Regional Anatomy Flashcards
2 main joints in the knee
- Tibiofemoral joint
2. Patellofemoral joint
When in flexion, the patella stays_____.
The patella stays still but the tibial condyles move
There is ____ change in the distance between the tibial tuberosity and the patella/ But the _____ moves and the ______ unfolds.
- No
- Femur
- Suprapatella pouch (synovial)
Attachments of the capsule (knee)
- Edges of the tibial condyle
- Margins of the patella
Are cruciate ligaments intra-synovial or extra-synovial?
Extra-synovial
Are cruciate ligaments intra-capsular or extra-capsulare?
Intra-capsular
An infrapatella fat (fat pad) is highly innervated/sensitive and is a good space filler. True or false.
True
Tibiofemoral joint is __axial
Uniaxial
What are the two articular surfaces that make up the tibifemoral joint?
- Femoral condyles
- Tibial plateau
What are the main movements of the tibiofemoral joint?
- Flexion-extension in a sagittal plane around a coronal axis
- Some rotation (IR and ER) around vertical axis
What allows for the rotation around a vertical axis of the tibiofemoral joint?
- Longer articular surface on medial femoral condyle (from A to P)
- Screw-home mechanism
What is the screw home mechanism’s function?
Allows for extra stability as it locks the knee into extension
What is the screw-home mechanism?
The discrepancy between the length of surfaces of condyles
How does the screw-home mechanism work in extension?
EXTENSION + MEDIAL ROTATION
Due to the longer medial condyle from anterior to posterior, when knee is extended, there is medial rotation of the femur on a fixed tibia (eg. sit –> stand)
So most stable as locked in extension
How does the screw-home mechanism unscrew in flexion?
Need to unlock to get into flexion
Popliteus will pull lateral condyles –> laterally rotate femur –> unlocks knee –> femur and tibia in sagittal plane –> flex
O: latera femoral epicondyle
I: tibia
What is the normal frontal plane alignment of the knee?
5 degrees anatomical genu valgus
What does genu valgus mean?
- Medial femoral condyle extends further distally
- Shaft of femur inclined laterally
- Femoral condyles in same transverse alignment
What is the benefit of 5 degrees genu valgus?
Brings feet closer to midline for bipedal gait
What is something that can be determined by the alignment of the femoral condyles in the transverse plane?
Orientation of the flexion/extension axis of the knees
- Relative torsion of distal condyles in relation to proximal condyles
Femur torsion= medially rotated
The distal portion of the femoral condyle is ___ flat. Anterior and posterior portions are ____ flat. Why?
More flat = larger radius of curvature
When in extension (standing), the flat portion articulates with the tibial plateau = more stable
When in fexion, the curve part articulate with the plateau = less stable
What is the medial and lateral tibial slope? What is P-line? What is line A-B?
Angle between the line P and line A-B
Line P: line perpendicular to long axis of tibial diaphysis
Line A-B: line from anterior tibial peak to posterior tibial peak.
What is the function of the meniscus?
- Increase congruency (contact area betwene the femoral condyles and the tibial plateau)
- Decreases stress
- Protects articular cartilage
What shape is the tibiofemoral meniscus?
- Semi-lunar shaped (superior view)
- Wedge-shaped (anterior view)
What was the difference between the medial and lateral menisci?
- Thinner longer medially and less mobile = less able to move out of way = covers more tibia plateau = has more tibia plateau to cover (cause longer)
- Thicker laterally (to fill condyle space) and more mobile
What is meniscus made of? Why?
Fibrocartilage
- Able to withstand shear force
- Protects underlying hyaline cartilage (which withstand compression but not shearing)
What are the 5 ligaments of the tibiofemoral joint?
- Tibia collateral (capsular)
- Fibular collateral (extracapsular)
- Anterolateral
- Anterior cruciate
- Posterior cruciate
What is the function of the tibial collateral ligament (TCL)?
Resist valgus
Superficial (longer and stronger) resist valgus throughout flexion
Deep (shorter) reists anterior translation of tibia too
What is the function of the fibular collateral ligament? (FCL)
Resists varus
What is the function of the anerolateral ligament (ALL)?
- Resists tibia IR in 30 degrees flexion
- Anterolateral stability
Where does the fibular collateral ligament (FCL) attach?
Femoral lateral epicondyle –> head of fibula
Where does the anterolateral ligament (ALL) attach?
Lateral femur –> anterolateral tubercle (Gerdy’s tubercle)
When does the anterolateral ligament (ALL) tighten?
In flexion and internal rotation of tibia
Where does the anterior cruciate ligament (ACL) attach?
Attach to anterior tibia
What are the 2 bands of the ACL?
- Posterolateral band (PLB)- largest, tighest in extension
2. Anteromedial band (AMB)- tightens in flexion
What does the Anterior cruciate ligament (ACL) resist?
- Anterior translation of tibia on femur
- Posterior translation of femur on tibia
- Rotation stability
- Valgus
- End of range extension
What does the Anterior cruciate ligament (ACL) allow?
10 degrees internal and external rotation in 30 degrees flexion
What are some injuries of the ACL?
- Often non contact
- Large valgus moment and tibia ER
- Adolescence
- pivoting sports
- females 3-5 x
The slope of the tibial plateau has a direct relationship with anterior tibial translation during the transition from non-weightbearing to weightbearing conditions. Why?
Increase tibial slope = increase shear force
ACL prevents tibia from translating anteriorly and femur from translating posteriorly.
What does the posterior cruciate ligament (PCL) resist?
- Posterior translation of tibia on femur
What are some common injuries of the PCL?
- Dashboard (eg. car injury- knee hits dashboard)
- Hyperflexion or hyperextension
What is a PCL sag test?
PCL deficiency = posterior shift of tibia on femur at 90 degrees flexion
What is the patellofemoral joint? Articulations?
Patella –> patella surface of the distal femur
In extension, is there contact between the patella and femur?
Little contact
In flexion, is there contact between the patella and femur?
Femur moves underneath patella –> Patella and patellar surface come in contact (intercondylar area)
Which way does the patella usually dislocate? Why?
Laterally due to the pull of the quadriceps (moves proximally and increases contact)
More flat = more dislocations
Translations of the patella in 0-30 degrees flexion
Glides medially
Translations of the patella in 30-90 degrees flexion
Glides laterally
Rotations of the patella in knee flexion
Tilts laterally
How is the line of action and moment arm of the quadriceps group changed with the presence of a patella?
Patella = more strength in quads
It deflects the quads = increased moment arm = more effective = more strength
What are 10 structures found in anterior thigh compartment
- Sartorius
- Quadriceps femoris
- Rectus femoris (RF)
- Vastus lateralis (VL)
- Vastus intermedius (VI)
- Vastus medialis longus (VML)
- Vastus medialis obliquus (VMO)
- Quadriceps tendon
- Patella tendon
- Tibial tuberosity
All the quads attach inferiorly on the______?
Tibial tuberosity
Rectus femoris has ________ fibres
Bipennate
Vastus intermedius has a _____ line of action.
Vertical
Action of vastus lateralis
Lateral pull
Action of vastus medialis obliquus
Horizontal action
- Only muscle that can offset the lateral pull of the pther quad muscles
- if knee problems exist, work on VMO as an active component to stabilise patella in medial direction
Tibial tuberosity IS OR ISN’T quite vulnerable to 2nd ossification (before being ossified)
IS
What are 4 structures found in the posterior thigh compartment?
- Semimebranosus
- Semitendionsus
- Biceps femoris long head
- Biceps femoris short head
Action of biceps femoris long head
Hip extension
Knee flexion
Tibial ER
Action of bicpes femoris short head
Knee flexion
Tibial ER
Action of semimebranosus and semitendinosus
Hip extension
Knee flexion
Tibial IR
What are 2 structures of the posterior leg?
- Gastrocnemius
2. Plantaris
Action of gastrocnemius. Insertion?
Crosses knee joint = knee flexion
Inserts on femoral condyles
Function of popliteus
Screw home mechanism is medial rotation of femur on tibia.
Popliteus will laterally rotate femur on tibia to unlcok the extended knee.
Where does popliteus attach?
Medial tibia –> Lateral femoral condyle
Which structures are found in the medial thigh knee? What 3 muscles does it consist of?
Pes anserinus:
- Sartorius
- Gracilis
- Semitendinosus
What are 4 structures that are found in the lateral thigh and knee?
- Tensor fascia latae
- Iliotibial band
- Biceps femoris long head
- Biceps femoris short head
What is the Iliotibial band (ITB)?
Thickening of TFL (ligament/tendon)
What is tensor fascia latae (TFL)?
Small muscle which attaches inferiorly to the long thick strip of fascia, known as the iliotibial band (ITB).
Where does the ITB attachment inferiorly?
Gerdy’s tubercle
What is the function of the ITB?
Resists varus forces
In standing, the anterior tibia is under tension or compression?
Tension
In standing, the posterior tibia is under tension or compression? Why?
Compression.
- The posterior muscle bulk is greater
What is a tibial stress fracture? How does it occur?
Repeated loading with insufficient time for recovery
Where do 90% of tibial stress fractures occur? Why?
Posteriomedial
- The junction between the proximal 2/3 and the distal 1/3
- It is the narrowest part of bone
Where is another common area for a tibia stress fracture other than posteromedial tibia? Better or worse?
Anterior cortex
Worse and can have serious consequences
- poor blood supply.
- bone responds to compression force to stimulate bone to produce bone cells
so when bone breaks = less compression stimulus = less ability to heal
What is the degree of external tibial torsion?
20-40 degrees
What is external tibial torsion?
The distal parts are laterally rotated with respect to condyles
How many tarsals, metatarsals, phalanges?
7 tarsals
5 metatarsals
5 phalanges
Explain a heel strike?
When walking,
Land on lateral heel but weight is medially –> Foot pronates –> weight goes to 1st/2n MTP and hallux
What 2 bones make up the hindfoot?
- Calcaneus
2. Talus
What bones make up the midfoot?
All tarsal bones except calcaneus and talus
What bones make up the forefoot?
Metatarsals and tarsals
What bones make up the 1st ray?
1st MT and medial cuneiform
What bones make up the 2nd ray?
2nd MT and intermediate cuneiform
What bones make up the 3rd ray?
3rd MT and lateral cuneiform
What bone make up the 4th ray?
4th MT
What bone makes up the 5th ray?
5th MT
Why is a navicular stress fracture not ideal?
Central zone of hypovascularity
How does a navicular stress fracture occur?
Medial and lateral compressive forces though 1st and 2nd ray (both sides of the navicular)
What are the 3 functions of the arches of the foot?
- Shock absorption (weight bearing)
- Energy return wen locomotion (spring back)
- Protection for neurovascular structure and intrinsic foot muscles (4 layers)- won’t be compressed
What bones does the medial longitudinal arch consist of?
- Talus
- Calcaneus
- Navicular
- Medial cuneiform
- 1st MT
Which bones does the lateral longitudinal arch consist of?
- Calcaneus
- Cuboid
- 5th MT
What bones does the transverse arch consist of?
From medial to lateral
- Head of talus
- Cuneiforms
- Cuboid
Which longitudinal arch is longer? Medial or lateral?
Medial
What are 4 passive structures that support the arches of the foot?
- Plantar aponeurosis (Medial calcaneal tuberosity to metatarsal phalangeal joints, thickening of the fascia)
- Long plantar ligament
- Short plantar ligament
- Spring ligament (support the head of talus)
How is calcaneus specialised for weight bearing?
- Thin cortical shell around sparse trabecular bone
- Trabecular bone –> shock absorption. Bone marrow and blood –> Hydrodynamic shock absorber
- Calcaneal fat pad returns 70% energy into locomotion
What are 3 extrinsic active structures that support the arches of the foot? Attachments?
- Tibialis anterior (coming down over the medial aspect will attach to medial cuneiform and base of first metatarsal. On medial inferior aspect)
- Tibialis posterior (coming down under the foot, most of the insertion on navicular and medial cuneiform so many connections widely spread)
- Fibularis longus
(comes down on the lateral malleolus, under the cuboid and crosses the sole of the foot on plantar aspect and insert onto the same bones as tibialis anterior)
What is 1 intrinsic active strcuture that supports the arches of the foot?
Abductor hallucis longus
How many bones articulate with the tibia distally?
2 bones
- Fibula
- Talus
What ligament resists the talus when it is forced down medially?
Spring ligament
What is the plantar fascia?
1Plantar fascia is a very specialised structure. Very tough structure, twice the tensile strength of other plantar ligaments very rich in proprioception.
Arises: Medial calcaneal tuberosity
Inserts: Onto capsules of all MTP joints
What tenses the plantar fascia?
When you go into MTP extension and when gastrocnemius and soleus pull superiorly on calcaneus, plantar flexing it.
Plantar fascia functions to hold the foot rigid for push off
What is the ankle joint also known as?
Talocrural joint
What articulates in the talocrural joint?
Talus + tibia/fibula
1 tarsal bone articulates with 2 bones of leg
What kind of joint is the talocrural joint? What movement does it produce?
Synovial hinge joint
Dorsiflexion and plantarflexion
Pronation of the foot is a combination of____?
Dorsiflexion
Eversion
Abduction
“flat feet”
The tarsal bones are more mobile = good = usually unsure surface
Supination of the foot is a combination of ___?
Plantarflexion
Inversion
Adduction
What plane is DF/PF in?
Sagittal plane
What plane is adduction/abduction of the foot in?
Transverse plane
What plane is inversion/eversion of the foot in?
Coronal plane
Tarsal bones are more mobile in supination or pronation? Why?
Pronation.
Used on unsteady surface
Explain the movements of the foot in gait (Landing –> pushing off)
Land on posterolateral heel –> pronate foot to transfer weight to the anterior/medial side for shock absorption (adaptation of –> midstance –> supination –> ridged –> push off
Is the distal tibiofibular joint a synovial joint or not?
No- is a syndesmosis
Is the distal radioulnar joint a synovial joint or not?
Yes- synovial gliding joint
Distal tibiofibular joint is supported by what ligaments? Why is the stability of this joint so important?
- Anterior tibiofibular ligament
- Posterior tibiofibular ligament
- Interosseous membrane
Forms the superior part of the talocrual joint (dome of the talus + tibia and fibula)
The dome of the talus is widest anteriorly. What could that mean?
So when you are in planter flexion –> narrowest part articulating with tibia and fibula
When you are is dorsiflexion –> widest part articulating with tibia and fibula
Therefore, dorsiflexion –> closed pack.
What type of movement is pronation and supination of the foot?
Triplanar
What is the subtalar joint?
Talus and calcaneus
Separates vertical leg & talus with rest of the foot at 90 degrees = links movement
How many articulations are there in the subtalar joint? What/where are they?
3 articulations
- Anterior
- Middle
- Posterior
What movements does the subtalar joint allow?
Supination and pronation
What is function of the subtalar joint?
Translates movements from foot to the leg (vice versa)
When a foot pronates, does it IR or ER the tibia?
Tibial IR
When a foot supinates, does it IR or ER the tibia?
Tibial ER
When a foot supinates, does it IR or ER the tibia?
Tibial ER
What is the transverse tarsal?
Talonavicular + calcaneocuboid
The joint between the rearfoot and the midfoot
What are some joints of the foot? Starting from intertarsal –> DIP.
Intertarsal TMT MTP PIP DIP
The joint capsule is continuous with the ______ and _____ subtalar joint capsule.
Anterior & middle
Talocalanonavicular joints surrounded by ____ large capsule
1
Name 16 ligaments in the foot
- Anterior talofibular (ATFL)
- Calcaneofibular (CFL)
- Posterior talofibular (PTFL)
- Talocalcaneal interosseous
- Dorsal calcaneonavicular (Bifurcate)
- Dorsal calcaneocuboid (Bifurcate)
- Cervical
- Deltoid
- Posterior tibiofibular
- Spring
- Anterior tibiotalar
- Posterior tibiotalar
- Tibiocalcaneal
- Tibionavicular
- Short plantar
- Long plantar
What is a closed-pack position?
Both articular surfaces are at maximal congruency = max. stability and energy transfer
When are the tarsal joints in a closed-packed position?
Full supination (inversion)
When are the metatarsaophalangeal joints in a closed-packed position?
Extension
When are the interphalangeal joints in a closed-packed position?
Extension
What muscle groups are found in the anterior compartment (foot/leg)?
Dorsiflexors
Invertors
What muscle groups are found in the posterior compartment (foot/leg)?
Plantar flexors
Evertors
What muscle group is found in the lateral compartment (foot/leg)?
Evertors
What nerve innervates the anterior compartment (foot/leg)?
Deep fibular nerve L4,L5, S1
What nerve innervates the posterior compartment (foot/leg)?
Tibial nerve L4,L5,S1,S2
What nerve innervates the lateral compartment (foot/leg)?
Superficial fibular nerve L4,L5,S1
Action of tibialis anterior
Strong dorsiflexor (forward of axis- agonist) Inversion (midfoot)
Action of tibialis posterior
Inversion (large moment arm- agonist) Weak plantarflexor (posterior to axis)
Action of fibularis tertius
Plantarflexion
Eversion
Action of fibularis longus/brevis
Strong evertor (agonist) Plantarflexion (small contribution)
Which 2 muscles are in Triceps Surae? Action?
- Gastrocnemius (2 heads)
- Soleus
Strong plantarflexor (agonist) Some inversion (line of action is slightly to midline)
Attachments of fibularis longus
Crosses plantar aspect of the foot to insert onto the medial cuneiform and base of 1st MT
- Stabilises lateral longitudinal arch
- Stabilises 1st ray durin 1st toe extension and push off
What is one pathway into the foot? Where?
Tarsal tunnel
Area behind medial malleolus
Which two tendons cross (foot/leg)?
Flexor digitorum longus & tibialis posterior
Eg. when palpating the posteromedial area of the tibia, usually palpate the origin of FDL not tib. posterior
Usually tib. posterior = deep = some discomfort
What are 4 intrinsic muscles of the foot?
- Extensor hallucis brevis
- Extensor digitorum brevis
- 3 PAD
- 4 DAB
How many layers of intrinsic muscles are there in the foot?
4 layers
How many vertebrae do we have?
24
How many vertebral discs do we have?
23
Because don’t have one between C1 and C2. They are between vertebral bodies and C1 has no vertebral body
What are the 3 functions of the vertebral column?
- Protection (Spinal cords, nerves, vertebral artery, protection of viscera by attaching the ribs, forming part of the pelvis by sacrum fusing: Protection of pelvic organs)
- Weightbearing
- Mobility
Lordosis = mobility or stability?
Mobility
Kyphosis = mobility or stability?
Stability
The ______ vertebrae moves on the ______ vertebrae.
Superior
Inferior
The vertebral column motion segment includes:
- 2 vertebrae
- 1 intervertebral disc
- 3 joints (interbody joint and 2 z-joints)
- ligaments
- muscles
- nerves
What are the gross movements of the vertebral body?
- Flexion
- Extension
- Lateral flexion
- Axial rotation ** (Do not write lateral rotation!!!)
What are 3 translations of the vertebral column?
- Left /right
- Superior/inferior
- Anterior/posterior
What are the 3 rotations of the vertebral column?
- Lateral flexion (tilt of vertebrae)
- Axial rotation
- Flexion/extension
What is a ring apophysis?
Apophysis –> Secondary ossification centre: site where annulus fibrosis attaches.
What is a vertebral end plate?
Hyaline cartilage that fills in the ring apophysis
Vertebral end plate is more firmly attached to intervertebral disc than the vertebral body. So, if pulled, end plate will remain with the disc.
Name 5 characteristics of a cervical vertebrae
- Large vertebral foramen
- Transverse foramen present
- Bifid spinous process
- Anterior and posterior tubercle on the transverse foramen (NEW)
- Articular facet 45 degrees to transverse plane
Name 4 characteristics of a thoracic vertebrae
- Articular demifacets on body articulate with ribs
- Long, downward spinous process
- Relatively small and round vertebral foramen
- Articular facet almost in coronal plane
Name 5 characteristics of a lumbar vertebrae
- Large vertebral body
- Small triangular vertebral foramen
- Mammillary process
- Accessory process
- Articular facet almost in sagittal plane
What degree is the cervical articular facet at?
45 degrees
What degree is the thoracic articular facet at?
60 degrees
What degree is the lumbar articular facet at?
90 degrees
What is the main function of the vertebral body? How does the structure support this function?
Weight bearing and withstanding compression
- Vertical and horizontal trabeculae + bone marrow and blood (hydrodynamic shock absorber)
- Vertical struts are the thickest and you have smaller horizontal struts that support them.
While it can withstand compressive forces, which 2 forces can the vertebral body not resist?
- Translational forces
2. Rotational forces
Describe the fibre direction of annulus fibrosis (4 characteristics)
- 10-20 concentric layers
- All fibres in 1 layer = same orientation and
- Each layer is opposite to adjacent layers
- 65 degrees angel to the vertical
What type of collagen is the annular fibrosis? Why
Collagen type I
It is good at withstanding tension
Where does the annular fibrosis attach?
Annulus fibrosis attaches to ring apophysis for secure attachment.
What is annulus fibrosis in the lumbar region like? What would this predispose you to?
Round anteriorly but indented posteriorly and may have some incomplete layers in posterolateral corners
Hence an area of weakness.
What is the consistency of nucleus pulposus? What is this due to?
Gel like, 90% water incompressible. Dissolved proteoglycans and collagen makes it viscous and slows down the movement.
Nucleus pulposus is enclosed by ______ and ________.
Annulus fibrosis and vertebral end plate.
What is the role of intervertebral disc in weight bearing? Describe the force transmission in 4 steps
- Nucleus pulpous cannot be compressed (decreased vertical height = NP will expand radially= pressure on annular fibres)
- Annular fibres will resist the tension = exert the pressure back onto Nucleus Pulposus = resist bulge
- Nucleus Pulposus and annular fibres share the forces = pressure onto vertebral endplates
- Transmit force to the inferior vertebrae
What is the function of intervertebral disk in movement?
- Allows compression forces to go through
- Provides more room for the superior vertebrae to tilt (Permits rocking of the superior vertebra)
The intervertebral disc can ______ and _______ the movement as well.
Provide
Limit
Are the articular surfaces of intervertebral bodies curved or flat? Why? Why is there an intervertebral disc.
Flat
This is because it permits rocking of the superior vertebrae = stability and mobility
- With the disc, there is more room for tilt before impact of the bones - mobility
- Without disc, the flat surfaces are stable under compressive forces but limit the rolling/tilting movement
They are NOT CURVED
While it could facilitate rolling, it would also increase instability under compressive loads
Greater the height of intervertebral disc (as compared to the vertebral body), the _______ movement you will get.
More
Describe the forces on each side of the vertebrae in lateral flexion. What %?
Compression and tension
(50% each)
Only so much compression before resist
Only so much tension before resist
Left axial rotation is when the superior moves ______ in relation to the inferior.
Left
The nucleus pulposus is made of _____ cartilage
Fibrocartilage
Explain the action of flexion (vertebral column)
Compresses anterior AF –> NP moves posteriorly –> tensions posterior AF –> tensions z joints –> tensions posterior ligaments –> tensions posterior muscles
Explain the action of extension (vertebral column)
Compresses posterior AF–> NP moves anteriorly –> tensions anterior AF –> tensions z joints –> tensions anterior ligaments –> tensions anterior muscles
Explain the action or axial rotation (vertebral column)
When rotate, will tension 50% fibres and 50% (opposite direction) will go slack
Same with translation
In cervical vertebrae, annulus fibrosis is divided in an “A” direction posteriorly. This is called “B” and it develops at “C” years of age. So, the superior part of the annulus fibrosis can move against the inferior part of annulus fibrosis, facilitating movement, particularly axial rotation, posteriorly. Thick D fibrosis acts as a pivot for rotation. Therefore, these structures together facilitate great range of movement that is available at the cervical spine.
A- transverse
B- posterolateral uncovertebral cleft
C- 9 years of age
D- anterior annular
What makes up a zygapophyseal joint? Are they the same for all vertebral regions? What characteristics will affect its resistance on forward sliding and/or rotation of the upper vertebrae
Superior articular process of the vertebral below hooks onto inferior articular process of the vertebrae above.
Alignment of the zygapophyseal joint is different in different regions, affecting stability and mobility.
Depend on:
- Orientation of articular facets
- Height of the superior articular process
3 characteristics of the cervical z-joints
- Aligned in coronal plane, 45 deg
- Almost coronal orientation
- Superior articular process not very tall = doesn’t block the inferior vertebrae.
What movements does the cervical z-joints allow?
All movements
MOST MOBILE
What movements does the thoracic z-joints allow?
If you have superior articular processes aligned tall and vertically in the coronal plane (Straight down the ears), anterior translation will be difficult = Superior articular process of the vertebrae below will run into the inferior articular process of the vertebrae above.
Blocks flexion/extension but allows rotation and lateral flexion
3 characteristics of the thoracic z-joints
- Almost coronal orientation
- ‘Tall” superior articular processes
- 60-80 deg. to transverse (more vertical than Cx)
2 characteristics of the lumbar z-joints
- Sagittal plane orientation
2. Vertical
What movement does the lumbar z-joints allow?
Flexion-extension
Blocks axial rotation and lateral flexion
What do you need to consider when explaining structural reason for the degree of movement available at a vertebral column?
- Orientation and alignment of zygapophyseal joints
- Intervertebral discs
- Height of the superior articular process
- Ribs
Majority of the force should go through ______ elements but you’ll get some weight bearing through the posterior elements ESPECIALLY IN _______! Some weight bearing through posterior elements in extension.
Anterior
Extension
What is pars interarticularis?
“Part between the two articular processes”
Neck of the dog
What is a common mechanism of injury of the pars interarticularis? What is this called?
Repetitive extension in weight bearing
Collar stress fracture
A pars interarticularis fracture/ collar fracture is most common in?
- Gymnastics
- Divers
- Ballet dancers
- Cricket fast bowlers
Why is it important to have strong pedicles? How do you know pedicles are strong?
So that muscles can move the vertebral body (which are attached)…
Pedicles transmit bending and sharing forces from the muscles through to the vertebral body..
Fan shaped trabeculae spans between the vertebral body and the posterior elements to help transmit the force
So that you don’t get break down…
You know your pedicles are strong becauseAs a result of the compression and the pull, you will get increased density of compact bone near the base of the pedicles.
When vertebral column flexes anything posterior to the COR, it will tighten. If we go into extension, anterior longitudinal ligament will tighten. What ligament limits flexion the most and why?
Supraspinous ligament because it is the furthest from axis, vertical.
Joins tips of spinous processes
What does ligamentum flavum do?
Majority are elastin fibres –> not so much about resisting the movement. Its more aligning in the posterior part of the vertebral canal and it blends with the anterior part of the zygapophyseal joint capsule. When you move it deforms and does not buckle up and take up space.
Interspinous –> the multidirectional arrangement of fibres
Ligamentum flavum –> paired, thick, segmental, elastic ligaments
What does the ligamentum flavum form?
- Posterior wall of the vertebral canal
- Anterior capsule of z-joints
Joins adjacent lamina
Name 5 ligaments found in the vertebral column
- Supraspinous Ligament
- Interspinous ligament
- Ligamentum flavum
- Posterior longitudinal ligament
- Anterior longitudinal ligament
Interspinous ligament has oblique direction of fibres. What is the significance of that?
Fibres go anteriorly and inferiorly
This is important during flexion:
- combines anterior rotation with anterior translation, keeping the zygapophyseal joints in contact.
- It also resists posterior shear of the superior vertebrae
Cervical spine can be divided into two components. What is that?
Upper cervical spine
Lower cervical spine
Name 7 characteristics of C1- ATLAS
- Shaped like a ring
- Does not have a vertebral body –> therefore no intervertebral disc between c1 and c2.
- Anterior and posterior arches
- Two lateral masses weight transfer - 2 large kidney shaped concave superior articular facets (articular facet on superior and inferior surface of the lateral mass) –> Cradle occiput
- Large transverse process –> muscle attachment and leverage
- Large vertebral foramen –> protect vertebral artery.
- Deep sockets (concave superior zygapophyseal facets and the convex occipital condyle) makes rotation and lateral flexion minimal
Name 4 characteristics of C2 (AXIS) and state the functions.
- DOES have a vertebral body.
- Superiorly from the vertebral body is the dens occiput and C1 stay together and rotate around the dens.
- Zygapophyseal joints and vertebral body weight transfer Combined load of head and C1
- Odontoid process provides axis for axial rotation for head and C1 on C2.
Describe the joint C0/1. The _____ occipital condyles articulate with _____ articular facet of C1 located on top of lateral mass. This is where you get the _____ motion.
convex
concave
nodding (yes)
*minimal rotation and lateral flexion due to deep sockets
What is the convex-concave rule? (C0/1)
Roll of the condyles
Glide occur in opposite direction
Eg. When you are flexing, your occipital condyles are moving forward but will glide posterilrly. Will keep the convex surface of occipital condyle in the centre of concave surface of C1.
What are the 3 joints at C1, C2?
- Median atlanto-axial joint
2. 2 x Lateral atlanto-axis joint
The lateral atlanto-axial joints is composed of________ and ______.
- Convex inferior articular facets of C1
- Conves superior articular facts of C2.
*plane joint
The median atlanto-axial joint is composed of _____ and ________.
- Odondoid process
- Osseoligamentous ring
What does osseoligamentous ring composed of?
- Anterior arch of C1
- Transverse ligament of atlas.
C1/2 joint contributes to ______% of cervical rotation
50%
What does the transverse ligament resist and what structure does it protect? What is the fibre that makes up this ligament? Where does it arise from?
Fibre –> predominantly collagen fibres (strong ligament, no elastic fibres)
Resist anterior translation of C1 on C2.
Protects the cervical spinal cord (prevents the posterior arch from going over the vertebral canal)
Arise from inner surface of each lateral mass
Alar ligaments. What is the direction of travel? Where does it arise? Where does it attach to? What movement does it resist? What does it NOT have in terms of fibres?
Direction of travel: Posterior and superior
Arises from posterior odontoid process
Attaches to margins of foramen magnum
Resists:
- occiput and C1 moving anteriorly.
- Lateral flexion
- Axial rotation (since it arises posteriorly from the dens, when you rotate, it will WIND around the dens, limiting rotation)
- Flexion
- Main limit for axial rotation of the head & C1 on C2
No elastic fibres
Which ligament limits axial rotation of head (C1/C2) the most?
Alar ligament
What is the possible consequence of strong rotation of head and C1 on C2?
You can stretch and tear contralateral vertebral artery.
State 2 functions of lower cervical spine.
- Transmit load
2. Mobility and stability
Explain the pathway of the vertebral artery.
Arise from the subclavian artery –> enters C6 transverse foramen (misses C7) –> ascends to C2 –> exits C2 foramen -> C1 foramen (wide- sharp turn) –> runs along the groove above C1 –> foramen magnum –> meet vertebral from other side
What are the movements available at lower cervical spine? What morphology is responsible for this?
- Flexion- Extension
- Rotation and lateral flexion (coupled and ipsilateral)
MORPHOLOGY:
- Interbody joint
- Zygapophyseal joint
What are uncinate processes?
Bony prominences, projecting edges on the posterolateral margins of the superior end plates of C3-C7.
What do uncinate processes allow and limit?
Allows flexion/extension
Limit transverse or sliding motion of superior vertebrae LATERAL FLEXION AND AXIAL ROTATION, TRANSVERSE GLIDING (guide rails)
What does uncinate processes protect?
Vertebral artery and Spinal nerve.
Start –> vertebral artery takes up most of the vertebral foramen and then the spinal nerve will be exiting just posterior…
Protects from distorted disc material.
Where do you not have annulus fibrosis?
Where uncinate processes are present
What is the characteristics of the intervertebral disc in the cervical region?
- Thick annulus fibrosis
- Fibrocartilaginous disc (consistency of soap)
- Posteriorly, annulus fibrosis is thin, narrow bands of vertical fibres
*Cervical intervertebral disc is innervated by both somatic and autonomic nervous system potential area of pain.
__________ joints are the MAIN reason why axial rotation and lateral flexion is coupled. (cannot isolate and do just one movement), explain why?
*Coupled movement= primary movement in one plane accompanied by an automatic movement in another plane.
Zygapophyseal joints
For axial rotation you will need: Transverse plane and vertical axis.
For lateral flexion you will need: frontal plane and sagittal axis
But axis of lower cervical rotation is: 45 degrees to the transverse plane.
Ipsilateral “coupled” rotation/lateral flexion
Do uncinate processes allow or limit movement?
Limit (bony block)
Do uncovertebral clefts allow or limit movement?
Allow
Name 4 ligaments (with subparts specified) found in the cervical spine?
- Anterior longitudinal ligament (ALL)
- Posterior longitudinal ligament (PLL)
- Ligamentum flavum
- Ligamentum nuchae (replaces supraspinous ligament)- dorsal raphne & midline septum)
Do uncovertebral clefts allow or limit movement?
Allow
What are the 2 parts of the ligamentum nuchae? What are they?
Dorsal raphne
(occipital protuberance –> C6/7 spinous processes)
- interlacing tendons of: trapezius, splenius capitis, rhomboid minor
Midline septum (fascia from ventral aspect of dorsal raphne --> cervical spinous processes & occiput)
In the cervical region, what is the supraspinous ligament replaced with?
Ligamentum nuchae
What are 4 characteristics of small, deep muscles?
- Fine tuning
- Rich in muscle spindles
- Proprioceptive role
- Segmental control
What are 3 characteristics of large, superficial muscles?
- Greater PCSA
- Greater moment arm
- Prime movers
Attachments of upper trapzius
O: occiput
I: lateral 3rd of clavicle
Unilateral and bilateral action of levator scapulae
Unilateral:
Ipsilateral lateral flexion
Ipsilateral axial rotation
(scapular fixed)
Bilateral:
Cervical extension
Attachments of levator scapulae
O: C1-4 transverse processes
I: Superior medial border/angle of scapula
Unilateral and bilateral of sternocleidomastoid
Unilateral:
Ipsilateral lateral flexion
Contralateral axial rotation
Bilateral:
Upper cervical extension
Lower cervical flexion
What are the prime movers for right head rotation? (be specific)
Left SCM
Right splenius
Where is the centre of gravity of your head in relation to occipital condyles?
Centre of gravity is anterior
Need to keep head up (all day)
Name all the 4 muscles in the anterior cervical compartment
- Rectus capitis anterior
- Rectus capitis lateralis
- Longus capitis
- Longus cervicis (colli)
Name all the 3 muscles in lateral cervical compartment
- Anterior scalene
- Middle scalene
- Posterior scalene
What innervates the anterior and middle cervical muscles?
Ventral rami cervical nerves
Action of longus capitis VS longus cervicis
Capitis
Flex head and upper cervical spine
Cervicis
Cervical flexion
What are the 5 major groups of intrinsic muscles in the posterior compartment of the back?
- Suboccipital
- Segmental
- Transversospinales
- Erector spinae
- Spinotransverse
What are 4 intrinsic muscles in the suboccipital group?
- Rectus capitis posterior major
- Rectus capitis posterior minor
- Obliquus capitis superior
- Obliquus capitis inferior
What are 2 intrinsic muscles in the segmental group?
- Interspinales
2. Intertransversales (medial not lateral)
What are the 3 intrinsic muscles in the transversospinales group?
- Rotatores
- Multifidus
- Semispinalis
What is the 1 intrinsic muscles in the spinotransverse group?
- Splenius
What is the innervation of the suboccipital group?
Suboccipital nerve (dorsal ramus of C1)
Unilateral and bilateral of the suboccipital group?
Unilateral:
Ipsilateral axial rotation/lateral flexion
Bilateral:
Head/C1 extension on C2
Attachments of rectus capitis posterior minor
C1 –> occiput
Attachments of rectus capitis posterior major
C2 spinous process –> occiput
Attachments of obliquus capitis superior
C1 transverse process –> occiput
Attachments of obliquus capitis inferior
C2 spinous process –> C1 transverse process
Longus cervicis has _____ parts
3 parts (upper, middle, lower)
Where do middle and posterior scalenes attach?
C2-6 cervical processes –> first rib (anterior: anterior first rib, middle: lateral: first rib and posterior: posterolateral second rib)
What is the purpose of scalenes?
Stabilise cervical spine
Stabilise the contralateral cervical spine when carrying heavy weight
What are the posterior back muscles innervated by?
Dorsal rami
Why is it a problem if there is tightening..etc on the anterior and middle scalenes? What are they? (2)
Brachial plexus and subclavian artery travel between anterior and middle scalenes.
So any tightness..etc will affect these structures (crush them)
Which subocciptal muscle will be the main one to do rotation? Why?
Obliqus capitis inferior- due to its alignment.
2 characteristics of segmental muscles
- Small PCSA
- Small moment arm
= small force production
2 characteristics of rotatores
(brevis/longus)
- Most developed in throacic region
- Very small PCSA
2 characteristics of multifidus
- Most developed in lumbar spine
- Most oblique alignment in thoracic region = Better line of action for segmental rotation and lateral flexion tham in lumbar region
2 characteristics of semispinalis
- Most developed in cervical and capitis regions = main cervical extensors
- Semispinalis thoracics spinous attachments C4-T4
Which is deeper? Semispinalis capitis or cervicis? Why?
****help check
column 2 p.15
Semispinalis cervicis is deep to semispinalis capitis.
Because…inferior attachment is transverse process and superior attachment is spinous process
Attachments of spinalis
Superior and inferior attachments on spinous processes
Name 4 erector spinae muscles of the cervical region
- Iliocostalis cervicis
- Longissimus cervicis
- Spinalis cervicis
- Spinalis capitis
3 & 4 blends with semispinalis cervicis and capitis
Unilateral and bilateral action of splenius capitis and cervicis (spinotransverse group)
Unilateral:
Ipsilateral axial rotation/lateral flexion
Bilateral:
Head and neck extension
What curve is in the thoracic region? Kyphosis or lordosis?
Kyphosis
What is 1 reason why there is a kyphosis curve in the thoracic region?
- Wedge-shaped vertebral body = Anterior height is less than posterior height (vertebral body)
What are 4 reasons why there is less mobility and movement in the thoracic region?
- 12 pairs of ribs = less mobility
- Lowest IVD to body height ration = less tilt of superior vertebrae = less mobility
- Superior articular process are tall and vertical (coronal) = more block for anterior translation = less mobility (FLEXION)
- Long, downward spinous processes and inferior articular processes impact on lamina/superior articular processes below = less mobility (EXTENSION)
Explain the coupled movement in upper thoracic spine
When you laterally flex, you ipsilaterally rotate as well.
Due to the 45 degree to the transverse plane alignment of the articular processes (at cervical spine).
When the inferior articular process of the superior vertebrae slides inferiorly it also moves
posteriorly (like mid & lower Csp)
Articular process in the lumbar region align in the _________ plane.
Sagittal
Why are there more processes in the lumbar vertebrae? Name the 2 processes.
For muscle attachments (smaller, deeper lumbar muscles)
- Mammillary process
- Accessory process
Where is the mammillary process located on the lumbar vertebrae?
On superior articular process
Where is the accessory processes located on the lumbar vertebrae?
On dorsal, medial aspect of the transverse process
What are 3 characteristics of L1-4 vertebrae?
- Flat superior and inferior ends of vertebral bodies (not wedge-shaped)
- Almost sagittal orientation of z-joints
- Anteriorly curved
What is the main characteristic of L5 vertebrae?
Wedge-shaped (taller anteriorly)
Generally we say that the superior articular process of the lumber region has a ________ alignment. Anterior part of the articular process is curved to limit _______ transition. But when you start to come down to L4, 5 the majority of superior articular process is in the ________ plane. This makes sense to prevent ______________.
Sagittal
Anterior
Coronal
Forward slipping of L5 on S1 (therefore sacrum is anteriorly tilted)
What are 5 causes for lumbar lordosis?
- Sacrum is tilted anteriorly
- L5/S1 IVD is wedge-shaped (taller anteriorly)
- L5 vertebra similarly wedge-shaped
- superior vertebrae incline slightly backwards
- L1 aligned vertically over S1
How is a vertebral region lordosis? Is it naturally evident or does it have to be developed?
Requires active maintenance by muscles.
(Muscles pulling on posterior (eg. spinous processes) –> tilting superior vertebrae backwards (eg. lumbar multifidus)
Eg. if a child does not learn to be upright, it will not develop
What is the 2 function of iliolumbar ligament?
- Resists L5 slipping anteriorly off sacrum (maintain stability)
- Resists all direction of movement of L5 on the sacrum
Attachments of the iliolumbar ligament
L5 transverse processes –> ilium
What are 4 ligaments in the lumbar region?
- Anterior longitudinal ligament
- Lumbosacral ligament
- Anterior sacro-illiac ligament
- Iliolumbar ligament
What are 3 causes that limits flexion of the lumbar vertebral column?
- Impact of articular processes = anterior curve
- Tension in:
- Zygapophyseal joint capsules (very strong)
- Supraspinous ligament
- Interspinous ligament
- Ligamentum flavum - Compression of anterior annulus fibrosis (resists further movement)
What are 2 causes that limits extension of the lumbar vertebral column?
- Impaction of spinous processes or inferior articular process with lamina below (when actively extending)
- Tension in the anterior AF
What are 3 causes that limits axial rotation of the lumbar vertebral column?
- Impaction of zygapophyseal joints
- Tension in posterior ligaments (supraspinous and interspinous)
- Tension in annulus fibrosis (oblique/diagonal fibres)
***If the superior vertebrae is rotation to the left, it is the right articular process that will limit the movement. 1
What are 2 (suspected) causes that limit lateral flexion of the lumbar vertebral column?
- Ipsilateral impact in articular process
2. Lengthen anything ** (AF fibres on other side)
What is scoliosis?
Three dimensional torsional deformity of the spine and trunk
What is structural scoliosis?
- Deformity arises from vertebral column itself
- Same regardless of body position
- Idiopathic = don’t know cause
= Have onsets at different times
What is functional scoliosis?
- Extrinsic cause
- Can be caused by leg length difference, can be caused by muscles
- Change of body position makes scoliosis go away
What is a cobb angle?
Angle of scoliosis
It is a scoliosis when > 10 degrees or more
30 deg. can have complications
50 deg. definite complications
_____________ group is superficial to the segmental muscles and from the deepest and shortest _______, to Multifidus (intermediate depth) to Semispinalis (capitis, cervices and thoracis)
Transversospinalis
Rotatores
It is important to note that erector spinae group are ______ muscles whereas transversospinalis which comprises of (______ , ______ and _______) are not as large as the erector spinae group.
large
rotatores, multifidus and semispinalis
Multifidus have 3-5 fascicles innervated by the same dorsal rami that diverge inferiorly and attach to
“A” in cervical spine
“B” in thoracic spine
“C” in lumbar spine as well as “D” and “E” (depending on the region)
A- Superior articular process B- Base of transverse process C- Mamillary process D- Iliac crest E- Sacrum
What does multifidus do? Action (2)
- Vertical line of action and posterior axis laterally
Pull spinous process inferiorly, cause pure extension (maintain lumbar lordosis = compression)
No posterior translation. (not diagonal) - Abdominal muscles produce flexion/LF = multifidus produces extension = F and E cancel = produce LF
How does multifidus assist in rotation?
Abdominal muscles will want to rotate and flex you at the same time. Multifidus remain in extension
What muscles in the erector spinae group have pars thoracis and pars lumborum?
Longissimus thoracis and illiocostalis lumborum
With Longissimus thoracis and Illiocostalis lumborum, there’s pars thoracis and pars lumborum. So how do you know whether you are looking at pars thoracis or pars lumborum?
If you can see erector spinae aponeurosis you are looking at pars thoracis!
What is the attachments of longissimus thoracis pars thoracis?
- Lumbar vertebrae spinous process, PSIS and sacrum –> Thoracic vertebrae transverse process medial ribs
What are the attachments of illicostalis lumborum pars thoracis?
- Illium and sacrum –> Lower 8 rib angles
What is the unilateral and bilateral actions of longissimus thoracis pars thoracis and illiocostalic lumborum pars thoracis?
Unilateral:
Lateral flexion
Bilateral:
Extension
Why are erector spinae muscles be prime extensors of the thoracolumbar spine?
- Superficial
- Large PCSA
- Vertical alignment
What is the special movement of illiocostalis lumborum pars thoracis?
It can DEROTATE You
Superficial, large PCSA, doesn’t even attach to lumbar, vertical extension. Contract unilaterally –> ipsilateral lateral flexion.
Illiocostalis lumborum pars thoracis better
Illiocostalis lumborum pars thoracis can de-rotate you once your rib angles are changed.
How do you see pars lumborum of longissimus thoracis and illiocostalis lumborum?
Remove ESA.
From around the PSIS area, you will have fibres attaching to lumbar transverse process. Not going up to thoracic region.
5 tips to identify longissimus thoracis pars lumborum
- Just lateral to lumbar multifidus
- Prokect superiorly and anteriorly to medial transverse process from PSIS.
- Almost cover eachother in anterior to posterior direction
- 4 fascicles
- Long tendon
4 tips to identify Illiocostalis lumborum pars lumborum
- Medial iliac crest
- Tips of transverse process
- 5 fascicles
- Just lateral to longissimus thoracis pars lumborum
What is the unilateral and bilateral action of longissimus thoracis pars lumborum and Iliocostalis lumborum pars lumborum?
Unilateral: Lateral flexion (vertical, lateral to the axis)
Bilateral:
- Extension (vertical and posterior to axis)
- Component of horizontal line of action (posterior shear)
- Posteriorly translate superior vertebrae or prevent anterior translation of the vertebrae
Direction of force of multifidus
Vertical
- Compressive
- Maintains lordosis
Direction of force of pars lumborum
Diagonal
- Resists anterior shear
Direction of force of pars thoracic
Vertical
- Superficial
- Minimal compression
- Maximum extension
Multifidus, pars lumborum, pars thoracic are all _______
Extensors
When you flex what is happening at your lumbar spine?
Curve is flattening
Vertebral structures are innervated by ______.
Dorsal rami but different branches.
What are the 3 branches of the dorsal rami?
- Medial branch
- Intermediate branch (in lumbar spine)
- Lateral branch
Medial branch of the dorsal rami in the lumbar spine innervates:
- Zygapophyseal joint above and below
- All muscles attach to spinous process and lamina (interspinales, rotatores, multifidus, semispinalis, cutaneous branches in cervical and upper thoracic vertebrae)
Intermediate branch of the dorsal rami in the lumbar spine innervates:
Longissimus
Lateral branch of the dorsal rami in the lumbar spine innervates:
- Erector spinae
- Cutaneous branches in lower thoracic and lumbar vertebrae
What forms the anterior plexus? (anterior to the vertebral bodies). What are some innervated structures?
- Branches from the sympathetic trunks
- Grey rami
- Anterior outer annulus fibrosis
- ALL
- Anterior vertebral periosteum and vertebrae
- Blood vessels
What forms the posterior plexus? What are some innervated structures?
- Branches from sinuvertebral nerve
- Posterior out annulus fibrosis
- PLL
- Anterior and ventral/lateral dura and nerve root sleeves
- Posterior vertebral periosteum and vertebrae
- Blood vessels
Abdominopelvic cavity is enclosed by? Superiorly Inferiorly Posteriorly Anterolaterally Anteriorly
Superiorly: Diaphragm
Inferiorly: Pelvic floor
Posteriorly : Psoas major and Quadratus lumborus
Anterolaterally: External oblique, internal oblique, transversus abdominis
Anteriorly: Rectus abdominis
What are the attachments of diaphragm?
Superiorly —> central tendon
Inferiorly —> L1,2,3, lower 6 costal cartilages and ribs.
What are the three openings of the diaphragm? At what thoracic vertebral level does it correspond?
Inferior vena cava —> T8
Oesophagus —> T10
Descending aorta —> T12
What innervates the diaphragm?
Phrenic nerve, C3,4,5,alive!
What are the 2 muscles of the pelvic floor?
- Levator ani
2. Coccygeus
Psoas major has two bodies posterior and anterior. Where does it arise from?
Posterior body: from transverse processes
Anterior body: from vertebral bodies
***You see lumbar plexus coming out between the bodies!!!
What does psoas major do to the lumbar spine?
Vertical line of action and close to the joint
- Compress
- Flexion (small moment arm)
When it exerts as hip flexor it will compress the lumbar vertebral column.
What are the attachments of quadratus lumborum?
- 12th rib
- Iliac crest
- Transverse processes
***Posteriorly quadratus lumborum is lateral to pars lumborum fibres and ventrally, it is lateral to psoas major
What movements can quadratus lumborum produce?
Flexion/extension of vertebral column (limited: small moment arm) However, active during flexion and extension, meaning it doesn’t do flexion or extension as you can’t do flexion and extension.
Providing STABILITY for vertebral column
Lateral flexion- significant moment arm for lateral flexion good lateral flexor.
What innervates quadratus lumborum?
Thoracolumbar ventral rami
What are the three layers of the abdominal wall?
- External oblique
- Internal oblique
- Transversus abdominis
What are the attachments for external oblique abdominal?
Posterosuperior attachment:
- Posterolateral aspect of the ribs
Inferior attachment:
- Anterolateral iliac crest
- Linea alba via aponeurosis
What is the innervation of external oblique?
T7-12 ventral rami
What is the uniaxial and biaxial movement of external oblique abdominal?
Uniaxial:
Contralateral rotation and ipsilateral lateral flexion
Biaxial:
Trunk flexion, increase intra-abdominal pressure
What are the attachments of internal abdominal oblique?
Posterior:
- Thoracolumbar fascia
Inferior:
- Anterolateral iliac crest
- Inguinal ligament
Superior:
- Inner surfaces of lower 4 ribs and cartilages
Anterior attachment
- Linea alba via aponeurosis
Fibre above ASIS superior line of action
Fibre below ASIS transverse/inferior line of action
What is unilateral and bilateral action of the internal oblique?
Uniaxial:
- Ipsilateral rotation
- Lateral flexion
Biaxial:
- Trunk flexion
- Increase intra-abdominal pressure (not as effective as external onliques)
If you want to have axial rotation of your trunk to your left, which muscles will you contract?
- Right external oblique abdominal
- Left internal oblique abdominal
If you want axial rotation, what muscles will be activated along with abdominal muscles?
Multifidus to keep you in extension.
Abdominal muscles produce flexion with rotation so need to activate lumbar multifidus for extension
What are the attachments of Transversus abdominis?
Posterior:
- Thoracolumbar fascia
Superior:
- Internal aspect of the lower ribs and cartilages
Inferior:
- Iliac crest
- Inguinal ligament
Insertion:
- Linea alba
- Pubic crest
What are the actions of transversus abdominis?
Since the fibres are TRANSVERSE, it cannot be a flexor or rotator…. (NO VERTICAL LINE OF ACTION)
Increase intrabdominal pressure, no movements associated with them.
What is the innervation of transversus abdominis?
T7-L1 ventral rami
What are the attachments of rectus abdominis?
Superior attachment:
- Xyphoid process
- Adjacent rib cartilages
Inferior attachment:
- Pubic crest and symphysis
What are the movements of rectus abdominis?
Since fibres are purely vertical flexion. Very good moment arm as well. The tendinous intersections of rectus abdominis exists so that:
- Muscle can fold onto each other
- Gives it strength (when external and internal oblique attach, give muscle fibre some strength, so internal and external oblique can’t just pull the rectus abdominis apart)
What is the innervation of rectus abdominis?
T7-L1 ventral rami
What is the rectus sheath?
The rectus sheath is formed by the aponeuroses of the transverse abdominal and the external and internal oblique muscles. Can be divided into anterior and posterior portions
What 2 muscles make up the upper anterior rectus sheath?
Aponeurosis of
- External oblique abdominal
- 1/2 of internal oblique abdominal
What 2 muscles make up the upper posterior rectus sheath?
Aponeurosis of
- Internal oblique abdominal
- 1/2 of transverse abdominis
What is the function of rectus sheath?
- Re-directing the line of action of external and internal oblique
- Enhanced line of action of flexion
Thoracolumbar fascia is a 3 layered structure. What are the three layers?
Anterior and middle layer:
- Attach to lumbar transverse processes - Envelope quadratus lumborum - Anterior and middle layer fuse laterally and attach to transversus abdominis and Internal oblique (NOT EXTERNAL OBLIQUE)
Posterior layer:
- Attach to spinous processes - Enclose erector spinae - Attach to the middle layer laterally.
Thoracolumbar fascia blends with…? (3)
- Erector spinae aponeurosis
- Latissimus dorsi
- Gluteus max.
What is stability?
Control of the motion segment
What controls the motion segment?
- Bony
- Ligamentous
- Muscular (vertical line of action, compression)
- Muscular (counteracting movements, eg pars lumborum)
- Intra-abodominal pressure
Muscles can provide stability by attaching onto ________
Thoracolumbar fascia
Muscle attach to TLF attach spinous and transverse processes
TLF function: vertebral stability and muscle attachment.
If you are sitting and waving your arms around (displacing centre of mass) you diaphragm will begin to _____ only until it reaches 80% relaxation. Keep the stability by ______ intra-abdominal pressure
If you ______ available oxygen, it will start 100% relaxing because air is ___ important than postural stability.
relax
increasing
decrease
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