Session 1 - Osteology of the Head and Neck

Question 1

How are bones of the skull joined together? Why is the skull joined together like this?

Answer 1

Sutures (fibrous joints). Allows brain growth during adolescence

Question 2

Answer 2

Question 3

What can bones of the cranium be subdivided into?

Answer 3

Calvarium (skull cap) and cranial base

Question 4

Name the bones of the cavarium

Answer 4

• Frontal
• Occipital
• Two parietal bones

Cavarium - FOP

Question 5

Name the bones of the cranial base

Answer 5

• Frontal
• Sphenoid
• Ethmoid
• Occipital
• Parietal
• Temporal

Question 6

Answer 6

Question 7

How many face bones are there? Name the face bones

Answer 7

14 bones

Zygomatic x2 – cheek bones of the face.
Lacrimal x2
Nasal x2
Inferior nasal conchae x2
Palatine x2 –
Maxilla x2 –
Vomer –
Mandible –

Question 8

What is the TMJ? Where is it located?

Answer 8

Articulation between mandible and temporal bone. Located at ends of mandible

Question 9

What is the purpose of the inferior nasal conchae? Where is it located?

Answer 9

located within the nasal cavity. Serve to increase SA of the nasal cavity and therefore the amount of inspired air that can come into contact with the cavity walls.

Question 10

What is the purpose of the palatine bone?

Answer 10

Forms part of hard palate at rear of oral cavity

Question 11

What does the maxilla help to form?

Answer 11

hard palate

Question 12

what does the vomer form?

Answer 12

Posterior aspect of the nasal septum

Question 13

Why are sutures of the skull clinically relevant? Name the 3 most clinically relevant. What are fontanelles? Name them

Answer 13

Points of potential weakness.

Coronal, sagittal, lambdoid sutures

Fontanelles (incompletely fused suture joints in neonates). Frontal fontanelle and occipital fontanelle

Question 14

Answer 14

Question 15

What is the pterion? Where is it located? What happens if this were to be fractured?

Answer 15

Thinnest part of the skull. Fracture here can lacerate an underlying artery (middle meningeal artery) and result in an extradural haematoma (blood collects in between dura mater and skull, increasing intracranial pressure). Symptoms are nausea, vomiting, seizures, bradycardia.

Question 16

How do you treat an extradural haematoma?

Answer 16

Treated with diuretic in minor cases and drilling burr holes into skull in more extreme cases

Question 17

What is the anterior cranial fossa?

Answer 17

Depression of skull formed by frontal, ethmoid and sphenoid bones

Question 18

What is the middle cranial fossa?

Answer 18

Depression formed by sphenoid, temporal and parietal bones

Question 19

What is the posterior cranial fossa?

Answer 19

Depression formed by squamous and mastoid temporal bone, and occipital bone

Question 20

What are the 4 types of cranial fractures? How does basal skull fracture present?

Answer 20

Depressed – Bone depresses inwards. Possible brain injury,
Linear – Break in bone traversing its full thickness. Most common.
Basal Skull – Affects base of the skull. Presents with bruising behind ears, known as ‘Battle’s sign’ or bruising around the eyes / orbits, known as Raccoon eye’s.
Diastatic – Fracture that occurs along a suture line causing a widening of the suture. Most often seen in children.

Question 21

Answer 21

Question 22

What is the function of the squamous part of the temporal bone?

Answer 22

Lower part is the site of origin of the temporalis muscle

Question 23

What is the function of the zygomatic process of the temporal bone?

Answer 23

• Articulates with the zygomatic bone, forming the zygomatic arch (cheek bones)
• Masseter muscles attaches some fibres to lateral surface of the zygomatic process.
• Articular tubercle on the zygomatic arch forms part of the temporomandibular joint.

Question 24

What is the function of the tympanic part of the temporal bone?

Answer 24

Surrounds the external auditory opening

Question 25

What is the function of the petrous part and the mastoid part of the temporal bone?

Answer 25

* Mastoid process, inferior projection of the bone, is palpable just behind the ear and is a site of attachment for SCM. * Mastoid air cells – Hollowed out areas within the temporal bone that act as a reservoir of air, equalising the pressure within the middle ear in cases of auditory tube dysfunction. Can become infected, known as mastoiditis. * Petrous part lies at base of temporal bone and contains inner ear

Question 26

What is mastoiditis? Where can it spread to?

Answer 26

Infection of mastoid process can spread into the middle cranial fossa and into the brain causing meningitis.

Question 27

What is the function of the styloid process?

Answer 27

Acts as an attachment point for muscles and ligaments

Question 28

What are the features of cervical vertebrae?

Answer 28

* Triangular vertebral foramen * Bifid spinous processes * Transverse foramina

Question 29

What are the features of the atlas? What allows it to articulate with the dens?

Answer 29

* No vertebral body * No spinous processes * Anterior articular facet which articulates with the dens of the axis * Posterior arch has a groove for the vertebral artery and C1 spinal nerve.

Question 30

What are the 2 parts to the atlanto-axial joint?

Answer 30

* Has a medial and 2 lateral aspects * Medially – Made up of dens process and atlas facet for dens. Pivot type synovial joint. * Laterally – Made up of articulation between the inferior facets of C1 and the superior facets of C2. Plane type synovial joints.

Question 31

What is the atlanto-occipital joint?

Answer 31

* Articulation between the spine and cranium * Occurs between the superior facets of the Atlas and the occipital condyles at the base of the cranium. * Condyloid type synovial joints

Question 32

What are vertebral arch joints?

Answer 32

Formed by articulation of the superior and inferior articular processes of adjacent vertebrae

Question 33

What ligaments are found throughout the spine? What is found only in the cervical spine?

Answer 33

Throughout: * Interspinous ligament * Anterior and posterior longitudinal ligaments * Ligamentum flavum Only in cervical spine: * Nuchal ligament * Transverse ligament of Atlas

Question 34

Answer 34

Question 35

What is the function of the nuchal ligament?

Answer 35

Continuation of supraspinous ligament. Attaches tips of the spinous processes from C1-C7. Provides proximal attachment for the rhomboids and the trapezius.

Question 36

What is the function of the transverse ligament of Atlas?

Answer 36

Connects the lateral masses of the Atlas, and anchors the dens in place

Question 37

Through which transverse foramina does the vertebral artery travel?

Answer 37

C2-6

Question 38

How many cervical spinal nerves are there? Explain

Answer 38

* At C7, there are spinal nerves extending from above and below this vertebra * There are 8 spinal nerves associated with 7 cervical vertebrae.

Question 39

Where does the vertebral artery run at C1?

Answer 39

Vertebral artery runs along the groove for the vertebral artery.

Question 40

What is a jefferson fracture of the atlas? How does it occur? What happens?

Answer 40

* Occurs due to a vertical fall onto an extended neck * Results in compression of the lateral masses of the Atlas, driving them apart and fracturing one or both of the posterior / anterior arches. * Can also rupture the transverse ligament of the Atlas.

Question 41

What occurs in a hyperxtension / whiplash injury? Minor case, severe case, and worst case scenarios?

Answer 41

* Minor cases result in damage to the anterior longitudinal ligament of the spine * More severe cases fractures to any cervical vertebrae can occur due to sudden compression by rapid deceleration. * Worse case scenario is the dislocation or subluxation of the cervical vertebrae. Often happens at C2 level. Can lead to spinal cord injury, quadraplegia or death.

Question 42

What is a hangmans's fracture? What results?

Answer 42

* Fracture of the pars interarticularis, a bony column between the superior and inferior articular facets of the axis. * Likely to rupture the spinal cord and result in death.

Question 43

What is a den's fracture? What is it commonly caused by and what results?

Answer 43

* Commonly caused by falls and traffic collision * High risk of avascular necrosis * Slight risk of spinal cord involvement.