Trunk Flashcards
Briefly describe the structure of the sacrum:
fusion of 5 sacral vertebrae into an inverted triangular, concave shape. The bone has a base, apex and four articular surfaces
Why are the articular facets of C1 so large compared with those of other vertebrae?
There is no vertebral body in C1, so the large articular facets transfer forces from the occicpital facets to the vertebral body of C2
How many intervertebral discs are there?
23
What is the pars interarticularis? Explain the mechanism causing a pars interarticularis defect.
Under compression an extension weight can be transferred through the inferior articular processes to the laminar, causing a pars interarticularis fracture (collar fracture)
The suboccipital muscles move the head on C1 OR move the head & C1 on C2.
What movements occur at C0/1?
What movements occur at C1/2?
What bony features of C1 C2 provide increased moment arms?
• C1:
• C2:
What movements occur at C0/1? Head flexion and extension
What movements occur at C1/2? Head flexion and rotation
What bony features of C1 & C2 provide increased moment arms?
• C1: Anterior arch
• C2: Odontoid Process
Due to their small size and moment arm interspinous produce insufficient force to produce movement.
What is their function?
Proprioceptive
Explain the movements of the head and neck when the sternocleidomastoid contracts concentrically;
(i) Bilaterally:
(ii) Unilaterally
Explain the movements of the head and neck when the sternocleidomastoid contracts concentrically;
(i) Bilaterally:
Upper cervical extension & lower cervical flexion
Explanation:
The line of action of SCM has a vertical component that crosses posterior to the upper cervical spine (= ext) and anterior to the lower cervical spine (= flexion).
(ii) Unilaterally
Ipsilateral lateral flexion & contralateral axial rotation
Identify the diaphragm and briefly describe its structure.
Dome superiorly with central tendon,
attaches inferiorly to L1-3, costal cartilages 6-12, & lower ribs
Identify the three major structures that pass through or behind the diaphragm:
- inferior vena cava @ T8
- oesophagus @ T10
- descending aorta @ T12
Explain how can the diaphragm contribute to postural stability?
Contraction increases intra-thoracic volume. If the abdominal muscles are also contracted, the intra-abdominal pressure also increases. Increased pressure makes it more difficult to move the joint and thus increases stability
How does respiratory drive affect the postural activity of the diaphragm?
Respiratory drive will cause contraction, but not the accompanying increase stability, as the focus is on oxygen consumption
Identify the pelvic diaphragm and its two major components:
- levator ani
* coccygeus
Identify two structures that pass through the pelvic diaphragm:
- anal canal
* urethra
How does activity in the pelvic floor muscles relate to trunk / spinal stability?
Increases IAP to increase stability and stiffness of the spine
Is the TLF different to the erector spinae aponeurosis
They are different structures, but do have some blending
Considering all the muscles of the abdominal wall:
Which are the most powerful flexors of the thoracolumbar spine?
Justify your answer:
Which are the most powerful rotators of the thoracolumbar spine?
Justify your answer.
Which are the most powerful flexors of the thoracolumbar spine?
Justify your answer: Rectus abdominis, it has the largest flexion moment arm and PSCA
Which are the most powerful rotators of the thoracolumbar spine?
Justify your answer. Internal and external obliques, they have the greatest moment arm the greatest PSCA
Define:
Spondylolysis:
Spondylolisthesis:
At which vertebral levels are they most commonly found?
Spondylolysis: a stress fracture of the pars interticularis
Spondylolisthesis: a fractured pars interticularis shifts/ slips forward on the vertebra directly below it
At which vertebral levels are they most commonly found?
L5
What are uncovertebral joints?
Found bilaterally between adjacent cervical vertebrae, identified by the cat ear shaped uncinate processes of the C3-7 vertebrae
How does the intervertebral disc height: vertebral body height affect range of motion?
How does it differ in the vertebral column regions?
How does the intervertebral disc height: vertebral body height affect range of motion?
Greater disc height allows greater range of motion
How does it differ in the vertebral column regions?
The cervical and lumbar regions have a greater disc height
Is the vertebral endplate more firmly attached to the vertebra or the intervertebral disc?
Intervertebral disc
Which of the 4 suboccipital muscles is best aligned to produce rotation of the head & C1 on C2?
Obliquus capitus inferior
Which muscles are the primary cervical spine o extensors o flexors = o lateral flexors = o rotators:
o extensors = semispinalis capitis and semispinalis cervicis
o flexors = longus capitus and longus cervicis
o lateral flexors = scalenes,
o rotators: R rotation = L SCM + R splenius
Which muscles are the primary thoracolumbar o extensors o flexors o lateral flexors o rotators
o extensors = longissimus thoracics pars thorarcic and par lumborum
o flexors = psoas major and rectus abdominis
o lateral flexors = quadratus lumborum
o rotators = obliques
What action(s) does the external oblique perform?
Unilateral: Trunk contralateral lateral flexion and rotation
Bilateral: Trunk flexion and increases IAP
What action(s) does the internal oblique perform?
Unilateral: Trunk ipsilateral lateral flexion and rotation
Bilateral: Trunk flexion and increases IAP
What action(s) does the psoas major perform?
Trunk and hip flexion
Lumbar compression
What action(s) does the transverse abdominis perform?
Increases intra-abdominal pressure via the abdomen
What action(s) does the rectus abdominis perform?
Trunk flexion
What action(s) does the quadratus lumborum perform?
Unilateral: Trunk Lateral Flexion
Bilateral: Increases postural stability
What action(s) does the levator ani and coccygeus perform?
Increases intra-abdominal pressure
Assists with postural stability
Prevents pelvic organs from protruding
What separates the portions of the posterior rectus sheath?
What is the segment below this landmark called?
Arcuate line
Below = transversalis fascia
How can muscles of the abdominopelvic cavity contribute to stability of the lumbar spine? (3 ways)
- Increasing intra-abdominal pressure (IAP)
- Abdominal muscle co-contraction
- TLF (abdominopelvic muscle attachments)
- Increasing intra-abdominal pressure (IAP)
By increasing IAP, the diaphragm, pelvic floor, multifidus and abdominal wall muscles are engaged in co-contraction. This stabilisation minimises the chance of displacement of the abdominal contents into the thorax. Tension in the TLF also contributes to this increased spinal stability
Abdominal muscle co-contraction - Abdominal muscle co-contraction
When all of the abdominal muscles are co-contracting, they are also resisting the opposite of the usual action. Eg. Rectus abdominis resists trunk extension. This increases the stiffness of the spine and require more force to disturb the posture. - TLF (abdominopelvic muscle attachments)
When the muscles within the TLF contract, they expand and pull on the TLF, thus increasing pressure and stability. The TLF also acts as an attachment site for many supporting muscles, which when contracted also pull on the TLF and tensioning it. Thus also creating more stiffness and thus stability
Which abdominal muscle doesn’t attach to the TLF
External oblique
What action(s) does the longus capitus perform?
Head and upper Cx Flexion
What action(s) does the longus cervicis perform?
Cx flexion
What action(s) does the scalenes perform?
B: neck F
U: ipsilateral LF
(Anterior scalene also contralaterally rotates)
What segments of the spinal cord is the rotatores present in?
thoracis
What segments of the spinal cord is the multifidis present in?
cervicis
thoracis
lumborum
What segments of the spinal cord is the semispinalis present in?
capitis
cervicis
thoracis
What segments of the spinal cord is the spinalis present in?
cervicis
thoracis
What segments of the spinal cord is the longissimus present in?
capitus
cervicis
thoaracis pars thoracis
thoaracis pars lumborum
What segments of the spinal cord is the iliocostalis present in?
cervicis
thoracis
lumborum pars thoracis
lumborum pars lumborum
What action(s) does the transversospinales muscle group perform?
proprioceptive function
What action(s) does the erector spinae muscle group perform?
spinal extension
