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

aponeurosis An aponeurosis (; : aponeuroses) is a flattened tendon by which muscle attaches to bone or fascia. Aponeuroses exhibit an ordered arrangement of collagen fibres, thus attaining high tensile strength in a particular direction while being vulnerable ...

(a tough layer of dense fibrous tissue). It covers the upper part of the

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

human Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

s and many other animals.

Structure

In humans, the epicranial aponeurosis originates from the

external occipital protuberance External may refer to: * Externality, in economics, the cost or benefit that affects a party who did not choose to incur that cost or benefit * Externals, a fictional group of X-Men antagonists See also * * Internal (disambiguation) {{disa ...

and highest nuchal lines 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 lies over the occipital lob ...

. 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 the ...

. In front, it forms a short and narrow prolongation between its union with the

frontalis muscle The frontalis muscle () is a muscle which covers parts of the forehead of the skull. Some sources consider the frontalis muscle to be a distinct muscle. However, Terminologia Anatomica currently classifies it as part of the occipitofrontalis muscl ...

(the frontal part of the occipitofrontalis muscle). On either side, the epicranial aponeurosis attaches to the anterior auricular muscles and the

superior auricular muscle The superior auricular muscle is a muscle above the auricle of the outer ear. It originates from the epicranial aponeurosis, and inserts into the upper part of the medial surface of the auricle. It draws the auricle upwards. Structure The supe ...

s. Here it is less

aponeurotic An aponeurosis (; : aponeuroses) is a flattened tendon by which muscle attaches to bone or fascia. Aponeuroses exhibit an ordered arrangement of collagen fibres, thus attaining high tensile strength in a particular direction while being vulnerabl ...

, and is continued over the

temporal fascia The temporal fascia (or deep temporal fascia) is a fascia of the head that covers the temporalis muscle and structures situated superior to the zygomatic arch. The fascia is attached superiorly at the superior temporal line; inferiorly, it split ...

to the

zygomatic arch In anatomy, the zygomatic arch (colloquially known as the cheek bone), is a part of the skull formed by the zygomatic process of temporal bone, zygomatic process of the temporal bone (a bone extending forward from the side of the skull, over the ...

as a layer of laminated

areolar tissue Loose connective tissue, also known as areolar tissue, is a cellular connective tissue with thin and relatively sparse collagen fibers. They have a semi-fluid matrix with lesser proportions of fibers. Its ground substance occupies more volume ...

. It is closely connected to the

integument In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, Exoskeleton, shell, germ or Peel (fruit), rind. Etymology The term is derived from ''integumentum'', which is Latin for "a coverin ...

by the firm, dense, fibro-fatty layer which forms the

superficial fascia A fascia (; : fasciae or fascias; adjective fascial; ) is a generic term for macroscopic membranous bodily structures. Fasciae are classified as superficial, visceral or deep, and further designated according to their anatomical location. Th ...

of the

scalp The scalp is the area of the head where head hair grows. It is made up of skin, layers of connective and fibrous tissues, and the membrane of the skull. Anatomically, the scalp is part of the epicranium, a collection of structures covering th ...

. It is attached to the

pericranium The periosteum is a membrane that covers the outer surface of all bones, except at the articular surfaces (i.e. the parts within a joint space) of long bones. (At the joints of long bones the bone's outer surface is lined with "articular cartilag ...

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

Conservative management Conservative treatment is a type of medical treatment defined by the avoidance of invasive measures such as surgery or other invasive procedures, usually with the intent to preserve function or body parts. For example, in appendicitis, conservati ...

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 Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

), 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

* - "Cranial Fossae: Layers of the scalp" {{Authority control Muscles of the head and neck