Musculoskeletal Mechanics of the Neck and Head

Authors

Affiliations

Nathaniel Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Anatomy

Muscles

Superficial layer:

Traps
SCM
Lev scap
Rhomboids
scalenes

Deeper layer:

Splenius capitis
Semispinalis Capitis
Longissimus Capitis

Deepest layer:

Links cervical and thoracic vertebrae

Deepest Layer OIAN
Muscle	Origin	Insertion	Nerve	Action
Splenius Cervicis	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Superficial Intrinsic Back Muscles/splenius_cervicis.html#origin	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Superficial Intrinsic Back Muscles/splenius_cervicis.html#insertion	?var:ref-splenius-cervicis.nerve	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Superficial Intrinsic Back Muscles/splenius_cervicis.html#action
Semispinalis Cervicis	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Transversospinalis Muscles/semispinalis.html#origin	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Transversospinalis Muscles/semispinalis.html#insertion	?var:ref-semispinalis-cervicis.nerve	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Transversospinalis Muscles/semispinalis.html#action
Longissimus Cervicis	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Erector Spinae/longissimus.html#origin	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Erector Spinae/longissimus.html#insertion	?var:ref-longissimus-cervicis.nerve	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Erector Spinae/longissimus.html#action

Intervertebral Disc (IVD)

5x discs in C/S¹
First IVD between C2 and 3¹

Note

Named after vert above it¹

The main dysfunction at the IVD is a herniation

Kinematics

Head Flexion

Osteokinematics: Flexion: 45-50 deg

Arthrokinematics:

Initial phase: begins in low c spine(C4-7) ,
Second phase: occurs initially in C0-2 then c2-3, C3-4
Flexion is described as an anterior osteokinematic rock (tilt) of the superior vertebra in the sag- ittal plane, a superoanterior glide of both superior facets of the zygapophyseal joints, and an anterior translation slide of the superior vertebra on the IVD
Uncovertebral joint: anterior spin¹

Restriction: Anterior osteokinematic motion restricted by: PLL, interspinous, lig flavum, and extensor mm

Head Extension

Arthrokinematics:

Posterior osteokinematic sagittal rock, an inferoposterior glide and approximation of the superior facets of the zygapophyseal joints, and a posterior translation of the vertebra on the disk.
Uncovertebral joint undergoes a posterior arthrokinematic spin osteokinematic motion of extension is restricted by anterior prevertebral mm and ALL

Head Lateral SB

Osteokinematics: Side bend: 40 deg

Note

Sidebending: closer to 75 in supine because of hte muscles that limit SB with gravity: traps, scalenes, SCM (all are more lengthened in standing/sitting bc gravity pulling at insertions)(Harper 2023)

Muscle	Origin	Insertion	Nerve	Action
Sternocleidomastoid	/The Archive/Anatomy/Skeletal Muscles/Head and Neck/Neck Muscles/Sternocleidomastoid muscle/sternocleidomastoid_muscle.html#origin	/The Archive/Anatomy/Skeletal Muscles/Head and Neck/Neck Muscles/Sternocleidomastoid muscle/sternocleidomastoid_muscle.html#insertion	?var:ref-sternocleidomastoid.nerve	/The Archive/Anatomy/Skeletal Muscles/Head and Neck/Neck Muscles/Sternocleidomastoid muscle/sternocleidomastoid_muscle.html#action
I/L SB
Obliquus Capitis Superior	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/obliquus_capitis_superior.html#origin	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/obliquus_capitis_superior.html#insertion	?var:ref-obliquus-capitis-superior.nerve	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/obliquus_capitis_superior.html#action

Arthrokinematics

Superoanterior glide of contra superior facet posteroinferior glide of ipsi facet
C/L translation of vertebra on disk
Inferomedial glide of ipsi uncovertebral joint, superolateral glide of contral uncovertebral joint Limited by contra scalenes, intertransverse ligs, facet jt motions limited by joint capsule and translation limited by IVD

Head rotation

Rotation 70-90 deg Virtually all rotation in UPPER C/S occurs between Atlas & Axis

Muscle	Origin	Insertion	Nerve	Action
C/L head rotators
Obliquus Capitis Superior	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/obliquus_capitis_superior.html#origin	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/obliquus_capitis_superior.html#insertion	?var:ref-obliquus-capitis-superior.nerve	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/obliquus_capitis_superior.html#action
Sternocleidomastoid	/The Archive/Anatomy/Skeletal Muscles/Head and Neck/Neck Muscles/Sternocleidomastoid muscle/sternocleidomastoid_muscle.html#origin	/The Archive/Anatomy/Skeletal Muscles/Head and Neck/Neck Muscles/Sternocleidomastoid muscle/sternocleidomastoid_muscle.html#insertion	?var:ref-sternocleidomastoid.nerve	/The Archive/Anatomy/Skeletal Muscles/Head and Neck/Neck Muscles/Sternocleidomastoid muscle/sternocleidomastoid_muscle.html#action
I/L Head Rotators
Rectus Capitis Posterior Major	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/rectus_capitis_posterior_major.html#origin	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/rectus_capitis_posterior_major.html#insertion	?var:ref-rectus-capitis-posterior-major.nerve	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/rectus_capitis_posterior_major.html#action
Rectus Capitis Posterior Minor	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/rectus_capitis_posterior_minor.html#origin	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/rectus_capitis_posterior_minor.html#insertion	?var:ref-rectus-capitis-posterior-minor.nerve	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/rectus_capitis_posterior_minor.html#action
Obliquus Capitis Inferior	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/obliquus_capitis_inferior.html#origin	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/obliquus_capitis_inferior.html#insertion	?var:ref-obliquus-capitis-inferior.nerve	/The Archive/Anatomy/Skeletal Muscles/Muscles of the back/Suboccipital Muscles/obliquus_capitis_inferior.html#action

Arthrokinematics

Muscles: Global neck mm: SCM and semispinalis capitis and splenius captius Local neck: longus captius and colli, semispinalis cervicis, multifidus longus colli and post neck mm for a sleeve that supports spinal segments during mvmt

Tip

*same as sidebending motions

Coupled Motion

C0-C2: Opposite
C3-T3: Same
T4-L5: opposite

Note

Coupled motion has been observed to change with age

Joints

OA Joint

Occipitoatlanto joint

OA joint Hypermobility is considered a diagnosis If range of rotation exceeds 8 degrees → stability testing necessary

AA Joint

Atlantoaxial joint

Pure axial rotation 60% of total rotation in CS is here

Kinematics

Flexion

Greatest at lower C/S (C5-C6)

Least flexion at C2,3

Extension

Rotation

AA Joint performs pure axialrotation

Rotation and SB are coupled motions

Lateral flexion (SB)

Rotation and SB coupled motions

Coupled motion

Upper c spine: Sb and rotation — type 1 motion, OPPOSITE MOTION Regardless of posture Mid cervical: c3-c7 Same direction More type 1 motion: Changes in couple patterns

Clinical signifiance

If c spine motion is limited w sb and rotation to same side
0 mid/lower c facet is suspected (restriction)
Assess A/PROM
Soft tissue

Posture

Cervical Lordosis

C4/5 is midpoint of curve
COG for skull is ant to foramen magnum

Dysfunction

Vestibular and Visual symptoms

Upper c spine has more connections to vestib and visual systems than low c spine
So upper c spine dysfunction can cause more balance/visual disturbances

Sensorimotor control

Tip

Wearing a hard collar for 5 days has been shown to lead to altered eye mvmt control, increased postural sway and disturbed head neck awareness in healthy people^{kristjanssonSensorimotorFunctionDizziness2009?}

Examination

Screening

Canada C-spine rules

Age >= 65
Dangerous mech:
- Fall from >=3 feet or 5 stairs
- Axial load to head (ie diving)
- MVC high speed >= 100 km/hr, 60 mph
- Bike collision w object
- Motorized rec vehicles
<= 45 deg of rotation
New onset of neural sx (paresthesias in extremities)

Warning signs of cervical region:

Subjective
- Unexplained weight loss
- SB away from painful side that causes pain (if this is the only motion causing pain)
- Evidence of compromise of 2-3 spinal nerve roots
Pain
- Gradual inc in pain
- Expansion of pain in terms of the regions involved
- Arm pain in pt younger than 35 or pt for more than 6 months
ROM: Spasms w PROM
Motor
- painful/weak resistive testing
- Limited scapular elevation
- T1 palsy (weakness / atrophy of the intrinsic mm of hand)
Visual disturbances
Hoarseness
Horner syndrome–
VBI and cervical myelopathy

ROM

Upper C/S isolate rotation
- Cervical rotation Full Flexion

Special Tests

VBI Test
Sharp-Purser Test
Alar Ligament Test
Tectorial Membrane integrity
Spurling’s Test
TOS
- Allen’s Maneuver (should be performed before other TOS tests)
- CRLF Test (Lindgren’s test)
- Adson’s Test (TOS)
- ROOS Test
Canadian C-Spine Rules

Provocative tests

Disk herniation
Vertebral end plate fracture
Vertebral body fracture

Cervical Radiculopathy

Wainner et al 2003 Cervical radiculoapthy diagnostic tests

Positive ULTT1 (median nerve)
Involved sign cervical rotation range of motion < 60 deg Positive distraction test
Positive spurlings test
4/4 = 99 % specific, 30 x more likely to have cervical radiculopathy
¾ = 94% specific, 6 x more likely to have cervical radiculopathy

DDX

Reproduction of Pain with Cervical Distraction

Spinal lig tear
Annulus fibrosis (AF) Tear or inflammation
Mm spasm
Large disk herniation
Dural irritability

Compression

Arthritis
Nerve root irritation
Herniation
Vert end plate fx
vertebral body fx

Bearing down

Reproduction of pain = C/s herniation

References

Dutton M. Dutton’s Orthopaedic Examination, Evaluation, and Intervention. 5th ed. McGraw Hill Education; 2020.

Citation

For attribution, please cite this work as:

Yomogida N, Kerstein C. Musculoskeletal Mechanics of the Neck and Head. https://yomokerst.com/The Archive/MSK/Regions/Spine/neck_MSK.html