PT 793 Lumbar Muscles Flashcards
Transversospinalis
Multifidus: lumbar- spans 2-4 segments
Rotatores: thoracic- spans 1-2 segments
Semispinalis: cervical- spans 4-6 segments
in the bony gutter bwt transverse and spinous processes deep to spinalis muscle of erector spinae
unilateral action: ipsilateral lateral flexion and contralateral rotation
bilateral action: extension of vertebral column and head
Multifidus (transversospinalis) m.
o: post ilium, iliac spine, sacrum, transverse processes of T1-T3
i: spinous processes 2-4 segments superior to proximal attachment thickest in lumbar region
inn: post rami of spinal nerves
a: stabilize spine during local movement of vertebrae and extend spine
Rotatores (Transversospinalis) m.
o: transverse processes of vertebrae; best developed in thoracic region
i: superior transverse processes 1-2 segments superior to proximal attachment
inn: post rami of spinal nerves
a: stabilize vertebrae with some proprioceptive function. Assist in spinal extension and contralateral rotation
Semispinalis (Transversospinalis) m.
o: C4-T12 transverse processes
i: fibers run superomedially to occipital bone and spinous processes in cervical/throacic region 4-6 segments superior
inn: post rami of spinal nerves
a: extends bilaterally, unilaterally contributes to contralateral rotation of head and cervical/thoracic spine and ipsilateral lateral flexion
*deep to splenius
Erector spinae
Iliocostalis
longissimus
spinalis
“I Love Science” Lateral to Medial
action
-bilateral: extends spine and head; eccentrically contracts to control back flexion
-unilaterally: ipsilateral spinal lateral flexion
Iliocostalis (Erector spinae) m.
o: post iliac crest; post surface of sacrum; sacral/inf lumbar spinous processes
i: fibers run superiorly to angles of lower ribs and cervical transverse processes
inn: post rami of spinal nerves
a:
-bilaterally: ext spine and head; eccentrically contract to control spinal flexion
-unilaterally: ipsilateral lat spinal flexion
Longissimus (Erector spinae) m.
o: iliac crest, sacrum, sacral/inf lumbar spinous processes
i: fibers run superiorly to ribs and angle to throracic and cervical transverse processes
inn: post rami of spinal nerves
a: extends head and neck, rotates to SAME side (capitus)
Spinalis (erector spinae) m.
o: post iliact crest, sacrum, sacral/inf lumbar spinous processes
i: fibers run superior to spinous processes in upper thoracic region to cranium
inn: post rami of spinal nerves
a
-bilaterally: ext spine and head; eccentrically contract to control spinal flexion
-unilaterally: ipsilateral lat spinal flexion
Abdominals superficial to deep
rectus abdominis is just on the front
- external oblique
- internal oblique
- transverse abdominis
Rectus abdominis
o: pubic symphysis and pubic crest
i: xiphoid process and 5th-7th costal cartilages
inn: ant rami of T6-T12 spinal nerves
thoracoabdominal
a: flexes trunk (lumbar vertebrae) and compresses abdominal visceral; stabilizes and controls tilt of pelvis (antilordosis)
Abdominal bracing vs hollowing
Hollowing: drawing in ant core activating lateral muscles only: obliques (int and ext) and transverse abdomenis (drawing in belly button towards back)
Bracing: contraction of ALL core muscles forming a brace around entire trunk (inflating like you’re about to get punched in the stomach)
Transverse abodminis m.
o: int surfaces of 7th-12th costal cartilages, iliac crest
i: linea alba, pubic crest, and pectin pubis via conjoint tendon
inn: ant rami of T6-T12 spinal nerves and 1st lumbar n
a: compresses and supports abdominal viscera therefore increasing intra abdominal pressure key for spinal stability
one of the main core stabilizing muscles of lumbar spine
Internal oblique m.
O: ant 2/3 iliac crest
i: inf borders of 10th-12th ribs, linea alba and pectin pubis
inn: ant rami of T6-T12 spinal nerves and 1st lumbar n.
a: flexion of vertebral column, compression and supports abdominal viscera, ipsilateral lateral spinal flexion and rotation
External Oblique m.
o: external surfaces of 5th-12 ribs
i: linea alba, pubic tubercle and ant 1/2 iliac crest
inn: T7-T11 spinal nerves and subcostal n
a: ipsilateral lateral flexion to SAME side, rotation of spine to contralateral side when acting alone; compresses and supports abdominal visceral + flexion
*most superficial
Iliacus m.
o: sup 2/3 iliac fossa, ala of sacrum
i: lesser trochanter of femur and shaft
inn: femoral n (L2-L4)
a: flexes hip and stabilizes hip joint; acts with psoas major
Psoas major m.
o: transverse processes sides of T12-L5 vertebral bodies
i: lesser trochanter of femur
inn: ant rami of L1-L3 lumbar nerves
a: balances trunk
-inferiorly: with iliacus flexes hip in standing and trunk in sitting
-superiorly: ipsilateral trunk lateral flexion
Quadratus lumborum m.
o: 12th rib, lumbar transverse processes
i: internal lip of iliac crest
inn: T12 and L1-L4
a: extends and laterally flexes vertebral column; fixes 12th rib during inspiration
Pelvic floor
coccygeus
levator ani (puborectalis, pubococcygeus, iliococcygeus)
piriformis
obturator internus
Pelvic floor function
4 S’s:
- Support the viscera
- sphincter control
- sexuality
- stabilizer of lumbar spine
Coccygeus (ischiococcygeus) m.
o: ischial spine
i: sacrum and coccyx
Levator ani m.
o: body of pubis, ischial spine
i: coccyx
Obturator internus m.
o: pelvic surfaces of the ilium and ischium
i: greater trochanter
inn: nerve to obturator internus
a: rotates thigh laterally
Piriformis m.
o: pelvic surface of S2-4 segments, greater sciatic notch
i: greater trochanter
inn: S1-S2
a: rotates thigh laterally
