The iliohypogastric nerve is a

nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the Electrochemistry, electrochemical nerv ...

that originates from the

lumbar plexus The lumbar plexus is a web of nerves (a nerve plexus) in the lumbar region of the body which forms part of the larger lumbosacral plexus. It is formed by the divisions of the first four lumbar nerves (L1–L4) and from contributions of the su ...

that supplies

sensation Sensation (psychology) refers to the processing of the senses by the sensory system. Sensation or sensations may also refer to: In arts and entertainment In literature *Sensation (fiction), a fiction writing mode *Sensation novel, a British ...

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

over the lateral gluteal and hypogastric regions and motor to the internal oblique muscles and transverse abdominal muscles.

Structure

Origin

The iliohypogastric nerve originates from the superior branch of the

anterior ramus The ventral ramus (: rami) (Latin for 'branch') is the anterior division of a spinal nerve. The ventral rami supply the antero-lateral parts of the trunk and the limbs. They are mainly larger than the dorsal rami. Shortly after a spinal nerve e ...

of spinal nerve L1. It also receives fibers from T12 via the

subcostal nerve The subcostal nerve (anterior division of the twelfth thoracic nerve) is a mixed motor and sensory nerve contributing to the lumbar plexus. It runs along the lower border of the twelfth rib, often gives a communicating branch to the first lumbar ...

. The branch below it is the

ilioinguinal nerve The ilioinguinal nerve is a branch of the first lumbar nerve (L1). It separates from the first lumbar nerve along with the larger iliohypogastric nerve. It emerges from the lateral border of the psoas major just inferior to the iliohypogastric, ...

Course

It emerges from the upper lateral border of the

psoas major The psoas major ( or ; from ) is a long fusiform muscle located in the lateral lumbar region between the vertebral column and the brim of the lesser pelvis. It joins the iliacus muscle to form the iliopsoas. In other animals, this muscle is e ...

. It then crosses in front of the

quadratus lumborum muscle The quadratus lumborum muscle, informally called the ''QL'', is a paired muscle of the left and right posterior abdominal wall. It is the deepest abdominal muscle, and commonly referred to as a back muscle. Each muscle of the pair is an irregular ...

to an area superior to the

iliac crest The crest of the ilium (or iliac crest) is the superior border of the wing of ilium and the superolateral margin of the greater pelvis. Structure The iliac crest stretches posteriorly from the anterior superior iliac spine (ASIS) to the posterio ...

. It runs behind the

kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...

s. Just superior to the iliac crest, it pierces the posterior part of the

transversus abdominis muscle The transverse abdominal muscle (TVA), also known as the transverse abdominis, transversalis muscle and transversus abdominis muscle, is a muscle layer of the anterior and lateral (front and side) abdominal wall, deep to (layered below) the inter ...

and continues anteriorly in the abdominal wall between the transversus abdominis and internal oblique muscles. It divides into a lateral cutaneous branch and an anterior cutaneous branch between the transversus abdominis muscle and the internal oblique muscle.

Branches

Lateral cutaneous branch

The lateral cutaneous branch ("iliac branch") pierces the internal oblique muscles and the external oblique muscles immediately above the

. It is distributed to the skin of the gluteal region, behind the lateral cutaneous branch of the

; the size of this branch bears an inverse proportion to that of the lateral cutaneous branch of the

. When harvesting bone from the anterior iliac crest (AICBG), the lateral cutaneous branch of the Iliohypogastric nerve (L1) is most likely to be injured. File:Gray826and831.svg, Area supplied by the lateral cutaneous branch can be seen in blue near the hip.

Anterior cutaneous branch

The anterior cutaneous branch ("hypogastric branch") continues onward between the abdominal internal oblique and transverse muscles. It then pierces the internal oblique, becomes

cutaneous Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different d ...

by perforating the

aponeurosis An aponeurosis (; : aponeuroses) is a flattened tendon by which muscle attaches to bone or fascia. Aponeuroses exhibit an ordered arrangement of collagen fibres, thus attaining high tensile strength in a particular direction while being vulnerable ...

of the external oblique about 2.5 cm above the

subcutaneous inguinal ring The inguinal canal is a passage in the anterior abdominal wall on each side of the body (one on each side of the midline), which in males, convey the spermatic cords and in females, the round ligament of the uterus. The inguinal canals are lar ...

, and is distributed to the skin of the hypogastric region.

Communications

The iliohypogastric nerve communicates with the

and

Variation

The iliohypogastric nerve may be absent in up to 20% of people. Its fibres are instead carried on other nerves, such as the ilioinguinal nerve.

Function

The iliohypogastric nerve partially supplies the internal oblique muscles. It also provides sensory innervation to the superior gluteal region and part of the suprapubic region.

Clinical significance

The iliohypogastric nerve may be damaged at the points where it passes through the internal oblique muscle and the external oblique muscles. It is most often damaged by

medical error A medical error is a preventable adverse effect of care (" iatrogenesis"), whether or not it is evident or harmful to the patient. This might include an inaccurate or incomplete diagnosis or treatment of a disease, injury, syndrome, behavior, ...

. It may also be damaged by a nerve lesion.

References

External links

* * - "Posterior Abdominal Wall, Dissection, Anterior View" * - "Anterior Abdominal Wall: The Iliohypogastric and IlioInguinal Nerves" * - "Posterior Abdominal Wall: Nerves of the Lumbar Plexus" * * * * () {{Authority control Nerves of the lower limb and lower torso