Osteopathic Journals and Research by Darren Chandler

 

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  1. Lateral knee fascia

    Iliotibial band

    The iliotibial band is merely a lateral expansion of the fascia lata and made up of three layers: superficial, middle and deep.

    Superficial and middle layer: encloses the tensor fascia lata anchoring it to the iliac crest. These layers unite at the distal end of the tensor fascia lata to form a tendon for the muscle. These two united layers receive fibers from the gluteus maximus and runs down the lateral thigh. As it courses down the lateral thigh Fairclough et al (2006) found the Iliotibial band continuous with the strong lateral intermuscular septum, which was firmly anchored to the linea aspera of the femur. Evans (1979) found fibers from the lateral intermuscular septum form the horizontal fibers of the iliotibial band.

    Distally, after coursing through the Biceps Femoris and Vastus Lateralis Godin et al (2017) found the distal attachments of the Iliotibial band to be: 

    • Proximal bundle: runs nearly transversely from the superficial Iliotibial band to the distal femur. Inserts on the proximal ridge of the distal femoral body, distal to the lateral intermuscular septum 53.6 mm proximal to the lateral epicondyle.
    • Distal bundle: runs from the superficial Iliotibial band from a proximal and lateral to distal and medial direction inserting on to the supracondylar flare. This could be the Kaplan fibers mentioned below under 'lateral femoral condyle and epicondyle'.
    • Lateral femoral condyle and epicondyle: Herbst et al (2017) found transverse fibers from the deep layer of the ITB (Kaplan fibers) connect the superficial ITB to the distal femoral metaphysis and condyle. These authors also found accessory insertions of the deep iliotibial band located proximal and anterior to the lateral femoral epicondyle. Fairclough et al (2006) described the attachment of the ITB to the region of, or directly to, the lateral epicondyle as strong fibrous ‘tendonous’ strands and then more ‘ligamentous’ strands between the lateral epicondyle of the femur and Gerdy's tubercle on the tibia. Variable and indinstinct insertions from the capsulo-osseous layer are also attached to the lateral epicondyle.
    • Capsulo-osseous layer: a distinct fascial portion of the deep Iliotibial band. Runs from just proximal to the lateral gastrocnemius tubercle to the lateral tibial tubercle*. Herbst et al (2017) found variable and indistinct attachments from this layer around the lateral femoral epicondyle. The capsulo-osseous layer is intimately related to the lateral knee capsule and the fascia surrounding the lateral gastrocnemius tendon and biceps femoris (Herbst et al 2017). Evans (1979) found additional attachments to the lateral meniscus.
    • Gerdy tubercle: the superficial Iliotibial band attaches on to a wide area from Gerdy tubercle anteriorly to the anterolateral and lateral tibia posteriorly. Deep fibers of the Iliotibial band attach slightly posterior to Gerdy tubercle (Herbst et al 2017).
    • Iliopatellar Band: attaches to the lateral aspect of the patella and patellar tendon. The distal edge of this portion forms the lateral patellotibial ligament, part of the lateral retinaculum.

    *: lateral tibial tubercle is loacted on the anterolateral aspect of the proximal tibia, between the Gerdy tubercle and the fibular head (Godin et al 2017).

    Herbst et al (2017) failed to the find the anterior lateral ligament on dissection. These authors found the capsulo-osseous layer of the ITB and the mid-third capsular ligament both occupied anatomic locations that are similar to that of the anterior lateral ligament. This ligament is documented as resisting internal rotation of the tibia.

    Fairclough et al (2006) found conversely to popular belief no bursa was found between the tendonous fibrous bands of the Iliotibial band and the femur. There was just adipose tissue. 

    Wilke et al (2016) found more distally the Iliotibial band connected strongly to the crural fascia which in itself was hardly seperable from the peroneal longus fascia.

    Deep layer: The deep layer of the iliotibial band emerges where the superficial and middle layers fuse distal to the tensor fascia lata (Putzer et al 2017). From here it runs deep attaching to the vastus lateralis and rectus femoris fascia. Coursing deeper still it follows the iliofemoral ligament to attach to the supraacetabular fossa between the tendon of the reflected head of the rectus femoris and the hip joint capsule. It resists hip extension.

    Williams (1879) gives a description of the attachment of the deep layer of the iliotibial band to the rectus femoris. He describes at a short distance below the insertion of the tensor fascia lata into the deep layer of the iliotibial band a strong process of fascia lata arises from the iliotibial band passing obliquely upwards and inwards to join the tendon of the rectus femoris at the junction of its two heads. It also spreads backwards over the outer surface enclosing the reflected head of the rectus femoris, to which it is very firmly adherent, being fixed above to the inferior gluteal line, anterior inferior iliac spine and below blending with the capsule of the joint. This band of fascia binds down the tendon of the reflected head of the rectus femoris and connects the two heads.

    Additional muscular attachments to the Iliotibial band include:

    ·           Vastus Lateralis (Becker et al 2010).

    ·           Biceps Femoris.

    ·           Tensor Fascia Lata.

    ·           Gluteus Maximus.

    Lateral patella retinaculum

    The lateral patella retinaculum is made up of:

    • Iliopatellar band of the ITB (ITB-P).
    • Lateral patellofemoral ligament (LPFL).
    • Lateral patellomeniscal ligament (LPML).

    Fibers from the vastus lateralis form part of the lateral patella retinaculum (Waligora et al (2009).

    Iliopatellar Band of ITB (ITB-P)

    The ITB attaches to the lateral aspect of the patella and patellar tendon. The distal edge of this portion forms the ITB-P.

    These fibres criss-cross in a predominantly transverse orientation. They are easily separated from the underlying joint capsule (Merican et al 2009).

    These fibers are by far the strongest and stiffest structure in the lateral retinaculum. Being more transverse in orientation and densely arranged they resist medial displacement forces that pull the patella away from the ITB. 

    These fibers move anteriorly when the knee is extending knee slackening the ITB-P and is conversely pulled tight when the knee is flexed. Therefore these fibers are most tightly stretched in knee flexion and medial patella deviation. 

    Lateral patellofemoral ligament (LPFL) and lateral patellomeniscal ligament (LPML) 

    These capsulo-ligamentous bands are thickened bands of the lateral joint capsule. They are not always present as distinct fibre bands,

    i. Lateral patellofemoral ligament (LPFL): patella (middle third) --> femur (distal and anterior to lateral epicondyle) (Shah et al 2017). The vastus intermedialis reinforces the LPFL (Waligora et al 2009).

    ii. Lateral patellomeniscal ligament (LPML): lateral border of the patella --> anterior aspect of the lateral meniscus.

    Medial knee fascia

    Fascia lata

    Wymenga et al (2006) identified three layers of the fascia in the medial knee:

    Layer I: superficial fascia

    The superficial fascia is subcutaneous. It blends with the pes anserine and tibial periosteum distally, it covers the sartorius and quadriceps proximally, the retinaculum anteriorly, and forms the deep crural fascia posteriorly.

    The superficial portion of layer I adheres to the sartorius. The deep portion of layer I adheres to the gracilis and semitendinosus tendons.

    Layer II: superficial medial collateral ligament

    The superficial medial collateral ligament extends from the femoral epicondyle to the anteromedial tibial crest 5–7 cm below the joint line. LaPrade (2009) found a majority of the distal attachments of the superficial medial collateral ligament to be to the semimembranosus and pes anserine bursa rather than the tibia.

    Posteriorly these fibres are continuous with the oblique fibres of layer III although this was disputed by LaPrade (2009) who found no clear connection.

    Anterior to the femoral attachment these fibres are continuous with the medial patellofemoral ligament.

    Tuncay et al (2007) found the semitendinosus and gastrocnemius tendons to lie between layer I and II.

    Just as the superficial portion of layer I adheres to the sartorius, the deep portion of layer I adheres to the gracilis and semitendinosus tendons. Tuncay et al (2007) found two fascial bands associated with the semitendinosus:

    • Dense 3–4-cm band around the gracilis and semitendinosus tendons approximately 8–10 cm proximal to their tendon insertion.
    • Fascial band originating from the semitendinosus and extending to the gastrocnemius fascia.

    Layer III: the true capsular layer and mid-third medial capsular ligament (deep medial collateral ligament)

    Layer III thickens and forms the deep medial collateral ligament as a thickening of the medial joint capsule.

    The deep medial collateral ligament (layer III) separates the superficial medial collateral ligament (layer II) from the medial meniscus.

    The deep medial collateral ligament extends from the medial femoral condyle to the meniscus and from the meniscus to the tibia.

    Proximally the deep medial collateral ligament attachment merges into the superficial medial collateral ligament fibres, but sometimes it has a distinct attachment 0.5 cm distally.

    The meniscotibial attachment of the deep medial collateral ligament is clearly separated from the superficial medial collateral ligament but blends with it posteriorly.

    Anterior to the superficial medial collateral ligament layer III is thin and loose blending with layer I into the retinaculum.

    Conjoint attachments of layers II and III

    The conjoined tissue of layers II and III forms the posteromedial capsule

    A condensation of fibres within the posteromedial capsule forms the posterior oblique ligament. This ligament is an important stabiliser of the medial side of the knee.

    The femoral attachment of the posteromedial capsule is located at the adductor tubercle.

    The posteromedial capsule is augmented by:

    • Semimembranosus tendon: inserts into the posteromedial tibia just below the joint line. It has various extensions into the posteromedial capsule and the posterior capsule.
    • Adductor Magnus tendon: LaPrade et al (2009) found the distal-medial aspect of the adductor magnus tendon had a thick fascial expansion, which fanned out posteromedially and attached to the medial gastrocnemius tendon, the capsular arm of the posterior oblique ligament and the posteromedial capsule.
    • Gastrocnemius: as well as a thick fascial attachment to the adductor magnus the medial gastrocnemius has a thin fascial band extending to the capsular arm of the posterior oblique ligament (LaPrade et al 2009).

    Medial retinaculum

    The medial retinaculum is made up of the:

    • Medial patello-femoral ligament (MPFL).
    • Medial quadriceps tendon–femoral ligament (MQTFL).
    • Medial patello-tibial ligament (MPTL).
    • Medial patello-meniscal ligament (MPML).

    Medial patello-femoral ligament (MPFL)

    The MPFL is an hourglass-shaped structure. Femur: adductor tubercle, medial femoral epicondyle and gastrocnemius tubercle --> patella: superomedial aspect (Aframian et al 2017). The patella attachments occur mainly through the aponeurosis of the vastus medialis and vastus intermedialis (Placella et al 2014).

    Wymenga et al (2006) found attachments of the superficial medial collateral ligament (femoral epicondyle --> anteromedial tibial crest) to the MPFL. Waligora et al (2009) found the MPFL (as well as the LPFL) fused with the fibrous layer of the joint capsule.

    These authors also found attachment of the posteromedial joint capsule to the MPFL attachment to the adductor tubercle.

    Tanaka (2016) found variations in these attachment finding all MPFL fibers can either attach to the patella or quadriceps tendon.

    Medial quadriceps tendon–femoral ligament (MQTFL) 

    Medial aspect of the distal quadriceps tendon --> femur: adductor tubercle region. 

    Medial patello-tibial ligament (MPTL)

    Patella: medial to the inferior pole* --> tibia: anteromedial tibia (Kruckeberg et al 2019).

    Medial patello-meniscal ligament (MPML)

    Patella: medial to the inferior pole* --> medial meniscus (Hinckel et al 2019).

    *: MPTL and MPML share a common insertion.

    Mechanics of the medial patella ligaments

    Tanaka et al (2019) found the MPFL accounts for only half of the total restraint to lateral patellar displacement.

    These authors found the remaining contributions to patellar stability are derived from the combination of the MPTL and MPML, which function primarily in greater degrees of knee flexion.

    In contrast Decante et al (2019) found during knee flexion, the upper bands (upper patella --> femur) stretched while the lower bands (lower patella --> femur) shortened.

    Posterior knee fascia

    Popliteal fascia

    Satoh et al (2016) found the popliteal fascia a single aponeurotic sheet acting as a three-layered retinaculum:

    • Layer one. The superficial layer of the popliteal fascia. Strongly interwoven with the epimysium of biceps femoris along its lateral aspect and with that of the semimembranosus along its medial aspect. This ensures that the flexor muscles remained in their correct positions.
    • Layer two. The intermediate layer: arose from the medial side of biceps femoris and merged medially with the superficial layer.
    • Layer three. The deep layer: stretched transversely between the biceps femoris and the semimembranosus.

    These authors found this fascia was innervated by the posterior femoral cutaneous or saphenous nerve. These nerves are closely related and distributed to densely packed collagen fibers in layer one (superficial layer) as free or encapsulated nerve endings. Therefore this fascia could be a source of pain in the upper region of the popliteal fossa.

    Anterior knee fascia

    Fascial layers of the anterior knee (Waligora et al 2009)

    Fibrous layers that cover the knee anteriorly consist of:

    • Superficial aponeurotic layer is a continuation of the fascia lata proximally and the crural fascia distally.
    • Intermediate layer: is subdivided into the deep and superficial midline layers.

    i. Superficial midline layer: laterally is a thick extension of the ITB. Medially is a thin expansion from the sartorius that connects to the fascia lata.

    ii. Deep midline layer: fibers creating the quadriceps and patellar tendons and the crossed fibers of the vastus medialis and vastus lateralis traveling to the tibial condyles of the opposite side.

    • Deep layer: fibrous layer. Medial and lateral to the patella. Comprises the patellofemoral and meniscopatellar ligaments.

    Myofascial relations of the quadricep tendon (Waligora et al 2009)

    Traditionally the quadriceps femoris insertion into the patella as a common tendon has been described as a three-layered arrangement: 

    • Superficial layer: rectus femoris.
    • Middle layer: vastus lateralis (including vastus lateralis obliquus) and vastus medialis (including vastus medialis obliquus).
    • Deep layer: vastus intermedialis.

    The strict segregation of these layers can be misleading on dissection.

    Superficial layer: rectus femoris

    The rectus femoris inserts on to the anterior portion of the patella tendon. Some fibers continue on to the ligamentum patella.

    The thickening of the deep fascia posterior to the rectus femoris contribute to the quadricep tendon.

    Middle layer: vastus lateralis and vastus medialis

    The vastus lateralis and vastus medialis unite to form a continuous aponeurosis that inserts onto the patella posterior to the rectus femoris and continues laterally and medially inserting into the sides of the patella.

    Thickening of the fascia posterior to the vastus medialis and vastus lateralis contribute to the quadricep tendon.

    Vastus lateralis (& vastus lateralis obliquus)

    From the vastus lateralis fibers cross superficial to the patella to the medial condyle of the tibia.

    Other fibers blends with the capsule of the knee and form part of the the lateral patellar retinaculum 

    The vastus lateralis obliquus is a distinct group of vastus lateralis fibers. They are separated from the main belly of the vastus lateralis. Much like the vastus medialis obliquus they can be classified as the more distal oblique fibers of the vastus lateralis.

    This vastus lateralis obliquus can originate from the lateral intermuscular septum or ITB and attach on to the superolateral part of the quadriceps tendon.

    These fibers provide a more direct lateral pull on the quadriceps tendon due to their lateral insertion on the quadriceps tendon.

    Vastus medialis (& vastus medialis obliquus)

    Most fibers of the vastus medialis end in an aponeurosis that blends with the medial side of the suprapatellar tendon or the rectus femoris tendon.

    More distal fibers form a tendinous expansion attaching to the medial side of the patella. Deep fibers from this expansion reinforce the joint capsule as part of the medial patellar retinaculum.

    Obliquely oriented fibers from the vastus medialis obliquus (with the vastus intermedialis) attach the MPFL to the patella (Placella et al 2014).

    As with the vastus lateralis tendinous fibers from the vastus medialis obliquus pass across the patella to attach to the lateral tibial condyle.

    Deep layer: vastus intermedialis

    The vastus intermedialis inserts through a broad, thin tendon into the base of the patella.

    Medially and laterally it reinforces the MPFL and LPFL.

    Thickening of the deep fascia anterior to the vastus intermedialis contributes to the quadricep tendon.

    References

    Lateral Patellofemoral Ligament: An Anatomic Study (2017). Kalpit N. ShahSteven F. DeFroda,  James Kristopher Ware,  Sarath C. Koruprolu, and Brett D. Owens.

    Three-layered architecture of the popliteal fascia that acts as a kinetic retinaculum for the hamstring muscles (2016). Masahiro SatohHiroyuki YoshinoAkira FujimuraJiro HitomiSumio Isogai

    The structural properties of the lateral retinaculum and capsular complex of the knee (2009). Azhar M. Merican, Sanjay Sanghavi, Farhad Iranpour, and Andrew A. Amis

    Descriptive and dynamic study of the medial patellofemoral ligament (MPFL) (2019). Cyrille DecanteLoïc GeffroyCéline SalaudAntoine ChalopinStéphane PloteauAntoine Hamel

    Variability in the Patellar Attachment of the Medial Patellofemoral Ligament (2016). Miho J Tanaka 

    The postural function of the iliotibial tract (1979). P. Evans

    The functional anatomy of the iliotibial band during flexion and extension of the knee: implications for understanding iliotibial band syndrome (2006). John Fairclough, Koji Hayashi, Hechmi Toumi, Kathleen Lyons, Graeme Bydder, Nicola Phillips,Thomas M Best, and Mike Benjamin.

    Recognition of evolving medial patellofemoral anatomy provides insight for reconstruction (2019). Miho J Tanaka, Jorge Chahla, Jack Farr, Robert F LaPrade, Elizabeth A Arendt, Vicente Sanchis-Alfonso, William R Post, John P Fulkerson

    Quantitative and Qualitative Analysis of the Medial Patellar Ligaments: An Anatomic and Radiographic Study (2018). Bradley M Kruckeberg, Jorge Chahla, Gilbert Moatshe, Mark E Cinque, Kyle J Muckenhirn, Jonathan A Godin, Taylor J Ridley, Alex W Brady, Elizabeth A Arendt , Robert F LaPrade

    Concepts of the Distal Medial Patellar Restraints: Medial Patellotibial Ligament and Medial Patellomeniscal Ligament (2019). Betina B Hinckel, Lukasz Lipinski, Elizabeth A Arendt

    Origin and insertion of the medial patellofemoral ligament: a systematic review of anatomy (2016). Arash AframianToby O. Smith, T. Duncan Tennent, Justin Peter Cobb, and Caroline Blanca Hing.

    The fascial band from semitendinosus to gastrocnemius: the critical point of hamstring harvesting An anatomical study of 23 cadavers (2007) Ibrahim Tuncay, Hudaverdi Kucuker, Ibrahim Uzun and Nazim Karalezl

    The Anatomy of the Medial Part of the Knee (2009). Robert F. LaPrade, Anders Hauge Engebretsen, Thuan V. Ly, Steinar Johansen, Fred A. Wentorf, Lars Engebretsen

    Surgical anatomy of the medial collateral ligament and the posteromedial capsule of the knee (2006) Ate B Wymenga Sint Maartenskliniek, Jan-Jaap Kats, Jan G M Kooloos

    A Comprehensive Reanalysis of the Distal Iliotibial Band Quantitative Anatomy, Radiographic Markers, and Biomechanical Properties (2017). Jonathan A. Godin Jorge Chahla, Gilbert Moatshe, Bradley M. Kruckeberg, Kyle J. Muckenhirn, Alexander R. Vap, Andrew G. Geeslin, Robert F. LaPrade

    The Anterolateral Complex of the Knee (2017). Elmar Herbst, Marcio Albers, Jeremy M. Burnham, Freddie H. Fu, and Volker Musahl.

    Anatomical study of the morphological continuity between iliotibial tract and the fibularis longus fascia (2016). Wilke J, Engeroff T, Nürnberger F, Vogt L, Banzer W.

    Clinical Anatomy of the Quadriceps Femoris and Extensor Apparatus of the Knee (2009). Andrew C. WaligoraNorman A. Johanson, and Bruce Elliot Hirsch.

    Shape and size of the medial patellofemoral ligament for the best surgical reconstruction: a human cadaveric study (2016). G PlacellaM M TeiE SebastianiG CriscentiA SpezialiC MazzolaA GeorgoulisG Cerulli

  2. Muscular anatomy: masseter, temporalis, medial and lateral pterygoid and buccinator muscles

    Masseter

    Superficial layer: zygomatic bone and zygomatic arch --> mandibular ramus.

    Middle layer: zygomatic arch --> mandibular ramus.

    Deep layer: zygomatic arch --> mandibular ramus and coronoid process of the mandible. There is debate as to whether the masseter attaches to the articular disc of the TMJ.

    Temporalis

    Origin (superficial layer): temporal fossa, zygomatic bone, deep temporal fascia.

    Origin (deep layer): superior surface of the zygomatic arch and the muscle that passes beneath the arch.

    Insertion: mandible (coronoid process and ramus). It can attach on to the articular disc of the TMJ.

    Sphenomandibularis

    The sphenomandibularis is the deep belly of the temporalis muscle located on its medial side. It originates from the greater wing of the sphenoid and attaches on to the mandible at the temporal crest, the retromolar triangle and the anterior limit of the mandibular notch (Geers et al 2005). 

    Functions of the masseter and temporalis

    Whilst the masseter and temporalis close the TMJ the temporalis pulls the condyle backwards. This is opposed by the upper head of the lateral pterygoid which pushes the condyle forwards during mouth closing.

    Schmolke (1994) found the attachment of the temporalis fascia to the TMJ joint capusle and of the masseteric fascia to the TMJ articular disc to be much less extensive than the attachment of the lateral pterygoid muscle to the articular disc.

    Therefore this author proposed the function of the temporalis and masseter muscles, because of their extensive complement of muscle spindles, may help to register the position of the articular disc. This would make them a part of the control system regulating the position of the various elements of the TMJ.

    Another interesting finding was noted by Scmidt et al (2009) who found higher EMG activity in the right temporalis and suprahyoid muscles when the tongue was placed against the palate with slight pressure. Relaxation of the temporalis occured with resting the tongue on the floor of the mouth.

    Lateral pterygoid

    Origin (upper head): greater wing of sphenoid; (lower head): lateral pterygoid plate of sphenoid.

    Insertion: neck of the mandible. A part of the upper head may be attached to the TMJ capsule and disc.

    Actions: bilateral contraction results in opening and protrusion of the jaw i.e. the condyle being pulled forwards and slightly down. Only the lower head contracts during mouth opening whilst the upper head relaxes. The upper head pushes the condyle forwards during mouth closing opposing the backwards pull on the condyle from the temporalis.

    Unilateral contraction results in the mandible deviating medially to the opposite side.

    Medial pterygoid

    Origin (deep head): lateral pterygoid plate of the sphenoid; (superficial head): maxilla and palatine bone.

    Insertion: mandible.

    Action: elevates (and with the lateral pterygoid) protrudes the mandible. With the lateral pterygoid unilateral contraction results in the mandible deviating medially to the opposite direction.

    Buccinator

    Origin: alveolar processes of the maxilla, mandible and temperomandibular joint.

    Insertion: Orbicularis oris. It has anatomical connections to the lateral deep slip of the platysma (Hur et al 2015), temporalis (Hur 207), incisivus labii inderioris (Hur et al 2011), zygomaticus major (Shim et al 2008) and parotid duct where it is associated with its function (Kang et al 2006).

    At the aveolar process of the maxilla the buccinator blends with the superificial lamina of the masticatory facsia as it leaves the anterior border of the masseter (Gaughran 1957).

    Fascia of the masticatory space (Gaughran 1957)

    The masticator space is described as a fascial compartment containing:

    • Temporalis.
    • Masseter.
    • Lateral pterygoid.
    • Medial pterygoid.
    • Temporomandibular joint.
    • Ramus of the mandible.
    • Masticatory fat pad (corpus adiposum buccae).
    • Neurovascular structures.

    Inferiorly the fascia of the masticatory space is formed from the superficial lamina of the cervical fascia which attaches to the lower border of the mandible.

    From the mandible attachment arises a deep and superficial sheet of fascia:

    Deep sheet of fascia

    The deep sheet of fascia passes upward on the inside of the medial pterygoid muscle (medial pterygoid fascia). This fascia passes upwards from its attachment to the mandible, over the medial pterygoid, to above the insertion of the pterygoid muscles attaching on the greater wing of the sphenoid (spine of sphenoid, jct of body/greater wing at the pterygoid process) and temporal bone (petrotympanic fissure) (Stecco 2015). It should be noted Stecco et al (2015) described these attachments for both the medial and lateral pterygoid fascia.

    The superficial and deep layer of the fascia fuses:

    • Posteriorly: at the rear edge of the ramus of the mandible.
    • Anteriorly: along the anterior border of the masseter.

    Superficial sheet of fascia

    The superficial sheet of cervical fascia continues superiorly to cover the parotid gland (parotid fascia, Hinganu et al 2018) and masseter muscle (a dense masseteric fascia). The masseteric fascia attaches on to the articular disc of the TMJ (Schmolke 1994) and zygomatic arch (Gaughran 1957).

    From the upper border of the zygomatic arch the fascia continues:

    • Posteriorly and superiorly covering the temporal muscle (temporal fascia or temporal aponeurosis of Batson) attaching to the superior temporal line (Gaughran 1957).
    • Anteriorly and superiorly it continues as the zygomatic fascia (Hinganu et al 2018).

    Anteriorly the superficial fascia attaches on to the anterior border of the ramus of the mandible (possibly becoming continuous with the sheath of the lateral pterygoid muscle) and the buccinator fascia and maxilla.

    The superficial and deep layer of the fascia fuses:

    • Posteriorly: at the rear edge of the ramus of the mandible.
    • Anteriorly: along the anterior border of the masseter muscle.

    At the anterior border of the masseter the fusion of the superificial and deep fascia splits again into a deep and superficial layer of fascia.

    Deep layer of fascia

    The deep layer reflects around the anterior border of the masseter passing towards the anterior border of the mandibular ramus. Here it blends with the insertion of the temporalis muscle and attaches to the mandible. Extending superiorly it attaches to the epimysium of the temporalis muscle.

    Superficial layer of fascia

    Attaches to the maxilla blending with the buccinator fascia and attaches to the deep layer along the mandible

    Interpterygoid, lateral pterygoid and temporalis fascia

    Interpterygoid fascia

    The interpterygoid fascia extends between the pterygoid muscles sometimes reflecting onto the deep surface of the temporalis. It's pierced by the auriculotemporal nerve (Barker and Davies 1972) and merges with the main muscle of the tongue (styloglossus) and with the fascial system of the internal carotid artery (Bordoni 2020). Its attachments are (Barker and Davies 1972):

    • Superiorly: cranial base at the sphenoid and temporal bone (Bordoni 2020 & Komune et al 2019) and the suture between the palatine and sphenoid (Lang 2001). Maxilla (Lang 2001).
    • Posteriorly: extends between the lateral and medial pterygoid muscles.
    • Inferiorly: mandible from above the upper border of medial ptcrygoid insertion extending backwards to the neck of the condyle. Here it blends with the stylomandibular fascia.

    Forms the sphenomandibular ligament (spine of sphenoid --> mandible: lingula of the mandibular foramen). This ligament blends with the lateral pterygoid fascia (Lang 2001) and the discomalleoular ligament and anterior ligament of malleus (refer to 'relations of the TMJ to the middle ear') (Rowicki and Zakrzewska 2006).

    • Anteriorly: the fascia is usually flimsy but it may be reflected to form a septum between the pterygoids and the fascia on the deep surface of the temporalis muscle. This is called temporopterygoid fascia.

    Lateral pterygoid and the deep temporalis fascia are separated at their anterior and medial surfaces but are intimately united more posteriorly.

    Lateral pterygoid fascia

    The lateral pterygoid fascia is a triangular sheet. It extends over the lateral surface of the lateral pterygoid muscle (Lang 2001). Its attachments are:

    • Anteriorly: sphenoid (lateral pterygoid plate) and buccinator fascia (Lang 2001).
    • Superiorly: extends from the TMJ (lateral part of the capsule and disc) --> maxilla --> buccinator fascia --> sphenoid (greater wing)
    • Inferiorly: mandible. Attaches to the medial surface of the mandibular ramus --> coronoid process (below temporalis attachment) --> mandibular notch --> TMJ: lateral part of the joint capsule.

    The lateral pterygoid fascia blends with:

    • Inferior attachment of the interpterygoid fascia at its attachments from the mandible to the TMJ.
    • Sphenomandibular ligament (Lang 2001)
    • Buccinator fascia (Lang 2001)

    Schmolke (1994) found some collagen fibres separate from the lateral pterygoid fascia to attach to the same region as the upper lamina of the articular disc at the petrotympanic fissure. Separate fibres have been observed extending through the petrotympanic fissure into the anterior ligament of the malleus within the tympanic cavity (refer 'relations of the TMJ to the middle ear').

    Deep temporal fascia

    The deep temporal fascia covers the anterior surface of the temporalis. It blends with the epimysium above the level of the mandibular attachment at the coronoid process (Gaughran 1957), lateral ligament of the TMJ and TMJ joint capsule (Schmolke 1994). The fascia covering the temporalis tendons extends further down the mandible to attach on to the oblique line of the mandible and blend with the buccinator fascia.

    The deep temporalis and lateral pterygoid fascia fuse at:

    • Mandible: oblique line of the mandible.
    • Deep temporal fascia extends from the medial edge of the anterior border of the temporalis tendon posteriorly to fuse with the lateral pterygoid fascia.

    Because of this fusion the attachment of the deep temporal fascia to the base of the skull can be considered as being identical with that of the lateral pterygoid fascia. The areas of fusion between the deep temporal and lateral pterygoid fascia are:

    • Between the upper and lower heads of the lateral pterygoid muscle. Within the fascia at this level is the buccal nerve and several anterior deep temporal branches of trigeminal nerve (V3).
    • Superior to the upper and lower heads of the lateral pterygoid, the two fascia usually remain united underneath the temporalis muscle. The buccal nerve emerges superior to the upper head or between the upper and lower heads of the lateral pterygoid muscle. It passes within the fused lateral pterygoid and deep temporalis fascia, to lie against or imbedded within the most medial fibers of the deep part of the temporalis muscle.

    Relations of the TMJ to the middle ear

    Discomalleolar ligament (mandibular-malleolar ligament or the “tiny” Pinto ligament)

    Rowicki and Zakrzewska (2006) found this ligament to be a fibroelastic tissue connecting the TMJ capsule and articular disc to the malleus. It extends from the TMJ and the sphenomandibular ligament* --> through the petrotympanic fissure --> malleus.

    The discomalleolar ligament can attach to the anterior ligament of malleus (Rowicki and Zakrzewska 2006).

    Ligaments of malleus

    There are three ligaments of malleus:

    • Anterior ligament of malleus (Casserio’s ligament): malleus --> anterior wall of the tympanic cavity close to the petrotympanic fissure. Some of the fibers also pass through the fissure to the spine of sphenoid. Within the pterotympanic fissue the anterior ligament of malleus becomes continuous with the sphenomandibular ligament* (Rowicki and Zakrzewska 2006)
    • Lateral ligament of malleus: malleus --> roof of the tympanic cavity.
    • Superior ligament of malleus: malleus --> roof of the tympanic cavity.

    Both the discomalleolar ligament and anterior ligament of malleus pass through the petrotympanic fissure that connects the TMJ through the temporal bone into the tympanic cavity.

    Schmolke (1994) and Rowicki and Zakrzewska (2006) found the TMJ articular disc is tightly fixed to the border of the petrotympanic fissure. Fibres extend through the petrotympanic fissure into the anterior ligament of the malleus within the tympanic cavity.

    The petrotympanic fissure also serves as an attachment for the pterygoid fascia (Stecco et al 2015).

    * Sphenomandibular ligament: spine of sphenoid --> mandible: lingula of the mandibular foramen. It is formed from the interpterygoid fascia. As well as attaching to the discomalleolar and anterior ligament of malleus it also blends with the lateral pterygoid fascia (Lang 2001).

    References

    FASCIAE OF THE MASTICATOR SPACE (1957) GEORGE R. L. GAUGHRAN

    The skull base and related structures: atlas of clinical anatomy (2001). Johannes Lang

    The deep belly of the temporalis muscle: an anatomical, histological and MRI study (2005). C. Geers Æ C. Nyssen-Behets Æ G. Cosnard Æ B. Lengele

    Anatomical considerations on the masseteric fascia and superficial muscular aponeurotic system (2018) DELIA HÎNGANU, CRISTINEL IONEL STAN, CORINA CIUPILAN, MARIUS VALERIU HÎNGANU

    Effects of tongue position on mandibular muscle activity and heart rate function (2009) John E. Schmidt, PhD,a Charles R. Carlson, PhD,b Andrew R. Usery, MD,c and Alexandre S. Quevedo, DDS, PhD,d Rochester, MN, Lexington, KY, and Winston-Salem, NC

    Functional atlas of the human fascial system (2015) Carla stecco

    The relationship between the temporomandibular joint capsule, articular disc and jaw muscles CORDULA SCHMOLKE (1994)

    THE APPLIED ANATOMY OF THE PTERYGOMANDIBULAR SPACE (1972). B. C. W. BARKER AND P. L. DAVIES

    An anatomical study of the insertion of the zygomaticus major muscle in humans focused on the muscle arrangement at the corner of the mouth. (2008). Shim KS, Hu KS, Kwak HH, Youn KH, Koh KS, Fontaine C, Kim HJ

    A study of the discomalleolar ligament in the adult human (2006) T. Rowicki, J. Zakrzewska.

    Blending of the lateral deep slip of the platysma muscle into the buccinator muscle. (2015) Hur MS, Bae JH, Kim HJ, Lee HB, Lee KS.

    Inferior bundle (fourth band) of the buccinator and the incisivus labii inferioris muscle. (2011). Hur MS, Hu KS, Kwak HH, Lee KS, Kim HJ.

    Anatomical connections between the buccinator and the tendons of the temporalis. (2017). Hur MS

    An anatomical study of the buccinator muscle fibres that extend to the terminal portion of the parotid duct, and their functional roles in salivary secretion. Hyo-Chang Kang, Hyun-Ho Kwak, Kyung-Seok Hu, Kwan-Hyun Youn, Guang-Chun Jin, Christian Fontaine, and Hee-Jin Kim

    The Five Diaphragms in Osteopathic Manipulative Medicine: Myofascial Relationships, Part 1 (2020). Bruno Bordoni

    The Fascial Layers Attached to the Skull Base: A Cadaveric Study (2019). Komune N, Matsuo S, Nakagawa T.