Module 4_ Spine Kinesiology PDF

SPINE Normal Spine Curves ○ Lordotic Definition: Inward curvature of the spine. Location: Cervical (neck) and lumbar (lower back) regions. Normal Function: Helps distribute weight and absorb shock. Excessive Curve: May lead to...

SPINE Normal Spine Curves ○ Lordotic Definition: Inward curvature of the spine. Location: Cervical (neck) and lumbar (lower back) regions. Normal Function: Helps distribute weight and absorb shock. Excessive Curve: May lead to lordosis (swayback). ○ Kyphotic Definition: Outward curvature of the spine. Location: Thoracic (upper back) and sacral (pelvic) regions. Normal Function: Provides stability and supports the body's upright posture. Excessive Curve: May lead to kyphosis (hunchback). Spine Segments: 7 cervical, 12 thoracic, 5 lumbar, 5 sacrum (fused), 4 coccygeal (fused) Cervical ○ C1-7 ○ More flexible, supporting head ○ WIDE range of motion Flexion: 45–50° Extension: 60–70° Lateral Flexion (side bending): 40–45° Rotation: 70–90° Thoracic ○ T1-12 ○ Relatively immobile ○ Ribs attach Plays with the balance of mobility vs. stability Lumbar ○ L1-5  ○ Carries weight of upper body ○ Most prominent= supports the most amount of weight ○ Muscle attachments here are bigger + stronger than cervical They have to support and move more weight Sacral & coccygeal ○ Sacrum Triangle base of spine Connects spine to pelvis Delivers nerves to pelvic organs ○ Coccyx Few small bones Remnant of tail Mobility and Stability 3 aspects of the pyramid ○ Neuro- control ○ Bone structure -passive ○ Muscle -active This is why it is hard to find the root of back pain- issue in one = issue in all Body is great at being able to compensate - makes it difficult to diagnose Chronic back pain ○ Body will recruit bigger muscles instead of smaller stabilizers ○ Bigger muscles will stabilize This sacrifices mobility Which is why person is stiff Spinal Column Stability ○ Protect spinal cord ○ Maintain upright posture ○ Transmits weight to lower limbs  Mobility ○ Provide motion for head and trunk ○ Absorb force ○ Provide space for muscle attachments Dynamic = active subsystem Functional Spinal Unit ○ Allows for movement ○ Components: 2 adjacent vertebrae Intervertebral disc Intervening disc Intervening ligaments ○ Anterior column Vertebral bodies Disc Longitudinal ligaments ○ Posterior portion Vertebral arches Flavum Facet joints Transverse and spinous processes Posterior ligaments Vertebrae Motion 6 DOF ○ Can do a little bit of everything Distraction Compression Translation Extension Side flexion Intervertebral Joints Allows for small motion between each segment Separated by fibrous-cartilaginous discs Ratio is what dictates mobility ○ -ratio between vertebral body and disc ○ HIGHER ratio = thickest disc, more motion (cervical) ○ LOWER ratio = thinner disc, limits motion (thoracic) ○ Also can change day to day and throughout day This is why people are taller in the morning Vertebral disc Fluid filled- jelly donut ○ Outer layer= annulus fibrosus ○ Gel= nucleus pulposus ○ Shock absorbed ○ Maintains space between vertebrae Maintain vertebral column height 80-90% - decreases with age Avascular -nutrition via end plate ○ end plate= thin layer of cartilage, between the vertebral body and the intervertebral disc Structure: Made of hyaline cartilage and fibrocartilage. Function: Serves as an interface for nutrient diffusion from the vertebral bone to the disc. Role in support: Helps anchor the intervertebral disc to the vertebra and distributes mechanical loads. Importance: Maintains disc health by enabling the exchange of nutrients and waste products due to its semi-permeable nature. Disc anatomy: ○ Jelly donut Spongy center =nucleus pulposus Fibrous ring= annulus fibrosus Annulus= whole thing Annulus Fibrosus: The entire outer fibrous ring of the intervertebral disc made of concentric layers of collagen and fibrocartilage. Annular Wall= just the outer layer: outermost layers of the annulus fibrosus ○ (very outside ring)= 12-14 layers alternating obliquities of about 30°  ○ THICKER anterior ○ THINNER posterior Strength and flexibility: Alternating obliquities provide resistance to multidirectional forces. Load distribution: Thicker anterior wall handles compressive forces better. Injury risk: Thinner posterior wall is more prone to herniation under stress. Spinal stability: Layered structure supports motion while maintaining disc integrity. Annulus= whole thing ○ Forward bending: Back (posterior) of annulus = stretches. Increase tensile forces Front (anterior) of annulus =squeezed. Increase compressive force Rotation (twisting): Annulus fibers align diagonally. Fibers in the twist's direction tighten. Opposite fibers loosen. Disc under compressive loads Nucleus pulposus absorbs water Hydration decreases with increased load Develops internal pressure Compressive stress on disc = tensile stress in annulus fibrosis Increased stiffness = stability but sacrificing mobility pressure= all directions Laterally against annulus Increased stiffness superiorly / inferiorly against end vertebrae Compression force: When the vertebral disc is loaded, it pushes upward and downward. Endplate role: The disc’s pressure is transmitted through the cartilage endplates to the vertebral bodies above (superiorly) and below (inferiorly). Force distribution: This transfer ensures the load is evenly spread across the vertebrae, protecting the spine from localized damage. Disc kinematics Flattens under axial compression Nucleus flattens  Intradiscal pressure rises Annular stress increases- ring stress Uneven loading (bend/flex/est) Nucleus driven away from closure of space Allows nuclear material to evenly distribute pressures Disc pressure Always under some pressure- ○ annular= slightly elastic Seated usually greater than standing = more pressure Anterior longitudinal ligament ○ C2-Sacrum ○ Occiput to C1 = anterior ATLANTOaxial ligament ○ Resists extension forces ○ Limits excessive lordosis ○ Superficial fibers = span several segments ○ Deep fibers = span 1 segments Blend into annulus, reinforce anterior disc Posterior longitudinal ligament ○ Resist flexion  ○ C2-sacrum ○ Occiput to c2 = tectorial membrane ○ Located in vertebral canal Ligamentum flavum ○ Resist flexion ○ Very elastic-allow more ROM ○ Connects lamina of adjacent vertebrae ○ Has some constant tension to support disc ○ C2- Sacrum ○ C1-C2 = posterior atlantoaxial ligament Supraspinous Ligaments ○ Connect adjacent spinous processes ○ C7-sacrum ○ Resist flexion Ligamentum Nuchae ○ Continuation of supraspinous ligaments ○ Resist flexion ○ Connects all c-spine vertebrae ○ Provide surface for muscle attachments Good limiter for neck flexion Intertransverse ligaments ○ Attach adjacent transverse processes ○ Limits contralateral flexion and some forward flexion  ○ Poorly defined and thin Facet/ Zygoapophaseal Joints Consists of: ○ Inferior articular facet of superior vertebrae ○ Superior articular facet of inferior vertebrae Synovial biplanar joints ○ gliding/sliding Facet joint = hard stop Function: ○ Interlocking surface between adjacent vertebrae ○ Orientation guides and limits motion ○ Protects against excessive shear/torsion force Especially in lumbar spine ○ Transmits axial loads Greatest in lumbar region (due to lordosis) Increased lordotic posture can increase load ○ Facet has a lot of pain receptors/innervations Superior Facet Orientation ○ describes the direction the upper (superior) facet joints of each spinal region ○ When impact, can slide upwards because of the angle ○ “Guide rails for motion” Cervical “BUM” Backwards Upwards Medial ○ Allows for a wide range of motion, including rotation, flexion, and extension. Thoracic “BUL” Backwards Upwards Lateral ○ Permits some rotation and side bending but limits flexion/extension due to rib attachment. Lumbar -”BUM” Backwards Upwards  Medial ○ Primarily supports flexion/extension and limits rotation for stability under heavy loads. Facet Joint Motion ○ FLEXION Up- superior Forward- anterior ○ EXTENSION Down Backward ○ ROTATION Axis = in vertebral column Anterior column vs. posterior column Facet impaction and gapping Gap = SAME SIDE you’re turning to Impact = OPPOSITE SIDE Normal axial rotation 3 degrees close to the limit allowed for most intervertebral joints Primary limiter ○ Facet joints Protecting annular ring Cervical Spine Primary function: ○ Balance head- FIRST CLASS LEVER ○ Force of gravity anterior to axis (G) Need suboccipital muscles to counterbalance head weight  Atlanto-Occipital Joint = “YES” nodding joint ○ Condyles of occipital bone = CONVEX ○ Facets of atlas = CONCAVE ○ Allow: flexion/ extension Nodding C1-C2 = “NO” head joint ○ Accounts for about 50% of rotation in the transverse plane ○ Atlas = bony ring w/o body ○ PIVOT joint between dens and atlas ○ CONVEX on CONVEX ○ Motion: Allows transverse plane rotation Cervical Motion ○ Most flexible region ○ From anatomical position About 80° extension About 50° flexion And C1-C2 is responsible for 20-25° of sagittal plane motion ○ Resting position = 30-35° of lordosis Lateral Flexion ○ Down and back slide = same side we’re going to ○ Rotation is still down and back Cervical coupling ○ Combines all of the motions ○ C1-C2= NOT involved  ○ Rotation coupled with same side lateral flexion, dictated by facet plane Alar Ligament ○ Runs between axis and occiput ○ Major stabilizer of C1-C2 Transverse Ligament ○ Connects across atlas to HOLD dens ○ Acts as articulate surface with dens Limit translation between C1 + C2 Cervical Flexion ○ Muscles: Rectus capitis anterior Rectus capitis lateralis Longus capitis Longus colli And if activated bilaterally: Sternocleidomastoid Scalenes Cervical Extension ○ Muscles: Splenius capitis Splenius cervicis Assisted by: Rectus capitis post/major/minor Obliquus capitis superior/inferior Rotators ○ Ipsilateral rotation Muscles: Oblique capitis Erector spinae ○ Contralateral rotation Muscles: Multifidi Rotatores Semispinalis capitis and cervicis ○ *more effective in cervical spine Thoracic Spine Least mobile- because of the ribs ○ Sacrifices mobility for stability ○ Articulate with ribs  ○ Increasingly load bearing Thoracic Spinal Curve ○ 40° kyphotic curve ○ Curve comes from wedge shaped vertebral bodies Thoracic spine body ○ T1 similar C7 ○ Disc to height ratio is HIGHEST Decreases tensile forces Decreases possibility of disc injury ○ As you go lower… Posterior aspect becomes thicker End plate becomes larger This because they support weight Rib Anatomy 3 classifications (12 pairs) ○ True -direct connection ○ False -cartilage ○ Floating (also false) -no connection Costotransverse joint ○ Takes a lot to displace them ○ Radiate ligament connects anterior aspect of rib to two adjacent vertebrae and intervening disc Thoracic Motion Extension ○ Produced primarily by lumbar extensors ○ Muscles: Erector spinae group Quadratus lumborum Axial Rotation Abdominal muscles and trunk rotators ○ Abs (obliques) = further away from spine than rotatores = increased moment arm ○ Rotatores = high amount of sensory cells Studies showing for proprioception vs. just force production Side bending ○ Initiated by ipsilateral abs & erectors… continued by gravity Internal obliques = same side rotators External obliques = opposite side rotators Side bend activates both to hold a “neutral position” In theory would also be activating ½ rectus ab and ½ transverse ab Muscle actions ○ Increased moment arm means you don’t have to produce as much force @ muscle L5 Wedge shaped to fit with sacrum Anterior portion taller than posterior L4 + L5 ○ commonly injured L5-S1 ○ Most flex/ext ○ Less stable ○ GREATEST amount of sagittal plane motion in lumbar spine ○ Also commonly injured Lumbar Flexion Muscles: ○ #1 = rectus abdominis ○ Internal obliques ○ External obliques Lumbar Extension Layering effect of muscles 2 classes ○ Erector spinae - jumps 7-10 segments Spinalis Longissimus Iliocostalis Middle = semispinalis capitis, cervicis, thoracis ○ Deep Spinal Muscles - connect adjacent Multifidus Rotatores Technically included but not primary: Interspinales Intertransversarii Levatores costarum Erector spinae + multifidus = main extensors Lateral Flexion Quadratus lumborum Psoas major Unilateral flexors/extensors Opposite side of motion would be eccentric contraction = working side because the contraction is happening to hold position of get back to anatomical position Lumbar Stability Efficient stabilizers ○ Obliques ○ Transverse abdominis ○ Multifidus ○ Quadratus lumborum Inefficient stabilizers ○ Rectus ab ○ Longissimus ○ Latissimus dorsi Prevents spinal buckling ○ Co contraction of superficial flexors/extensors Rectus Abdominis Isometric contraction increases abdominal pressure Resists extension forces Controls against hyperextension ○ Lifting belt pushes/adds resistance to allow increase in intra abdominal pressure Stabilizes spine Holding breath while squatting can also increase pressure Psoas Function depends on position of lumbar spine Hip flexion/External rotation ○ I.e holding feet down while doing sit up Unilateral contraction = side bending Bilateral contraction = ○ Flexes trunk toward hip ○ Arches lower back External Oblique Understand the relationship and that they oppose each other… not necessarily a specific stabilizer vs. neutralizer Pulls chest down Compresses abdominal cavity Increases intra-abdominal pressure Flexion & rotation (opposite side) ○ Both sides working during side bending = they oppose which cancel each other out Internal Oblique Antagonist to diaphragm Compress organs into diaphragm causing exhalation Works with external oblique of opposite side to produce trunk rotation ○ “Same side rotators” Quadratus Lumborum Unilateral = Laterally flexes vertebral column Bilateral = extends lumbar column ○ Provides lateral stability Transverse Abdominis Paper thin Provides compression- provides support Internal belt/corset Important during valsalva maneuver Multifidus Superficial fibers ○ Span 2-5 segments ○ Active w/ erector spinae Deep fibers ○ Span 2 segments ○ Tonically active trunk movements ○ Stabilize the segment w/o motion ○ Length does not change ○ Controls shear & torsion w/o creating torque Lumbopelvic Rhythm Variations Lumbosacral Angle angle between the sacrum (base of the spine) and the lumbar spine (lower back) ○ helps determine the curvature of the entire spine, including the lumbar, thoracic, and cervical areas ○ Typical = 30° Increase angle = greater lordosis Compression can lead to arthritis Balance between compression and relaxation ○ Load joint and then let heal… incremental load Sacrum 1-3° of motion relative to ilium Must support weight of spine and entire upper body Acts as keystone Loads on the Spine In normal standing position ○ Body weight acts anterior to spine ○ Created forward bending load (moment of spine) ○ Erectors and spine extensors are always active @ some level Because spine is curved ○ Body weight acting vertically ○ Components of Compression = Fc Shear + Fs Spinal muscles = small moment arms ○ Very close to axis of rotation Requires large forces to counteract torque about the spine ○ High JRF = High Compression Force of spine Disc Failure Disc herniation Pressure elevated by bending, coughing, sneezing, straining Intradiscal pressure ○ In order of most to least: Sitting (forward lean) Sitting Standing Side lying Supine lying Disc Injuries Degenerative disc disease ○ Flattening disc over time ○ Can develop fissures in annulus Herniated discs ○ Pulposus migrates posteriorly ○ Can move beyond border of vertebral body Can apply pressure on nerves Degenerated Discs Up to 8x shear force on nucleus Lots of swelling pressure Compressive force on annulus can double Load on facet joints can increase 40-90% GAIT MECHANICS Walking speed ○ known as 6th vital sign ○ Key indicator of function of major body systems: Cardiorespiratory musculoskeletal Neuro Any major deficit in one of these will most likely present in gait speed ○ High scores in Reliability Consistency of a measurement, how repeatable Validity Accuracy of a measurement; if test is truly measuring what it is intended to measure ○ Can predict: Functional participation Health status Cognitive impairments Mortality ○ Normal Adult walking speed Men: 1.37 m/s  Women: 1.30 m/s ○ Energy efficiency occurs at around 3.5 mph Crosswalks adhere to a normal/faster walking speed- can potentially be a hazard for slower speeds Determinants of walking speed ○ Cadence # of steps in (steps/min) Men = avg 108 Women = avg 118 ○ Stride length How big of a step Initial contact-initial contact normal= Men- 1.51m Women- 1.32 m ○ ONE STRIDE = 1 complete gait cycle, meaning it completes every phase Step vs. stride ○ step= initial contact of one foot to the other ○ stride= 2 steps, initial contact of one limb to then initial contact again of same limb Gait Cycle = 1 complete stride 8 phases Double support phase: ○ Initial contact Start of gait cycle Part where foot hits ground ○ Loading Response Weight transfer Shock absorption Other limb is unloading Single Support ○ Mid Stance Center of mass travels over planted foot ○ Terminal Stance “Toes” Center of mass travels anterior to ankle of planted limb Heel raise begins on planted foot Double ○ Pre-Swing Before swing leg forward Support limb unloads Toe off ground indicates end of pre and start of swing phase  Swing ○ Initial Swing Foot lifts Limb starts to advance ○ Mid Swing Passes planted foot Minimal toe clearance ○ Terminal Swing Advances even further past planted foot Prep for initial contact Contract hamstrings as leg goes forward to “brake” or slow down Control where the heel is going to land for IC Example: sprinters will pull hamstring often because they’re trying to overcome a large eccentric hamstring contraction + terminal phase ○ Because planted leg is same length we need to shorten lifted leg Flex hip Dorsiflex ankle Flex knee Rockers ○ pivot ○ Describes where the pivot or rocking is occurring for normal gait ○ 1st - heel ○ 2nd- ankle ○ 3rd- forefoot (ball of foot) ○ 4th- toe Sagittal Plane Kinematics Initial contact ○ Thigh- (not hip!) 25° flexion ○ Knee 0-5° flexion Mainly close to 0 but can have some slight flexion ○ Ankle  Neutral Loading Response ○ Thigh -reference to vertical 25° flexion ○ Knee 15° flexion ○ Ankle 5° plantar flexion Mid Stance ○ Thigh 0° ○ Knee 0° ○ Ankle 5° dorsiflexion Terminal Stance ○ Thigh 15° extension ○ Knee 0° ○ Ankle 10° dorsiflexion Initial Swing ○ Thigh 15° flexion ○ Knee 60° flexion To shorten and bring through MOST important for toe clearance ○ Ankle 5° plantar flexion Mid Swing ○ Thigh 25° flexion ○ Knee 25° flexion ○ Ankle Neutral Have to have strong dorsiflexors, to prevent slap foot MOST important for toe clearance  Terminal Swing ○ Thigh 25° flexion ○ Knee 0° ○ Ankle Neutral Pre Swing ○ Thigh 0° ○ Knee 40° flexion ○ Ankle 15° plantar flexion Minimal Toe Clearance Distance between toes and ground Normal = 1-2 cm Initial swing ○ Most sensitive to knee flexion about 60° Mid swing ○ Most sensitive to dorsiflexion Frontal Plane FOOT kinematics Total Motion: 7° eversion 6° inversion ○ 13° total ROM Pronated = more flexion Supinated = more rigid phase Subtalar motion Transverse tarsal calcaneus function Initial contact RIGID supinated load Inversion 2° Loading Response FLEX pronate unlock Eversion 5°  Early Mid-stance FLEX pronate unlock Eversion 7° (peak) Late Mid-stance RIGID supinated lock Inversion to 5° eversion Terminal Stance RIGID supinated lock Inversion to 5° inversion Pre-swing RIGID supinated unload 6° Inversion Frontal Plane Kinematics Know the peaks in frontal! Mid Stance ○ Calcaneus PEAK eversion 7° Walking GRFs If braking = propulsive then you have a constant speed Joint Moments Blue = GRF Internal joint moment = what is body trying to do based on where force is coming from