Scalp & superficial temporal region

EXTENT OF SCALP:
  •  The scalp extends from the top of the forehead in front to the superior nuchal line behind. Laterally it projects down to the zygomatic arch and external acoustic meatus 
LAYERS OF SCALP:
 CONSISTS OF FIVE LAYERS
  • Skin:
  1. The skin is thick and hairy.
  2. It is adherent to the epicranial aponuerosis through the dense superficial fascia.
  3. Subcutaneous tissue:
  4. It is more fibrous and dense in the centre than at the periphery of the head.
  5. Provides the proper medium for passage of vessels and nerves of the skin
  6. Occipitofrontalis (epicranius) and it’s aponuerosis:
  7. It is freely movable on the pericranium along with the overlying and adherent scalp and fascia.
  8. On each side it is attached to the superior temporal lines.
  9. Anteriorly ,it receives the insertion of the frontalis.
  10. Posteriorly ,receives insertion of the occipital bellies.
  11. Subaponuerotic areolar tissue:
  12. Extends anteriorly into the eyelids.
  13. Posteriorly to the highest and superior nuchal lines and on each side to the superior temporal lines.
  14. pericranium:
  15. Loosely attached to the surface of the bones,but is firmly adherent to the sutures where the sutural ligaments bind the pericranium to the endocranium.
BLOOD SUPPLY:
  • ARTERIAL SUPPLY:
  1. IN FRONT OF AURICLE-
  2. Supratrochlear
  3. Supraorbital
  4. Superficial temporal arteries
BEHIND THE AURICLE
  1. Posterior auricular
  2. Occipital arteries
VENOUS DRAINAGE:
  • Emissary veins connect the extracranial veins with the intracranial venous sinuses to equalise the pressure.
  • The superficial temporal vein joins the maxillary vein to form retromandibular vein.
  • The supratrochlear and the supra orbital vein unite at the medial angle of eye to form angular vein
  • The posterior division of retromandibular vein unites with the posterior auricular vein to form external jugular vein
  • Frontal diploic- sphenoparietal sinus
  • occipital diploic- transverse sinus
LYMPHATIC DRAINAGE:
  • Lymph vessels from the frontal region above the root of the nose drain into the submandibular nodes
  • Vessels from rest of the forehead,temporal region,upper half of the lateral auricular aspect and anterior wall of the external acoustic meatus drain into superficial parotid nodes,just anterior to the tragus ,on or deep to the parotid fascia.
  • The occipital region of the scalp is drained by the occipital nodes,and partly by the vessel that runs along the posterior borderof the sternocleidomastoid to the lower deep cervical nodes
  • A strip of the scalp above the auricle drains to the upper deep cervical and retro auricular nodes.
  • The retro auricular in turn drain to deep cervical.
NERVE SUPPLY:
  • Scalp supplied by ten nerves on each side.
  • Five nerves (4 sensory and one motor) enter scalp in front of the auricle.
  • Remaining five(4 sensory one motor) enter behind the auricle.

IN FRONT OF AURICLE
(SENSORY)
BEHIND THE
AURICLE
(SENSORY)
SUPRATROCHLEAR POSTERIOR
DIVISION OF GREATER
AURICULAR
SUPRAORBITAL LESSER OCCIPITAL
ZYGOMATICOTEMPORAL GREATER OCCIPITAL
AURICULOTEMPORAL THIRD OCCIPITAL
( MOTOR) (MOTOR)
TEMPORAL BRANCH OF FACIAL POSTERIOR
AURICULAR BRANCH OF FACIAL
  • Supratrochlear nerve- smaller terminal branch of frontal nerve
  • Supplies the skin of the lower forehead near the midline
  • supraorbital-Divides into medial and lateral branches which supply the skin of the scalp nearly as far back as the lambdoid suture.The medial perforates the muscle to reach the skin & Lateral pierces the epicranial aponuerosis
  • Zygomaticotemporal-
  • Supplies skin of temple as it pierces the deep layer of temporal fascia it sends a slender wig between the two layers towards the lateral angle of the eye.
  • Lesser occipital-supplies the scalp above and behind the ear . Branch of cervical plexus
  • Greater auricular-derived from anterior rami of second and third cervical spinal nerves.
CLINICAL ANATOMY:
  • Since there are numerous sabaceous glands, the scalp is the commonest site for sabaceous cyst.
  • Scalp lacerations bleed profusely because elastic fibres of underlying galea aponuerotica prevent initial vessel retraction, the wounds may be associated with significant blood loss which can result in clinical shock.
  • Scalp flaps can be used in craniofacial surgery for correction of congenital deformity,for release of craniosynostosis, treatment of craniofacial fractures and for repair of scalp defects after excision of skin tumors.
  • Hemostasis in scalp wound is best achieved by pressure over wound
  • When suturing scalp lacerations, it is essential to control all bleeding points before repairing the scalp itself
  • Usually it is necessary to tie off larger arterioles and veins and use bipolar diathermy to control smaller arterioles and veins.
  • Repair of scalp require full thickness tension sutures because galea aponuerotica will otherwise gape as the occipital and frontal bellies contract
  • Lacerated wound appears as incised wound in scalp.
  • Failure to control bleeding points as a separate step can result in significant hematomas,often subgaleal, leading to breakdown of the orginal wound and sometimes necessitating surgical drainage
Exam Question
  • ubcutaneous tissue is the highly vascular layer of scalp
  • Nerve supply of scalp is by SUPRATROCHLEAR, POSTERIOR DIVISION OF GREATER AURICULAR, SUPRAORBITAL, LESSER OCCIPITAL, ZYGOMATICOTEMPORAL, GREATER OCCIPITAL, AURICULOTEMPORAL, THIRD OCCIPITAL, TEMPORAL BRANCH OF FACIAL, POSTERIOR AURICULAR BRANCH OF FACIAL
  • Hemostasis in scalp wound is best achieved by pressure over wound
  • Lacerated wound appears as incised wound in scalp.
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