Axial Skeleton Muscle and Joint Interactions Flashcards
What happens once the spinal nerve exits the foramen?
Divides into ventral and dorsal ramus
What does the dorsal ramus form?
Nerves that innervate muscles / joints /skin of the posterior trunk and neck
What does the ventral ramus form?
Nerves to innervate muscles/joints/skin of anterior/lateral trunk, neck, and extremities
What does the ventral ramus become?
AN individual nerve or a plexus
Where is the dorsal ramus dermatome?
Across most of the posterior trunk
Where does the dorsal ramus branch from? (generally)
Every spinal nerve root
What are the 4 major plexi?
Cervical - C1-4
Thoracic- C5-T1
Lumbar - T12-L4
Sacral - L4-S4
What ligaments does the dorsal ramus innervate?
ligaments posterior side of vertebrae; capsule of facets; dorsal ligaments of SIJ
What are the individual nerve branches from the ventral plexus?
Intercostal and recurrent meningeal
What is torque?
A measure of the force that causes an object to rotate around an axis
What can torque also be defined as?
The rotational equivalent of linear force
What kind of quantity is torque?
Vector quantity
What is the internal torque equal to?
The product of the muscle force and its internal moment arm
What is the strength of a muscle action equal to?
The distance and spatial orientation of the muscle’s line of force relative to the axis of rotation
What muscles are in the superficial layers of the back?
- trapezius
- latissimus dorsi
- rhomboids
- levator scapula
- serratus anterior
What muscles are in the intermediate layer of the back?
- serratus posterior superior
- serratus posteiror inferior
What are the three groups of the deep layer?
- Erector spinae group (spinalis, longissimus, iliocostalis)
- Transversospinal group (semispinalis muscles, multifidi, rotatores)
- Short segments group (interspinalis muscles, intertransversarius muscles)
What is the innervation of the deep layer of the back?
Dorsal rami innervation
What do the muscles of the back do as they get deeper?
Become progressively shorter/more angulated
Where is the erector spinae group?
ill-defined one hands width from the SP
- deep to thoracolumbar fascia
What torque is large at the erector spinae group?
Extension
Where are the attachments of the common tendon of the erector spinae?
- spinal tubercles of the sacrum
- spinous processes and supraspinous ligaments in the lower thoracic and entire lumbar region
- iliac crests
- sacrotuberous and sacroiliac ligaments
- Glut max
- multifidi
Where is the multifidi?
- posterior sacrum to C2
- TP to SP one or 2-4 vertebrae above
Where is the multifidi thickest?
In the lumbar region, 2/3 of muscular stabilizing capacity
What space is filled by the multifidi?
Between TP/SP
What should be know about rotatores?
- deepest
- most well developed in T/STP - lamina/base of SP 1-2 above
The short segments group crosses what?
1 intervertebral junction
The short segments group is most developed where?
In the cervical region
What ligament does the short segments group blend with?
Interspinous ligament
What is the short segment group rich in?
Muscle spindles and sensory feedback
Where does the multifidi attach inferiorly?
- mammillary process of lumbar vertebrae
- lumbosacral ligaments
- deeper part of the common tendon of the erector spinae
- posterior surface of the sacrum
- posterior-superior iliac spine of pelvis
- Capsule of apophyseal joints
What do the muscles of the anterior-lateral trunk do?
Support and protect viscera, increase intrathoracic and intrabdominal pressure
What forms the linea alba?
Anterior and posterior rectus sheaths
What are the two types of diastasis recti?
protruding and not protruding
What is the rectus abdominus intersected by?
- 3 transverse fibrous bands; tendinous insertions
Where does the rectus abdominus attach and insert?
- Attaches: xiphoid, 5-7 cartilaginous portion of the ribs
- Inserts: crest of pubis (can blend with adductor longus)
What does the rectus abdominus do?
Flexes the thorax and upper lumbar spine - and or tilts the pelvis posterior
Rectus abdominus has the longest ________ _______ and the smallest ________ _________ area
longest fascicle length, smallest cross sectional area
What does the external oblique do?
Lateral flexor and contralateral rotator
- bilateral trunk flexor, posterior tilt of pelvis
What direction does the external oblique run?
inferior and medial (pocket direction)
What muscle has the largest cross sectional area of the abs?
the internal oblique
What direction does the interal oblique run?
Cranially and medially
What does the internal oblique do?
- Ipsilateral rotator and lateral flexion
- bilateral flexion of trunk, posterior pelvic tilt and increased tension in TL fascia
What is the internal oblique a synergist with? (for ipsilateral rotation)
opposite external oblique via the linea alba
Which abdominal muscle is the deepest?
Transversus abdominus
How does the transversus abdominus stabilize?
via the thoracolumbar fascia
Where does the transverse abdominis have the most extensive attachments?
Into the thoracolumbar fascia
Where does the transversus abdominis run?
Ribs to iliac crest to inguinal ligament to the TL fascia
What is the role of the transverus abdominis?
Stabilization for other abdominal muscles; increases tension on the TL fascia; compression of abdominal cavity
A diagonal sit up incorporates what muscle groups?
trunk flexion and axial rotation to the left/right
With a diagonal sit up, there is bilateral activation of which muscles?
- rectus abdominis and transverse abdominus
With a standard sit up, the opposing axial rotation and lateral flexion torques are _________
neutralized
With a diagonal sit up to the left, which muscles are working on the left?
- external oblique, rectus abdominus, internal oblique
With a diagonal sit up to the left, which muscles are working on the right?
- SCM
- Pec major
- Serratus anterior
- External oblique
- transversus abdominis
Lateral flexion involves both _____ and ______ (muscle groups)
flexors and extensors
What is a stabilizer during rotation of the trunk?
Transversus abdominis
Which muscle group has a long lever arm?
Obliques
Which muscle group has more torque, flexors or extensors?
Extensors
Which muscle group has a larger moment arm?
Flexors
Which muscle group has more mass and overall more vertically aligned fibers (posture role)
Extensors
Where does the QL attach?
To the IC and iliolumbar ligament
With bilateral contraction, what does the QL do?
Extension and vertical stabilization
With unilateral contraction, what does the QL do?
Lateral flexion
What is the QL also known as?
‘Hip-hiker’
What can happen to the QL in LBP patients?
Can be hypertonic
The iliopsoas is a combination of what two muscles?
iliacus and psoas
What does the iliopsoas do? Innervation?
Hip flexor
- femoral nerve
What does the iliopsoas do to the pelvis and back?
Anterior tilt of pelvis and lumbar extenson (lateral flexion of trunk as well)
How does flexion primarily change the spine?
Through pelvic tilt
What do the QL and ilipsoas do together?
Run nearly vertical on both sides of the lumbar spine - strong bilateral contraction provides stability
What do we consider when looking at core stability>
- 3 subsystems of control
- global or regional
- intrinsic or extrinsic
What is the role of the neural subsystem?
Manage spinal stability
What do short deep local muscles do?
- control precise alignment and stiffness
- high density muscle spindles
- varying angles act as guidewires
- sail boat analogy
What do global or extrinsic muscles do?
- longer muscles
- important torque generators
- provide strong links between regions
Why is it important for the transversus abdominis to be the first muscle active?
- it is not influenced by movement direction, supporting the hypothesized role of this muscle in spinal stiffness generation
What type of patient was shown to have delayed contraction of the transversus abdominis?
LBP patients
What does the contraction of the transversus abdominius significantly decrease?
- the laxity of the SIJ
What happens with the lumbar multifidus following a low back injury?
- segmental atrophy which develops at the level of pathology (quickly as 24 hours after injury), which can persist beyond the resolution of symptoms
What are the two phases of the full sit up?
a.) trunk flexion phase, activation of abs esp rectus abdominus
b.) hip flexion phase
A curl up puts less demand on what?
hip flexors
A full sit up puts more pressure on what?
discs
When is there the greatest injury risk during the sit up?
During hip flexion without the trunk curl - can cause anterior shear forces
What should we NOT do during a sit up with our patients?
DO NOT hold the feet down, focus on TA and IO
What can lifting do that may lead to injury?
- generate large compression, shear, and tension forces
- may exceed structural tolerance
What can stooping do to the body?
- long external moment arm of load
- greater forces of trunk extensors needed
- compression and shear forces larger
- spine flexion = risk to discs
What can a squat do to the body?
- lumbar spine may stay extended
- reduced moment arm of load, less trunk extensor torque
- larger demand on knees
- greater work metabolically