General Anatomy: Scalp and Skull

• Neurocranium


  upper part of the skull that holds the brain
• Viscerocranium


  lower part of the skull that covers the face
• 1 frontal, 2 parietal, 2 temporal, 1 occipital, 1 ethmoid, 1 sphenoid

  Neurocranium consists of:
• 2 nasal, 2 lacrimal, 2 zygomatic, 2 maxillae, 2 inferior conchae, 1 vomer, 2 palatine bones, 1 mandible

  bones of viscerocranium
• Sagittal suture


  suture between 2 parietal bones
• Coronal suture


  suture that joins frontal and 2 parietal bones
• Lambdoidal suture


  suture that joins 2 parietal bones and occipital bone
• Bregma


  junction of 2 parietal and frontal bones; previous site of the anterior fontanelle
• Lambda


  junction of 2 parietal bones and occipital bone; previous site of the posterior fontanelle
• Vertex

  highest point of the skull that is midway across the sagittal suture
• External occipital suture (inion)


  roughened elevation of the occipital, marks the junction of the head and neck
• Superior nuchal line


  found on the side of external occipital protuberance that serves as attachment of muscles in the back
• Superciliary arches


  two prominent ridges on the frontal bone marks junction of face and scalp; marked externally by the eyebrows
• Pterion


  thinnest part of the cranium, located at lateral surface of skull, where anteroinferior corner of the parietal bone articulates with the greater wing of the sphenoid; some books describe it as the junction of the parietal, frontal, sphenoid, and temporal bones
• Anterior middle meningeal artery


  blood vessel found underneath the pterion
• Middle meningeal artery


  grooves or tunnels across the pterion of the skull
• Maxillary artery


  origin of middle meningeal artery
• Foramen spinosum

  middle meningeal artery enters the skull through the:
• Motor area of the cerebral cortex of the brain

  anterior middle meningeal artery branch lies close to:
• Epidural hematoma


  tearing of meningeal arteries/veins, accumulation of blood in the middle meningeal artery
• Scalp


  soft tissue covering the calvaria
• Superciliary arches


  anterior boundary of the scalp
• External occipital protuberance and superior nuchal lines


  posterior boundary of the scalp
• Temporal lines


  lateral boundary of the scalp
• Skin, Subcutaneous tissue (Connective tissue), Aponeurosis (Epicranial/galea aponeurotica), Loose Areolar Tissue, Periosteum

  SCALP means:
• Sebaceous cyst


  occurs due to duct obstruction of the sebaceous glands
• Punctum


  opening of duct obstruction of sebaceous glands
• Connective tissue


  dense fibrofatty layer with fibrous septa that unite the skin to the underlying epicranial aponeurosis; rich in blood vessels and nerves
• Superficial temporal, Occipital, Posterior auricular artery


  branches of external carotid artery that supplies the scalp
• Supratrochlear, supraorbital


  branches of internal carotid artery via ophthalmic
• Fibrous septa


  holds blood vessel in place preventing it to constrict and retract
• Supratrochlear + supraorbital minus median margin of the orbit

  facial vein
• Superficial temporal + maxillary in the parotid gland

  retromandibular vein
• Posterior auricular + posterior division of the retromandibular

  External jugular vein
• Suboccipital venous plexus to Vertebral veins or Internal Jugular Vein

  occipital drains to:
• Branches of trigeminal (anterior to the ear) and cervical spinal nerves (posterior to the ear)

  2 main groups of trunks of the sensory nerves in connective tissue
• Supratrochlear (V1), Supraorbital (V1), Zygomaticotemporal (V2), Auriculotemporal (V3)

  branches of trigeminal
• Lesser Occipital (C2 cervical plexus), Greater Occipital (post ramus C2)


  branches of cervical spinal nerve
• Caput succedaneum


  scalp edema due to difficult vaginal delivery (discoloration of scalp, pitting edema)
• Aponeurotic


  thin, tendinous sheets that unites occipitalis and frontalis or occipitofrontalis muscle; lateral margins attached to temporal fascia