(1.2) Osteology Flashcards
What structures does the ligamentum nuchae (nuchal ligament) attach to? What is its function?
Attaches to the Occipital bone -> Posterior tubercle of C1 -> Spinous processes of C3 to C7 -> continues as Supraspinous and Interspinous ligaments from C7 to Sacrum
Function to preserve the normal curvature of the cervical vertebrae
Why is the facial nerve at risk of damage during a forceps delivery?
Newborns’ temporal bone is still not fully developed, leaving a small mastoid process, therefore the facial nerve is more superficially placed when it leaves the stylomastoid foramen
How are the cervical vertebrae different from the other typical vertebrae in the body?
- Spinous processes bifid
- Foramen Transversarium in Transverse Processes for Vertebral arteries to pass through
- Largest & triangular Vertebral Foramina
What are the names of C1 and C2? How are they and C7 different from the other typical Cervical Vertebrae?
- C1 = Atlas, has no Body or Spinous Process
- C2 = Axis, projects Dens that is held by Transverse (Cruciform) Ligament of Atlas
- C7 does not have Spinous Process
Which joint allows shaking the head? Which joint allows nodding the head?
- Nodding: Atlanto-occipital
- Shaking: Atlanto-axial
(Say yes before say no)
Why are the Cervical vertebrae prone to whiplash injuries?
The Articular Facets of the Cervical vertebrae are more horizontally aligned
What is a Jefferson fracture?
A vertical transmitted force either from the head or leg, on to EXTENDED neck, bursting the Atlas (fracture either or both superior or poster arches)
What is a Hangman’s fracture?
Hyperextension of the head & neck, dislocating the Dens of Axis to crush the brain stem -> unconsciousness/respiratory or cardiac failure/death
Why is a sublaxation between C2 & C3 life-threatening? What common cause may result this?
- Compression to the outflows of Phrenic Nerve (C3-C5), as each nerve root exits above the corresponding vertebra. This disable the diaphragm to contract during inspiration
- Whiplash/Hyperextended injury - head being whipped back on to shoulder e.g. due to car accident/rugby tackle
What is a suture? What are their roles?
Sutures = fibrous joints of the skull
Serrated edges & directions -> interlock bones, preventing fractures from a pressure in one direction
Where is the weakest point in the skull? What may a fracture of the point cause? How may it be treated?
Pterion = junction of Frontal & Parietal & Temporal & Sphenoid
- > the Middle Meningeal A (br. of Maxillary A) runs underneath, which supplies the Dura and the Skull. Its damage may lead to Extracranial Haematoma hence a raised ICP -> nausea, bradycardia, limbs weakness
- treated with Diuretics or if severe, Burr Holes are made
How are the neonatal bones different from the adult ones?
- Open Sutures = Frontanelles
- Small Facial skeletons
- Alveolar processes & Paranasal sinuses aren’t fully developed
What are the 6 main parts of the Temporal bone?
- Squamous
- Zygomatic process
- Tympanic
- Styloid process
- Mastoid process
- Pteromastoid
http: //teachmeanatomy.info/head/osteology/temporal-bone/
What is a dipole in the clavaria? What is its function?
- Dipole = Spongy layer (containing bone marrow) that separate the 2 compact bones in the clavaria
- Reduces weight
- Haemopoeisis
Which two sutures meet to form the Bregma? Which two form the Lambda?
- Coronal & Sagittal
- Lambdoid & Sagittal
Suggest some functions of the skull
- Encloses and protects the brain & special organs
- Specialised environment in which the brain thrives
- Acts as a site of attachment for muscles & meninges
What is the clinical significance of foramina of the cranial floor?
- Reduces weight
- Allows exits/entries of structures
- Make the base of the skull weak
What structures can the Clavaria be divided into? What are the main bones of Clavaria?
- Cranial cap
- Cranial Base
- Frontal
- Parietal
- Temporal
- Occipital
What is a Basal skull fracture?
Fracture of cranial base, presenting with Battle’s sign
What is a Communicated fracture?
A fracture that breaks bones into pieces
What is the “antrum” in the facial skeletons?
Maxillary sinus which is located in the body of Maxilla
Suggest 6 anatomical sites in the H&N that are prone to fracture.
- Squamous Temporal bone & Parietal bone overlying temples and Sphenoid air sinus
- Foramen Magnum & inner part of Sphenoid wings
- Anterior cranial fossa - Cribiform plate of Ethmoid bone
- Anterior cranial fossa - roof of the orbits
- Middle cranial fossa - Pterion, weakest point of the skull (junction of Parietal & Temporal & Sphenoid & Frontal bones)
- Posterior cranial fossa - between Mastoid & Dural sinuses
What is a depressed fracture?
A LOCALISED fracture that cause a depression at the site that may compress the underlying brain and tissues
What is a Counterblow fracture?
A fracture that causes no damage at the site but the opposite side of the blown
What is a Linear Clavarial fracture?
A fracture of the Clavaria (skull cap) that causes RADIATING linear fractures away from the blown in MULTI-directions
What is a Simple fracture?
A fracture breaks the bone but doesn’t break through skin
What is a Compound fracture?
A fracture breaks both the skin and bone, accompanied by BRAIN injury & BLEEDing
What is a Diastatic fracture?
A fracture along the suture line, causing it to widen, mostly seen in kids
Where does the Pituitary gland sit? Through which route may a Pituitary tumour be removed?
- Sella Turcica of Sphenoid bone within cranial fossa
- Through nasal cavity -> open Sphenoid sinus -> Sella Turcica
Through which foramina do these structure pas through?
- Cranial nerves
- Middle Meningeal A
- Greater Petrosal N
- Basilar A
- Vertebral A
- Internal Carotid A
- CN I -> Cribiform plate of Ethmoid
- CN II -> Optic Canal
- CN III, IV, Vi, VI -> Superior Orbital Fissure
- CN Vii -> Foramen Rotundum
- CN Viii -> Foramen Ovale
- CN VII & VIII -> Internal Acoustic Canal
- CN IX & XI -> Jugular Foramen
- CN XII -> Hypoglossal Canal
- Middle Meningeal A -> Foramen Spinosum
- Vertebral A -> Foramina Transversalis -> Basilar A -> Foramen Magnum
- Internal Carotid A -> Carotid Canal
- Greater Petrosal N -> Foramen Lacerum
