What is the skull broadly divided into?
The neurocranium (upper back part of the skull) The Viscerocranium (Facial Skull) The Mandible (Lower Jaw)
What is the most common type of joint seen between most bones in the skull?
fibrous joint- sutures - bound by Sharpey's fibres (only found between flat structures)
Most bones of the skull are made up of an external and internal layer of compact bone separated by spongy bone known as?
Label this diagram
Where is the red marrow housed?
In the diploe
Label the diagram
Where is the external auditory meatus?
What type of joint are sutures?
Where do the sagittal suture lie between?
Between the parietal bone
What does the coronal suture lie between?
lies between Frontal and Parietal bone
What does the lambdoid suture lie between?
Pariental and occipital
What are fontanelles?
Areas of fibrous tissue.
- Bones of the skull are not fused in young children and so are connected by fontanelles
Bulging or depressions of fontanelles can be a sign of what?
A number of clinical conditions which will need investigated
Which fontanelles would close first?
The posterior fontanelles
What are the type of bones are the bones of the facial skeleton?
Mainly irregular bones
- they give attatchment to muscles of the toungue, mastication and pharynx
Label this diagram
What bony prominence is A and what bone does it belong to?
Part of the occipital bone
What bony prominence is B and what bone does it belong to?
A part of the temporal bone
What bony prominence is C and what bone does it belong to?
Made up of the zygomatic bone and the temporal bone
What bony prominence is D and which bone is it a apart of?
Part of the temporal bone
What bony prominence is E and what bone does it belong to?
part of the occipital bones
Which bondy prominences can be palpated?
Occipital protuberance, Mastoid process and Zygomatic arch
Where does the scalp extend to?
Anteriorly until the eyebrows
Posteriorly till the superior nuchal lines
Laterally as far as the superior temporal line and provides an attachment for muscle bellies.
What bone is the superior nuchal line a part of?
The occipital bone
What two bones form the zygomatic arch?
Anteriorly: Zygomatic Bone
Posteriorly: Temporal Bone
What do the layers of the skull divide the floor of the skull into?
The floor of the skull is on three levels dividing the cranial cavity into three fossae
What are the 3 layers of the skull floor?
1. Anterior cranial fossa
2. Middle cranial fossa
3. Posterior cranial fossa
What bone can be clearly visulaised here and what layer does it make up?
The sphenoid bone and it makes up most of the middle cranial fossa
Label the sphenoid bone
What are the five layers of the scalp?
Aponeurosis of the occipitofrontal msucle (epicrainial aponeurosis)
Loose areolar tissue
(N.B these two final layers are usually not easily visable)
label this diagram
What layer of the scalp does the epicranial aponeurosis make up?
Third layer of the scalp
This aponeurosis connects the anterior (frontal) and posterior (occipital) bellies of the occipitofrontalis muscle
What nerve innervates the area in front of the red line?
Cranial Nerve V (Cr.N.5)
What nerve innervates the area behind the red line?
C 2, 3, 4
What cervical spinal nerve has no cutaneous innervation?
No bit of skin is innervated by C1
What happens to C5-T1?
- go away and form the brachial plexus
Label this diagram
Describe spinal nerves
Both Ventral (motor) and Dorsal (sensory)
They only carry sympathetic fibres
White rami communicans takes away
grey rami carrues back
Only the sympatetic Ganglion
Describe crainial nerves
can have sensory, motor and parasympatetic fibres
Some have all, some have one only
How does the parasympatetic fibres make its way back to the trunk?
Via the vagus nerve (cranial nerve)
What fibres can the cranial nerves potentially carry?
- general sensory (Touch, temp, pain)
- special sensory (vision, hearing, smell, taste)
What fibres does Cr.N. 5 (trigeminal) carry?
Sensory- General sensation- dermatomes of the face
But can also carry motor fibres
What does the facial nerve carry?
The facial nerve carries special sensation of taste, motor and parasympathetic
How do sympathetic fibres reavh areas supplied by cranial nerves?
Postganglionic fibres from the sympathetic chain form a plexus and hitch a ride with the blood vessels
How many branches does crainial nerve 5 have (trigenimal) and what are these branches called?
Opthalmic division (V1)- forehead and upper part of the eye
Maxillary divison (V2)- sensory to the upper jawbone
Mandibular (V3)- lower jaw
All are general sensory (Temp, pain) no special sensors
however V3 also has motor fibres
NO PARASYMPATHETIC FIBRES
What is the anterior part of the scalp (anterior to the auricle or external ear) supplied by?
It is supplied by the branches of the trigeminal nerve
What supplies the posterior half of the scalp?
In the posterior half of the scalp (posterior to the auricle) nerve supply is from cutaneous branches of cervical spinal nerves C2 and C3.
Both the anterior and posterior rami of these spinal nerves supply the scalp
Label the sensory supply to the regions arrowed
What structure forms from the ventral rami of C5 to T1 and what does it innervate?