skull to
the front of the
shoulder
SPLENIUS
BRACHIOCEPHALICUS
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MUSCLE
FOUND
ORIGIN
INSERTION
ACTION
MULTIFIDUS CERVICUS
DYSFUNCTION
Spinous and
articular processes
and runs to end of
lumbar vertebrae
Flexes neck to one
side while rotating
head to the opposite
side. Supports spine
Bulges around C3 if
worked hard in an
outline. Tightness,
spasm, pain in neck.
Resistance in neck.
Poor bit contact. Poor
function in this muscle
can cause tension
in the surrounding
muscles. This can be
helped through carrot
stretching.
Spine and upper
Over the front of
cartilage of the
the shoulder blade
scapula
Lateral tuberosity
of humerus (side of
point of shoulder)
Open front of
shoulder and helps
take limb forward
(lateral work). Major
stabiliser of the
forelimb
If tight; shoulder
tightness. If poor
function, the spine of the
scapula will be obvious
(‘sweeny’), and may
well be sensitive
Over the back
of the shoulder
blade
Caudal (back) part
of lateral tuberosity
(side/back of
point of shoulder)
Stabilises shoulder.
Rotates shoulder and
limb outwards
If tight; shoulder
tightness. If poor
function, the spine of
the scapula will be
obvious (‘sweeny’), and
may well be sensitive
Starts at C2 to
end of lumbar
Entwined in
vertebrae.
cervical vertebrae.
Spinous (top) and
From C2 to end of
articular (join to
lumbar vertebrae.
other vertebrae)
processes
SUPRASPINATUS
INFRASPINATUS
Scapula cartilage
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MUSCLE
FOUND
ORIGIN
INSERTION
ACTION
DYSFUNCTION
Long head
originates on the
scapula. Lateral
and medial heads
originate on the
humerus
Olecranon process
(point of elbow)
Draws the forearm
and shoulder up and
back
If tight, the horse has
a short stride and may
dish
Stabilizes the
shoulder joint / locks
forelimb when weight
bearing. Extends the
shoulder joint and
flexes the elbow
Overuse can lead
to poor stability of
shoulder, causing
tripping. Tightness can
reduce joint flexibility in
the area
Brings forelimb
across body
If tight; short stride,
grumpy on girthing,
resisting correct canter
lead, and breathing
may be affected
TRICEPS
Triangular
shaped; from
under the back
of the shoulder
blade to the
elbow and the
back of the
shoulder
BICEPS BRACHII
From just above
point of shoulder
on the front of the
horse to the top
of the forearm
Supraglenoid
tubercle of the
lower scapular
Via tendon on to
the front of the
radius
Over the chest
between the legs
(breast bone to
ribs)
Sternum: xiphoid
and costal
cartilage
Humeral crest
(just below point
of shoulder) and
antebrachial fascia
DESCENDING
(SUPERFICIAL)
PECTORALS
Viewed from below--->
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MUSCLE
FOUND
ORIGIN
INSERTION
ACTION
DYSFUNCTION
ASCENDING
(DEEP) PECTORALS
Viewed from below--->
LATISSIMUS DORSI
LONGISSUMUS DORSI
Over the chest
between the legs
(breast bone to
ribs)
Xiphoid cartilage
and rib cartilage
1- 4
A triangular muscle;
from the back
of the withers,
along the spine to
the lower back.
Here, it connects
into a sheet of
fascia (lumbar
aponeurosis) which
continues over the
loins and into the
gluteals. The lower
part attaches to the
back of the humerus
under the shoulder
joint
From T3 into the
thoracolumbar
fascia, which
extends to the
fascia over the
croup
Has attachments
to the cervical
spine, and from
between the
withers to lower
back, where it
connects to fascia
that continues into
the middle gluteal
muscle. Biggest
and longest
muscle in spine
Spinous processes
of the sacrum /
upper surface
of ilium (croup)
/ supraspinous
ligament.
Medial tuberosity
of humerus (inside
point of shoulder)
Brings forelimb
across body
If tight; short stride,
grumpy on girthing,
resisting correct canter
lead, and breathing
may be affected
Inner surface of the
humerus, slightly
less than halfway
down the bone.
Draws the shoulder
blade down and
back, and takes
the forelimb back.
Supports the spine in
movement
If tight, the horse will
be stiff and on the
forehand, especially
turns and circles,
may be grumpy when
girthing and may affect
breathing
On the upper ends
of all the ribs, the
sides of all the
thoracic and all the
lumbar vertebrae,
and on the sides
of the cervical
vertebrae
Helps lateral (side)
bending, and part of
a group of muscles
that power the horse
forward. Stabilises
the spine during
impulsion
If tight; inability to flex,
cold backed, dipped
back, not working over
back or engaging hind
quarters. Susceptible
to uneven saddle or
rider pressure
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MUSCLE
FOUND
ORIGIN
INSERTION
ACTION
DYSFUNCTION
Stiff on forehand,
especially turns and
poor shoulder flexibility.
May affect breathing.
Affected by tightness in
C6/7
SERRATUS VENTRALIS THORACIS
Attached
between ribs
and underside of
shoulder blade
Lateral surface of
ribs 1 – 9
Medial (inner)
surface of the
scapula
Lifts trunk of the
body, suspends the
torso between the
scapulars, providing
a mobile elastic
sling. It aids in
smooth impulsion and
gives spring to stride
Over side of
thigh, between
sacrum (rump)
to cover a wide
area over the
stifle
Superior spines
of the sacrum,
Tuberosity of
Ischium (seat bone)
/ sacrum / sacroiliac ligaments
Anterior part of
patella, crest of
tibia (below side
of stifle), fascia of
hock
Bends stifle and
hock, and aids
propulsion, kicking
and rearing
If tight; short hind
stride, not tracking
up, resists lateral
movements
Down the back of
the thigh from the
point of buttock to
above the hoc
Tuber ischium
(point of seat
bone) and tendon
attachment on
sacrum
Crest of tibia
(below side of
stifle), tendon of
biceps, which
attaches to tuber
calcis (hock)
Bends stifle and
stretches limb out
behind, aiding
propulsion
Tightness; shortened
stride, resists
straightening stifle, may
hold leg bent at rest
BICEPS FEMORIS
SEMITENDINOSUS
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MUSCLE
FOUND
ORIGIN
INSERTION
ACTION
DYSFUNCTION
There are three
adductor muscles.
Adductor longus,
adductor magnus
and the brevis
muscle. These
muscles are found
in the deep layer
of the muscles.
All originate on
the pelvic joint
via the symphysial
tendon. Also near
the ischiatic arch,
the ventral surface
of the pubis and
ventral surface of
the ischium
Inserts into the
whole lateral lip of
the caudal rough
face of the femur
Adducts limb,
extends dogs hip and
stabilizes hind leg
Tension creates a close
action behind, and
restricts length of hind
stride
It lies on the back
part of the inner
side of the thigh
Pubic symphysis
via the symphysial
tendon
Medial aspect of
the stifle and hock
Tension creates a
close action behind,
and restricts length of
hind stride
Tension creates a close
action behind, and
restricts length of hind
stride
ADDUCTORS
GRACILIS
9
MUSCLE
GLUTEUS MEDIUS
SARTORIUS
FOUND
ORIGIN
Lies over the
rump between
the vertebrae of
the pelvis and
the hip joint
(top of thigh). It
sits under the
gluteal fascia,
and extends into
the lumbar area
via the ‘gluteal
tongue’
Surface of Ilium,
sacral tuber (either
side of spine at
start of sacrum),
dorsal sacro-iliac
ligament and
gluteal fascia
Starts on the
front end of the
pelvis and ends
on the inside of
the dog’s knee.
This muscle has
two long muscle
bands that are
next to each
other. A front
(Cranial) part and
a rear (caudal)
part
The cranial part
arises from the
iliac crest and the
cranial ventral
iliac spine, as
well as from
the lumbodorsal
fascia. The caudal
part arises on
the bony ridge
between the two
ventral spines of
the ilium
INSERTION
ACTION
DYSFUNCTION
Trochanter major
(top) of femur
Takes leg back and
out to the side.
Strong propulsive
muscle
If tight; discomfort,
restricted hip
movement, short hind
stride
Cranial border of
the tibia.
To flex the hip and
stifle while the limb
is being protracted
and to contribute to
stifle extension during
stance.
Poor extension of the
hind limb of tight. Stifle
instability if weak
Stabilises and flexes
hip
Short striding, restricted
hip extension, toe in on
forward stride. If weak
/ wasted, ilopsoas
may be tight
GLUTEUS SUPERFICIALIS
Lies over the rump
between the first
half of the sacrum
and the mid thigh
Gluteal fascia
3rd trochanter of
femur
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MUSCLE
FOUND
ORIGIN
INSERTION
ACTION
DYSFUNCTION
(of both): Via
common tendon
that insert into the
lesser trochanter
(upper femur
Supports lower back.
Lowers the pelvis
and braces the spine
to allow hind limbs
to push the body
forwards
May be tight due to
bracing against the
rider, prevents stepping
through with hind limbs,
and often a roached
back
Tuber coxae
(haunch)
Fascia lata of thigh
and patella. The
fascia also joins
the superficial
gluteal, and
therefore attaches
to the greater
trochanter (top of
femur)
Hip flexion.
Extension of stifle.
Assists in unlocking
the stifle. The fascia
late itself forms
a sling around
the stifle, thereby
absorbing loads from
the above structure
If tight; throws leg
outwards and resists
crossing legs in lateral
movement. Appears
wasted / hollow.
Prefers to stand on
opposite leg. Poor
stifle locking / unstable
Lateral surface
of ribs 4-18;
thoracolumbar
fascia
Abdominal tendon:
linea alba (mid
line of belly) &
prepubic tendon
(towards pubic
bone); pelvic
tendon: tuber
coxae & prepubic
tendon
Flexes the trunk; The
abdominal muscles
are vital in supporting
abdomen and
helping to maintain
spinal flexion.
Inhibility to bring
hind limb sufficently
underneath to support
rider & move forwards
ILIOPSOAS
Core muscles,
between the
underside of the
vertebrae in the
lower back to the
inside of the hip
joint (top of thigh)
Psoas Origin:
Last 2 ribs and
lumbar transverse
processes
Iliacus origin:
Wing of the
sacrum, surface of
ilium
TENSOR FASCIA LATAE
Point of hip to top
of stifle
EXTERNAL ABDOMINAL OBLIQUE
Lies over the
lower edge of the
ribs across the
abdominal area
to the ilium