Internal Iliac Artery

Origin and Course

• Gray's Anatomy for Students, p. 573

Branches

Posterior Trunk

Anterior Trunk

• Gray's Anatomy for Students, pp. 573-574
• Color Atlas of Human Anatomy Vol. 2, pp. 114-115

Diagrams

Key Relations

• The ureter crosses anterior to the internal iliac artery at the pelvic brim
• The internal iliac artery and its divisions lie in close relation to the sacroiliac joint - the bifurcation, iliolumbar artery, and superior gluteal artery are all at risk during anterior approaches to the SI joint
• The superior gluteal artery passes between the lumbosacral trunk and S1 before exiting the greater sciatic notch
• Imaging Anatomy Vol. 3, pp. 2710-2711

Clinical Points

Corona Mortis ("Crown of Death")

Uterine Artery and the Ureter

Ligation in Obstetric Hemorrhage

Iliac Aneurysms

Kidney Transplant

Summary Table of Branches

Mnemonic for Internal Iliac Artery Branches

Posterior Trunk — "I Like Standing"

Anterior Trunk — "2 UP, 2 In, 2 Out" logic

"U Smell Very Offensive, U Idiot! Put It Back!"

Cleaner All-in-One Mnemonic

Posterior: "I LS G" → "I LiSten to Glutes"

Iliolumbar, Lateral Sacral, Superior Gluteal

Anterior: "U MUSIC, Guys!"

The Classic One-Liner

"I Love Sex, Often Using Muscles, Vaginas, and Internal Pudendal Go Inferiorly"

Quick Recall Tip

• Posterior trunk = 3 branches only (ILS - easy to remember as a group)
• Anterior trunk = everything else (visceral + perineal + gluteal)
• The superior gluteal exits above piriformis; the inferior gluteal and internal pudendal both exit below piriformis

Internal Iliac Artery — Branches In Order, Easy to Remember

The Core Logic First

POSTERIOR TRUNK — "Go Backwards and Up"

Order (proximal → distal):

Posterior trunk
    │
    ├── 1. Iliolumbar artery        → goes UP and BACK (to lumbar/iliac region)
    ├── 2. Lateral sacral artery    → goes MEDIALLY (to sacral foramina)
    └── 3. Superior gluteal artery  → terminal branch, exits ABOVE piriformis

Memory hook:

"I Left Straight away" — Iliolumbar → Lateral sacral → Superior gluteal

ANTERIOR TRUNK — Follow the Logic of Territory

Anterior trunk
    │
    ├── 1. Umbilical artery ──────── (fetal remnant; goes to anterior abdominal wall)
    │       └── Superior vesical    (bladder top = first thing it supplies)
    │
    ├── 2. Inferior vesical (M)     (bladder bottom + prostate)
    │   / Vaginal artery (F)
    │
    ├── 3. Uterine artery (F only)  (uterus — crosses ureter here!)
    │
    ├── 4. Middle rectal artery     (rectum — posterior pelvic viscera)
    │
    ├── 5. Obturator artery         (exits obturator canal → thigh)
    │
    ├── 6. Internal pudendal artery (exits BELOW piriformis → perineum)
    │
    └── 7. Inferior gluteal artery  (terminal branch; exits BELOW piriformis → gluteal)

The Territory-Based Story

The anterior trunk first deals with the bladder (top → bottom: superior vesical via umbilical, then inferior vesical). In women it then sends the uterine artery (which famously crosses the ureter). Next it supplies the rectum (middle rectal). Then it sends the obturator artery out through the obturator canal to the thigh. Finally, two big branches head out the greater sciatic foramen below piriformis — the internal pudendal (to the perineum) and the inferior gluteal (to the buttock).

One Sentence Mnemonic (Anterior Trunk, in order)

"Uncle Sam's Very Ugly Moustache — Over It, Put Glue"

The "Exits" Rule — Never Confuse Superior vs Inferior Gluteal Again

Full Branch List at a Glance

INTERNAL ILIAC ARTERY
│
├── POSTERIOR TRUNK
│   ├── Iliolumbar
│   ├── Lateral sacral
│   └── Superior gluteal ← TERMINAL (exits ABOVE piriformis)
│
└── ANTERIOR TRUNK
    ├── Umbilical → Superior vesical
    ├── Inferior vesical (M) / Vaginal (F)
    ├── Uterine (F)
    ├── Middle rectal
    ├── Obturator
    ├── Internal pudendal ← exits BELOW piriformis → perineum
    └── Inferior gluteal ← TERMINAL (exits BELOW piriformis)

Internal Iliac Artery — Course (Exam Format)

Origin

• Smaller terminal branch of the common iliac artery
• Origin: opposite the lumbosacral disc (L5-S1), in front of the sacroiliac joint

Course

1. Passes downward and backward into the pelvis
2. Crosses the pelvic inlet (linea terminalis)
3. Reaches the upper margin of the greater sciatic foramen
4. Divides into anterior and posterior divisions

One-Line Exam Answer

"The internal iliac artery arises from the common iliac artery at the level of the lumbosacral disc, descends into the lesser pelvis, and divides into anterior and posterior divisions at the upper margin of the greater sciatic foramen."

Divisions & Branches (from your textbook diagram)

Posterior Division — "I Love Superior"

Anterior Division — "Some Opposing Ugly Men Mostly Ignore Vaginas"

The ONE Exam Note (from your textbook NB box)

All anterior division branches are VISCERAL — except inferior gluteal and obturator, which are parietal.

Exits Rule (1 mark question)