COXOFEMORAL OR HIP JOINT: ANATOMY, LIGAMENTS, MOVEMENTS, IRRIGATION - ANATOMY AND PHYSIOLOGY - 2024

The coxofemoral joint or hip joint is the joint formed between the femur and the acetabulum of the hip bone. It is a very resistant and stable ball-and-socket joint. It is a joint with a fairly wide range of motion and is designed to support the weight of the body.

Ball-and-socket joints are those joints in which a hollow segment of one bone articulates with a spherical and convex surface of another. It allows movements in the three axes: flexion and extension, abduction and adduction, rotation and circumduction.

Coxofemoral joint (Source: OpenStax / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0) via Wikimedia Commons)

In these joints the member, during circumduction, describes a cone whose vertex is the center of the sphere. Examples of these types of joints are the shoulder and hip joint.

In the upright position, the weight of the structures of the upper body is transmitted, through the hip bones, to the head and neck of the femoral bones. This joint, along with that of the knee, when subjected to the weight of the body is frequently subject to pathological processes and / or wear and tear due to use.

The bones of the hip joint are surrounded by powerful muscles and held together by a very strong capsule and ligaments. These structures are richly vascularized and innervated.

Anatomy

Bony anatomy of the hip

The hip bones or innominate bones form the pelvis, they meet in front at the pubic symphysis and each one meets dorsally (behind) with the upper part of the sacrum to form the sacroiliac joint. The innominate bones form the anterior and lateral walls of the bony pelvis. The posterior wall is formed by the sacrum.

Each hip bone (one right and one left) is made up of three bones that, in adults, fuse at the acetabulum to form a single bone. These bones are the ilium, ischium, and pubis.

The body of the ilium forms the 2/5 parts of the acetabulum and has an upper widened part that forms the upper part of the wing-shaped hip bone; its upper border forms the iliac crest, which can be felt in living humans. The body of the ilium joins the ischium and the pubis.

Hip: cross section of the hip joint. - 1. Semi-annular ligament area - 2. Cotyloid impeller - 3. Reflex tendon of the rectus anterior - 4. Fat of the fundus of the cotyloid cavity - 5. Round ligament - 6. Transverse ligament of the great notch - 7. Membrane shutter (Source: Cecilia Grierson / Public domain, via Wikimedia Commons)

The name ischium derived from ischial or sciatic constitutes the posteroinferior portion of the coxal bone. It has a body and a branch. The upper border of the body of the ischium fuses with the ilium and the pubis and forms part of the acetabulum (2/5 parts). The branch of the ischium joins the lower branch of the pubis.

The pubis has two branches, one upper and one lower, and a body. The right and left bodies unite to form the pubic symphysis. The upper branch is part of the acetabulum (1/5 part) and there it joins the ilium and the ischium. The lower branch is directed backward and outward and joins the branch of the ischium.

The acetabulum has a caudad, ventral and external or outward orientation, is cup-shaped, and is located on the external part of the innominate bone on each side. It articulates with the head of the femur and forms the hip joint.

Femur Anatomy

The femur or thigh bone is the longest and heaviest bone in the human body. It is composed of a diaphysis and two epiphyses, one upper and one lower. The superior one, which is the one that forms the hip joint, is made up of a head, a neck and two trochanters, one major and one minor.

The lower diaphysis consists of two condyles that form the tibiofemoral joint and articulate anteriorly with the patella. The diaphysis of the femur has a ventral convexity, this is more accentuated in the upper part.

Muscular anatomy of the hip joint

The psoasiliac muscles, the tensor fasciae latae, and the rectus quadriceps are the flexor muscles of the thigh. The sartorius helps this function. The extensors are the muscles of the goose foot and the gluteus maximus.

The abductors are the gluteus medius and gluteus maximus. There are three adductors: the adductor magnus, the short and the long (I, II and III), are assisted in their function by the pectineus and the internal rectus.

The internal rotators are the tensor fascia lata, the gluteus medius, and the gluteus minimus. The external rotators are the short muscles of the gluteal region that are: the internal and external obturator, the superior and inferior calves, the pyramidal and the crural square, all of them assisted by the gluteus maximus.

Ligaments

The hip bones are joined by a very strong capsule. More than half of the head of the femur is housed in the cotyloid cavity, which is surrounded by the acetabular rim that continues below with the transverse ligament.

The joint capsule inserts on the edge of the acetabulum and fuses anteriorly with the acetabular rim and posteriorly with the transverse ligament.

The thickest and most powerful ligament in this joint is the iliofemoral ligament. Its proximal insertion is the anterior inferior iliac spine and it fuses with the tendon of the rectus anterior thigh. Its distal insertion is the femoral intertrochanteric crest.

The pubiofemoral ligament runs from the pubic region of the acetabulum and areas adjacent to the upper ramus of the pubis to run horizontally down the intertrochanteric crest and then down the neck of the femur.

Round ligament is flattened and triangular going from the pubic and ischial roots to inserting into the fossa of the head of the femur.

Ischiofemoral or ischiocapsular ligament itself runs from the ischium into the acetabulum, inserting itself into the neck of the femur and in the vicinity of the greater trochanter.

Movements

The movements of the thigh at the hip joint are flexion and extension, abduction and adduction, and rotation and circumduction. The movements of the trunk at the hip joint are also important and are verified when the trunk is raised from the supine position.

The extension and flexion of the thigh occurs around the horizontal axis that passes through the head of the femur. Adduction and abduction around the anteroposterior axis of the head of the femur. Rotation occurs around the vertical axis that corresponds to the longitudinal axis of the femur.

The rotation covers 1/6 of the circle with the thigh extended and a little more when flexed. Circumduction draws a cone whose vertex is the center of the head of the femur.

Irrigation

The gluteal arteries originate from the internal iliac artery, however, their origin can be highly variable.

The superior gluteal artery is the thickest branch that later divides into a superficial and a deep branch. In the pelvis it emits muscular branches and nutritional branches for the hip bone. The superficial branch irrigates the gluteus maximus and the skin in the area. The deep branch irrigates the neighboring muscles.

The inferior gluteal artery provides muscular branches and branches for supplying the urinary bladder, seminal vesicles, and prostate. It irrigates the gluteal muscles, thigh flexors, hip joint, and underlying skin.

The deep femoral artery gives rise to the perforating arteries that anastomose with the inferior gluteal arteries and with the internal and external circumflex arteries, supplying the femur with nourishing supply.

The veins are generally double, accompany the arteries on their way and flow into the internal iliac vein. They communicate with the tributary veins of the femoral vein and are an important venous return route for blood from the lower limb.

Function

The hip joint is the junction site between the trunk and the lower extremities. In the upright position, the function of this joint, along with all the attached muscular and ligamentous structure, is to support the weight of the upper body and transmit it to the tibia. Both in static and dynamic conditions.

It provides mobility to the lower limb that allows ambulation and the different movements already described that allow raising the legs, rotating them, running, etc.

References

1. Gardner, E., Gray, DJ, & O'Rahilly, R. (1960). Anatomy-A regional study of human structure. Academic Medicine, 35 (7), 726.
2. Kouyoumdjian, P., Coulomb, R., Sanchez, T., & Asencio, G. (2012). Clinical evaluation of hip joint rotation range of motion in adults. Orthopedics & Traumatology: Surgery & Research, 98 (1), 17-23.
3. Marín-Peña, O., Fernández-Tormos, E., Dantas, P., Rego, P., & Pérez-Carro, L. (2016). Anatomy and function of the hip joint. Arthroscopic anatomy of the hip. Spanish Journal of Arthroscopy and Articular Surgery, 23 (1), 3-10.
4. Netter, FH, & Colacino, S. (1989). Atlas of human anatomy. Ciba-Geigy Corporation.
5. Sobotta, J. (2006). Atlas of human anatomy Vol. 1 and Vol. 2 Ed. Médica Panamericana.