This document provides information on the anatomy and surgical approaches related to the scalp and skull. It describes the layers of the scalp, muscles like the temporalis, nerves like the frontal branch of the facial nerve, and blood vessels. It discusses landmarks and principles for scalp flaps. Various incisions for craniotomies are outlined, including the pterional, bicoronal, question mark, and mitre flaps. Details are provided on procedures like burr holes and craniotomies. Surgical approaches to different brain regions are summarized.

1. DR. AJAY KUMAR SINGH
DNB NEUROSURGERY
VPIMS

2. Layers of the Scalp

3.  The 1st three, regarded as a single layer, contains fibro-
adipose tissue, nerve and vessels.
 The epicranius divided into Occipitofrontalis and
Temporoparietalis part.
 Laterally the superfacial facia continue into the temporal
facia and posteriorly as superfacial facia of neck.

5. The temporoparietalis lies
below the frontal part of
the Occipitofronatlis and
anterior and posterior
auricle muscle.

7. Temporalis muscle:
 T’ fossa and from deep T’ fascia
 Pass below the zygomatic arch and attached to coronoid
process and the anterior wall of mandibular ramus.
 T’ fascia contains T’ muscle, it is attached above along
the Supr T’ line and below it has two layers- one is
attached to lateral margin of upper border and the other
to the medial margin of zygomatic arch

9.  Deep T br of ant trunk of Mandibualr N.
 The Frontal br of the Facial n is contained in the
superficial layer of T’ fascia (as it crossed the
zygomatic arch into the temporal region, 1.5 -3 cm
above the arch and 1-1.5 cm posterior to lateral orbital
rim, where it crossed from the facia to run within the
superficial temporal fascia.

11.  Recommended that the superior layer is cut from its
attacement on the inferior Temporal line till near to
its attachment on the zygoma and it is separated
from the inferior layer and reflected along the flap.

14. Vascular Supply
 Branches of external carotid:
Occipital.
Posterior auricular.
Superficial temporal.
 Branches of internal carotid:
Supratrochlear.
Supraorbital.

16. Venous supply
 Freely anastomse with one another
 Connected to the diploic veins of the skull bones and the
intracranial dural sinuses through several emissary veins.
 Supratrochlear and supraorbital: facial vein
 Superficial temporal vein: in front of auricle: IJV
 Posterior auricular vein: EJV
 Occipital vein : suboccipital plexus, EJV

18. Landmarks
 Nasion
 Bregma : 13 cm from Nasion
 Inion: EOP
 Lambda: 6.5 cm. above the inion.
 Pterion: Middle meningeal artery, 3.5 cm behind, and
1.2 cm above, the level of the frontozygomatic suture.
 Asterion: Transverse sigmoid junction, 4 cm behind
and 1.2 cm above the level of the auricular point.

19. PRINCIPLES OF SCALP FLAPS
 Position of lesion in imaging in axial coronal and
sagittal plane.
 Relationship with the external landmark like, Ext ear
canal, margin of the ear, glabella, EOP.
 Deep refrence point, anatomical midline, tentorium,
formen of monro, the lateral ventricle.
 Position of important structures

20.  Plan for enlarging incision, obtain adequate closure
 Adequate exposure of the lesion
 Based on at least two named arteries.
 Length not more than 1.5 times base of flap
 Burr hole depend on size and location of craniotomy,
nature of lesion, patient age, and degree of adherence
of dura to the inner table.
 Incisions within the hairline
 No cross incisions

21. TAYLOR HAUGHTON LINES

22.  Taylor Haughton line
In 1900 Taylor and Haughton described a technique to
define a line on the scalp directly above the central
fissure.
 1. Draw a Nasion-Inion line ( Nasion - Just below
Glabella and Inion -External Occipital protruberance)
 2. Divide the Nasion-Inion line in to 25%, 50% and 75%
 3. Bregma is the point between the 25% and 50% points
and Lambda is at 75% point

23.  4. Sylvian fissure is drawn from the orbito-temporal
angle (A point of depressin where eyebrow ends) to the
75% point on naso-inion line.
 5. Draw a line perpendicular to the root of the zygoma
starting at preauricular point
 6. Central sulcus is drawn from 50% point on naso-inion
line to the point where the sylvian line cuts the
perpendicular line

24. The Incisions
Supratentorial
 Anterior incision
 Frontal
 Bicoronal/Souttar flap
 Unilateral frontal flap
 Fronto-temporal
(Pterional)
 Temporal
 ? Mark incision
 Horse shoe shaped
 Cushing’s linear
temporal
 Parietal
 Occipital
 The Mitre
 Horse shoe shaped
occipital

25. Infratentorial
 Retromastoid
 Paramedian
 Median
 Far lateral
 Combined
 Petrosal

26. Types Of Flaps
 Pterional (fronto-temporal) flap
 Fronto-temporo-parietal (question mark) flap
 Bicoronal/Souttar flap
 Frontal flap
 Temporal flap
 Horse shoe skin flap
 Occipital skin (Mitre) flap
 Midline suboccipital incision

27. Types of craniotomy
 Flap craniotomy:
Osteoplastic: Musculofascial attachment
Low infection rate
Free bone flap: Free of all its soft tissue
Temporary removed
Minimize bleeding
 Trephine flap: 2 inch in dia
ideal for EDH
Tearing the dura

28. FRONTO-TEMPORAL (PTERIONAL) FLAP
 Walter dandy

29.  I/L and C/L ACF, I/L orbit,
sellar/parasellar, cavernous,
clival, and retroclival areas.
 I/L MCF, and mediobasal T
areas, circle of Willis,
 I/L MCA, ICA, PCoA, AChA,
A1, Proximal A2 Distal
basilar, P1, SCA, Proximal P2
and C/L ICA, A1, ICA
bifurcation.

31. The Pterional craniotomy
 Position: 20-30 degree in opp direction, inclined about
20 degree towards the floor, and slightly towards the
C/L shoulder.
 Highest point: Malar eminence
 Incison : 1 cm anterior to the tragus or 1 cm superior to
the anterior aspect of the auricle and extend to the
temporal crest becoming perpendicular to the zygoma
and then it curves sharply ending at the hairline 2 cm
away from the midline. (Supr temporal art)

33. Upon retraction of the skin
flap, pericranial lines of
incision are made through
the fascia and periosteum
underneath the
frontozygomatic process, 0.5
cm superiorly to the
temporal line, and diagonally
along the frontal bone.

34.  The loose areolar tissue is
dissected with the periosteum
and a thin layer from the
temporalis muscle and reflected
back over the aponeurosis.
 The fat layer between the two
facial layer should be dissected
separately to avoid injury to the
frontal branch of the facial
nerve.

35.  The pericranium of the
temporalis muscle is
separated from the
inferior surface of the
frontozygomatic
process and from the
temporal fossa and
reflected.

37.  A single burr hole is placed in the parietal bone,
approx 2-3 cm posterior to the pterion below the
temporal line in the shallow depression that runs
obliquely over the lateral pterional wing.
 This shallow depression approximate the course of
MMA.

38.  No pressure over the I/L eye.(Gauze).
 Flap raise upto supraorbital ridge.
 Key burr hole (6.8 mm superior and 4.5 mm posterior to
the frontozygomatic suture)
 2nd burr hole 2 cm medially and 4-5 cm above key hole.
 3rd burr hole, 5-7 cm lateral to the 2nd.
 4th if necessary, in the temporal squama, just above the
root of zygoma.

40.  In connecting key hole with temporal hole, resistance
will be met where greater wing of sphenoid meet the
temporal squama.
 MMA may bleed after elevation of bone flap.

41. Temporal- Subtemporal
 Due to voluminous nature of
the temporal lobe and the
necessary retraction required
to reach the lateral basal
cistern (ambient)
 Pterional flap is extended in
both postero-temporal and
medio-frontal direction

42.  Middle cranial fossa
 Lesion in Meckel’s Cave, trigeminal neuromas
 Inferior temporal and lateral temporo-occipital
gyrus
 Tentorial edge
 Petroclival and petrous tumors
 Basilar terminus aneurysm

43.  Posterior to the
mastoid process and is
carried upward the
superior temporal line
before decending to
inscribe a sqaure flap
based on ear and
terminates at mid
zygoma

45. BICORONAL/SOUTTAR FLAP

46. BICORONAL/SOUTTAR FLAP
 Indication : Frontal lobe, frontobasal lesion
anterior to chiasma, genu of CC, circle of willis,
and sella.
 B/L side Fronto-temporal lesions and cranial base.
 Position: Straight, 10-20 degree towards floor

47.  Incision: Superior to zygomatic arch, 1 cm anterior to tragus-
extends over the bregma to the corresponding site on the opposite
side. Reflect up to orbit rim.
 Artery: Supraorbital/trochlear vessels.
 Burr hole:
1. Fronto-temporal line and the zygomatic process of the frontal
bone
2. Glabella, either removed as single piece or two separate frontal
flaps
3. Two burr hole on either side of SSS.
 4. 5-7 cm lateral to the SSS burr hole.

48. Drawback:
 Late visualisation of optic
nerves, ICA
 Risk of CSF leak
 Frontal lobe injury
 Risk of injury to SSS.

49. QUESTION MARK SKIN FLAP (TRAUMA
FLAP) or Falconer’s incision

50. Indication: Cranial trauma, malignant MCA infarct
Incision:
 Start at the zygomatic arch< 1 cm ant to the tragus
 Proceed superiorly and then curve posteriorly at the level
of top of the pinna
 4-6 cm behind the pinna it is taken superiorly
 1-2 cm I/L to the midline curve anteriorly to end behind
the hairline.
 Arterial supply: superficial temporal and supra orbital
vessels.

51. MITRE SKIN FLAP

52. Mitre skin flap
 Mitre hats worn by bishops
 Medial limb begins from the inion to the vertex and
then curves to come over the ear.
 Occipital lobe, posterior falx and superior tentorial
surface.
 Blood supply from the occipital artery

53. Supratentorial Paramedian
Indication:
 Tumor on the surface
 Within a sulcus or fissure
 Deep within the white matter
 Intraventricular tumor
Frontal paramedian
Paramedian centroparietal
Paramedian parieto-occipital

55. Median (Parasagittal) interhemispheric
 The medial part of the sup F’, paracentral, and anterior two third
of the cingulate gyrus and corpus callosum.
 Lateral and third ventricle.
 Sellar and suprasellar masses.
Frontal (anterior and posterior)
Central
Pareito-occipital

56. Frontal anterior :
Indicatoin: parasagittal and falcine lesion, medial
frontal and cigulate gyrus, anterior callosal and lateral
and third ventricle and paraventricular lesion.
 Incision: Bicoronal incision, curvilenear.
 Burr hole: Single burr hole 1-2 mm from midline on
the C/L side of SSS to the lesion.

57. Anterior and posterior frontal median
craniotomies for parasaggital and
interhemispheric exploration

58. Frontal posterior:
 Indication: Posterior part of medial frontal gyrus and
paracentral lesion, lateral ventricle and paraventricular
areas.
 Incison: Curvilinear.
 Burr hole: same as Anterior frontal but posterior to
coronal suture.

59. Pareito-occcipital :
Indication:
 Medial surface of parietal and occipital lobes,
posterior part of cingulate gyrus, superior partof
parahippocampal gyrus, posterior part of CC and the
lateral ventricle.
 Pineal and parapenial areas.
 Burr hole : medially, a few mm across the midline on
the C/L side of SSS

61. Infratentorial
 Suboccipital
 Lateral suboccipital retrosigmoid
 Paramedian
 Median

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