Definition: the scalp is made up of five layers of tissues
covering the calvaria
Extent: the scalp extends from the eyebrow to the superior
nuchal line at the back of the skull and down to the ears and zygomatic arches
at the sides.
Layers of the scalp:
1.      
Skin
2.      
Connective tissue
3.      
Aponeurosis
4.      
Loose connective tissue
5.      
Periosteum (pericardium).
–         
Skin: this is the most superficial layer of the
scalp hair covers scalp. The skin is thin. It contains sweat gland, sebaceous
glands.
–         
Connective tissue: this layer consists of
lobules of fat bound in tough fibrous septa. The blood vessels of the scalp lie
in this layer.
–         
Aponeurosis: this layer contains the muscle
occipito-frontalis, which is fibrous over the dome of the skull but muscular in
the occipital and frontal regions.
–         
Loose connective tissues: this layer is
sponge-like. It has many spaces capable of distension with fluid. It is this
layer that allows free movement of the scalp.
–         
Pericardium: this layer adheres to the suture
lines of the skull. It is made of specialized connective tissue.
Blood supply: from external carotid arteries through the
occipital, posterior auricular and superficial temporal arteries, and from the
internal carotid artery through the supratrochlear and supraorbital arteries. Veins
accompany arteries and have same names.
Lymph drainage: lymph from the scalp drains into the
superficial lymph nodes located at the junction of the head and neck.
Nerve supply:
1.      
Anterior to the auricles sensory innervations is
through branches of all three divisions of the trigeminal nerves.
2.      
Posterior to the auricles the nerve supply of
the scalp is from the spinal cutaneous nerves of the neck from the cervical
plexus.