dog muscles of back, neck and abdomen Flashcards
epaxial vs hypaxial muscles
epaxial; above transverse processes
hypaxial; below transverse processes
3 groups of expaxial muscles
most dorsal to most ventral: transversospinalis, longissimus, iliocostalis
contract expaxials
extension of back
contract hypaxials
flexion of back
contract ipsilateral epaxials and hypaxials
lateral bending of back
contract lumbar epaxials and contralateral thoracic hypaxials and rotators
rotation of back
for hypaxial muscles, which region is most important and why
Lumbar ones most important (not really needed in thoracic area because there is ribs and a sternum)
what 2 muscles make the iliopsoas muscle
psoas major and iliacus
psoas major
- origin ventral surface L3/4-6
- joins iliacus
- inserts on lesser trochanter of femur
psoas minor
- origin T10/11-L3/4
- inserts ileopectinal line (pelvis)
quadratus lumborum
- origin T11/12-13 and transverse processes of L vert
- inserts on ilium
quadratus lumborum is much ____ in horse
smaller
abdominal mm assist the true
hypaxial mm
4 main abdominal muscles
- external abdominal oblique
- internal abdominal oblique
- transversus abdominus
- rectus abdominus
external abdominal oblique
fiber direction
- origin; ribs and lumbosacral fascia
- insertion; linea alba and prepubic tendon (via large aponeurosis)
- fibers run caudo-ventrally
internal abdominal oblique
fiber direction
- origin; tuber coxae, lumbo-sacral fascia and inguinal lig
- insertion; linea alba and last 4-5 ribs
- fibers run cranio-ventrally
transversus abdominus
fiber direction
- origin; transverse processes L vertebra and asternal ribs
- insertion; linea alba and xiphoid cartilage
- fibers run dorso-ventrally
rectus abdominus
fiber direction
- origin prepubic tendon
- inserts on sternum
- distinct transverso tendinous intersections (tendinous inscriptions)
- fibers run cranio-caudally
3 main longitudinal columns of epaxial muscles
iliocostalis
longissimus
transversospinalis group
iliocostalis mm
- thoracic and lumbar parts
- most lateral
- origin wing of ilium
-inserts on transverse processes of L vert and last few ribs - fused with longissimus lumborum
iliocostalis fuses with what muscle in lumbar region
longussimus lumborum
iliocostalis thoracis found on ____
fascicles run in what direction
- dorsal ribs
- cranio-ventrally including to transverse process last C vert
longissimus mm
- middle group
- capitis part, cervicis part, lumbar and thoracic part fused (longissimus dorsi)
longissimus dorsi (thoracis and lumborum parts)
- originates from wing of ilium
- inserts on various processes of L and T vertebra and last few ribs
longissimus cervicis
how many fascicles
4 fascicles from canial T vert to caudal C vert
longissimus capitis
from cranial T vert to mastoid process of temporal bone
transversospinalis system
- most dorsal and medial
- several diff muscles including
- multifidus
- spinalis
- semispinalis
- rotatores; long and short
- interspinales
- intertransversarii
multifidus
- 3 parts; lumbar, thoracic and cervical
- consists of little bundles of muscle
extrinsic neck muscles all run from
body to skull so move head and neck relative to body
extrinsic neck muscles are mainly ____ to cervical vertebra
dorsal
extrinsic neck muscles include
- splenius
- semispinalus capitis (biventer and compelxus)
- spinalis et semispinalis dorsi et cervicis
splenius
- origin lumbodorsal fascia
- inserts of nuchal crest and mastoid process (in conjunction w longissimus capitus)
splenius is deep to what 2 muscles
rhomboideus and cleidocervicalis
semispinalis capitis 2 parts
2 parts; biventer (dorsal) and complexus (ventral)
semispinalis capitis is deep to
splenius
biventer
- dorsal part of semispinalis capitis
- origin T2-4
- insert occipital bone
- sits slightly below splenius
complexus
- ventral part of semispinalis capitis
- origin from C4-T1
- inserts on nuchal crest of occipital bone
- really intrinsic (run from neck to head while extrinsic means run from body to head)
intrinsic neck muscles
run from neck to head (or other part of neck) and move head relative to neck
while extrinsic means run from body to head
lateral neck mm are muscles that pull head and or neck to
side
lateral neck muscles include
- brachiocephalic
- serratus ventralis
- sternocephalicus
- scalenus
sternocephalicus
- origin from sternum
- insert on ramus of mandible
scalenus
- origin from last few C vert
- insert on first 7 or 8 ribs
- flex neck laterally, flexes back
- also assists in respiration
