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anatomy of the layers of scalp with surgical aspect
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SCALP
Dr ARJUN SHENOYDEPT OF OMFS
CONTENTS
EXTENT LAYERSBLOODY SUPPLYVENOUS DRAINAGELYMPHATICSNERVE SUPPLYAPPLIED CLINICAL ANATOMYSCALP AVULSION INJURIES
EXTENT
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
CONSISTS OF FIVE LAYERS
SkinSubcutaneous tissueOccipitofrontalis (epicranius) and it’s
aponuerosisSubaponuerotic aereolar tissuepericranium
SKINThe skin is thick and hairy.
It is adherent to the epicranial aponuerosis through the dense superficial fascia.
SUPERFICIAL FASCIA
It is more fibrous and dense in the centre than at the periphery of the head.
Provides the proper medium for passage of vessels and nerves of the skin
EPICRANIAL APONUEROSIS
It is freely movable on the pericranium along with the overlying and adherent scalp and fascia.
On each side it is attached to the superior temporal lines.
Anteriorly ,it receives the insertion of the frontalis.
Posteriorly ,receives insertion of the occipital bellies.
LOOSE AEREOLAR TISSUE
Extends anteriorly into the eyelids.
Posteriorly to the highest and superior nuchal lines and on each side to the superior temporal lines.
PERICRANIUMLoosely 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 SUPPY
ARTERIAL SUPPLY
IN FRONT OF AURICLE-SupratrochlearSupraorbitalSuperficial temporal arteries
BEHIND THE AURICLEPosterior auricularOccipital arteries
VENOUS DRAINAGEEmissary 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 sinusoccipital 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
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 BEHIND THE AURICLE
SUPRATROCHLEAR POSTERIOR DIVISION OF GREAT AURICULAR
SUPRAORBITAL LESSER OCCIPITAL
ZYGOMATICOTEMPORAL GREATER OCCIPITAL
AURICOTEMPORAL 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 skinLateral 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.
Opthalmic nerve- skin over the forehead
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.
It is very easy to raise a flap within the plane between the galea and the pericranium without compromising the blood or nerve supply of the scalp.
Similar flaps are seen in traumatic scalp avulsion,when hair is trapped in moving machinery
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
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.
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
LOCATING THE INCISION LINE AND PREPARATION
INCISION
ELEVATION OF CORONAL FLAP AND EXPOSURE OF ZYGOMATIC ARCH
SUBPERIOSTEAL EXPOSURE OF THE PERIORBITAL AREAS
HARVESTING CRANIAL BONE GRAFTS
SCALP AVULSION INJURIES
Dr. S. Raja Sabapathy, Dr. Ravindra Bharathi, Dr. Hari Venkataramani, Dr. Deepak . K.L., Dr. Divakar Raju. K. (Department of Plastic and Reconstructive Micro Surgery)BMMSRC
HANDLING THE AVULSED SCALP
The inner smooth surface of the avulsed scalp is first placed on a spherical vessel or container. This is done before clipping any hair. The long hair is then clipped and shaving commences from front to back and side to side, taking care not to shave the eyebrows. After the shaving is complete, the scalp is washed thoroughly in running tap water and only after all hair has been removed completely, the scalp is taken off the container. In this way, the scalp is well prepared and no hair is found on the inner side. This step hardly takes 10 min.
All patients had acceptable recovery of sensation of forehead and scalp by 6–9 months after replantation. In two of our cases, the line of avulsion was along the level of medial canthus.Hair growth in all patients has been satisfactory and the cosmetic result excellent.
REFERENCES
Journal of Plastic, Reconstructive & Aesthetic Surgery
Volume 59, Issue 1, January 2006, Pages 2–10
GREYS ANATOMY