1. The scalp enjoys a rich blood supply in which there is an exentesive antero-posterior and right-left anastomosis.

Thus wounds of the scalp bleed profusely but heal very rapidly. The blood vessels are located in the connective

tissue layer.  The tunica adventitia of the vessels merges with the connective tissue. When lacerated, the elastic

recoil of theconnective tissue holds the vessels open.

2. The veins of the scalp are connected to the intracranial venous sinuses by emissary veins. Therefore

• Raised intracranial pressure may be manifested in dilatation of scalp veins
  
  
• Infections or malignancies can spread between intracranial and extracranial sites

3. The aponeurosis connects the frontalis and occipitalis muscles. If it is cut coronally. contraction of the muscle

usually gapes the wound.

4. The layer of loose connective tissue constitutes the plane of avulsion. The superficial three layers usually peel

off as a unit with their blood vessels. Therefore such injuries still heal well. Fluid, for example, that accumulates in

this layer spreads over the entire extent of the aponeurosis reaching the eyelid and presents as a black eye.

5. The pericranium, that is the periosteum of the skull bones is tightly adherent to the sutures. Accordingly,

blood that accumulates and clots i.e cephalohematoma is confined to one bone for example the right parietal.

Applied anatomy of the Skull

• The pterion: Meeting point of frontal, parietal, temporal and greater wing of sphenoid. This point overlies the anterior branch of middle meningeal in the epi dural space. Therefore, fractures commonly tear the artery causing epidural hematoma.
  
  
• Squamous temporal
  
  
• Orbital roof
  
  
• Nasal bones
  
  
• Cribriform plate

These points are easily fractured causing injury to the underlying organs.

2. In fractures of cribriform plate and petrous temporal bone, meninges and mucous membranes may be torn

causing CSF to leak through the nose (CSF rhinorrhoea) or ear (CSF otorrhoea)

3. The foramina have rigid boundaries. So , in space occupying lesions, contents of the foramina are often

compressed e.g jugular foramen syndrome in which cranial nerves and jugular veins are compressed causing

neurological and vascular symptoms.

4. Abscence of diploe in babies facilitates moulding.

5. Fontanelles and sutures in newborns permit brain growth, delayed closure suggests retarded skeletal

growth or raised intracranial pressure.