Comprehensive Review Cranial Mechanics Darlene Myles D.O. Block 8

Objectives Review Cranial anatomy Describe the basic components of the Cranial concept Describe the major axes of motion in the Cranial base and vault Describe motion mechanics of the Cranium Review SBS strain patterns Review visual diagnosis of SBS strain patterns

Primary Respiratory Mechanism (PRM) 5 Components to Model Motility of CNS Fluctuation of CSF Mobility of intracranial / intraspinal membranes (reciprocal tension) Articular mobility of cranial bones Involuntary motion of sacrum between ilia Will be on the test

5 poles of attachment of the Dural Membrane Anterior-superior pole The falx attaches to the cristi galli of the ethmoid and to the frontal crest Anterior-inferior pole The tentorium attaches to the anterior and posterior clinoid processes of the sella turcica 3. Lateral poles The tentorium attaches to the petrous ridge of the temporal bone and the transverse ridge of the occiput 4. Posterior pole The internal occipital protuberance (opisthion) 5. Sacral pole The dura exits the foramen magnum attaches to C2 and then hangs loosely until it attaches to the S2 sacral segment Know where the points of attachment are

Primary Respiratory Mechanism (PRM) Expansion and Contraction of the CNS discussed in relation to what happens at the major keystone joint of the Cranial mechanism (The SBS) During the expansion phase the SBS Flexes During the Contraction Phase the SBS Extends Know the SBS is the joint where everything works around

SBS Sphenobasilar Synchondrosis All movement and strain is around the SBS Know what SBS stands for and where it is

Axes of Motion for Sphenoid and Occiput AP Axis ( 1 axis) From Nasion through SBS to Opisthion Vertical Axes (2 axes) Through Foramen Magnum of the Occiput Through Body of the Sphenoid Transverse Axes ( 2 axes) Just above the Jugular Process on a level with the SBS Know where these axes are, not necessarily what each axis good.

Flexion Sacrum moves posterior = counternuation

Extension Sacrum moves anterior = nutation

Cranial Bone Motion Each individual bone in the cranium has a predictable motion based on bevel changes All Midline individual bones are said to either Flex or Extend around a transverse axis All Paired bones are said to either internally rotate or externally rotate During Flexion Phase all midline bones Flex During Flexion Phase all paired bones Externally Rotate During Extension phase all midline bones Extend During Extension phase all paired bones Internally Rotate Def know this She said there will be a question on this

Articular … Cranial Bones - Sphenoid Transverse axis through the center of its body is in the area of the sella turcica Vertical Axis through the center of its body is in the area of the sella turcica AP Axis through the center of its body is in the area of the sella turcica AP Axis The motion of the sphenoid occuring in the sagittal plane described as flexion and extension Flexion: Posterior aspect of the body elevates. The sella turcica moves anterosuperiorly. Greater wings move forward and slightly laterally and inferiorly. The pterygoids move posteriorly and inferolaterally. The body expands a little as it carries the resistance of the facial bones. Primarily influences ethmoid, vomer and facial bones Adapted from a lecture by Barry Malina, D.O., F.A.A.F.P. – AZCOM Know that the sphenoid primarily influences ethmoid, vomer and facial bones  test question -she also said this is all you need to know from this slide and for boards as well

Articular … Cranial Bones - Occiput Occipital Motion The occiput has physiologic motion of flexion & extension in the sagittal plane around a transverse axis, lying just above the jugular processes. Flexion - the occipital base moves superiorly - the posterior aspect moves posterior-inferiorl - the occipital condyles move anteriorly. The occiput primarily influences the parietals & temporal bones. Adapted from a lecture by Barry Malina, D.O., F.A.A.F.P. – AZCOM Know that the occiput primarily influences the parietals & temporal bones  question -she also said this is all you need to know from this slide and for boards as well

Articular … Cranial Bones – Temporal The motion of the occiput is directly responsible for the motion of the temporal bones. The axis of physiologic motion runs from the jugular surface to the petrous apex parallel to the petrous ridge. In the flexion phase, the temporal bones externally rotate. The squama moves anterolaterally and the mastoid portion moves medially and slightly posteriorly. In the extension phase, the reverse occurs External Rotation Internal Rotation Adapted from a lecture by Barry Malina, D.O., F.A.A.F.P. – AZCOM Meh, only know what is in red

Articular Mobility of Cranial Bones

Articular … Cranial Bones - Frontal Axis of rotation runs from the center of the orbital plate up through the center of the orbital eminence near the change of bevel at the cranial border. Hinge-like action along the metopic suture, remains a line of persisting flexibility. In external rotation, the inferior lateral angles (zygomatic angles) of the frontal bone move laterally, inferiorly and slightly forward. The opposite occurs in internal rotation. The glabella tends to recede slightly in external rotation due to the pull of the falx cerebri. Adapted from a lecture by Barry Malina, D.O., F.A.A.F.P. – AZCoM Know both the frontal and parietal bones are paired

Articular … Cranial Bones - Parietal Axis runs parallel to the sagittal suture through the change of bevel at the anterior & posterior borders of each parietal bone In external rotation, the inferior borders of the parietal bone moves laterally. A “widening” occurs which is greatest at the posterior aspect of the bones. Internal rotation the inferior borders move medially. Adapted from a lecture by Barry Malina, D.O., F.A.A.F.P. – AZCOM Know both the frontal and parietal bones are paired

Parietal In flexion, paired bones (like the parietal bone) will externally rotate  this will widen the head and shorten the AP diameter In Extension, paried bones (like the parietal bone) will internally rotate  this will lengthen the AP diameter, making the head less wide

Motions of Flexion and Extension Midline Bones Flex Paired bones externally rotate Bi-parietal diameter increases AP diameter decreases Midline bones extend Paired bones internally rotate Bi-parietal diameter decreases AP diameter increases Test questions will come from this slide This basically summarizes a bunch of slides so far

A few key relationships Osteology A few key relationships

These four bones overlap in alphabetical order from within outward Pterion These four bones overlap in alphabetical order from within outward Netter Presenter: 2001. Frontal - anterosuperiorly Parietal – posterosuperiorly Sphenoid –lateral surface of great wing, anteroinferiorly Temporal - centrally Frontal Parietal Temporal Sphenoid This was a test question before, it will probably be a test question again Know which four bones overlap to form the pterion Know where the pterion is if given a pic

Pterion

Strain Patterns Patterns of the SBS

Strain Patterns Flexion Extension Torsion Side Bending Rotation Right Left Side Bending Rotation Lateral Strain Vertical Strain Superior Strain Inferior Strain Compression

Physiologic Strain Patterns of SBS Flexion Extension Torsion Right Left Side Bending Rotation Know what of the strain patterns are physiological  test question

Flexion - Extension Are the expected physiologic motions Can be pathological if restricted in one extreme or another

Flexion/extension Longer than usual cycle, typically (Similar to prolonged exhalation in COPD) Will have different feels at the ‘endpoints’ of the phases Will have decreased flow in the opposite phase (e.g., flexion dysfunctions will have diminished extension pattern) Extension Flexion Flexion, SBS moves up, tension is cephlad of dural sheath, sacrum will move posterior, midline bones flex, paired bones externally rotate, AP diameter shortens. Extension is opposite of all of this This is no different than a normal physiological motion, it is just one way moves way better than the other, therefore you have a dysfunction

FLEXION

EXTENSION

Flexion ER ER ER ER Findings-all quadrants in external rotation Increased transverse diameter Forehead wide and sloping(brow prominent with forehead receding) AP diameter equal on both sides Sagittal suture flattened or depressed Sphenoid Superomedial-inferolateral diameter greater Orbits wider Eyeballs protuberant Increased fronto-zygomatic angle Frontal processes of maxillae are nearly in coronal plane Maxillary palantine processes flattened Occiput Protruding ears Mastoid tips posteromedial Maxillae Nasolabial crease deeper This is retarded. Just know what their face looks like with a flexion dysfunction and ignore that stupid circle

Extension IR IR IR IR Findings-all quadrants in internal rotation Long narrow head Decreased transverse diameter Forehead prominent with Brow receding Sphenoid Superomedial-inferolateral diameter decreased Decreased frontozygomatic angle Orbit narrowed Eyeballs retruded Frontal processes of the maxillae are nearly in sagittal plane Maxillary palantine processes arched Occiput Ears close to head Mastoid tips anterolateral Maxillae Nasolabial crease shallow This is retarded too Again, just know what their face looks like with an extension dysfunction and ignore that stupid circle

TORSION One axis Antero-superior to Infero-posterior Spenoid and occiput rotate in opposite directions Named for superior great wing of sphenoid Just know it is on an AP axis and you name it for the wing of the sphenoid that is higher

Torsion Torsion of the sphenoid about an anteroposterior (AP) axis extending from the nasion through the symphysis to opisthion The sphenoid & anterior skull components are in one direction, the occiput & posterior components in the other. This strain is named for the side of the high wing of the sphenoid, right torsion (RT) or left torsion (LT)

Right Torsion IR ER IR ER Findings- asymmetric quadrants Sphenoid-1 quadrant in external rotation Higher greater wing side relative to the other Orbit wide Frontolateral angle anterior Zygomatic orbital rim everted Maxillary frontal processes in more coronal plane Maxillary palantine processes flattened Occiput-1 quadrant in external rotation Low occiput side relative to the other Protruding ears Mastoid tips posteromedial This pic for ex would be a right torsion Nothing else on this slide is prob relevant at our level

SIDEBENDING ROTATION Two axes: A-P and bilateral vertical axes Occiput and Sphenoid rotate same direction on AP axis; side-bend away from each other on parallel vertical axes. Named for convexity

Sidebending – Rotation Strain Occurs around an AP axis & around 2 parallel vertical axes: one through the body of the sphenoid & one through the foramen magnum, perpendicular to the physiologic transverse axes & the A-P axis As the SBS sidebends, it also rotates inferiorly to the convex sidebending side (coupled motion) Named for the convex side of sidebending Lt Sidebending – Rotation Strain

Right Sidebending Rotation ER IR IR ER Findings- 1 side of face full and convex with the opposite side flattened (side of the lower greater wing of the sphenoid) Sphenoid- Side of low greater wing in internal rotation Lateral fontal angle posterior Orbit narrower Eyeball retruded Frontozygomatic angle lessened Zygomatic tuberosity prominent Maxillary frontal process more sagittal Maxillary palantine process more arched Occiput Mastoid tip –posteromedial Ear protruding Meh

Non-physiologic Strain Patterns of SBS Lateral Strain Right Left Vertical Strains Superior Strain Inferior Strain Compression Know these types of strains are non physiological  test question

LATERAL STRAIN Bilateral vertical axes Shearing force at SBS causing Sphenoid and Occiput to rotate same direction on axes Named for position of basisphenoid Head appears “parallelogram”

Lateral Strain Sphenoid and occiput have the same rotation about a vertical axis, resulting in a lateral strain pattern Can happen with a one-sided impact from the front or back of head (off-center impact) Named for the position of the base of the sphenoid, relative to the occiput at the SBS Also known as “parallelogram head” Left lateral strain KNOW that it is caused by a one sided impact (off centered) and that it is called a parallelogram head

VERTICAL STRAINS Sphenoid and Occiput rotate same direction on parallel horizontal axes Named for position (superior/inferior) of base of Sphenoid

Vertical Strain -Superior/Inferior Sphenoid and occiput have the same rotation about a transverse axis, resulting in a vertical strain pattern Named for the position of the base of the sphenoid, relative to the occiput at the SBS Superior Shear Inferior Shear Superior Shear

SBS Compression Aka, ‘bowling ball head’ This is where the SBS has been compressed (think of a ‘jammed’ finger), causing a near total lack of motion at the SBS in any particular direction Most commonly seen in frontal impact trauma, difficult births, and circumferential loads to the skull, but can also be seen in severe psychiatric & emotional states

SBS Patterns Axes Naming A-P Transverse Vertical Paired SB-Rot=Convexity Torsion=High Gr Wing Rest=Sphenoid Base Direction

Overview of Motions Occiput, sphenoid, ethmoid, vomer Rotate about a transverse axis during physiologic Flexion and Extension Paired bones of the periphery Frontals, temporals, parietals, maxilla, palatines, zygomae Rotate externally during cranial flexion Rotate internally during cranial extension

Observational Diagnosis Flexion Extension Torsion Sidebending Rotation Observational diagnosis Observe face from the frontal and from superior view of the head Know what is in red  could be a test question

Picture Effect on Internal/External Rotation on Paired Bones of Face Easiest: Flexion or Extension Type Palate/Dental Arch: Extension = high & narrow Flexion = low & wide Face affected most by Sphenoid; Temporals & Sacrum by Occiput

Diagnosis by Visual Observation Flexion Extension Orbit widens/ protrudes Nasolabial crease deeper Flattened Cheek Ears – outflared Decreased Frontal Eminence Sloping forehead Prominent Brow/Superciliary ridge Orbit narrows/ recedes Nasolabial crease shallow Cheek prominent Ears- inflared Increased Frontal Eminence Vertical forehead Receding Brow/Superciliary Ridge

Vault Hold Pt supine, you gently place your hands on the lateral aspects of the cranium with the following landmarks: Index fingers in the temple (not temporal) region, over the greater wings of sphenoid Middle finger just in front of the ear on the temporal bone Ring finger just behind the ear on the temporal bone Little finger as close to the mastoid portion of the occipitomastoid suture as possible Thumbs gently resting on parietals or frontal bone, wherever they fall for your hands on the patient’s skull

Flexion Shortening with flexion

Extension Elongation with extension

Fronto-Occipital Hold Patient supine, with head at 3/4 of table. Physician at side of head of table. One hand cupping occiput. Other hand lightly palpating frontal bone General sensation is that of: Shortening of A/P axis with Flexion Elongation of A/P axis with Extension Meh, not impt

Flexion = Shortening of A/P axis Extension = Lengthening of A/P axis

Temporal Bone as “Trouble-Maker” External Rotation of Temporal = Pressure on Trigeminal Ganglion & Tightens Cave

Cranial Nerves - Summary Temporal Bone as “Trouble-Maker” For all the cranial nerves, know what their name is and know what the do CN 11 definitely goes through the foramen magnum….not the jugular formamen CN 1 – cribiform plate CN 2 – optic canal (not foramen) V2 – foramen rotundum V3 – foramen ovale CN V1, 3,4,6  all through superior orbital fissure

Olfactory Nerve - CNI Hx: Blow to head Anosmia Altered sense smell Physical: Ability to smell Frontal bone motion Also sphenoid, ethmoid, vomer motion Tx of Dysfunction: Frontal lift – Ethmoid pump OMT

Motor to Extra-Ocular Ms’s CN III, IV, VI Group: Motor to Extra-Ocular Ms’s III: Parasympathetic (Accommodation)

Petrosphenoidal Ligament and its association with CN III, IV, VI Attached border of Tentorium “Petrosphenoidal Ligament” (Ligamentous thickening from end of Petrous Temporal to Sphenoid) CN III over; CN IV through; CN VI under & at tip of the temporal She will not ask this External Rotation

CNV - Trigeminal Sensory to the Face Function Structure Dysfunction History Physical examination Sensory to the Face Motor to the muscles of mastication V1=SOF, V2=Foramen rotundum, V3=Foramen ovale; Meckel’s cave, petrosphenoid ligaments, Cervical spine Anesthesia, Trigeminal neuralgia (“Tic douleroux”) Trauma, Plagiocephaly Test sensation, corneal reflex Evaluate temporal (petrobasilar), sphenoid

CN VII - Facial Nerve Motor to facial muscles Function Parasympathetic to glands Special sense to tongue Stylomastoid foramen internal acoustic meatus Paralysis, weakness, no or poor taste sense Viral illness, trauma Test facial expression, taste External rotation of temporal and sphenoid bones Function Structure Dysfunction History Physical examination Bells palsy

CN VIII - Vestibulocochlear Nerve Function Structure Dysfunction History Physical examination Sensory - hearing and balance Internal acoustic meatus Hearing deficit, tinnitus, vertigo, otitis media and interna Trauma, infectious diseases Evaluation of temporals & sphenoid; balance; hearing

CN IX - Glossopharyngeal Nerve Function Structure Dysfunction History Physical examination Motor to muscle; Parasympathetic to glands; Sensory to palate Jugular foramen Difficulties swallowing, excessive gag reflex Trauma to occiput &/or temporals Test gag reflex Evaluation of temporals, occiput, occipitomastoid suture

CN X - Vagus Nerve Function Structure Dysfunction History Motor to striated muscle; Parasympathetic to smooth muscle and glands; Sensory from viscera Jugular foramen, Foramen magnum Numerous Somatovisceral; Posterior Headaches; More Trauma occiput, temporal Test gag reflex Evaluate OA, AA, C2, temporal, occiput, OM suture Function Structure Dysfunction History Physical examination

CN XI - Accessory Nerve

CN XI - Accessory Nerve Motor Function Cervicals, Foramen magnum, Jugular foramen Weakness/paralysis, torticollis; Recurrent Trigger Points in SCM & Trapezius Trauma to cervicals, occiput, temporals Test SCM & Trapezius muscles; Evaluate cervicals, occiput, temporals Function Structure Dysfunction History Physical exam

CN XII - Hypoglossal Nerve Function Structure Dysfunction History Physical examination Motor to Tongue Hypoglossal canal Dysphagia, tongue function Trauma to occiput (condyles) Test tongue motions Evaluate occiput (condyles), upper cervicals

Questions?