The epicranial aponeurosis (aponeurosis epicranialis, galea aponeurotica) is an

aponeurosis An aponeurosis (; plural: ''aponeuroses'') is a type or a variant of the deep fascia, in the form of a sheet of pearly-white fibrous tissue that attaches sheet-like muscles needing a wide area of attachment. Their primary function is to join musc ...

(a tough layer of dense fibrous tissue). It covers the upper part of the skull in humans and many other animals.

Structure

In humans, the epicranial aponeurosis originates from the external occipital protuberance and

highest nuchal lines The nuchal lines are four curved lines on the external surface of the occipital bone: * The upper, often faintly marked, is named the highest nuchal line, but is sometimes referred to as the Mempin line or linea suprema, and it attaches to the ep ...

of the

occipital bone The occipital bone () is a neurocranium, cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobe ...

. It merges with the

occipitofrontalis muscle The occipitofrontalis muscle (epicranius muscle) is a muscle which covers parts of the skull. It consists of two parts or bellies: the occipital belly, near the occipital bone, and the frontal belly, near the frontal bone. It is supplied by th ...

. In front, it forms a short and narrow prolongation between its union with the frontalis muscle (the frontal part of the occipitofrontalis muscle). On either side, the epicranial aponeurosis attaches to the anterior auricular muscles and the superior auricular muscles. Here it is less aponeurotic, and is continued over the temporal fascia to the zygomatic arch as a layer of laminated areolar tissue. It is closely connected to the integument by the firm, dense, fibro-fatty layer which forms the

superficial fascia A fascia (; plural fasciae or fascias; adjective fascial; from Latin: "band") is a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches to, stabilizes, encloses, and separates muscles and other internal orga ...

of the scalp. It is attached to the pericranium by loose cellular tissue, which allows the aponeurosis, carrying with it the integument, to move through a considerable distance.

Clinical significance

Subgaleal haemorrhage is defined as bleeding between the epicranial aponeurosis and the skull. Conservative management is usually appropriate for these, as there is little risk of further damage to surrounding structures.

History

The epicranial aponeurosis is also known as the aponeurosis epicranialis (from Latin), and the galea aponeurotica.

Additional images

File:Gray1196.png, Diagrammatic section of scalp. 1106 Front Views of the Muscles of Facial Expressions numbered.jpg, Epicranial aponeurosis from a frontal view, labeled 1

References

External links