Axis and Motion of Cranial Bones

Question 1

What are the Midline/Unpaired bones?

Answer 1

Occiput

Sphenoid

Mandible

Vomer

Ethmoid

Question 2

What are the Pair Bones?

Answer 2

Frontal

Parietal

Temporal

Inferior nasal concha

Lacrimal

Maxilla

Nasal

Palatine

Zygoma

Question 3

General Motion of Midline Bones

Answer 3

Flexion and Extension

Question 4

General Motion of Paired Bones

Answer 4

Internal and External Rotation

Question 5

Movement of Ethmoid during SBS Flexion

Answer 5

Rotated by the sphenoid

Bottom of perpendicular plate goes inferior

The crista galli swings superior and posterior

Lateral masses externally rotate

Question 6

Movement of Ethmoid during SBS Extension

Answer 6

Crista galli rotates anterior and inferior

Perpendicular plate rotates posterior and superiod

Lateral masses internally rotate

Question 7

Movement of Vomer during SBS Flexion

Answer 7

Widens Palate

Posterior part goes superior

Anterior part goes inferior

Question 8

Movement of Vomer during SBS Extension

Answer 8

Narrow tall palate

Posterior part of vomer moves inferiorly

Anterior part of the vomer moves superiorly

Question 9

How do the ethmoid and vomer move in relation to the occiput and sphenoid?

Answer 9

Ethmoid and occiput move together

Vomer and sphenoid move together

Question 10

Clinical Correlation of the Vomer

Answer 10

SD of the vomer usually secondary to the position of the sphenoid

Usually from facial trauma

Question 11

Movement of Occiput and Sphenoid in SBS Flexion

Answer 11

Sphenoid rotates anteriorly

Occiput rotates posteriorly

Making cranial “bowl” bigger

Question 12

Movement of Occiput and Sphenoid in SBS Extension

Answer 12

Sphenoid rotates posteriorly

Occiput rotates anteriorly

Making cranial “bowl” smaller

Question 13

What axis does the vomer and ethmiod rotate around

Answer 13

Transverse axis

Question 14

What axis of motion do the Parietal bones rotate?

Answer 14

AP axis

Question 15

When the SBS is in flexion how does the Parietal bone rotate?

Answer 15

External rotation

Causing cranium to wide

Question 16

When the SBS goes into Extension, how does the Parietal bone move?

Answer 16

Internal rotation

Cranium narrows

Question 17

Signs and Symptoms of Mechanical Parietal Bone Dysfunction

Answer 17

Cranial synostosis - Premature closure of sutures

Head pain - pain along sutures that radiates from point of restriction (usually to oxipitomastoid and asterion)

Tension headaches

Pterion involved in temporal headaches

Question 18

Signs and Symptoms of Organ/Nerve Parietal Bone Dysfunction

Answer 18

Middle Meningeal A. (trauma or giant cell arteritis)

Head, face, and tooth pain - temporal muscle SD, parietosquamosal, or P-sphnoid

Question 19

Sagittal Synostosis

Answer 19

Most common synostosis

Premature fusion of the sagittal suture

Causes elongation of the craium - kinda looks like a football

Question 20

Lambdoid Synostosis

Answer 20

Commonly mistaken for posterior positional deformational plagiocephaly

Results in flattening on one side of the back of the head, ear on ipsilateral side is more posterior

Other half of head continues to grow - head looks like “banana”

Causes a “tilt” at cranial base

Question 21

When SBS is in flexion how do the temporal bones move?

Answer 21

Externally rotates

Zygomatic process less prominent

Bottom moves interiorly

Top moves externally

Widens cranium

Question 22

When SBS is in extension how do the temporal bones move?

Answer 22

Internal rotation

Zygomatic process more prominent

Bottom moves externally

Top moves internally

Question 23

What axis does the temporal bone rotate around?

Answer 23

An Oblique axis located just inferior to the petrous ridge

Question 24

Mechanical Signs and Symptoms of Temporal Bone SD

Answer 24

TMJ pain

Head pain - pain along suture

Neck pain - interdependent dysfunction with SCM and other muscles

Question 25

Organ/Nerve Signs and Symptoms of Temporal Bone SD

Answer 25

Dizziness

Ear Infections

Swallowing and chewing problems

Tinnitus and eustachian tube dysfuction

Bell’s Palsy

Question 26

Axis of Movement of the Frontal Bones

Answer 26

Vertical Axis through the center of the orbital roof

Question 27

During SBS flexion, how do the frontal bones rotate?

Answer 27

Externally rotate

Lateral sides move anterior/lateral

Glabella (smooth top part of frontal bone) moves slightly posteriorly

Question 28

During SBS extension, how do the frontal bones rotate?

Answer 28

Internal rotation

Lateral sides move posterior/medial and slightly superior

Glabella (smooth top part of frontal bones) - move slightly anterior

Question 29

Mechanical Signs and Symptoms of Frontal Bone SD

Answer 29

Focal head pain - pain along sutures

Global head pain - diminished respiration and CSF flow

Frontalis muscle - common cause of nerve and suture compression

Question 30

Organ/Nerve Signs and Symptoms of Frontal Bone SD

Answer 30

Sinusitis (allergic or infectious)

Visual problems

Anosmia

Question 31

Bicoronal Synostosis

Answer 31

Bilateral premature fusion of the frontal and parietal bones

Restriction of growth of the anterior fossa - bradycephaly

Compensatory vertical growth - turricephly

Question 32

Unicoronal Synostosis

Answer 32

Premature fusion of one side frontal and parietal bones

Leads to head shape = Anterior plagiocephaly

Looks like banana

Base of nose drawn toawrds the affected side with tip point away

Flat forehead on affected side and contralatera forehead is anterior

Question 33

Temporal bones in external rotation produces what type of tinnitus?

Answer 33

Low pitched tinnitus due to opening of the eustation tube

Question 34

Temporal bone in internal rotation presents with what type of tinnitus?

Answer 34

High pitched tinnitus due to a compression of the eustaion tube