Neuro

Surface Anatomy of the Brain: Gyri & Sulci

FRONTAL LOBE

  • Frontal Pole

  • Orbital Gyrus

  • Superior Frontal Gyrus

  • Middle Frontal Gyrus

  • Inferior Frontal Gyrus

    • Pars orbitalis

    • Pars triangularis

    • Pars opercularis

  • Precentral Gyrus

  • Subfrontal Gyrus

  • Cingulate Gyrus

PARIETAL LOBE

  • Postcentral Gyrus

  • Superior Parietal Lobule

  • Inferior Parietal Lobule

    • Supramarginal Gyrus

    • Angular Gyrus

  • Paracentral Lobule

  • Precuneus

OCCIPITAL LOBE

  • Superior Occipital Gyrus

  • Middle Occipital Gyrus

  • Inferior Occipital Gyrus

  • Cuneus

  • Lingual Gyrus

TEMPORAL LOBE

  • Temporal Pole

  • Superior Temporal Gyrus

  • Middle Temporal Gyrus

  • Inferior Temporal Gyrus

  • Fusiform Gyrus

  • Parahippocampal Gyrus

Neurovascular Anatomy

ICA Segments

  1. Cervical = Athero, dissection, retropharyngeal course, infection causes pseudoaneurysm.

  2. Petrous = In carotid canal. Big aneurysms

  • Petrolingual ligament separates

  1. Lacerum = Close to Meckl’s cave

  2. Cavernous = CC fistulas

  3. Clinoid = Aneurysm compresses optic nerve

  • Start of dural ring

  1. Ophthalmic = ophthalmic artery branch. Common aneurysm.

  • Supraclinoid start

  1. Communicating = PCom and Anterior choroidal branches. Aneurysm compresses CN 3.

C1 ends as the ICA enters bone

C2 starts in bone

C2 is S-shaped in bone. Ends at bone exit

C3 is tiny, just a 1mm bend as it exits T-bone

C4 is oblique in cavernous sinus

C5 is the bend outside the cavernous sinus

C6 is horizontal, origin of ophthalmic artery

C7 is vertical, origin Pcomm, ant. choroidal

MCA Segments

4 segments total

M1 is horizontal, ends at the insula

M1 is horizontal, ends at the insula

M2 squiggles up and down over the insula and goes posterior.

and distal M2 goes cranial

Proximal M2 goes posterior

At the peak, M2 turns into M3

M3 goes caudal then lateral

M4 are cortical branches

ACA Segments

5 segments total

A1 from ICA to Acom

A2 is vertical from Acom to callosal branches

A2 is vertical from Acom to callosal branches

A3 branches are calossomarginal and pericalossal

A3 pericalossal next to callosum

A3 calossomarginal next to cingulate gyrus

A4 and A5 are cortical. A5 is more posterior.

PCA Segments

4 segments total

P1 from basilar origin to Pcom

P2 starts after Pcom

P2A, anterior through crural cistern

P2P, posterior through ambient cistern

P3 through quadrigeminal cistern

P4 cortical branches

Vertebral Segments

V1 from origin to start of foramina

V2 in the foramina

V3 out of foramina

V4 intracranial

Cerebellar Arteries


PICA origin from vertebrals

AICA origin from lower basilar

SCA origin from upper basilar

Dural and Superficial Sinuses

External Carotid Artery

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TMJ MRI

Anatomy

  • Condylar Head

  • Articular Disc

    • Anterior band

    • Intermediate zone

    • Posterior Band

      • Superior attachments -> Squamotemporal suture

      • Bilaminar Zone (vessels, nerves)

      • Inferior attachments -> Posterior ramus

  • Joint Spaces

    • Superior compartment

    • Inferior compartment

      • Anterior recess

      • Posterior recess

Closed Mouth View

  • Post disc sits at 12* (condylar apex, w/i 10 degrees)

  • Displacement:

    • Usually anterior, anteromedial/lateral (rotational) vs med/lateral, rarely posterior (open mouth lock)


Open Mouth View

  • Approximately 50% of the disc should remain posterior to the condyle (capture)

Internal Derangement & Grading

INTERNAL DERANGEMENT

  • Partial Internal Derangement: Displaced w/ appropriate capture

  • Complete Internal Derangement: Displaced w/o appropriate capture

V&A GRADING SYSTEM

  • Mildly displaced meniscus w/ appropriate capture

  • >30 displaced meniscus w/ appropriate capture

  • >30 displaced meniscus w/o capture

  • Displacement w/o capture, early OA

  • Displacement w/o capture, moderate OA

  • Perforated meniscus, attachment rupture