Session 3: Osteology Flashcards
how is the neonatal skull different to that of an adult?
Open sutures and fontanelles to allow moulding during birth.
2 Frontal bones normally fuse but occasionally persist in an adult (metopic suture)
bony proportions are different, Facial skeleton is small at birth
Alveolar processes and paranasal sinuses underdeveloped at birth
What consequence during childbirth may result from the relative small size of the foetal mastoid process?
Small mastoid process leaves the facial nerve exposed as it exits from the stylomastoid foramen. A superficially placed nerve is likely to be injured during forceps delivery.
What is another term for the ‘antrum’ in the facial skeleton?
Frequently used to describe the maxillary air sinus which is located in the body of the maxilla
What is Paget’s disease of bone and what is its effect on the skull?
Affects people past middle age. Bones frequently involved are the pelvis, femora, vertebrae and skull.
There is a rapid, irregular and exaggerated resorption and replacement of bone causing thickening, swelling and increased vascularity often with severe pain.
When skull is affected - slowly enlarges and so does the jaw.
Teeth may become displaced and fuse with bone.
What is the ligamentum nuchae?
Also called nuchal ligament.
Found in the cervical region and is a continuation of the interspinous and supraspinous ligaments of the thoracic and lumbar vertebrae.
Attaches to the external occipital proturbence and the posterior borde of the foramen magnum to the spinous processes of the vertebrae
Main function: Preserve normal curvature of cervical spine
Why are the cervical vertebrae prone to dislocation in whiplash injuries?
Due to almost horizontal alignment of their respective articular facets between successive vertebra
Why might posterior prolapse of intervertebral disc between C2 and C3 prove fatal?
May cause pressure on spinal cord above the phrenic nerve outflow of C3,4,5
If happens suddenly, respiration will cease immediately. (C3, C4, C5 - diaphragm)
Why might fracture of the mandible cause numbness of the lower lip?
Fracture may involve the inferior alveolar nerve that lies within the bone, They supply the mucous membranes of the lower lip and chin.
What is the pterion?
An area on the side of the skull were 4 bones join (frontal, parietal, temporal and sphenoid). Bones are thin in this area and can fracture more easily, severing the anterior branch of the middle meningeal artery.
What is the clinical importance of the pterion in high energy impacts to the temporal region?
Due to the thin bones, this area can fracture more easily, severing the anterior branch of the middle meningeal artery
Explain what is meant by an ‘extradural haematoma’?
Dura mater consists of 2 layers, an outer periosteal layer and an inner meningeal layer. An extradural haematoma arises when a torn meningeal vessel bleeds between the outer periosteal layer of the dura mater and the cranium.
Why should fractures of the pterion constitute a medical emergency?
Middle meningeal artery lies underneath the pterion. Rupture can lead to extradural haematoma,
this compresses the brain which can lead to midline shift, coning and death.
Surgical decompression of this lesion is required.
