Vertebral Levels
C3 Level
- Hyoid bone
- 3 → Hai
C4 Level
- Bifurcation of the common carotid artery
- Thyroid cartilage
- 4 → always Bifurcation
- T4 → bifurcation of CCA
- + Thyroid cartilage
- L4 → bifurcation of Abdominal aorta
- + LP


- Extends from C5 to T1 vertebral level
- A- C5
- B- C6
- C- C7
- D- T1

Sibson's Fascia
- Also known as suprapleural membrane.

- Remnant of scalenus minimus.
- From 1st Rib to C7 Vertebrae
- SibsOne → Seven to One
T1 Level
- Sternoclavicular joint
T2 Level
- Superior angle of scapula
- Suprasternal notch
- Scapula superior angle → C2
- Scapula inferior angle → T7 > 8

T4 Level




- Thoracic plane or plane of Ludwig
- Sternal angle of Louis (marked) (T4-T5)
- Arch of aorta (T3-T4)
- Bifurcation of trachea (carina)
- Division between superior and inferior mediastinum
- Azygos vein drains into SVC
- Dermatome of Nipple

- ”Mneumonic:
- Ludwig and Loius had asha (Azygous) for Archa (after seeing her nipple). At 4, Archa (Arch of aorta) told Louis (angle of Louis) is inferior to Ludwig (superior and inferior mediastinum) , so they bifurcated at base of a tree (Bifurcation of trachea )
T8 Level
- IVC hiatus
- Inferior angle of the scapula (T7-T8)
- Scapula superior angle → C2
- Scapula inferior angle → T7 > 8


T9 Level
- Xiphisternal joint
T10 Level

- Oesophageal hiatus
- Marked level → T10 (count down from Nipple)
T12 Level
- Aorta hiatus
- T12 vertebra → Posterior of Epiploic foramen
Mneumonic:
- I (IVC) ate (T8) 10 (T10)eggs (esoph) at (aorta) 12(T12)
- T8 → I’m (IVC) the Right Person (right phrenic)
- T10 → Very (Vagus) Easy (esophagus) Going (Gastric)
- T12 → And (Aorta) Truthful (thoracic)
Opening of Diaphragm | Level | Structures Passing Through | On inspiration |
Caval opening In the central tendon | T8 | IVC, Right phrenic nerve (Inferior angle of the scapula (T7-T8)) | Dilatation (VR↑) |
Esophageal opening Surrounded by the (R) crus of the diaphragm | T10 | Esophagus, Vagus nerves (R & L), Esophageal branch of left gastric artery | Constriction Contraction of diaphragm "Pinchcock" action: → Closes esophageal opening |
Aortic opening = b/w crus | T12 | Aorta, Thoracic duct, Azygos vein, sometimes Hemiazygos vein | No change (lies behind diaphragm) |
L1 Level
ㅤ | ㅤ |
Celiac Trunk | Lower border of T12 |
Superior Mesenteric Artery | Lower border of L1 |
Inferior Mesenteric Artery | Body of L3 |




Mnemonic: Common (CIA) Inferior People (Inf phre) are Ready (rena) to Go (gona) Middle (middle supra) east
Mneumonic:
- Pyli → Pylorus
- Funda →Fundus
- 9 → 9th CC tip
- Smokes → SMA
- Drunk kili→ Trunk Celiac
- climb Hill → Hilum
- So Pyli ne Veetukar Addich (Addisons Plane)
L2 Level
- Renal veins
- Thoracic duct begins
- Portal Vein formed (from SMV and Splenic Vein)
- Azygos and hemiazygos begin
- Mnemonic: L2 → too large → Thoracic duct
L3 Level

- Umbilicus
- Inferior Mesenteric Artery
- Spinal cord ends in children in upper border
- Subcoastal Plane (at lower border)
- Mnemonic: U (Umbilicus), I’m A (IMA) child (Spinal cord) in Coastal () area

L4 Level
- Iliac crest
- Bifurcation of abdominal aorta into left and right common iliac arteries
- Lumbar Puncture (L4-L5)
- Mnemonic:
- 4 → always Bifurcation
- T4 → bifurcation of CCA
- + Thyroid cartilage
- L4 → bifurcation of Abdominal aorta
- + LP
- L4 → remember LumBar puncture → LB → iLeac Crest, Bifurcation
L5 Level
- IVC formed (convergence of right and left common iliac veins)
- Transtubercular plane (at upper border of L5)
S1 Level
- Sacral promontory
- Mnemonic: PromOnetory → S1
S2 Level
- Posterior superior iliac spine
- Dural sac ends
- Mnemonic: S2 → Dual Pieces (Dural sac, PSIS)
