Muscle Slips Research Articles

Unilateral observation of axillary (Langer’s) arch during dissection: A case report

The axilla is a clinically significant region with a complex structure. One of the most common anatomical variations in this area is Langer’s axillary arch, also known as the axillopectoral muscle, pectodorsal muscle, or arcus axillaris. During a routine dissection of an embalmed elderly female cadaver for educational purposes, we identified an unusual muscle slip originating from the latissimus dorsi. This muscle crossed over the neurovascular structures in the axilla and inserted into the pectoralis major, forming a rare axillary arch (of Langer’s). This variation can be clinically relevant, as it may cause neurovascular compression, leading to conditions like thoracic outlet syndrome, hyperabduction syndrome, or median nerve entrapment. Recognizing this arch before surgery is important in axillary and breast reconstruction procedures, allowing surgeons to decide whether to preserve or cut the arch during the operation.

The use of an ultrasonic dissection device for the P1 method in prosthetic breast reconstruction

Background The P1 method in prosthetic breast reconstruction has the advantage of preventing rippling and ensuring a smooth upper pole contour. This study presents our experience with using an ultrasonic dissection device instead of a monopolar electrocautery device for the P1 method.Methods Patients who underwent prepectoral breast reconstruction at our institution between June and September 2021 were retrospectively reviewed. Among the 39 breasts analyzed, 17 underwent the P1 procedure using an ultrasonic dissection device for the superior slip of the pectoralis major muscle, while 22 underwent P0 prepectoral breast reconstruction. We compared surgical outcomes, including operative time, presence of rippling, capsular contracture, and animation deformities, and complications such as seroma, hematoma, and mastectomy skin flap necrosis.Results Patient demographics were comparable between the groups, except for chemotherapy exposure. Rippling occurred more frequently in the P0 group (36.4% vs. 23.5%); however, capsular contracture was absent in the P1 group. Despite these observations, the differences lacked statistical significance. The average operative time was longer in the P1 group than in the P0 group (104.35 minutes vs. 90.05 minutes), although this difference was not statistically significant (P=0.095). There were no instances of postoperative hematoma, infection, implant exchange, animation deformity, or implant explantation in either group.Conclusions Using an ultrasonic energy device for additional dissection in the P1 method was non-inferior in terms of complications such as bleeding, infection, or animation deformity. The ultrasonic device can facilitate safe and effective dissection when elevating the superior pectoralis muscle slip, despite requiring additional operative time.

An unreported variant of palmaris longus muscle.

Palmaris longus is a highly variable muscle of the forearm. Knowledge of its variability is of importance to plastic surgeons, hand surgeons and radiologists. During our routine dissection classes for undergraduate medical students, a peculiar palmaris longus muscle was noted in the left upper limb of an adult male cadaver. The muscle had a fleshy belly in the middle and two tendons: a proximal and distal. The distal tendon of palmaris longus gave origin to a variant fleshy slip of muscle which was inserted partly to the pisiform bone and partly merged with the hypothenar muscles. The ulnar nerve and artery passed deep to this variant fleshy slip. The ulnar artery was tortuous both proximal and distal to this slip. The distal loop of the ulnar artery was very superficial and was in the median position. Both the palmaris longus and the variant fleshy slip were innervated by median nerve.

Growing stylohyoideus muscle insertion to the hyoid bone with special reference to its topographical relation to the intermediate tendon of digastricus muscle: A histological study using human fetuses

BackgroundIn adults, the intermediate tendon of digastricus muscle usually runs along the medial or lateral side of the stylohyoideus muscle insertion. To provide a better understanding of the variations, we examined the topographical anatomy of the muscle and tendon in fetuses. MethodsWe examined histological sections from six early-term, 26 mid-term and six near-term fetuses (approximately 8–9, 12–18 weeks and 25–33 weeks). ResultsAt early-term, an initial sheath of intermediate tendon of digastricus muscle received the stylohyoideus muscle at the superior aspect. The muscle and tendon was distant from the hyoid. At mid-term, near the insertion to the hyoid greater horn, the stylohyoideus muscle consistently surrounded more than 2/3 of the intermediate tendon circumference. In contrast, we found no near-term specimen in which the stylohyoideus muscle surrounded the intermediate tendon. The multilayered tendon sheath was fully developed until near-term and connected to the body of hyoid by an intermuscular septum between the thyrohyoideus muscle and one or two of suprahyoid muscles. Therefore, the hyoid insertion of the styloglossus muscle was a transient morphology at mid-term. ConclusionThe stylohyoideus muscle insertion was appeared to move from the tendon sheath to the hyoid greater horn and, until near-term, return to the tendon sheath. A fascia connecting the tendon sheath to the body of hyoid was strengthened by the suprahyoid and infrahyoid muscles. The latter muscles seemed to regulate fixation/relaxation of the intermediate tendon to the hyoid. The stylohyoideus muscle slips sandwiching the intermediate tendon might be a rare morphology.

A case report on the bilateral absence of fourth tendinous slip of the flexor digitorum brevis muscle in the foot: Exploring evolutionary and surgical relevance

The flexor digitorum brevis (FDB) muscle extends across the central region of the sole, positioned deep beneath the plantar aponeurosis. It inserts into the lateral four toes through four slender musculotendinous slips. Functionally, this muscle reinforces the foot arch by facilitating flexion at the interphalangeal and metatarsophalangeal joints of the lateral toes. In clinical contexts, the FDB muscle serves as a musculocutaneous flap in reconstructive surgeries, addressing various foot deformities. Despite its small size, the FDB muscle carries significant evolutionary importance, indicating potential phylogenetic degeneration in humans due to adaptations to diverse lifestyles. The anatomical variation presented in this case report holds importance, as the presence or absence of the FDB muscle can play a crucial role in maintaining arch integrity and holds relevance from a surgical perspective.

Associated Factors and Prevention of Upper Pole Rippling in Prepectoral Direct-to-Implant Breast Reconstruction.

Background Despite its many advantages, prepectoral breast reconstruction also carries the risk of implant rippling. The recent introduction of partial superior implant coverage using a pectoralis muscle slip in prepectoral direct-to-implant (DTI) breast reconstruction has shown the potential to minimize upper pole rippling. The purpose of this study was to identify factors associated with rippling and the effectiveness of our surgical technique. Methods In total, 156 patients (186 breasts) who underwent prepectoral DTI breast reconstruction between August 2019 and March 2021 were identified retrospectively. Patient data were analyzed from medical records. Univariable and multivariable logistic analyses were performed to contextualize the risks associated with rippling deformity relative to demographic characteristics and other clinical factors. Retrospective propensity-matched analysis was performed to identify the relationship between rippling deformity and the reconstruction method. Results Patients with body mass index (BMI; odds ratio [OR], 0.736; p < 0.001), those with a postoperative chemotherapy history (OR, 0.324; p = 0.027) and those who received breast reconstruction via the superior coverage technique (OR, 0.2; p = 0.004), were less likely to develop rippling deformity. The median follow-up period was 64.9 weeks, and there were no significant differences between patients in types of mastectomy, implant, or acellular dermal matrix. Patients who underwent superior coverage technique-based reconstruction showed significantly reduced rippling (OR, 0.083; p = 0.017) Conclusion Patients with higher BMI and prior postoperative chemotherapy were less likely to develop rippling deformity. The superior coverage technique can be effective in minimizing upper pole rippling.

Clinical Considerations of First Extensor Wrist Compartment (FEWC) Variants and De Quervain's Disease: A Review Study.

The first extensor wrist compartment (FEWC) displays significant variants. This review highlights all possible variants that may be associated with the occurrence and pathophysiology of de Quervain's tenosynovitis. A thorough search of PubMed and MEDLINE databases, following the PRISMA guidelines, was conductedfrom 2002 to 2022 to evaluate all FEWC variants, including the following: 1) the presence of an inter-tendinous septum, 2) the number of tendinous slips of the abductor pollicis longus (APL) and the extensor pollicis brevis (EPB) muscles, 3) their distal insertions and 4) the presence of a bony ridge within the FEWC.A total of 3878 wrists (1277 cadaveric and 1296 de Quervain patients) were included.Of the 1234 cadavers, a total of 701 (56.8%) were males and 533 (43.2%) were females. Regarding the 883 patients, 178 (20.2%) of them were males and 705 (79.8%) were females. An inter-tendinous septum was identified in 42.9% (47% of the patients' wrists compared to 39.3% of the cadaveric wrists, p<0.0001). Cadaveric wrists presented two or more slips for the APL in a significantly higher percentage (92.5%, p < 0.0001) compared to de Quervain patients' wrists (74.5%). Regarding the EPB muscle, de Quervain patients' wrists had a single slip in 93% (p=0.0007) and two or more slips in 3.6%, compared to cadaveric wrists (a single slip in 87%, and two or more slips in 11%, p< 0.0001). A bony ridge over the radial styloid process was recorded in 58.9% of the cadaveric wrists compared to 17.8% of the patients' wrists (p < 0.0001). Remarkable diversity concerning the structures within the FEWC was reported. The presence of an inter-tendinous septum dividing the FEWC and a single EPB muscle slip is more likely to be found in patients with de Quervain's disease.

Deep parasternal intercostal plane nerve block: an anatomical study

IntroductionThe superficial and deep parasternal intercostal plane (DPIP) blocks are two new blocks for thoracic pain. There are limited cadaveric studies evaluating the dye spread with these blocks. In this...

Accessory Muscles Associated With the Levator Palpebrae Superioris Muscle in 100 Cadavers.

This study aimed to determine the variations of the levator palpebrae superioris muscle and to reveal its morphological features. This study conducted on 100 adult orbit cadavers in the Department of Anatomy, Istanbul University, used an exploratory, descriptive research design. The anatomical and morphological variations of the levator palpebrae superioris muscle and its relationship with the superior ophthalmic vein were evaluated. Variations of levator palpebrae superioris muscle were discovered in 11 of 100 orbits. Single (9%), double (1%), and triple (1%) accessory muscle slips were observed. The origin of accessory muscle slips showed variation as the accessory muscle slips originated either from the proximal or distal half of the levator palpebrae superioris muscle. Also, the insertions of accessory muscle slips were variable, as they were inserted into levator aponeurosis, trochlea, lacrimal gland, lateral orbital wall, or the fascia of the superior ophthalmic vein. Accessory muscles associated with levator aponeurosis were found in a significant proportion of cadavers. These muscles may cause confusion in orbital surgery and should be taken into account during surgical planning and orientation in the superior orbit.

The unilateral muscular slip of the two-bellied Serratus Posterior Inferior muscle: a case report and a review of literature.

The two-bellied serratus posterior inferior (SPI) muscle with a muscular slip is a rare variation of the back region, which can cause significant discomfort to patients. Patients typically present with symptoms of chronic pain syndrome, radiating back pain, myofascial pain, or lower back pain. This report describes a case of a female cadaver with a two-headed SPI muscle and a right muscular slip, along with a literature review. A case of an unusual back muscle was observed in a female cadaver during advanced cadaver dissection of the back region. The SPI muscle was found deep to the latissimus dorsi muscle and superficial to the erector spinae and thoracolumbar fascia. Its oblique arrangement and insertion onto the 8th-11th costae were consistent with its known anatomy, but the presence of two separate fibrotendinous heads and an uncommon variance between the erector spinae and latissimus dorsi muscles was observed. The SPI muscle fibers were found to be attached to the 8th costa on the right side and displayed two heads on both sides. In our study, the presence of muscular and tendinous digitations towards the twelfth rib was not detected, which aligns with the characteristics described for types D and E. However, we observed a separation between the digitations. Therefore, it is appropriate to classify our findings as type E according to the established categorization. Simultaneously, an anomalous muscular slip, which did not conform to any of the aforementioned classifications, was identified as extending towards the 8th rib. The underlying cause of unilateral oblique muscular fiber extension is thought to result from aberrant muscle migration during embryonic development or alterations in tendon attachment sites. Differential diagnosis of unidentified lower back pain should consider the various types and alterations of the SPI muscle.

Commentary: Scleral penetration or perforation during strabismus surgery.

Commentary: Scleral penetration or perforation during strabismus surgery.

The subscapularis muscle: A meta-analysis of its variations, prevalence, and anatomy.

The subscapularis (SSC) is the largest rotator cuff muscle and is involved in the medial rotation, abduction, adduction, and anterior stabilization of the shoulder. It is anatomically variable, as is the morphology and prevalence of the accessory SSC (aSSC), a rare muscle slip attached to the SSC. There is no current review investigating the prevalence and morphometrics of the SSC and aSSC. To investigate the prevalence of the morphological variants of the SSC and aSSC via meta-analysis and review the relevant literature involving cadaveric, magnetic resonance imaging, and ultrasonographic studies. Meta-analysis. Literature data reporting the prevalence rates and morphometrics of the SSC and aSSC and their variants were pooled. Literature searches and data analyses were performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Anatomical Quality Assurance guidelines. Forty-six studies, totaling 2166 shoulders, were assessed. The SSC showed an overall length, thickness, cross-sectional area, and volume of 152.2 mm (95% confidence interval, CI, 103.8-200.5 mm), 5.6 mm (95% CI, 4.6-6.6 mm), 18.1 cm2 (95% CI, 14.2-22.0 cm2 ), and 126.9 cm3 (95% CI, 87.2-166.5 cm3 ), respectively. The SSC displayed substantial variations in its origin and insertion points and in the composition of its tendon. The aSSC had an overall pooled prevalence of 24.6% (95% CI, 0.0%-76.9%). The SSC and aSSC have been implicated in multiple shoulder pathologies, including muscle and tendon ruptures and neurovascular compromise. A better understanding of SSC and aSSC variants when diagnosing and treating their related pathologies will reduce patient morbidity and improve treatment regimens.

371 Topographical Anatomy of the Annulus of Zinn

Abstract Aim The anatomy and even existence of a common tendinous origin of the extraocular eye muscles, or annulus of Zinn, has widely been debated in anatomical literature. This study explored the anatomical origins of the recti muscles, their course into the orbit and the dural connections of the common tendinous origin with the skull base. Method Twenty orbits of ten adult human cadavers were dissected. The orbital apex and its dural connections were photographed. Histological examination of apical specimens was performed. Results In all cadavers, extraocular muscles were observed to have a common tendinous origin at the orbital apex, continuous with dural connections extending into the skull base. Accessory slips of the medial rectus were observed across all cadavers. Dual heads of the lateral rectus were observed in fourteen orbits of seven cadavers. The origin of the levator palpebrae superioris appeared to be contiguous with the superior rectus at the common tendinous origin in all but one cadaver. Conclusions These results support the existence of a common tendinous origin of the extraocular muscles, that is continuous with the skull base dura. In addition, they support the existence of variations in orbital anatomy including dual or accessory muscle slips of the extraocular muscles.

Surgical Technique: Abductor Reconstruction With Gluteus Maximus and Tensor Fascia Lata in Revision Total Hip Arthroplasty.

Abductor deficiency in revision total hip arthroplasty (THA) is a common problem that can lead to pain, limping, and instability. Repair and reconstruction of the abductors is challenging, with a high rate of failure reported in the literature. The purpose of this study is to describe a simplified technique of abductor repair augmented with the transfer of gluteus maximus (Gmax) and the tensor fascia lata (TFL). We describe a novel abductor reconstruction with transfer of the anterior 30% of Gmax and the posterior 70% of TFL to the vastus lateralis origin. These transfers can be used in isolation or to augment repair of torn abductors to the greater trochanter. The technique is simple and quick to perform via a lateral approach, requiring dissection of only two muscle slips and minimal additional soft tissue dissection. We describe the use and outcomes of this technique on three patients undergoing revision THA with severe and irreparable abductor deficiency. Although these patients reported improved function after the reconstruction, there was persistence of mild to moderate limping. Abductor reconstruction with partial transfers of Gmax and TFL is a promising approach to manage abductor deficiency in revision THA. Larger series are required to determine the efficacy of this technique for restoring abductor function and improving patient reported outcomes.

Anatomical Association Between Articularis Genus and Vastus Medialis Oblique: A Cadaveric Investigation

Objectives The articularis genus (AG) muscle is thought to elevate the suprapatellar bursa during knee extension. Failure of this function may cause impingement of the bursa, and lead to anterior knee pain. The AG may work in synergy with the vastus medialis oblique (VMO) to fulfil this function. The AG and the VMO both attach to the vastus intermedius aponeurosis, and fibres of the VMO have been found to attach to the superficial layer of the AG. The VMO is also implicated in anterior knee pain, as VMO insufficiency can lead to patellar maltracking. The aim of the study was to investigate if an anatomical association could be shown between the AG and the VMO. Methods Twenty-nine lower limbs were dissected to show the muscles of the anterior thigh. The maximum VMO pennation angle and the VMO insertion ratio on the medial border of the patella were measured. The AG area was determined by measuring the length and maximum width of each individual muscle slip. Results The mean area of the AG was 2554.67 mm2. The mean VMO angle was 56.6°, whilst the mean insertion ratio was 48.93%. The association between area and each of the covariates was not statistically significant (VMO angle: P=0.921; insertion ratio: P=0.822). The mean area for the left leg was greater than that for the right (2876.12 versus 2233.22; P=0.049). Conclusion The articularis genus does not appear to have an anatomical association with the vastus medialis oblique. The dimensions of the superficial layer of the AG were not influenced by sex or age. However, the AG area was greater on the left limb than the right.

Variant Femoral Nerve: The Path Beneath the Iliacus Muscle and Into Neuropathic Symptoms

Introduction and ObjectiveOriginating from the lumbar plexus, the femoral nerve has a native course along the anterior surface of the iliacus then travels deep to the inguinal ligament, branching into separate anterior and posterior divisions that provide innervation to the anterior thigh muscles (Figure 1). Clinically, the spatial relationship between the iliopsoas complex and the femoral nerve has been noted for the potential risk of entrapment and compressive neuropathies. Variations in the femoral nerve course following surgical and medical interventions can produce symptoms related to muscle weakness and sensory loss in patients. Relevant literature regarding variant femoral nerve distributions is most often related to aberrant slips of the iliacus muscle and following surgical or medical intervention. In this case study, we describe a variation in the descent of the femoral nerve that travels within the belly of the iliacus muscle without evidence of an aberrant slip or surgical intervention and discuss the clinical implications and appropriate non‐invasive osteopathic treatment options.MaterialsThis anatomical variation was revealed in one donor being evaluated at Sam Houston State University College of Osteopathic Medicine’s anatomy lab. The donor was previously dissected by medical students for a first‐year anatomy course. The iliacus and surrounding structures were left intact. Additional dissection necessary for this study was performed from March 2021 to April 2021.ResultsIn a 70‐year‐old male cadaver, the right femoral nerve originated from the lumbar plexus, descended, and then bifurcated (Figure 2A). Most of the femoral nerve remained within the Iliacus muscle (Figure 2B) while a small portion of the femoral nerve followed the typical course anterior to the iliacus (Figure 2C). The bulk of the femoral nerve traveled within the iliacus, exiting inferior to the inguinal ligament, then merged with the smaller portion of the nerve (Figure 2D). The left femoral nerve followed a typical course.Significance/ConclusionPrevious discussions report an aberrant slip of the iliacus splitting the femoral nerve and having the potential for nerve compression, although unlikely due to the smaller muscle belly involved. This highlighted variant is significant because the bulk of the femoral nerve remains beneath the iliacus as it crosses over the pubic eminence. This pathway would be predisposed to a greater degree of compression against the pubic eminence, with potential for certain movements to increase these forces.This patient presentation is hypothesized to include anterior thigh weakness during hip flexion and knee extension activities, such as stair‐climbing, as well as sensory loss to the anteromedial thigh and medial leg via the saphenous nerve. Sensation to the lateral thigh should remain intact as the lateral femoral cutaneous nerve would be unaffected. conservative treatments, such as osteopathic manipulative techniques, could be an effective form of treatment. Techniques including counterstrain to the psoas and iliacus or muscle energy to the hip flexors could lessen such nerve compression and improve patient symptoms.Awareness of this variation could provide clinicians with another potential diagnosis to consider when managing femoral neuropathy, as well as rationale for a non‐invasive treatment option.

Topographical anatomy of the annulus of Zinn

The anatomy and even existence of a common tendinous origin of the extraocular eye muscles, or annulus of Zinn, has widely been debated in anatomical literature. This study explored the anatomical origins of the recti muscles, their course into the orbit and the dural connections of the common tendinous origin with the skull base. Twenty orbits of ten adult human cadavers were dissected. The orbital apex and its dural connections were photographed. Histological examination of apical specimens was performed. In all cadavers, extraocular muscles were observed to have a common tendinous origin at the orbital apex, continuous with dural connections extending into the skull base. Accessory slips of the medial rectus were observed across all cadavers. Dual heads of the lateral rectus were observed in fourteen orbits of seven cadavers. The origin of the levator palpebrae superioris appeared to be contiguous with the superior rectus at the common tendinous origin in all but one cadaver. These results support the existence of a common tendinous origin of the extraocular muscles, that is continuous with the skull base dura. In addition, they support the existence of variations in orbital anatomy including dual or accessory muscle slips of the extraocular muscles.

Revision of the morphology of longissimus capitis, longissimus atlantis, longissimus cervicis, and the cranial part of longissimus thoracis in the domestic goat (Capra hircus): a cadaveric study.

Veterinary anatomical texts have generally described the longissimus muscle only in terms of its attachment in the ox as the basic species and have not thoroughly addressed its morphology in small ruminants. Hence, the present study was designed to present the anatomical features of longissimus capitis, longissimus atlantis, longissimus cervicis, and the cranial part of longissimus thoracis of domestic goats by comparing them with the existing descriptions of these muscles in the ox. Bilateral dissections of the neck and the cranial thoracic regions of 10 domestic adult goats of both sexes were carried out. The longissimus capitis and longissimus atlantis consisted of about 5 muscle slips originating from the articular processes of C3-C7 (including their bony ridges) or T1 and the transverse process of T2. In 7 (37%) of the 19 muscles dissected, the last slips in the longissimus capitis and longissimus atlantis or in one of them showed no attachment to the vertebrae. Rather, the thoracolumbar fascia in the cranial part of the thoracic region, the cranial edge or the deep face of longissimus thoracis, and the deep face of longissimus cervicis served as the origins of the muscles. The attachment sites of the longissimus cervicis and the cranial part of the longissimus thoracis in the goat demonstrated no remarkable differences with those of the ox. Whether the attachment sites of these variants should be considered as normal or anomalous needs to be evaluated with a larger number of animals of different breeds.

Gross and histological morphology of the cervical gill slit gland of the pygmy sperm whale (Kogia breviceps).

Odontocete cetaceans have undergone profound modifications to their integument and sensory systems and are generally thought to lack specialized exocrine glands that in terrestrial mammals function to produce chemical signals (Thewissen & Nummela, 2008). Keenan-Bateman et al. (2016, 2018), though, introduced an enigmatic exocrine gland, associated with the false gill slit pigmentation pattern in Kogia breviceps. These authors provided a preliminary description of this cervical gill slit gland in their helminthological studies of the parasitic nematode, Crassicauda magna. This study offers the first detailed gross and histological description of this gland and reports upon key differences between immature and mature individuals. Investigation reveals it is a complex, compound tubuloalveolar gland with a well-defined duct that leads to a large, and expandable central chamber, which in turn leads to two caudally projecting diverticula. All regions of the gland contain branched tubular and alveolar secretory regions, although most are found in the caudal diverticula, where the secretory process is holocrine. The gland lies between slips of cutaneous muscle, and is innervated by lamellar corpuscles, resembling Pacinian's corpuscles, suggesting that its secretory product may be actively expressed into the environment. Mature K. breviceps display larger gland size, and increased functional activity in glandular tissues, as compared to immature individuals. These results demonstrate that the cervical gill slit gland of K. breviceps shares morphological features of the specialized, chemical signaling, exocrine glands of terrestrial members of the Cetartiodactyla.

Popliteal entrapment syndrome-The case for a new classification.

To assess the ability of the current classification system for popliteal entrapment syndrome to accurately capture all patients, and if not, to design an all-inclusive new classification. Retrospective review of all interventions performed for popliteal entrapment syndrome between 1994 and 2013 at our institution was performed. Preoperative imaging and intraoperative findings were used to establish the compressive morphology of popliteal entrapment syndrome. Patients were categorized, when possible, into six types of the current classification system (Rich classification, modified by Levien) and into seven types of a new classification. Sixty-seven limbs of 49 patients were operated on for unilateral (31) or bilateral (18) popliteal entrapment syndrome. The current classification system captured the anatomy of only 43 (64%) of 67 limbs with popliteal entrapment syndrome. Compressive morphologies without a defined class included aberrant insertion of the lateral head of gastrocnemius muscle, muscle slip originating from the lateral head of gastrocnemius or hamstrings, hypertrophied hamstring muscle, abnormal fibrous bands, perivascular connective tissue, and prominent lateral femoral condyle. The new classification captured 100% of the limbs with popliteal entrapment syndrome. Current classification of popliteal entrapment syndrome is inadequate as more than one-third of the cases reviewed fell outside of the standard classification system. Consideration of a more inclusive new anatomic classification system is warranted.