lecture 10: Equine trunk myology Flashcards
How many vertebrae do horses have
18 +- 1
1.Disc between C7 & T1
2. First ribs
3.First costal cartilages
4. Manubrium of the sternum
Ribs 1-8 are called and why
Sternal; connect directly to sternum
Ribs 9-18 are called and why
Asternals; join with cartilage not directly to sternum
T/F horses have floating ribs
false
identify which rib number is being pointed to
identify the parts of the ribs
costal arch
**can palpate
what shape is the horse sternum
keel shape (kinda V shaped)
identify the parts of the sternum
- manubrium
- body
- xiphoid process and cartilage
what part of the sternum is being pointed to
manubrium
why do horses lay like this when they lay down
because of their keel shaped sternum
what “condition” may horses have if there is too much angulation in their vertebrae
Kissing spinous processes
Why is Kissing spinous processes bad
-creates inflammation and pain
-may need treatment
what foramen is in a horse vertebrae that IS NOT in a dog
lateral vertebral foramen
**spinous process is also obviously a lot longer
are the first ribs very mobile
No, shorter/stronger/ less mobile
What important structure does the first costal cartilages help create
thoracic inlet
Is the manubrium of the sternum in a horse considered a landmark
yes; can palpate
What does the Articular surface of the head of the rib join with compared to the articular surface of the tubercle of the rib join with?
Articular surface of the head: joint with bodies of vertebrae
articular surface of the tubercle: join with transverse process
importance of the intercapital ligament
Helps keep ribs together
The costal arch helps create a longer ____ compared to one of a dog
diaphragm
How does the sternum of a horse compare to a dog
dog= tubular shape
horse= keel shape
What does the nuchal ligament continue into
Supraspinous ligament
what additional ligament do horses have that aids in carrying/distributing the weight of their abdomen
connects to top of the spinous processes near scapula
Dorsoscapular lig.
what is located under the Supraspinous lig. that helps prevent friction
Supraspinous bursa (first 3 ribs)
what is Fistulous withers
Bursitis and infection of supraspinous bursa
How many Lumbar vertebrae are in the horse
Usually 6 lumbar vertebrae present
Although 5 have been reported in the domestic horse, donkey, Arabian horse, Przewalski horse, ass, and mule
Transverse processes:
Length (increase/decrease) to the third or fourth then (increase/decrease) to the last
increases, decreases
Lumbar vertebrae in the horse :
First two curve (caudally/ cranially) , last two curve (caudally/cranially)
caudally, cranially
L5 articulates with L6; L6 articulates with the ______
sacrum
what is another name for the process that is stared
transverse process
do horses have accessory processes like dogs on their lumbar vertebrae
NO
identify the ligaments
**dorsal longitudinal runs dorsal to the spine, ventral longitudinal runs ventral!!
what is being pointed to
transverse process of the lumbar vertebrae
how does the position of transverse processes vary from dog to horse
dog= cranio-ventral
horse= horizontal
In the horse, the transverse process of L5 and L6 articulate to form a _____.
The transverse process of L6 articulates with the ____ of the sacrum
joint
wing of sacrum
when L5 forms a joint with L6 and L6 forms a joint with the sacrum
-what kind of joint is formed?
-what does this provide the horse?
plane-synovial joint
provides extra stability to the lumbosacral region
what is important to note about the spinous process of the sacrum in a horse
they are partially fused
action of Rectus thoracis m.
draw cartilages and ribs cranially and
laterally to assist in inspiration
location of Rectus thoracis m.
Lateral surface of the first rib to the cartilage of the 4th rib
Serratus dorsalis cranialis m
location and action
❑ Thoracolumbar fascia to lateral surfaces of ribs
❑ Action: draw the ribs cranially and laterally
assisting in inspiration
Serratus dorsalis caudalis m
location and action
Thoracolumbar fascia to lateral surfaces of the last 7 or 8 ribs in the horse
Action: draw the ribs caudally assisting with
expiration
list the types of intercostal muscles and where they are located
External intercostal mm.
Internal intercostal mm.
Intercostal muscles – run from rib to rib and function to unite the ribs together (i.e., “if you’re moving, I’m moving too”)
How are the fibers of the external and internal intercostal mm. oriented
External intercostal mm. – fibers oriented caudoventrally
Internal intercostal mm. – fibers oriented cranioventrally
what is the MAIN action of the external intercostal mm. versus the internal intercostal
external= inspire
internal= expire
Deep fascial sheet of elastic tissue
Assists the abdominal muscles in supporting the weight of the abdominal viscera
Tunica flava abdominis = abdominal tunic
Tunica flava abdominis ventrally it covers and adheres to the ____________ of the external
abdominal oblique m
aponeurosis
Tunica flava abdominis laterally, covers the what 3 muscles
external abdominal oblique
external intercostal
serratus ventralis thoracis mm
what is this showing
hint: Deep fascial sheet of elastic
tissue
Tunica flava abdominis = abdominal
tunic
what happens when the Tunica flava abdominis gets cut
why is it important
tends to curl due to it being ELASTIC
its extra support to hold abdominal weight
what muscle is this
O: Lateral surfaces of 4th-18th ribs and the fascia over the external intercostal mm.;
thoracolumbar fascia
◼ External abdominal oblique m.
where does the External abdominal oblique m. insert
Linea alba and prepubic tendon, coxal tuber and body of the ilium
action of External abdominal oblique m., Internal abdominal oblique m., Transversus abdominis m.
Compress the abdominal viscera, as in
defecation, urination, parturition and expiration; flex the trunk
External abdominal oblique m. fibers are directed
ventrocaudally
what muscle originates at the coxal tuber and adjacent part of the inguinal ligament
◼ Internal abdominal oblique m.
insertion of the Internal abdominal oblique m.
Cartilages of the last 4-5 ribs; linea alba and
prepubic tendon
what innervates the Internal abdominal oblique m., External abdominal oblique m., Transversus abdominis m., and Rectus abdominis m.
Ventral brs. of thoracic and lumbar spinal
nn.
what direction do the fibers of the Internal abdominal oblique m. run
Fibers course ventrally,cranially and medially
what is the cranial border of the internal abdominal oblique m.
cord of the flank
what muscle has this origin:
Medial surface of the ventral ends or cartilages of the asternal ribs and the transverse processes of the lumbar vertebrae via thoracolumbar fascia
◼ Transversus abdominis m.
where does the Transversus abdominis m. insert
Xiphoid cartilage and linea alba
what types of fibers form the Transversus abdominis m.
Dorsal part is muscular,
ventral part is aponeurotic
what are the borders of the Paralumbar fossa
Can palpate all 3
Similar to that of external and internal
abdominal oblique mm. (abdominal
compression); flex the lumbosacral joints and
the lumbar and thoracic parts of the spine
what muscle is this
◼ Rectus abdominis m.
what muscle is this
originates at cartilages of the 4th or 5th to 9th ribs and the
adjacent surface of the sternum
◼ Rectus abdominis m.
insertion of the Rectus abdominis m.
Pubis via the prepubic tendon
do dogs have accessory ligaments like horses
NO
purpose of accessory ligament
strong connective tissue, LIMITS (doesn’t 100% stop) ABduction of coxal joint in horses
Median fibrous raphe extending from the xiphoid cartilage to the prepubic tendon
◼ Linea alba
Linea alba is formed by the junction of ________ of external abdominal, internal abdominal and____________mm.
aponeuroses, transversus abdominis
- umbilical region
- xiphoid process and cartilage
what is the way to the abdomen (what do we cut)
LINEA ALBA
- transverse abdominis
- rectus abdominis
- linea alba
