SCALP -..pptx presentation subcutaneouss

Scalp

1. SCALP

2. OBJECTIVES: Definition • Extent • Structure – layers of scalp • Arterial supply • Venous drainage • Lymphatic drainage • Nerve supply • Applied anatomy

3. DEFINITION: • The scalp is a soft tissue which covers the calvaria of the skull.

4. EXTENT: It extends: • Anteriorly – supraorbital margin • Posteriorly – external occipital protuberance and superior nuchal line. • On each side – zygomatic arch

5. LAYERS OF SCALP: The scalp consists of five layers namely (mnemonic): 1. S – Skin 2. C – Cutaneous tissue 3. A – Aponeurosis 4. L – Loose areolar tissue 5. P - Pericranium

6. 1. S - SKIN: •Thick and hairy • Sebaceous and sweat glands

7. 2. C - CUTANEOUS TISSUE Subcutaneous or superficial fascia. • Composed of close network of fibro-fatty tissue. • It binds the skin to the subjacent aponeurosis. • It provides a medium for passage of vessels and nerves to the skin.

8. 2. C - CUTANEOUS TISSUE The walls of the vessels are adherent to the fibrous network. • So that when the vessels are torn in an open wound they are unable to retract and produce profuse bleeding. • However bleeding can be arrested by pressure against the underlying bone.

9. 3. A - APONEUROSIS Galea aponeurotica ( epicranial aponeurosis). • Sheet of fibrous tissue which connects occipitalis and frontalis muscles. Extent: Behind – external occipital protuberance and highest nuchal line. Front – blends with subcutaneous tissue of root of nose. On each side – zygomatic arch Temporal extension of the aponeurosis gives attachment to: • Auricularis anterior and • Auricularis superior muscles.

10. 4. L – LOOSE AREOLAR TISSUE Loose subaponeurotic tissue. • Potential space beneath the occipitofrontalis muscle and its aponeurosis. • This space contains emissary vein. • Emissary vein – are devoid of valves and communicates the veins of scalp with intracranial venous sinuses. • An infection in this space may spread to intracranial sinuses through the emissary veins and hence the 4th layer of scalp is called as dangerous area of scalp.

11. 5. P - PERICRANIUM Outer periosteum of skull • Loosely covers the bone • At the sutures it is continuous with the endocranium through the sutural membrane.

12. ARTERIAL SUPPLY: In front of auricle: Supratrochlear artery – ophthalmic artery – internal carotid artery 2. Supraorbital artery – ophthalmic artery – internal carotid artery 3. Superficial temporal artery – external carotid artery. Behind the auricle: 4. Posterior auricular and 5. Occipital arteries, both are branches of external carotid artery.

13. VENOUS DRAINAGE 1. Supratrochlear vein 2. Supraorbital vein 3. Superficial temporal vein 4. Posterior auricular vein 5. Occipital vein

14. LYMPHATIC DRAINAGE: Anterior part of scalp: preauricular lymph nodes (superficial parotid nodes). • Posterior part of scalp : post auricular lymph nodes or mastoid group of nodes and Occipital lymph nodes.

15. NERVE SUPPLY OF SCALP:

16. TRIGEMINAL NERVE Supratrochlear nerve – branch of the ophthalmic nerve which supplies the anteromedial forehead Supraorbital nerve – branch of the ophthalmic nerve which supplies a large portion of the scalp between the anterolateral forehead and the vertex Zygomaticotemporal nerve – branch of the maxillary nerve , this supplies the temple Auriculotemporal nerve – branch of the maxillary nerve which supplies skin , anterosuperior to the auricle Temporal branch of facial nerve – supplies frontal belly of occipitofrontalis.

17. CERVICAL NERVES Lesser occipital nerve – derived from the anterior ramus of C2 and supplies the skin posterior to ear Greater occipital nerve – derived from the posterior ramus of C2 & supplies the skin of the occipital region Greater auricular nerve – derived from the anterior rami of C2 & C3 and supplies the skin posterior to the ear & over the angle of mandible Third occipital nerve – derived from the posterior ramus of C3 & supplies the skin of the inferior occipital region Posterior auricular branch of facial nerve – supplies occipital belly of occipitofrontalis muscle.

18. NERVE SUPPLY OF SCALP:

19. APPLIED ANATOMY: 1. Skin : Common site for the formation of sebaceous cysts.

20. APPLIED ANATOMY 2. Cutaneous tissue Wound in the scalp bleed profusely? The walls of the vessels are adherent to the fibrous network, so that when the vessels are torn in an open wound they are unable to retract and produce profuse bleeding. However bleeding can be arrested by pressure against the underlying bone.

21. APPLIED ANATOMY 3. Aponeurosis Wounds of the scalp do not gape unless the epicranial aponeurosis is divided transversely. • Operation on the scalp should be preferably done under general anaesthesia , the nerves from the face and neck overlap, so it’s hard to numb one area completely.The scalp tissue is thick, so the local anaesthetic doesn’t spread well. • First three layers of scalp are called surgical layers of the scalp, these are called as scalp proper also.

22. APPLIED ANATOMY 4. LOOSE AREOLAR TISSUE Dangerous area of scalp because the emissary veins, which course here may transmit infection from the scalp to the cranial venous sinuses. • Collection of blood in this layer due to a blow on the skull produces generalized swelling. The blood slowly gravitates into the eye lids because the frontalis has no bony attachments results in Black eye.

23. APPLIED ANATOMY 4. LOOSE AREOLAR TISSUE Caput succedaneum is a condition in which edema is observed on an infant’s scalp shortly after delivery. It is a benign condition associated with birth-related trauma to the scalp during delivery.

24. APPLIED ANATOMY 5. PERICRANIUM Collection of fluid beneath the pericranium produces localized swelling in the form of cephalohematoma or traumatic cephalohydrocele which assumes the shape of related bones.