Myofascial Relations of the Femoral & Lateral Femoral Cutaneous Nerves
Femoral and lateral femoral cutaneous nerve symptoms are a common presentation in osteopathic practise. These symptoms, whilst not always caused by an entrapment neuropathy can be amenable to osteopathic treatment that can be greater understood by appreciating the relation of the femoral nerve and lateral femoral cutaneous nerve to the psoas, iliacus, fascia iliaca and inguinal ligament.
The key clinical points in this article are:
The relationship of the psoas major with the femoral and lateral femoral cutaneous nerves.
The relationship of the psoas minor with the fascia iliaca.
The relationship of the fascia iliaca and iliacus muscle sandwiching the femoral nerve.
Entrapment of the lateral femoral cutaneous nerve in the fascia iliaca-internal oblique septum.
Entrapment of the lateral femoral cutaneous nerve in the fascia between the tensor fascia lata and sartorius (including the iliolata ligaments).
Treatment options for the fascia iliaca in relation to its anatomical connections to the iliacus, psoas major, psoas minor, inguinal ligament and fascia lata.
This article outlines:
Anatomy of the femoral nerve.
Anatomy of the lateral femoral cutaneous nerve.
Anatomy of the fascia iliaca.
Anatomy of the inguinal ligament (& mechanical movement of the inguinal ligament).
Anatomy of the lacunar ligament.
Function of the inguinal and lacunar ligaments.
Anatomy of the femoral nerve
The femoral nerve is the largest branch of the lumbar plexus originating from the dorsal divisions of the ventral rami of L2-4. The L1-5 spinal nerves roots emerge in front of the lumbar transverse processes and enter into the part of the psoas major which is in between the muscle fibres originating from (i) the vertebral bodies and intervertebral discs and (ii) the muscle fibres originating from the transverse processes.
Desouki et al (2016) found the psoas major composed of two sections. The whole of the lumbar plexus, including the femoral and lateral femoral cutaneous nerves, runs between these two sections:
Anterior section: comprises of fleshy slips that arise from the anterolateral part of the vertebral bodies of T12-L5 and their corresponding intervertebral discs. This makes the main part of the psoas major.
Posterior section: comprises of strips that originate from the front and lower border of the transverse processes of T12-L5. This makes the accessory part of the psoas major.
After descending through the psoas major in its own fascial sheath (Kulow et al 2021) (refer ‘Anatomy of the fascia iliaca; psoas fascia’), the femoral nerve emerges from its postero-lateral border at the junction of the muscles upper two thirds and lower one third. After exiting the psoas major the femoral nerve then travels caudally in the gutter between the bulk of the psoas major and the iliacus deep to the fascia iliaca.
It enters the thigh behind the inguinal ligament in the potential space of the fascia iliaca compartment (lacuna musculorum). The nerve travels in this compartment tightly sandwiched between the floor, (formed by the iliacus and psoas major) and the roof, (formed from the fascia iliacus). The femoral nerve then descends in the fascia iliaca compartment to pierce the inferior opening of the fascia iliaca compartment. This inferior opening is formed from the conjoint tendinous sheet of the iliacus fascia formed from the aponeurotic fibers of the psoas and iliacus, internal oblique and transverse abdominis allowing the femoral nerve to communicate with the adipose space under the fascia lata in the femoral triangle (Xu et al 2020). The fascia iliaca compartment is lateral to the femoral artery and vein being separated from the femoral artery by the fascia iliaca (iliopectineal ligament, refer anatomy of the fascia iliaca).
Motor innervation: quadriceps femoris and sartorius muscles.
Sensory innervation: anteromedial surface of the thigh. Via the femoral nerves terminal branch, the saphenous nerve, the medial aspect of the lower leg, ankle and foot.
Lateral femoral cutaneous nerve
The lateral femoral cutaneous nerve arises from the dorsal divisions of L2 and L3.
It emerges from the lateral border of the psoas major and runs on the anterior surface of the iliacus muscle being covered by the fascia iliaca. The relation of all the nerves of the lumbar plexus to the psoas major is described by Desouki et al (2016) in the section above ‘femoral nerve’.
Passing behind the inguinal ligament close to its lateral insertion at the ASIS, the lateral femoral cutaneous nerve perforates the fascia iliaca.
The lateral femoral cutaneous nerve exits the pelvis via a conjoint tendinous sheath of the iliacus fascia, within the internal oblique-iliac fascia septum at the level of the ASIS (Xu et al 2020) making it susceptible to mechanical entrapment (Xu et al 2018).
The nerve then runs in an adipose compartment between the sartorius and iliolata ligaments inferior to the ASIS.
Xu et al (2018) found the iliolata ligaments are 2-3 curtain strip-like structures which attached to the ASIS superiorly and are interwoven with the fascia lata inferomedially, and continued laterally as skin ligaments anchoring to the skin.
Between the sartorius and tensor fasciae lata, the lateral femoral cutaneous nerves runs in a longitudinal ligamental canal bordered by the iliolata ligaments.
Putzer et al (2017) noted dense fascial fibers after dissecting the interval between the tensor fascia lata, sartorius, and rectus femoris. They described a strong band of fibers extending from a proximal-lateral to distal-medial direction.
Henry (1957) possibly described these same fascial webs that are found in the layers that occupy “the space between the origins of the rectus femoris and tensor fasciae [lata] muscles, uniting the deep aspects of their sheaths”.
Xu et al (2018) identified possible sites of entrapment of the lateral femoral cutaneous nerve in the internal oblique-iliac fascia septum and the iliolata ligaments. Could the dense fascia between the tensor fascia lata and sartorius with the iliolata ligaments also be a site of entrapment for the lateral femoral cutaneous nerve?
Once in the thigh the lateral femoral cutaneous nerve splits into its terminal cutaneous branches, which usually cross over the sartorius muscle and are covered by the fascia lata.
Innervation: sensory supply to the lateral aspect of the thigh as far distal as the knee.
Anatomy of the external oblique
Origin: rib 5-12 (interdigitates with serratus anterior and latissimus dorsi), rib cartilage.
Insert:
Ribs 11 and 12: descend vertaically to attach on to the anterior half of iliac crest.
Rib 5-10: ends in an aponeurosis along a line drawn vertically from the ninth costal cartilage to just below the umbilicus and then inclining laterally to the ASIS. This aponeurosis terminates in the linea alba (running continuous with the opposite external oblique, pubic symphysis and pubic crest (as far as the pubic tubercle), and between the ASIS and pubic tubercle this aponeurosis forms the inguinal ligament and lacunar ligament.
External oblique bands are (Manuel et al 2013 pg 10&11):
Costoabdominal epigastric or supraumbilical bands: ribs 5 and 6 —> upper half xifo-umbilical line; rib 7 —> middle xifo-umbilical bottom line.
Costoabdominal hypogastric or infraumbilical bands: ribs 8 —> upper half umbilicus-pubic; rib 9 —> the pillars of the superficial inguinal ring.
Costoinguinal band: anterior part of rib 10 —> forms inguinal ligament (Doyle 1971).
Costoiliacal band: formed by rib 11 and 12 —> aponeurosis inguinal ligament and the anterior wall of the inguinoabdominal region.
External oblique fascia (Stecco 2015 pg 167-170)
External oblique fascia is superficial to the external oblique muscle. It envelopes the rectus sheath with the superficial layer (true epimysial fascia) and deep (thicker, external oblique tendon). These deep fibers cross the midline to the opposite side, with some of the fibers from the superficial layer to form the superficial layer of the opposite external oblique aponeurosis, and other fibers passing deep to become continuous with the fibers of the contralateral internal oblique.
Distally the external oblique fascia is thicker forming the inguinal ligament with its superficial fibers running continuous with the fascia lata and its deeper fibers attaching to the ASIS and pubic tubercle. It is continuous with the pectineal fascia and has a triangular opening immediately above the pubic crest forming the superficial inguinal ring of the inguinal canal.
Anatomy of the fascia iliaca
The fascia iliaca covers the iliacus and psoas muscle. Whilst a single structure the fascia of the iliacus and psoas major are described separately.
Iliacus fascia
The iliacus fascia and is formed by the peripheral fascicular aponeurotic sheets of the iliacus and psoas (rather than the epimysium of the muscles) (refer ’psoas fascia’) (Xu et al 2020). It gradually disappears at the level of L5 (uppermost origin of the iliacus from the ilium) (Xu et al 2020), attaching to the sacrum (Khanfour & Khanfour 2019), to then line the pelvis (inner lip of the iliac crest, ASIS and pelvic brim). It merges very intimately with the periosteum around the pelvic brim and the innominate bone where no muscles separated the fascia from the underlying bone (Meyer 1927) to eventually extend down the anterior thigh.
Around the pelvic brim, at the iliopubic ramus, the iliacus fascia receives a slip, when present, from the psoas minor. Its anteroinferior part is further enhanced by the aponeurotic fibres of the transversus abdominis and internal oblique (Xu et al 2020) blending superiorly with the transversalis fascia. This anterior part of the fascia iliaca that intermingles with aponeurotic fibres of the internal oblique and transversus abdominis forms the conjoint tendinous sheet of the iliacus fascia* (Xu et al 2020).
*the conjoint tendinous sheath of the iliacus fascia is formed from the aponeurotic fibers of the psoas and iliacus, internal oblique and transverse abdominis.
Inferiorly the iliacus fascia blends with the transversalis fascia at:
Femoral sheath: the iliacus fascia forms the posterior wall of the femoral sheath. The transversalis fascia, scarpa's fascia and fascia lata form the anterior wall (Lytle 1956).
Beneath the lateral part of the inguinal ligament: McWhinne (1835) described the fusion of the iliacus and transversalis fascia as forming a fibrous cul-de-sac preventing the viscera prolapsing beneath the lateral part of the inguinal ligament. Teale (1846) found by "destroying" this aponeurotic cul-de-sac the peritoneum could be pushed "very easily" by the finger between the inguinal ligament and iliacus muscle.
The transversalis fascia is the fascia anterior to the transverse abdominis and quadratus lumborum extending medially to cover the anterior aspect of the psoas major where it gets renamed the psoas fascia. The fascia separates these muscles from the retroperitoneal abdominal contents. Superiorly it forms the subdiaphragmatic fascia travelling through the medial and lateral arcuate ligaments and aortic hiatus to become the endothoracic fascia. Inferiorly it blends with the iliacus fascia (Elsharkawy et al 2019) and forms the endopelvic fascia, that lines the walls and floor of the pelvis covering the obturator internus, piriformis, levator ani and coccygeus (Raychaudhuri & Cahill 2008).
Lateral to the femoral vessels the iliac fascia is continuous with the posterior margin of the inguinal ligament.
Posterior to the inguinal ligament the iliacus fascia relations are:
Iliopectineal ligament (or arch): the denser medial fibers of the fascia iliacus forms the iliopectineal fascia, with the most anterior part of the iliopectineal fascia forming an even more stout ligament like structure the iliopectineal ligament (Khanfour & Khanfour 2019).
The iliopectineal ligament extends from the lateral part of the inguinal ligament (1.5-2cm from the ASIS) to the iliopectineal eminence (Khanfour & Khanfour 2019). It can receive attachments from the psoas minor. The fascia iliacus then extends from the iliopectineal eminence to reenforce the hip joint capsule (along with the iliocapsularis, fascia of the gluteus minimus and rectus femoris). It acts as a septum dividing the space under the inguinal ligament into a lateral compartment (psoas major, iliacus and femoral nerve) and medial compartment (femoral artery laterally and femoral vein medially).
The lateral compartment contains the fascia iliaca compartment (lacuna musculorum). The floor of this compartment is formed by the iliacus and psoas major, the roof by the fascia iliacus. Sandwiched between the floor and the roof is a potential space containing the femoral nerve.
The medial compartment contains the femoral sheath. The posterior wall of the femoral sheath is formed from the iliacus fascia (lacuna vasorum). The anterior wall of the femoral sheath is formed from the transversalis fascia, fascia lata and fascia of Scarpa (Lytle 1956). The femoral sheath contains the femoral artery and vein.
Pectineal ligament: the iliacus fascia passes behind the femoral vessels to become the pectineal ligament (lacunar ligament --> pectineal line of the pubic bone).
Muscular attachment: the iliacus fascia, in its own right and as a continuation of the transversalis fascia, gives attachment to the internal oblique and transverse abdominis muscles (Lytle, 1974). At the lateral third of the inguinal ligament, the fascia iliaca is strengthened by the aponeurotic fibres of the transversus abdominis and internal oblique forming a conjoint tendinous sheet of the iliacus fascia (Xu et al 2020). The internal oblique-iliac fascia septum as a potential site of entrapment for the lateral femoral cutaneous nerve (Xu et al 2018).
Iliopubic tract: the iliopubic tract is a thickening of the transversalis fascia. The fascia iliacus provides a lateral attachment to the iliopubic tract as it extends from the transversalis fascia to the fascia iliacus (Teoh et al 1998).
The fascia iliacus is very thick between the ASIS and fascial partition between psoas and pectineus (refer ‘pectineal fascia). The medial half of this fascia forms the floor of the lateral half of the lacuna vasorum (the medial half is formed by the pectineus fascia).
As the iliacus leaves the pelvis it receives, on its lateral side, a large bulging contribution of muscle fibres arising from the notch between ASIS and AIIS* and a tendon which fuses with a tendon on the superficial surface of psoas medial to the AIIS. The fascia iliacus covers the fibres from the notch between the ASIS and AIIS*, and serves as an attachment for fibers from the external oblique aponeurosis at this level. Distally from this attachment of the external oblique aponeurosis, the fascia iliacus is considerably thickened, particularly along the line of sartorius to withstand the pull of the fibres of the external oblique, and runs continuous with the pectineus fascia (Doyle 1970).
The fascia iliacus descends into the thigh to reenforce the anteromedial surface of the hip joint capsule (along with the iliocapsularis, fascia of the gluteus minimus and rectus femoris) (Tsutsumi et al 2019), and then continues as the fascia lata being continuous with the sartorius and pectineal fascia (a condensation of the transversalis fascia overlying the pectineal ligament) at the middle third of the inguinal ligament. At the middle third of the inguinal ligament the fascia iliaca is also strengthened laterally by the peripheral fascicular aponeurotic sheets of the iliacus and rectus femoris (Xu et al 2020).
*: these fibers maybe the anomalous muscle of the gluteus minimus known as the gluteus quaratus (or scansorious). This muscle can present as either small fibers or a distinct muscular bundle. It has variable origins and insertions. Origin: AIIS, ASIS, the notch between the two and/or deep laminae of the gluteus minimus. Insertion: hip joint capsule, anterior intertrochanteric line, greater trochanter and/or vastus lateralis.
Neurological relations:
The iliacus fascia covers the:
Femoral nerve.
Obturator nerve.
Lateral femoral cutaneous nerve.
The fascia iliaca compartment is a funnel-shaped adipose space between the fascia iliaca and the epimysium of the iliopsoas. Along with the psoas compartment, the fascia iliaca compartment lies between the psoas and quadratus lumborum but is not enclosed within the same fascial envelope. It has a superior opening at the level of L5 (uppermost origin of the iliacus from the ilium) that communicates with the extraperitoneal space, and an inferior opening that communicates with the superior and inferior opening of the femoral triangle.
The inferior opening of the fascia iliaca compartment is formed by the femoral nerve piercing the conjoint tendinous sheet of the iliacus fascia to communicates with the adipose space underneath the fascia lata (refer ‘from fascia lata to femoral nerve; fascia like structures under the fascia lata’). In contrast to the femoral nerve that traverses the fascia iliaca compartment and has an intact epineurium the lateral femoral cutaneous nerve pierces the conjoint tendinous sheet of the iliacus fascia at the level of the ASIS.
The fascia iliaca compartment contains the femoral, lateral femoral cutaneous but not the genitofemoral nerve or obturator nerve (Xu et al 2020).
Psoas Fascia
The peripheral fascicular aponeurotic sheets of the iliacus and psoas (rather than the epimysium of the muscles) gives rise to the iliacus and psoas fascia. The peripheral fascicular aponeurotic sheets of the psoas (Xu et al 2020):
Above the L5 level (where the iliacus fascia gradually dissapepars) anchors at the attachment site of the mesocolon.
Below the L5 level is continuous anteromedially with the transversalis fascia.
Posteriorly extends to the posterior edge of the iliacus, form a small triangular aponeurotic septum. This septum separates the fascia iliaca compartment from the paravertebral space (that disappears after the two muscles united) and the obturator nerve from the fascia iliaca compartment making the superior opening of the fascia iliaca compartment at the L5 level.
The transversalis fascia, around the inner surface of the transverse abdominis, posteriorly divides into two lamina. The posterior lamina attaches onto the transverse processes forming the anterior layer of the thoracolumbar fascia attaching to the iliolumbar ligament. The anterior layer extends around the quadratus lumborum and psoas major, where it gets renamed the psoas fascia to attach onto the anterior longitudinal ligament, vertebral bodies and discs where it joins to the transversalis fascia on the opposite side (Stecco 2015 pg 213). Extending superiorly, to form the subdiaphragmatic fascia, the transversalis fascia passes through the medial and lateral arcuate ligaments and aortic hiatus to be renamed the endothoracic fascia (Elsharkawy et al 2019). Inferiorly, the transversalis fascia descends as the endopelvic fascia lining the walls and floor of the pelvis covering the obturator internus, piriformis, levator ani and coccygeus. The psoas fascia attachments are:
Superior: the psoas fascia blends with the diaphragm (medial arcuate ligament, Van Dyke et al 1987 and right and left crus, Sajko & Stuber 2009) and lumbar spine via the diaphragmatic attachments (including anterior longitudinal ligament, Sajko and Stuber 2009). Kulow et al (2021) found the psoas fascia attaches to the fascia containing iliohypogastric nerve which attaches on to another fascia enveloping the subcostal nerve which in turn is then attached to the diaphragmatic fascia. Van Dyke et al (1987) found the psoas fascia continuous superiorly with the endothoracic fascia.
Inferior: the psoas fascia merges with the endopelvic fascia of the pelvic floor (this forms a link with the conjoint tendon, transverse abdominus, and the internal oblique, Sajko & Stuber 2009), pelvic brim (as the psoas major courses over the pelvic brim the fascia of the posterior fascicles attach firmly to it Sajko & Stuber 2009), reenforces the anteromedial surface of the hip joint capsule (along with the iliocapsularis, fascia of the gluteus minimus and rectus femoris) and the deep and medial surfaces of the rectus femoris (Tsutsumi et al 2019) and the fascia lata (Van Dyke et al 1987). The posterior aspect of the psoas fascia, at the level of L4-5, iliac crest and the iliolumbar ligament, joins the anterior part of the psoas fascia to blend with the iliac fascia (Kulow et al 2021).
Anteriorly: the psoas fascia merges with the fascia that covers the kidneys, the pancreas, the descending aorta, the inferior vena cava, the colon (ascending and descending), the duodenum and the cecum (Bordoni and Varacallo 2019)
Posteriorly: the psoas fascia merges with the transversalis fascia covering the quadratus lumborum.
Laterally: the anterior part of the psoas fascia attaches to the posterior aspect of the retrorenal fascia (Zuckerkand's fascia) (Kulow et al 2021).
Medially: the posterior part of the psoas fascia attaches to the vertebral bodies, pedicles, and discs. Here the soft tissue components lateral to the vertebrae are attached to the spinal dura mater. Traction to these outer soft tissues, lateral to the vertebrae, can produce movement in the spinal dura mater (Kulow et al 2021).
Contiguous structures include (Van Dyke et al 1987):
Vertebral bodies.
Intervertebral discs.
Posterior paraspinal muscles.
Innominate bone.
Lumbar vessels.
Branches of the sympathetic trunk that pass beneath the tendinous arches of the psoas major.
Nerves of the lumbar plexus pass through the psoas major. The lateral femoral cutaneous nerve is enveloped by the posterior aspect of the psoas fascia and the iliacus fascia. The femoral nerve passes in a separate fascial sheath anterior to the posterior part of the psoas fascia, this ‘fascial plate’ merges with the psoas medially, iliacus laterally and posterior aspect of the iliacus fascia superiorly (Kulow et al (2021).
Iliopectineal fascia (Stecco 2015 pg 314-315)
The iliopectineal fascia originates in the anterior portion of the iliopsoas fascia (Moreno et al 2021). It attaches to the iliac crest immediately posterior to the origin of the inguinal ligament to then inferomedially to the iliopectineal eminence (Barker et al 2021) (refer ‘iliopectineal ligament’) and then descends further to run continuous with the obturator internus fascia (Moreno et al 2021). At this level it also gives origin to the internal oblique and transversus abdominis (Barker et al 2021). The iliopectineal fascia can also be seen as a cephalic extension of the deep layer of fascia lata (Steinke et al 2019) as where the iliopsoas attaches on to the lesser trochanter the iliopectineal fascia continues with the portion of the fascia lata that covers the rectus femoris, and connects with the pectineus (Stecco 2015) and pectineal ligament (of Cooper) (Steinke et al 2019). At this level, originating from the anterior iliopsoas fascia, the iliopectineal fascia forms the posterior wall of the femoral sheath accompanying the external iliac vessels as they pass into the thigh.
This anterior portion of the iliopsoas fascia is thin but becomes thicker medially as it forms the iliopectineal fascia with the most anterior part of the iliopectineal fascia becoming even thicker forming the iliopectineal ligament. The iliopectineal ligament can this be seen as being the stoutest part of the iliopectineal (and iliopsoas) fascia (Khanfour & Khanfour 2014).
Anatomy of the pectineal fascia
As a condensation of the transversalis fascia overlying the pectineal ligament (of Cooper)* the pectineus fascia covers and gives origin to the pectineus muscle. It runs from the lateral side of pubic tubercle, along pectineal line to ilio-pubic eminence where it turns down between pectineus and psoas, forming a partition between these muscles. Where the fascia is attached to the pectineal line it contains bundles of fibres that continue into the periosteum of the superior pubic ramus forming the pectineal ligament (of Cooper) (Doyle 1971).
In the femoral triangle inferior prolongations of the inguinal ligament originating from the aponeurotic fibres of the external oblique, internal oblique and transversus abdominis form a two or three layered fascia anterior to the femoral nerve that fuses with the pectineal fascia. It contributes to the anterior and medial walls of the femoral vascular sheath (Xu et al 2020).
As the fascia iliacus descends into the thigh as the fascia lata it is also continuous with the pectineal fascia and sartorius.
*Pectineal ligament (of Cooper): lacunar ligament --> pectineal line of the pubic bone)
Anatomy of the inguinal ligament
The inguinal ligament extends from the ASIS to the pubic tubercle and pectin pubis. Some fibres near the ASIS may end in the fascia lata.
The inferior surface of the narrow lateral half of the inguinal ligament is fixed to the fascia lata. This part of the fascia lata is an extension of the fascia iliaca. The fascia iliaca descends over the iliacus, under the inguinal ligament attaching to its underside and into the thigh as the fascia lata.
The under surface of the medial part of the inguinal ligament, before it reaches its attachment to the pubic tubercle and pecten pubis, is fixed to the pectineus muscle and fascia (a condensation of the transversalis fascia overlying the pectineal ligament).
The superior aspect of the inguinal ligament gives attachment to the internal oblique and transverse abdominis. The fascia iliaca, posterior to the inguinal ligament, also gave attachment to muscle fibres of the internal oblique and transverse abdominis muscles (Lytle 1974), the internal oblique-iliac fascia septum is a potential site of entrapment for the lateral femoral cutaneous nerve (Xu et al 2018). As well as the external oblique aponeurosis forming the inguinal ligament it attaches the fascia iliacus 2-3cm medial to the ASIS with the fascia being considerably thickened at this level, particularly along the line of sartorius to withstand the pull of the fibres of the external oblique; it then continues medially to blend with the pectineus fascia (Doyle 1970).
Fascia lata arises from the posterior border of the inguinal ligament.
Femoral sheath: the fascia lata passes down to cover and blend with the anterior wall of the femoral sheath. Here it blends with Scarpa’s fascia and the transversalis fascia as it descends from the anterior abdominal wall over the inguinal ligament (Lytle 1956). The posterior wall of the femoral sheath is formed from the fascia iliaca.
Lacunar ligament: medial to the femoral sheath the fascia lata attaches to the posterior border of the inguinal ligament to form the lacunar ligament.
The myofascial attachments of the inguinal ligament are:
External oblique aponeurosis: the external oblique aponeurosis forms the inguinal (and lacunar) ligament.
Cremaster muscle (Lunn 1948).
Deep fascia of pectineus (Lunn 1948)
Fascia iliaca: a thickened strip of the fascia iliaca forms the superolateral part of the iliopectineal arch (Acland 2008).
Fascia lata (Lytle 1974).
Transversalis fascia.
The iliopubic tract or deep femoral arch (Lytle 1974).
Mechanical movement of the inguinal ligament
Lunn (1948) found the medial half of the inguinal ligament is more mobile than the lateral. (No author, 1835) found when the thigh is extended and rotated outwards this produced a stretch on the crural arch (inguinal ligament) drawing it downwards without producing much effect upon the lacunar ligament. This was produced by stretching the part of the fascia lata attaching on to [and forming] part of the lacunar ligament and anterior part of the femoral canal. The author found flexing and rotating the thigh inwards had the opposite effect.
Anatomy of the lacunar ligament
The lacunar ligament is attached in front to the posterior border of the inguinal ligament and behind the pecten pubis being fused, along with the inguinal ligament, to the pectineus muscle and its fascia (a condensation of the transversalis fascia overlying the pectineal ligament).
The lacunar ligament, with the pectineus muscle and its fascia, passes upwards and backwards to reach the pectineal ligament on the pecten pubis
The lacunar ligament is derived from the fascia lata of the thigh. It is reinforced by the transversalis fascia. It gives rise to the anterior part of the femoral canal and supports the femoral vein.
The fascia lata attaches to the lacunar ligament and continues down to blend with the medial aspect of the femoral sheath. As it descends in the thigh it is known as the cribiform fascia.
Function of the inguinal and lacunar ligaments
The inguinal and lacunar ligaments:
Forms a strong protective diaphragm between the abdomen and the thigh.
Forms a broad aponeurotic floor for the inguinal canal which keeps its anterior and posterior walls apart to give roomy passage for the spermatic cord.
Supports the femoral sheath and holds open the lumen of the large thin-walled femoral vein, fixed within the walls of the femoral sheath, amid the stresses and strains of thigh movement and variations of intra-abdominal pressure and body posture.
From fascia lata to femoral nerve
Fascia lata
The fascia lata in the femoral triangle had two origins (Xu et al 2020).
Medial part of the fascia lata: inferior prolongation of the inguinal ligament originates from the aponeurotic fibres of the external oblique, internal oblique and transversus abdominis. It is a two or three layered fascia anterior to the femoral nerve that fuses with the pectineal fascia. It contributes to the anterior and medial walls of the femoral vascular sheath.
The lateral part of the fascia lata overlaps the sartorius forming the iliolata ligaments (refer ‘lateral femoral cutaneous nerve’).
Fascia like structures underneath the fascia lata
In addition to areolar tissue there are two groups of fascia-like structures deep to the fascia lata (Xu et al 2020):
Lateral group: composed of multiple transverse or obliquely orientated fascial layers originated from the aponeurotic fibres of the sartorius and rectus femoris.
Medial group: composed of longitudinally orientated fibrous bundles originated mainly from aponeurotic fibres of the transversus abdominis, internal oblique and external oblique.
The femoral nerve, passes through, and pierces the inferior opening of the fascia iliaca compartment. This inferior opening is formed from the conjoint tendinous sheet of the iliacus fascia formed from the aponeurotic fibers of the psoas and iliacus, internal oblique and transverse abdominis allowing the femoral nerve to communicate with the adipose space under the fascia lata.
References
THE COMPARATIVE ANATOMY OF THE INGUINAL LIGAMENT (1948) By H. F. LUNN
The inguinal ligament and its lateral attachments: Correcting an anatomical error† (2008). Robert D. Acland
The inguinal and lacunar ligaments W. J. LYTLE (1974)
STUDY OF ANATOMICAL PATTERN OF LUMBAR PLEXUS IN HUMAN (CADAVERIC STUDY) BY Prof. Gamal S Desouki, prof. Maged S Alansary,dr Ahmed K Elbana and Mohammad H Mandor
Review of iliopsoas anatomy and pathology (1987). Jerrold A. Van Dyke, Howard C. Holley, Susan D. Anderson.
The iliopubic tract: an important anatomical landmark in surgery (1998) LAURENCE S. G. TEOH , GUY HINGSTON , SAAD AL-ALI, BRENDA DAWSON AND JOHN A. WINDSOR
THE COMPARATIVE ANATOMY OF THE INGUINAL LIGAMENT (1948) By H. F. LUNN
Inguinal anatomy. (1979). W J Lytle
Anatomical Description of the Parts Concerned in Inguinal and Femoral Hernia (1835). No author
Review of iliopsoas anatomy and pathology (1987)
Jerrold A. Van Dyke, M.D. Howard C. Holley, Susan D. Anderson.
Psoas Major: a case report and review of its anatomy, biomechanics, and clinical implications (2009). Sandy Sajko and Kent Stuber.
Anatomy, Bony Pelvis and Lower Limb, Iliopsoas Muscle (2019). Bruno Bordoni; Matthew Varacallo
Fascia Iliaca Compartment Block: LANDMARK AND ULTRASOUND APPROACH ANAESTHESIA TUTORIAL OF THE WEEK 193 23rd AUGUST 2010 Dr Christine Range and Dr Christian Egeler.
FEMORAL HERNIA Lecture delivered at the Royal College of Surgeons of England on 12th October 1956 by W. J. Lytle.
Fine architecture of the fascial planes around the lateral femoral cutaneous nerve at its pelvic exit: an epoxy sheet plastination and confocal microscopy study (2018). Xu Z, Tu L, Zheng Y, Ma X, Zhang H, Zhang M.
The deep layer of the tractus iliotibialis and its relevance when using the direct anterior approach in total hip arthroplasty: a cadaver study (2017). David Putzer, Matthias Haselbacher, Romed Hörmann, Günter Klima, and Michael Nogler
Extensile Exposure. 2nd ed. (1957). Henry AK. pp. 209–210.
Quadratus Lumborum Block Anatomical Concepts, Mechanisms, and Techniques (2019) Hesham Elsharkawy, Kariem El-Boghdadly, Michael Barrington.
Anatomical Description of the Parts Concerned in Inguinal and Femoral Hernia (1835). No author
Pelvic fasciae in urology (2008). Raychaudri B, Cahill, D
THE PELVIC FLOOR—CONSIDERATIONS REGARDING ITS ANATOMY AND MECHANICS (1927). A. W. Meyer
A practical treatise on abdominal hernia (1846). Thomas Pridgen Teale
Anatomical description of the parts concerned in inguinal and femoral hernia, translated from M. Jules Cloquet; with lithographic plates from the original etchings and a few additional explanatory notes (1835). Andrew Melville.
Kulow C, Reske A, Leimert M, Bechmann I, Winter K, Steinke H (2021). Topography and evidence of a separate “fascia plate” for the femoral nerve inside the iliopsoas – A dorsal approach
Xu Z, Mei B, Liu M, Tu L, Zhang H, Zhang M (2020). Fibrous configuration of the fascia iliaca compartment: An epoxy sheet plastination and confocal microscopy study
Stecco C (2015). Functional atlas of the human fascial system
DOYLE J (1970). Superficial inguinal arch. A re-assessment of what has been called the inguinal ligament
Manuel J, Grau S, Antonio J, Luque B (2013). Advances in Laparoscopy of the Abdominal Wall Hernia
Barker JP, Yang Y, Matz J, Marmor MT, Morshed S. (2021). The Iliopectineal Fascia: A Cadaveric Anatomical Study
Khanfour A & Khanfour A (2019). ILIOPECTINEAL LIGAMENT AS AN IMPORTANT LANDMARK IN ILIOINGUINAL APPROACH OF THE ANTERIOR ACETABULUM: A CADAVERIC MORPHOLOGIC STUDY
Moreno G, Ponce de León JG, Rickman M. (2021). The Anatomic Relevance of the Iliopectineal Fascia for Acetabular Surgery.
Tsutsumi M, Nimura A, Honda E, Utsunomiya H, Uchida S, Akita K. (2019). An Anatomical Study of the Anterosuperior Capsular Attachment Site on the Acetabulum.
