kinesiologyweek6 Flashcards
Typical Spinal Nerve
ventral root - efferent axons, movement; dorsal root - afferent axons, sensory
Dorsal Ramus
posterior trunk and neck
Ventral Ramus
anterolateral trunk, neck and extremities
Ventral Ramus Innervation - Plexus
cervical C1-4; brachial C5-T1; lumbar L1-4; sacral L4-S4
Ventral Ramus - Segmental Innervation
intercostal nerves T1-L2 (intercostal mm and cutaneous), recurrent meningeal nerves C1-S4 (interbody joints, primarily posterior annulus, PLL)
Dorsal Ramus Innervation
branches from every spinal nerve, short distance, segmental innervation of posterior mm of back, dermatome sensation to posterior back, sensation to ligaments of posterior vertebra, apophyseal joints, and dorsal SI ligaments
Muscles of the Trunk
anterior-lateral - abdominals; posterior - superficial trap & lat, intermediate serratus, deep erector (additional - iliopsoas and QL)
Muscles of the Craniocervical Region
anterior-lateral - SCM, scalene; posterior - superficial (splenius capitis and cervicis); deep (suboccipitals)
Internal Torque
muscle force x internal moment arm
Trunk Flexion/Extension
sagittal plane, longissimis thoracis and rectus abdominis
Trunk Lateral Flexion
frontal plane, obliquus externus abdominis and iliocostalis thoracis
Trunk Axial Rotation
horizontal plane, obliquus externus abdominis and multifidus
Spatial Orientation
determines the effectiveness or potential to produce particular action, for example horizontal force will produce axial rotation and vertical force will produce lateral flexion and flexion for the obliquus externus abdominis (line of force in sagittal plane 30 degrees from vertical)
Special Considerations for Muscle Action with Axial Skeleton
bilateral or unilateral activation, which attachments are stabilized (assume cranial end free), influence of gravity
Superficial Layer of Posterior Trunk Muscles
consider dual action or “reverse action” due to origin (upper and middle trap rotate cervical and upper thoracic spine and stabilize the position of the scapula relative to the thorax)
Intermediate Layer of the Posterior Trunk
role in breathing and rib movement for thoracic expansion (serratus posterior superior and inferior)
Deep Layer of the Posterior Trunk
erector spinae, transversospinal group, short segmental group (innervated dorsal rami)
Erector Spinae
large mass 3 columns, subdivided regionally, gross movements, “common tendon” insertion, bilateral action is extension (anterior pelvic tilt), unilateral action is lateral flexion and some ipsilateral rotation
“Common Tendon”
thoracolumbar fascia/lumbodorsal fascia, median sacral crests, spinous processes of lower thoracic and all lumbar, supraspinous ligaments of lower thoracic and all lumbar, iliac crests, sacrotuberous and sacroiliac ligaments, gluteus maximus, multifidi
Transversospinal Group
multifidi, rotatores, semispinalis; deep to erector spinae, transverse to spinous process of superior vertebrae, produce fine controlled movement, bilateral extension, unilateral lateral or contralateral rotation (primarily prevent rotation versus promoting it)
Semispinalis Muscles
thoracis, cervicis, and capitis; cervicis and thoracis can be palpated anterior lateral to upper trap, 30-45% of extension torque of head, some with capital extension
Multifidi
transverse to spinous processes of vertebrae 2-4 segments superior, most developed in lumbar region, high angle of insertion to spinous process, produces rotary torque, stabilization
Rotatores
deepest of transversospinal, transverse to spinous process 1-2 segments superior, most developed in thoracic
Short Segmental Group
interspinalis and intertransversarius, cross one vertebral junction, fine motor movements cervical spine, low level torque, mm fibers blend with interspinous or intertransverse ligaments, coordinated movements of C-spine and head
Rectus Sheath and Linea Alba
anterior and posterior rectus sheath, linea alba is the thickening and crisscross as the sheaths cross midline, mechanical link for muscles and contributes to strength
Rectus Abdominis
runs longitudinal, sleeve formed by anterior and posterior sheaths, intersected with fibrous bands (tendinous intersections)
Internal and External Obliques
external is largest and most superficial, internal is deep 2nd layer, nearly perpendicular fibers to EO
Transverse Abdominis
deepest, “corset muscle,” increases intraabdominal pressure, attachments to thoracolumbar fascia
Action of Abdominal Muscles
trunk flexion, trunk rotation (synergistic obliques)
Trunk Flexion vs. Extension Torque
flexion torque < extension torque, flexors have better leverage but extensors have greater mass and vertical orientation of mm fibers, extensors counteract gravity, extensors high function with carrying loads in front
Iliopsoas
iliacus and psoas major, anterior tilt of pelvis, psoas major functions for lateral flexion, trunk flexion, vertical stabilizer
Quadratus Lumborum
bilateral extension and stabilization, unilateral lateral flexion (hip hiking), works with psoas major to provide vertical stability
Core Stability
stable base for movement of limbs, intrinsic muscular stabilizers are short segmented and transversospinal groups which promote stability in all planes
Extrinsic Stabilizers of the Trunk
general stability, semi-rigid link between vertebral column and lower extremity
Trunk Flexion Phase of Sit-Up
rectus abdominis, posterior pelvic tilt, low hip flexor EMG regardless of LE position
Hip Flexion Phase of Sit-Up
hip flexors contract, abdominals isometric
Controlling the Sit-Up Movement
weak abs = hip flexors dominate and lordosis or anterior pelvic tilt; legs fixed = more hip flexors
Anterior-Lateral Craniocervical Muscles
SCM, scalenes, logus colli and capitis, rectus capitis anterior and lateralis
Sternocleidomastoid
bilateral flexion, uinlateral actionis lateral flexion and contralateral rotation
Scalenes
transverse processes to first 2 ribs, brachial plexus between anterior and middle (tightness/spasm = motor and sensory changes), unilateral contraction causes lateral flexion (anterior scalene has some contralateral rotation), bilateral action causes some flexion, rib elevation (vertical stability)
Longus Colli and Capitis
essential for vertical stability, L. colli flexes cervical spine, L. capitis flexes craniocervical
Rectus Capitis Anterior and Lateralis
transverse process of C1 to inferior occipital bone, anterior = flexor, lateralis = lateral flexor
Muscles of Posterior Craniocervical Region
splenius cervicis and capitis, suboccipital muscles
Splenius Capitis and Cervicis
unilateral - lateral flexion, ipsilateral rotation, bilateral - extension/capital extension
Suboccipital Muscles
fine control of movement at AO and AA, cervical sidebending coupled with same side rotation, contralateral occipital mm for rotating head to orient
Stabilization of Craniocervical Region
vertical stability - compress intervertebral segments, interaction of precise control from segmented muscles and long muscles, stability in sagittal plane - positioning
Coordinated Movements of Head and Neck
optimize positioning of eyes, ears, nose; craniocervical region - greatest triplanar mobility
Biomechanical Issues of Lifting
lifting - creates large compression, tension, shear forces and can exceed structural tolerance
Muscle Mechanics of Extension while Lifting
consider muscular peak torque, ligamentous tension, compression/shear forces at IV or apophyseal joints
Reduction of Force Demands on the Back While Lifting
- reduce speed of lifting, 2. reduce magnitude of external load, 3. reduce length of external moment arm, 4. increase length of internal moment arm
Intra-Abdominal Pressure & Lifting
contraction of abdominal musculature - increases vertical compression forces on spine, requires counterbalance of extensors; corset effect - co-contraction with contraction of transverse abdominis and internal oblique (myogenic compression & splinting), intra-abdominal pressure result of strong abdominal contraction
What else could contribute to extension torque in the trunk?
passive tension of posterior ligamentous system (assists with load), erector spinae have “silent EMG” in full flexion then engage as extension increases
What ELSE could contribute to extension torque in the trunk?
muscular-generated tension through thoracolumbar fascia, needs to be stretched to develop tension (slight forward flexion when preparing to lift), active contraction of muscles that attach (TA, IO, lat., gluteus max), provides static bracing
Lifting Techniques
squat lift powered by LE with a short moment arm (decrease extension torque) and neutral spine, stoop lift powered by greater extension of low back with long external moment arm and LEs work 23-24%
