Surgical Anatomy Layers if the Scalp

The basic mnemonic for the layers of the scalp (Fig. 6-1) is : S = skin

C = subcutaneous tissue A = aponeurosis and muscle L = loose areolar tissue P = pericranium (periosteum)

The skin and subcutaneous tissue of the scalp are surgically inseparable, unlike these same structures elsewhere in the body. Many hair follicles and sweat glands are found in the fat just beneath the dermis. Also, no easy plane of cleavage exists between the fat and the musculoaponeurotic layer.

The musculoaponeurotic layer, also inappropriately called the galea (which refers to aponeurosis only), consists of the paired frontalis (epicranius) and occipitalis muscle, the auricular muscles, plus a broad aponeurosis. The aponeurosis is the true galea and has two portions, an extensive intermediate aponeurosis between the frontalis and occipitalis muscles and a lateral extension into the temporoparietal region known as the temporoparietal fascia. Farther inferiorly, the temporoparietal fascia is continuous with the superficial musculoaponeurotic layer of the face (SMAS). The paired frontalis muscles originate from the galeal aponeurosis and insert into the dermis at the level of the eyebrows. An extension of the galea separates the two quadrilateral frontalis muscle in the middle of the forehead.

The galea is a dense, glistening sheet of fibrous tissue, approximately 0,5 mm thick, stretching between the occipitalis and frontalis muscles. When the galea moves, the skin and fat move with it because of their close attachment. Laterally, the galea (or temporoparietal fascia as it is usually called) becomes less dense, but is still readily dissectable. The superficial temporal artery lies on or in this layer.

The subgaleal fascia is the layer usually referred to as the "loose areolar layer" or the "subaponeurotic plane". This layer cleaves readily, allowing the skin, subcutaneous tissue

Figure 6 1 Layers of the scalp above the superior temporal line (top insert) and below the superior temporal line (right inset). Top inset : Skin, subcutaneous tissue, the musculoaponeurotic layer (galea in this illustration), the subgaleal layer of loose tissue, periosteum (pericranium), and bone of the skull. Right inset : Skin, subcutaneous tissues, the temporoparietal fascia (note temporal branch of VII N), the superficial layer of the temporalis fascia, a superficial pad of fat, the deep layer of temporalis fascia, the temporalis muscle above, the buccal fat pad below, skull.

Figure 6 1 Layers of the scalp above the superior temporal line (top insert) and below the superior temporal line (right inset). Top inset : Skin, subcutaneous tissue, the musculoaponeurotic layer (galea in this illustration), the subgaleal layer of loose tissue, periosteum (pericranium), and bone of the skull. Right inset : Skin, subcutaneous tissues, the temporoparietal fascia (note temporal branch of VII N), the superficial layer of the temporalis fascia, a superficial pad of fat, the deep layer of temporalis fascia, the temporalis muscle above, the buccal fat pad below, skull.

musculoaponeurotic layers to be stripped from the pericranium.It is in this fascial plane that cleavage occurs during traumatic avulsion of the scalp. The loose tissue of the subgaleal fascia allows free movement of the skin over the periosteum when the frontalis muscle is contracted. Anatomic dissection have also revealed that the subgaleal frontalis muscle is contracted. Anatomic dissections have also revealed that the subgaleal fascia can be mobilized as an independent fascial layer. For the routine coronal approach to the fascial skeleton, however, this fascial layer is used only for its ease of cleavage.

Anteriorly, the subgaleal fascia is continuous with the loose areolar layer deep to the orbicularis oculi muscles. Laterally, it is attached to the frontal process of the zygoma. This attachment continues along the superior surface of the zygomatic arch, above the external auditory meatus, and over the mastoid process. It terminates by fusing with the periosteum along the superior nuchal line.

The pericranium is the periosteum of the skull. The pericranium can be elevated from the skull, although it is more firmly attached along cranial sutures. When released by subperiosteal dissection, the pericranium retracts owing to its elasticity.

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Responses

  • Penelope
    Is galea of scalp a subcutaneous tissue?
    8 months ago
  • guendalina
    Why 1st 3 layers of scalp is surgical?
    8 months ago
  • barbara
    Is the galea deep to temporalis fascia?
    5 months ago
  • Catriona Stevenson
    Is the galea below the fascia in the scalp?
    1 month ago
  • NEIL ROSS
    Is subgaleal superficial?
    7 days ago

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