MSAK lec - midterm 3 Flashcards
which muscles are found in the 6 layers of the back
layer 1: traps & lats
layer 2: rhomboids & levator scapulae
layer 3: serratus posterior superior & inferior
layer 4: spinotransversales - splenius capitis & splenius cervicis
layer 5 - erector spinae - iliocostalis, longissimus, spinalis
layer 6 - transversospinales - semispinalis, multifidus, rotatores
name the fascias of the back
nuchal (cervical, continuous with nuchal ligament) and thoracolumbar (3 layers, over erector spinae, very strong in lumbar region)
what are the 3 layers of thoracolumbar fascia
posterior (SPs, interspinous ligament, median sacral crest attachments), middle (TPs, intertransverse ligaments, iliac crest to 12th rib), & anterior (attaches to TPs and covers anterior QL. very deep. becomes arcuate ligament of diaphragham and blends with transversus abdominis)
where do the erector spinae muscles sit in the thoracolumbar fascia
between posterior and middle layers
which muscles fill the lamina groove
erector spinae (and also transversospinales)
which erector spinae muscle has a lumborum subdivision
iliocostalis
what is the common origin for erector spinae muscles
aponeurosis - lumbar SPs, supraspinous ligament (T11-L5), median sacral crest, sacrotuberous ligament, posterior sacroiliac ligament, lateral sacral crest, posterior iliac crest
what do the erector spinae muscles assist in
extension, lateral flexion, and ipsilateral rotation of trunk, neck, and head. maintaining the lumbar lordosis (anterior pelvic tilt)
which erector spinae muscles attach to the pelvis
iliocostalis lumborum and logissimus thoracis
which erector spinae muscle does not attach to the common origin
spinalis (does not have a lumborum region)
which erector spinae attaches to the mastoid process of the skull
longissimus
describe the transversospinales (layer 6 muscles)
- they course superiomedially (think christmas tree)
- they become shorter from superficial to deep
- primarily postural
describe how semispinalis attaches to vertebrae
runs superiorly 6 or more vertebrae above origin.
describe how multifidus attaches to vertebrae
runs superiorly 2-4 vertebrae above origin
describe how rotatores attaches to vertebrae
brevis goes from TP to SP IMMEDIATELY above. longus goes from TP to SP 2 vertebrae above. in the transverse plane
which muscle is spinalis capitis considered the deep fibres of
semispinalis capitis
where is multifidus most developped
lumbar spine
which layer 6 muscle has 3 subdivisions and what are they
multifidus. lumborum, thoracis, cervicis
where on the vertebrae does multifidus attach in each of its regions
- lumborum: mamillary processes
- thoracic: TPs
- cervicis: articular processes of C4-C7
what are the spinotransversales muscles
splenius capitis and splenius cervicis
what are the common actions of the spinotransversales muscles
extension of head and neck, lateral flexion, ipsilateral rotation
compare and contrast the actions of the erector spinae group
iliocostalis does the most actions (extension, ipsilateral lateral flexion/rotation). longissimus does the same but rotation is weaker. spinalis just does extension because it’s right in the middle on the spine
what is another name for the erector spinae group
sacrospinalis
describe the different subdivisions of spinalis (in terms of size/strength)
most developed in the thoracis region. infrequent or even absent in the cervicis region. indistinct in the capitis region (blends with semispinalis)
