Dense and fibrous in middle and thin in the periphery.
It has vessels and nerves
Clinical significance: injury to scalp deep up to this layer causes profuse bleeding, bleeding can be arrested by pressing against the skull. inflammation of this layer causes little swelling and more pain.
Freely movable on the pericranium along with the skin and superficial fascia
Anteriorly,it has insertion of frontalis muscle and posteriorly insertion of occipitalis and is attached to the external occipital protuberances and to the highest nuctal lines between occipital bellies.
Each side of aponeurosis is attached to the superior temporal line but sends a thin expansion to the temporal fascia and is attached to the zygomatic arch