The galea aponeurotica refers to a flat sheet of fibrous tissue, an aponeurosis, that covers the skull and links the two parts of the epicranius muscle. The epicranius muscle, also known as the occipitofrontalis muscle, consists of the frontalis muscle and the occipitalis muscle. The galea aponeurotica serves as a connective tissue and plays an essential role in the movement and function of these muscles.

Fun Medical History: The galea aponeurotica has a fascinating history, with its name originating from the helmets worn by soldiers in ancient Greece. Physicians throughout history referred to the soft tissue between the skin and the skull as "panniculus". In the Middle Ages, the entire scalp was called a "great panicle that is called pericranium". It wasn't until 1724 that the tendinous sheath connecting the frontalis and occipitalis muscles was defined as "Galea tendinosa cranii," and by 1741, it became conventionally referred to as the galea aponeurotica.

During the early Renaissance, the renowned artist and scientist Leonardo da Vinci famously compared the dissection of the cranium to peeling an onion. The galea aponeurotica gained surgical significance during wartime experiences, particularly at Army Base Hospital No. 5, under the observation of Harvey Cushing. The use of buried sutures in the galea helped reduce operative mortality significantly. This practice became a tenet of modern neurosurgical practice, emphasizing the importance of this structure in surgical techniques.

For a more thorough history, check out the resource below: 

Connor DE Jr, Chittiboina P, Nanda A. From Pergamon to Army Base Hospital No. 5: the history and significance of the galea aponeurotica in the evolution of neurosurgery. J Neurosurg. 2014 Aug;121(2):333-7. doi: 10.3171/2014.3.JNS13148. Epub 2014 Jun 13. PMID: 24926652.