The lateral cutaneous nerve of the thigh (also called the lateral femoral cutaneous nerve) is a

cutaneous nerve A cutaneous nerve is a nerve that provides nerve supply to the skin. Human anatomy In human anatomy, cutaneous nerves are primarily responsible for providing cutaneous innervation, sensory innervation to the skin. In addition to sympathetic and ...

of the

thigh In anatomy, the thigh is the area between the hip (pelvis) and the knee. Anatomically, it is part of the lower limb. The single bone in the thigh is called the femur. This bone is very thick and strong (due to the high proportion of bone tissu ...

. It originates from the dorsal divisions of the second and third

lumbar nerves The lumbar nerves are the five pairs of spinal nerves emerging from the lumbar vertebrae. They are divided into posterior and anterior divisions. Structure The lumbar nerves are five spinal nerves which arise from either side of the spinal cord ...

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 ...

. It passes under the

inguinal ligament The inguinal ligament (), also known as Poupart's ligament or groin ligament, is a band running from the pubic tubercle to the anterior superior iliac spine. It forms the base of the inguinal canal through which an indirect inguinal hernia may ...

to reach the thigh. It supplies sensation to the

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 ...

on the lateral part of the

by an anterior branch and a posterior branch. The lateral cutaneous nerve of the thigh can be investigated using

ultrasound Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply ...

Local anaesthetic A local anesthetic (LA) is a medication that causes absence of all sense, sensation (including pain) in a specific body part without loss of consciousness, providing local anesthesia, as opposed to a general anesthetic, which eliminates all sen ...

can be injected around the nerve for

skin grafts 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 ...

and

surgery Surgery is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...

around the outer thigh. Nerve compression (usually around the

) can cause

meralgia paraesthetica Meralgia paresthetica or meralgia paraesthetica is pain or abnormal sensations in the outer thigh not caused by injury to the thigh, but by injury to a nerve which provides sensation to the lateral thigh. Meralgia paresthetica is a specific in ...

Structure

The nerve is usually 1-2 mm thick.

Origin

The lateral cutaneous nerve of the thigh is a nerve of the

. It arises from the

anterior rami 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 the second and third

(L2-L3).

Course and relations

It passes through

psoas major muscle 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 equ ...

, and emerges from its lateral border. It crosses the

iliacus muscle The iliacus is a flat, triangular muscle which fills the iliac fossa. It forms the lateral portion of iliopsoas, providing flexion of the thigh and lower limb at the acetabulofemoral joint. Structure The iliacus arises from the iliac fossa on ...

obliquely, toward the

anterior superior iliac spine The anterior superior iliac spine (ASIS) is a bony projection of the iliac bone, and an important landmark of surface anatomy. It refers to the anterior extremity of the iliac crest of the pelvis. It provides attachment for the inguinal ligament, ...

(ASIS). It is crossed by the

deep circumflex iliac artery The deep circumflex iliac artery (or deep iliac circumflex artery) is an artery in the pelvis that travels along the iliac crest of the pelvic bone. Course The deep circumflex iliac artery arises from the lateral aspect of the external iliac arte ...

and the

deep circumflex iliac vein The deep circumflex iliac vein is formed by the union of the venae comitantes of the deep iliac circumflex artery. It drains venous blood from the walls of the iliac fossa. It empties into the external iliac vein about 2 cm superior to the i ...

. It enters the thigh by passing beneath (the lateral part of) the

in the

muscular lacuna The muscular lacuna (Latin: ''lacuna musculorum'') is the lateral compartment of the thigh beneath the inguinal ligament. It is separated from the medial vascular lacuna by the iliopectineal arch. It is occupied/traversed by the iliopsoas muscle, ...

, or through (the lateral part of) the

itself. It then passes over the

sartorius muscle The sartorius muscle () is the longest muscle in the human body. It is a long, thin, superficial muscle that runs down the length of the thigh in the anterior compartment. Structure The sartorius muscle originates from the anterior superior ilia ...

, travelling from medial to lateral.

Branches

The lateral cutaneous nerve of the thigh usually divides into an anterior (or anterolateral) branch and a posterior branch.

Anterior branch

The anterior branch becomes superficial about 10 cm below the inguinal ligament. It divides into branches which are distributed to the skin of the anterior and lateral parts of the thigh, as far down as the knee. The terminal filaments of this nerve frequently communicate with the anterior cutaneous branches of the

femoral nerve The femoral nerve is a nerve in the thigh that supplies skin on the upper thigh and inner leg, and the muscles that extend the knee. It is the largest branch of the lumbar plexus. Structure The femoral nerve is the major nerve supplying the ant ...

, and with the infrapatellar branch of the

saphenous nerve The saphenous nerve (long or internal saphenous nerve) is the largest cutaneous branch of the femoral nerve. It is derived from the lumbar plexus (L3-L4). It is a strictly sensory nerve, and has no motor function. It commences in the proximal (u ...

, forming with them the peripatellar plexus.

Posterior branch

The posterior branch pierces the

fascia lata The fascia lata is the deep fascia of the thigh. It encloses the thigh muscles and forms the outer limit of the fascial compartments of thigh, which are internally separated by the medial intermuscular septum and the lateral intermuscular sept ...

. It subdivides into filaments, which pass backward across the lateral and posterior surfaces of the thigh. It supplies the skin around the

greater trochanter The greater trochanter of the femur is a large, irregular, quadrilateral eminence and a part of the skeletal system. It is directed lateral and medially and slightly posterior. In the adult it is about 2–4 cm lower than the femoral head.Sta ...

Distribution

It provides sensory innervation to the lateral aspect of the thigh (as far as the knee), as well as the

iliac fascia The iliac fascia (or Abernethy's fascia) is the fascia overlying the iliacus muscle. Superiorly and laterally, the iliac fascia is attached to the inner aspect of the iliac crest; inferiorly and laterally, it extends into the thigh to unite with ...

and perineum of the

Variation

The lateral cutaneous nerve of the thigh may have multiple branches. Its position with relation to the ASIS can be very variable. It may partially pass through

rather than over its surface. It may be absent, and the sensory supply replaced by branches of the

and 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, ...

Function

The lateral cutaneous nerve of the thigh is a

sensory nerve A sensory nerve, or afferent nerve, is a nerve that contains exclusively afferent nerve fibers. Nerves containing also motor fibers are called mixed nerve, mixed. Afferent nerve fibers in a sensory nerve carry sensory system, sensory information ...

. It supplies the

on the lateral (outer) part of the

Clinical significance

Ultrasound

The lateral cutaneous nerve of the thigh can be studied using ultrasound. A patient lies on a bed facing upwards (supine). The ultrasound probe is moved along the length of the nerve, often starting from near the ASIS. The nerve is easier to see over the

than in other subcutaneous tissue, as there is greater contrast. It can sometimes be difficult to see due to surrounding soft tissue.

Nerve block

The lateral cutaneous nerve of the thigh can be blocked with

local anaesthetic A local anesthetic (LA) is a medication that causes absence of all sense, sensation (including pain) in a specific body part without loss of consciousness, providing local anesthesia, as opposed to a general anesthetic, which eliminates all sen ...

. Ultrasound is used to guide needle insertion. This is used for procedures in the supplied area of skin, such as

surgical incisions A surgical incision is a cut made through the skin and soft tissue to facilitate an operation or procedure. Often, multiple incisions are possible for an operation. In general, a surgical incision is made as small and unobtrusive as possible to ...

over the outer thigh, and

Meralgia paraesthetica

Entrapment of the lateral cutaneous nerve of the thigh is caused by compression of the nerve near the

and the

. This causes

(Bernhardt-Roth syndrome). This may be diagnosed with ultrasound, which changes the morphology of the nerve. Changes can include general enlargement, and a hypoechoic appearance. In patients who only have meralgia paraesthetica on one side, ultrasound scans are performed on both thighs to compare the appearance of the nerve.

History

The lateral cutaneous nerve of the thigh may also be known as the lateral femoral cutaneous nerve.

Additional images

File:Gray546-LFC.png, Lateral cutaneous nerve of thigh and other structures passing behind the inguinal ligament File:Gray580.png, The great saphenous vein and its tributaries at the fossa ovalis. File:Gray823.png, The lumbar plexus and its branches. File:Gray824.png, Deep and superficial dissection of the lumbar plexus. File:Gray826-LFC.png, Diagram of segmental distribution of the lateral cutaneous nerve (shaded) and other nerves of the right leg. Front view. File:Gray826and831.svg, Cutaneous nerves of the right lower extremity. Front and posterior views.

References

External links

* * - "Posterior Abdominal Wall: Nerves of the Lumbar Plexus" * () {{Authority control Nerves of the lower limb and lower torso

Structure

Origin

Course and relations

Branches

Anterior branch

Posterior branch

Distribution

Variation

Function

Clinical significance

Ultrasound

Nerve block

Meralgia paraesthetica

History

Additional images

See also

References

External links