Skip to main content

New Biomechanics in Illustrations

 

The New Biomechanics of the Hip Joint: A Pictorial Essay

S.V. Arkhipov 

INTRODUCTION 

First in the history of humanity, the mention of ligamentum capitis femoris (LCF) and the pathomechanics of walking associated with its damage is found in the ancient literary monument “Book of Genesis” (32:24-24,31-32), created approximately 3600 years ago (2019Arkhipov_Skvortsov; 2023Архипов).

Fig. 1 The LCF = ligamentum teres of the hip joint, drawing by H.V. Carter (1870Grey).

Fig. 2 Pencil drawing “Crossing of the Jabbok River” based on the “Book of Genesis” 32:22 (author: Lyudmila Arkhipova, 2008).

The first description of LCF in a medical text is given by Hippocrates of Kos in the treatise “Instruments of Reductions” or “Mochlicus”, written in the V-IV centuries BCE (1844Littre).

We know that with the normal LCF, walking it is light, rhythmic, and symmetrical, but we don't know “why”. See video: Supplement 1 Normal Walking

We don't even know why we wiggle our pelvis when walking!

It is known that during single-leg support in normal walking, adduction occurs in the hip joint and the pelvis tilts in the opposite direction.

Fig. 3. Walking in vivo – single-leg support phase in norm; video frame.

Fig. 4. Walking in vitro – single-leg support phase in norm; video frame (2013Архипов).

Fig. 5. Instrumental 3D gait analysis; left – single-leg support phase in normal walking; right – graphs of pelvic and thigh movements in the frontal plane.

Pelvic tilt and adduction in the supporting hip joint in a single-support position are observed.

Fig. 6. Transition from two-legged to single-legged stance (2013Архипов).

In the statue's pose, a pelvic tilt and adduction in the supporting hip joint are observed too.

Fig. 7 Biblical David (artist: Michelangelo, 1501–1504; copy in the Pushkin State Museum, Moscow).

Such a pelvic position was noticed in ancient times, see: Logios Hermes (5th century BCE), Diadumenos (about 420 BCE), Aphrodite of Knidos (4th century BCE), Hercules of the Forum Boarium (2th century BCE), Victorious Youth (300–100 BCE), Antikythera Ephebe (70–60 BCE).

The first image of the pelvic tilt in a medical book is an illustration Andreae Vesalius' treatise “De humani corporis fabrica” (1543Vesale).

Fig. 8. Drawing in the book “De humani corporis Fabrica” (1543Vesale); illustration “Studio of Titian” (Tiziano Vecelli) or Jan Stephan van Calcar (1987Harcourt).

Later, we see this in William Cheselden's “Osteographia” (1733).

Fig. 9. Drawing in the book “Osteographia” (1733Cheselden); author Gerard Vandergucht and/or Jacob Schijnvoet (2011Kornell).

Why do we wiggle pelvis while the walking and the tilt it in the standing position? Our hypothesis: for tensioning of the LCF.

Galen of Pergamum (II-III c. AD) in “Hippocratis de articulis liber Galeni in eum commentarii quatuor” calls LCF - “ἰσχυρότατος” i.e., “strongest” (1829Kühn). Wenger et al (2007): LCF strength can reach 882±168 N! Theoretically, LCF can function as a pelvic suspension.

Fig. 10 Galen of Pergamon; drawing from the book “Operum Hippocratis Coi, et Galeni Pergameni…” (1638René).

Nobel Laureate János (Hans) Selye (1907-1982) wrote that a significant contribution to the study of stress was made through simple means (1960Селье).

Fig. 11 Photographic portrait of prof. Hans Selye (original on the site wikipedia.org, CC BY-SA 4.0, ½ part of the image).

We also initiated research on the biomechanics of the hip joint using simplified models...

DISCUSSION 

I. Initially, it was confirmed that the tilt of the pelvis and hip adduction lead to tensioning of the LCF.

Fig. 12 A planar model of the hip joint with the LCF analog (made before 2004); overall view of the model.

Fig. 13 Simulation of adduction and abduction on a planar model of the hip joint with an LCF analogue.

II. Experiments on a model of the hip joint (synthetic bones) with the LCF analog.

Fig. 14 The model of the hip joint with the LCF analog; modeling of abduction and adduction; visualization of the LCF tension.

III. Experiments on a mechanical model of the hip joint with the LCF analog.

Fig. 15 The mechanical model of the hip joint with the LCF analog; connection of the components and overall view of the model.

Fig. 16 The mechanical model of the hip joint with the LCF analog; modeling of abduction and adduction.

We have proven that LCF serves as the adduction limiter and pelvic stabilizer.


IV. Experiments on a mechanical model of the hip joint with a planar model of the pelvic part and the LCF analog, as well as, a mechanical model of the femoral head with the LCF analog.

We observed the effect of pressing the acetabulum to the head of the femur.

Fig. 17 The mechanical model of the hip joint with a planar model of the pelvic part and the LCF analog – modeling of adduction (left); mechanical model of the femoral head with the LCF analog – emergence of the resultant force (right).

The effect of pressing the acetabulum against the femoral head is important in preventing hip dislocation.

V. Tensioning of the LCF forms a cable-stayed type of pelvic suspension and provides additional support to the body.

Fig. 18 The planar model of the hip joint with the LCF analog (1/2 of the pelvic part); modeling of adduction.

A cable-stayed bridge as an analogy of the pelvic–LCF system.

Fig. 19 The cable-stayed bridge (Vladivostok, Russia).

The LCF functions as a cable-stayed type of pelvic suspension.

VI. Transformation of the hip joint into a class three lever and compression on the lower sector of the femoral head; experiments on a mechanical model of the proximal femur with the LCF analog.

Fig. 20 The mechanical model of the proximal femur with the LCF analog; modeling of adduction.

Fig. 21 The planar model of the hip joint with the LCF analog (1/2 of the pelvic part); modeling of adduction – compression on the lower sector of the femoral head occurs.

Tensioning of the LCF causes the appearance of compression in the lower sector of the femoral head.

VII. The reaction force of the LCF reduces compression on the upper sector of the femoral head and increases it in the lower sector.

Fig. 22 The mechanical model of the hip joint with a planar model of the pelvic part and the LCF analog; modeling of abduction.

VIII. Morphological Evidence.

In the lower sector of the femoral head, the cartilaginous layer is thinner because the compression from the lower sector of the acetabulum is greater.

Fig. 23. Fracture of the femoral neck and traumatic rupture of the LCF; intraoperative observation; pay attention to the thickness of the cartilage in the lower sector of the femoral head.


Ligamentous-muscular interaction provides compression of the upper end of the femur.

Fig. 24 Simplified scheme of the interaction between LCF and muscles in the hip joint area.

The medial sector of the second trabecular system of the upper end of the femur is the result of pressure on the lower sector of the femoral head from the acetabulum side.

Fig. 25 Trabecular systems of the femur and pelvis; II M – medial area of the second trabecular system.

IX. Tensioned LCF shunts the body mass and unloads the abductor muscle group of the hip joint.

Fig. 26. Mechanical model of the hip joint with an LCF analog and an analog of the abductor muscle group.

LCF serves as a shunt for body mass and transforms the hip joint into a class three lever.

X. Without LCF, the hip joint functions only as a class one lever.

Fig. 27 Mechanical model of the hip joint with an analog of the abductor muscle group and without an LCF analog.

XI. Contradiction as evidence.

In “classic biomechanics” (without LCF), the hip joint functions as a class one lever. Compression of the femoral head in a single-support stance is 175 kg (1976Pauwels), reaching 229 kg during normal walking (1993Bombelli).

Fig. 28 Schemes of “classic biomechanics” of the hip joint (illustrations from Pauwels (1976), and Bombelli (1993) as graphic quotations).

In some cases, during walking, compression exceeds the subject's weight by 5.8 times (1966Paul).

Some researchers question, “...what compensates for the enormous forces applied to the femoral head?” (1975Янсон).

Indeed, what can compensate for the immense pressure on the femoral head?

Paul (1966), Pauwels (1976), and Bombelli (1993) are correct; in the absence of LCF, the force generated by the abductor muscle group is approximately three times the body weight: i.e., equivalent to 210 kg with a total body mass of 70 kg.

Fig. 29. Lever model of the hip joint (without an LCF analog).

Kapandji (2009): m. gluteus medius can develop force – 16 kg, m. gluteus minimus – 4.9 kg, m. tensor fascia lata – 7.6 kg; i.e., a total of 28.5 kg!

XII. Paradox of the m. gluteus medius as evidence.

During single-leg support, in the middle and end of the single-support phase of the gait cycle, the force (electromyographic activity) of the m. gluteus medius is reduced.

Fig. 30 EMG of the m. gluteus medius; instrumental 3D gait analysis.


The reason for the reduction in muscle activity is the tensioning of LCF.


XIII. During single-leg stance, in the pose of the ancient statue, and in the single-support phase of the gait cycle, LCF is tensioned.

Fig. 31. Pelvic tilt and thigh adduction during walking; LCF is tensioned.

XIV. X-ray in a single-leg standing position (radiographic confirmation).

Fig. 32. Upward displacement of the femoral head pit (red arrow) during adduction in the supporting hip joint.
LCF - tensioned.

Fig. 33. Downward displacement of the femoral head pit (red arrow) during abduction in the supporting hip joint.

LCF - relaxed.


XV. Tensioned LCF is a synergist of the abductor muscle group of the hip joint.

Fig. 34. Lever model of the hip joint with an LCF analog.

XVI. Pelvic tilt and adduction in the hip joint without ligaments.

Fig. 35. Modeling the single-support phase of the gait cycle during normal walking, on a dynamic model of the hip joint with an analog of the m. gluteus medius (without ligament analogs).

The force of the m. gluteus medius analog increases.

XVII. Pelvic tilt and adduction in the hip joint with only LCF.

Fig. 36. Modeling single-leg support during walking on a dynamic model of the hip joint with an LCF analog and an analog of the m. gluteus medius.

The force of the m. gluteus medius analog decreases.

XVIII. Pelvic tilt and adduction in the hip joint with the presence of external ligaments and LCF.

Fig. 37. Modeling single-leg support during walking on a dynamic model of the hip joint with an LCF analog, analogs of external ligaments, and an analog of the m. gluteus medius.

The force of the m. gluteus medius analog decreases, and pelvic stability increases.

IXX. Experiments on a dynamic model of the hip joint.

Modeling the single-leg support phase during normal walking.

Watch the video: Supplement 2 Gluteus Medius & LCF

It has been experimentally confirmed that LCF acts as a thigh adduction limiter, transforms the hip joint into a class three lever, prevents dislocation, suspends the pelvis, and acts as a synergist to the abductor muscle group.


XX. Modeling on a single leg pose with maximum pelvic tilt and thigh adduction.

Fig. 38. Dynamic model of the hip joint with analogs of ligaments and muscles.

The greatest pelvic stability is achieved when all hip joint ligaments are tensioned.

XXI. Modeling on a single leg pose without pelvic tilt.

Fig. 39. Dynamic model of the hip joint with analogs of ligaments and muscles.

Pelvic stability is achieved only by the force of the m. gluteus medius and the m. rectus femoris.

XXII. Modeling on a single leg pose with optimal pelvic tilt and hip adduction.

Fig. 40 Dynamic model of the hip joint with analogs of ligaments and muscles.

Pelvic stability is achieved through the tension of LCF and the force of the m. gluteus medius.

XXIII. When activating the abductor muscle group, with the tension of LCF and external ligaments, pressure on the femoral head is evenly distributed.

Normally, pressure on the upper sector of the femoral head is approximately equivalent to body weight.

Fig. 41. Distribution of forces in the hip joint when standing on one leg, as well as in the pose of an ancient statue, and in the single-leg support phase during normal walking (with pelvic tilt and thigh adduction).

XXIV. Moment rule for the supporting hip joint when standing on one leg, as well as in the pose of an ancient statue, and in the single-leg support phase during normal walking (considering only the reaction forces of ligaments, abductor, and adductor muscles).

Fig. 42. Moment rule for the supporting hip joint when standing on one leg, as well as in the pose of an ancient statue, and in the single-leg support phase during normal walking.

CONCLUSION

LCF is an essential component of the hip joint. Pelvic tilt and thigh adduction in the supporting hip joint when standing on one leg, in the pose of an ancient statue, as well as in the single-leg support phase during normal walking, provide tension to LCF. This element supports the pelvis as a suspension, unloads the abductor muscle group of the hip joint, and contributes to the even distribution of pressure on the femoral head.

LIMITATIONS

We acknowledge that this study has limitations inherent to experimental research on mechanical models. Additional research is needed to refine the pressure distribution on the femoral head for the supporting hip joint when standing on one leg, in the pose of an ancient statue, and in the single-leg support phase during normal walking.

References

Arkhipov SV, Skvortsov DV. Ligamentum capitis femoris: first written mentions. Muscles, Ligaments and Tendons Journal. 2019, 9(2)156–64.

Bombelli R. Structure and function in normal and abnormal hip: how to rescue mechanically jeopardized hip. 3-rd. ed. Berlin, Heidelberg, New York: Springer-Verlag, 1993.

Cheselden W. Osteographia, or the anatomy of the bones. London: W. Bowyer [?], 1733.

Gray H. Anatomy, descriptive and surgical / by Henry Gray. The drawings by H. V. Carter. With additional drawings in the second and later editions by Dr. Westmacott. The dissections jointly by the author and Dr. Carter. With an introduction on general anatomy and development by T. Holmes. Philadelphia: H.C. Lea, 1870.

Harcourt G. Andreas Vesalius and the anatomy of antique sculpture. Representations. 1987;17:28–61.

Kapandji AI. The physiology of the joints: Lower limb. Vol. 2. New Delhi: Elsevier Exclusive, 2009.

Kornell M. (2011, August 22) Accuracy and Elegance in Cheselden’s Osteographia (1733). Retrieved September 20, 2019. from publicdomainreview.org 

Kühn CG (Ed). Galeni opera omnia. In Hippocratis librum de articulis et Galeni in eum commentarii IV. T. XVIIIA. Leipzig, 1829.

Littre E. Oeuvres complètes d'Hippocrate, traduction nouvelle avec le texte grec en regard, collationné sur les manuscrits et toutes les éditions; accompagnée d'une introduction, de commentaires médicaux, de variantes et de notes philologiques; Suivie d'une table générale des matières, Par É.Littré. Tome quatrieme. Paris: J.B.Baillière 1844.

Paul JP. The Biomechanics of the hip-joints and its Clinical Relevance. Proceedings of the Royal Society of Medicine. 1966;59:943–8.

Pauwels F. Biomechanics of the normal and diseased hip: Theoretical foundation, technique and results of treatment. An atlas. Berlin: Springer-Verlag, 1976.

René C. (Ed.) Operum Hippocratis Coi, et Galeni Pergameni, medicorum omnium principum, T. III. Paris, 1638.

Vesale A. Andreae Vesalii bruxellensis, scholae medicorum Patauinae professoris, de Humani corporis fabrica. Libri septem. Basileae: J.Oporinum, 1543.

Wenger DR, Miyanji F, Mahar A, Oka R. The mechanical properties of the ligamentum teres: a pilot study to assess its potential for improving stability in children's hip surgery. J Pediatr Orthop. 2007;27(4) 408–10.

Архипов С.В. Дети человеческие: истоки библейских преданий в обозрении врача. Обновляемое электронное эссе, снабженное ссылками на интерактивный материал. Йоэнсуу: Издание Автора, 2023; версия 1.0.0.

Архипов СВ. Роль связки головки бедренной кости в патогенезе коксартроза: дис. … канд. мед. наук. М., 2013.

Селье Г. Очерки об адаптационном синдроме. Москва: Медгиз, 1960; [transl. Selye H. The story of the adaptation syndrome. (Told in the form of informal, illustrated lectures). Montreal: Acta Inc., 1952.]

Янсон ХА. Биомеханика нижней конечности человека. Рига: Зинатне, 1975.

.                                                                     

In translating to English, the author is assisted by ChatGPT (version 3.5) and the Google Translate service.

If you notice an error, please let us know!

The first version:

Arkhipov SV. New Biomechanics of the Hip Joints: Ligamentum Teres as a Functional Relation. Part I. Pictorial Essay. Ligamentum Teres – Ligamentum Incognitum. 2019, September 22:1–25. DOI: 10.13140/RG.2.2.11991.62881 [researchgate.net , ligteres.com]

Keywords: ligamentum capitis femoris, ligamentum teres, ligament of head of femur, abductor muscle group, hip joint, model, biomechanics, walk, gait cycle, gluteus medius, single-legged stance

BLOG CONTENT

BIOMECHANICS AND MORPHOMECHANICS

Comments

Popular posts from this blog

21cent.bcBaqetIII

Groups of wrestlers on the walls of tomb BH15, belonging to Baqet III – a contemporary of Pharaoh Mentuhotep II (frescoes, Beni Hasan, Egypt). These images depict wrestling scenes and the circumstances under which injuries to the hip joint —  including the ligamentum capitis femoris (LCF) — might occur. The frescoes appear to have served as the basis for the description of wrestling found in the Book of Genesis: 25 And Ja cob was left alone; and there wrestled a man with him until the breaking of the day.  26 And when he saw that he could not pre vail against him, he struck against the hollow of his thigh ; and the hollow of Jacob's thigh was put out of joint, as he was wrestling with him. … 33 Therefore do the children of Israel not eat the sinew which shrank, which is upon the hollow of the thigh, unto this day; because he struck against the hollow of Jacob's thigh on the sinew that shrank. ( 1922LeeserI , Genesis (Bereshit) 32:25-26,33) More about the plot in our work: Nint...

20cent.bcAmenemhet

  Groups of wrestlers on the walls of tomb BH2, belonging to Amenemhat (Ameni)—a contemporary of Pharaoh Senusret I (frescoes, Beni Hasan, Egypt). These images depict wrestling scenes and the circumstances under which injuries to the hip joint—including the ligamentum capitis femoris (LCF)—might occur. The frescoes appear to have served as the basis for the description of wrestling found in the Book of Genesis :  25 And Ja cob was left alone; and there wrestled a man with him until the breaking of the day.  26 And when he saw that he could not pre vail against him, he struck against the hollow of his thigh ; and the hollow of Jacob's thigh was put out of joint, as he was wrestling with him. … 33 Therefore do the children of Israel not eat the sinew which shrank, which is upon the hollow of the thigh, unto this day; because he struck against the hollow of Jacob's thigh on the sinew that shrank. ( 1922LeeserI , Genesis (Bereshit) 32:25-26,33) More about the plot in our work...

NEWS 2026

New publications of our resource   in 2026 The initial phase of collecting data on LCF, accumulated prior to the 20th century, is largely complete. Next, we plan to analyze and synthesize thematic information, adding data from the 20th and 21st centuries. The work will focus primarily on: prevention, diagnosis, arthroscopy, plastic surgery, and endoprosthetics.  November 1 , 2026  LCF in 2026 (November) Quotes from articl es and books published in November   2026 mentioning the ligamentum capitis femoris .    October 29 , 2026  22cent.bcBaqetI . Fresco. A depiction of the circumstances surrounding a hip joint injury. October 28 , 2026  17cent.Akrotiri . Fre sco. A depiction of the circumstances surrounding a hip joint injury.  20cent.bcAmenemhet . Fresco. A depiction of the circumstances surrounding a hip joint injury. 20cent.bcKhety . Fresco. A depiction of the circumstances surrounding a hip joint injury.  21cent.bcBaqetIII . Fresco....

Tweet of October 26, 2026

  The new book about the first patient with a #ligamentum_teres injury. PDF: http://books.google.com/books/about?id=OcogEgAAQBAJ Manuscript: https://roundligament.blogspot.com/2026/10/medical-record-title-and-contents.html Tweet of October 26, 2026 #Bible #Genesis   BLOG CONTENT TWITTER OR X                                                                            

1893GriffithFL

  Griffith F.L. (1893): A group of wrestlers on the wall of the tomb of Baqet III (fresco, late 20th century BCE, Egypt). A depiction of the circumstances surrounding a hip joint injury—possibly involving the ligamentum capitis femoris (LCF) – which served as the basis for the description of a wrestling match in the Book of Genesis:   25 And Ja cob was left alone; and there wrestled a man with him until the breaking of the day.  26 And when he saw that he could not pre vail against him, he struck against the hollow of his thigh ; and the hollow of Jacob's thigh was put out of joint, as he was wrestling with him. … 33 Therefore do the children of Israel not eat the sinew which shrank, which is upon the hollow of the thigh, unto this day; because he struck against the hollow of Jacob's thigh on the sinew that shrank. ( 1922LeeserI , Genesis (Bereshit) 32:25-26,33) More about the plot in our work: Ninth month, eleventh day ( 2024АрхиповСВ )  and Medical Record (2026Ar...

20cent.bcKhety

   Groups of wrestlers on the walls of tomb BH17, belonging to Khety—possibly the son of Baqet III and a contemporary of Pharaoh Senusret I (frescoes, Beni Hasan, Egypt). These images depict wrestling scenes and the circumstances under which injuries to the hip joint — including the ligamentum capitis femoris (LCF) — might occur. The frescoes appear to have served as the basis for the description of wrestling found in the Book of Genesis:   25 And Ja cob was left alone; and there wrestled a man with him until the breaking of the day.  26 And when he saw that he could not pre vail against him, he struck against the hollow of his thigh ; and the hollow of Jacob's thigh was put out of joint, as he was wrestling with him. … 33 Therefore do the children of Israel not eat the sinew which shrank, which is upon the hollow of the thigh, unto this day; because he struck against the hollow of Jacob's thigh on the sinew that shrank. ( 1922LeeserI , Genesis (Bereshit) 32:25-26,33...

17cent.Akrotiri

  The " Akrotiri Boxer Fresco ", found on the wall of a room in a house in the town of Akrotiri on the island of Thera—a site destroyed by the Minoan eruption (late 17th century BCE). The image depicts a bout that may have served as the basis for the legend concerning an injury to the hip joint and the *ligamentum capitis femoris* (LCF), as described in the Book of Genesis:   25 And Ja cob was left alone; and there wrestled a man with him until the breaking of the day.  26 And when he saw that he could not pre vail against him, he struck against the hollow of his thigh ; and the hollow of Jacob's thigh was put out of joint, as he was wrestling with him. … 33 Therefore do the children of Israel not eat the sinew which shrank, which is upon the hollow of the thigh, unto this day; because he struck against the hollow of Jacob's thigh on the sinew that shrank. ( 1922LeeserI , Genesis (Bereshit) 32:25-26,33) More about the plot in our work: Ninth month, eleventh day ( 202...

MEDICAL RECORD. Chapter 2

  Book manuscript: Arkhipov S.V. Medical Record: The Contribution of a Middle Bronze Age Egyptian Physician to the Book of Genesis. Kyrö: Author’s Edition, 2026. – 312 pp. – 2 tables. – Bibliographical references: 856 entries.  play.google.com , books.google.com Introduction Chapter 2 Chronology of the Medical Record CONTENT [i] Text [ii] Navigation [iii] Application [i] Text When reading the Book of Genesis , we learn that the first recorded patient with an injury to the ligament of the head of femur was a man named Ya'akov (Gen. 32:25, 33). In adapted usage, the name is rendered as Jacob. According to the narrative, he was born near the well of Beer-Lahai-Roi, between Kadesh and Bered in the Negev Desert, which is in the south of the "Canaanite" land (Gen. 16:14, 23:19, 24:62). As is clear from the text, the "Canaanite land" is the western part of the current State of Israel, excluding the vicinity of the Jordan River (Gen. 13:11–12). Jacob's father ...

MEDICAL RECORD. Title and contents

  Book manuscript: Arkhipov S.V. Medical Record: The Contribution of a Middle Bronze Age Egyptian Physician to the Book of Genesis. Kyrö : Author’s Edition, 2026. – 312 pp. – 2 tables. – Bibliographical references: 856 entries.  Google Books ID: GGKEY:5GXG1LS275N ,  play.google.com , books.google.com Title,  Abstract and  Contents  CONTENT [i] Abstract [ii] Dedication [iii] Book Covers and Title [iv] Table of Contents [v] Application [i] ABSTRACT Before you is the final medical record compiled by the author over a professional career as an orthopaedic surgeon. This work outlines information regarding a patient who sustained a hip joint injury in the Middle Bronze Age. The source material is extracted from the Book of Genesis and cross-referenced with facts from history, archaeology, natural science, and medicine past and present.  Along the way, it is demonstrated that the protograph was composed in Ancient Egypt during the Second Intermediate P...

Key Role of the LCF

  In the experiments conducted on the pelvis-femur-muscle-ligaments model, we found that when the contralateral pelvic drop occurs, the ligament of the head of femur become maximally tense; simultaneously, there is relaxation and lengthening of the gluteus medius muscle; the pelvis spontaneously rotates towards the stance limb (forward), and the load on the hip joint decreases. Thanks to the functioning of the ligament of the head of femur the walking is smooth, rhythmic, and energy-efficient. Track Music:  Blue Dot Sessions , Vittoro (CC BY-NC 4.0 DEED / fragment)  "Take care of the ligament of the head of femur for yourself and your neighbor!" .                                                                       . keywords: ligamentum capitis femoris, ligament of head of femur, ligamentum te...