The Surgical Anatomy of the Hip Joint | Orthopaedic Academy

[00:00] In its most simplistic description, the hip is referred to as a ball and socket joint. However, the true complexity of the hip must be fully appreciated to achieve successful outcomes in the treatment of hip pathologies, both conservatively and surgically. This video will comprehensively address the hip, beginning with the surface anatomy.

[00:20] then onto osteosanatomy, and lastly, capsular and ligamentous anatomy. Superficial landmarks of the hip are critically relevant in describing symptoms of pathology around and within the joint on physical exam. A clinically important anterior anatomic landmark is the femoral triangle.

[00:40] The structures contained within the femoral triangle determine its clinical relevance as a superficial landmark. The borders of the triangle include the inguinal ligament superiorly, the lateral border of the adductor longus medially, and the medial border of the sartorius laterally. The area can be readily identified

[01:00] identified by a palpable femoral artery, but also contains the femoral nerve, femoral vein, and deep anguinal lymph nodes. Anterially, the most easily identifiable superficial landmark is that of the anterior superior iliac spine, abbreviated ASIS.

[01:20] The ASIS is a readily palpable anterior prominence of the ilium on the pelvis. Moving medially along the inguinal ligament toward the midline of the body anteriorly, the pubic symphysis can also be identified. The coronal plane of the pelvis is defined by the

[01:40] ASIS and the pubic symphysis. Beginning anteriorly at the ASIS, the superior iliac crest can be palpated, arching posteriorly to another prominence, the posterior superior iliac spine, also referred to as the PSIS.

[02:00] SIS can also be identified through the distinctive dimpling of the skin. Additional palpable landmarks located posteriorly include the spinous processes of the lumbosacral spine, the sacroiliac joints, ischial tuberosities of the ischium, and the greater sciatic notch.

[02:20] Lateral, the greater trochanter of the femur, is another easily palpable prominence. Transitioning now to the deeper osseous anatomy, the ball and socket configuration of the hip allows a wide range of motion and is described as an articulation between the head of the femur and the acetabulum of the pelvis.

[02:40] At the hip articulation, the femur begins as a femoral head and tapers down into a femoral neck before widening at the point of the greater and lesser trochanters and then narrows once more into the shaft of the femur. The greater and lesser trochanters of the femur are bony prominences that serve as insertion of the femur.

[03:00] points for tendons about the hip. Anteriorly, between the greater and lesser trochanters is the intertrochanteric line, which is the attachment site of the iliofemoral ligament, the largest of the ligaments that make up the hip capsule, and the most proximal origin of the vastus medialis.

[03:20] Posteriorly, the diaphysis of the femur has a ridge called the linea aspera that serves as the origination and insertion point for muscles and intramuscular septa about the hip. The acetabulum is a concave surface formed by the three bones of the os coccyx.

[03:40] The ischium, ilium, and pubis. The inferior and side boundaries of the acetabulum are provided by the ischium, the superior boundary by the ilium, and the remainder by the pubis. This cup-like socket consists of a central non-articulating surface

[04:00] and a lunate articular surface towards the periphery. Hyaline cartilage overlies the lunate articular surface. Peripherally, a fibrocartilaginous rim of tissue, referred to as the acetabular labrum, acts to deepen the articular surface of the acetabulum. The capsule of the hip

[04:20] encapsulates the joint circumferentially and attaches to the labrum medially. In the incomplete area of the acetabulum inferiorly, the capsule is attached to the transverse acetabular ligament. The hip capsule, comprised of dense, cylindrically arranged fibers,

[04:40] attaches proximally through the acetabular periosteum and distally along the intertrochanteric line of the femur anteriorly, the greater trochanter superiorly, and the lesser trochanter inferiorly. An arched free border of the capsule is formed by the zona obicularis posteriorly,

[05:00] medial to the intratrocantaric crest, and medial to the femoral neck, resulting in the absence of a direct point of attachment. The zona obricularis is also described as the annular ligament. Continuous with the hip capsule, strong extrinsic capsule ligaments also surround the joint to reach the

[05:20] reinforce the stability of this remarkably mobile diarthrotal ball and socket joint. The three reinforcing structures are the ileofemoral, pubofemoral, and ischiofemoral ligaments. The ileofemoral ligament is oriented along the anterior hip capsule, with the tensile

[05:40] greater than 350 kg, the iliofemoral ligament is arguably the strongest ligament in the human body. Also referred to as the Y-shaped ligament or the ligament of bigelow, the iliofemoral ligament is made up of longitudinally arranged fibers that bridge superiorly from the anterior inferior iliac spine and

[06:00] in anteriorly from the iliac portion of the acetabular rim to distally along the intracantaric line of the femur. The iliofemoral ligament contributes to the stability of the hip by limiting and preventing hyperextension of the hip joint. The pubofemoral ligament positioned anterior inferiorly

[06:20] superiorly, attaches proximally along the iliopubic eminence, obturator crest, and superior pubic rames to distally where it merges with the deep fibers of the vertical band of the iliofemoral ligament and the hip capsule. It functions to prevent excessive abduction and extension of the hip

[06:40] joint. Lastly, the triangular band of fibers forming the ischiofemoral ligament spans centrally from the ischium superlateral and attaches to the acetabulum posteroinferially before coursing distally and merging with the posterior hip capsule posterior to the femoral neck and attaching to the greater triclid.

[07:00] trochanter. This attachment is deep to the iliofemoral ligament. From the medial and lateral parts of the ischiofemoral ligament, the distal attachment is along the posterior circumference of the femoral neck. The weakest of the hip ligaments, the ischiofemoral ligament, functions to prevent hyperextension.

[07:20] Together, the ligaments provide stability to the hip by compressing the femoral head into the acetabulum. In addition to the extraarticular ligamentous stabilizers of the hip, there is an intraarticular ligament extending from the fovea capitis of the femoral head to the acetabular notch, called the ligamentum teres,

[07:40] or foveal ligament. The ligamentum teres is a triangular, flat band made up of one to three bundles and varies in size from patient to patient. Contained within the ligamentum teres lies the acetabular branch of the obterator artery, also called the artery of the head of the femur.

[08:00] which provides a minor source of arterial blood supply to the hip.

[08:20] overall stability, functional range of motion, gait, and balance. The muscles can be separated into three groups, iliosauus muscles, gluteal muscles, and adductor muscles. The iliosauus muscle group is comprised of the iliacus, psoas major, and iliosauus.

[08:40] and psoas minor. These muscles contribute to hip function by allowing flexion of the hip or flexion of the trunk at the hip as well as lateral flexion of the trunk through contraction of the psoas major and minor muscles and lateral rotation of the hip. Triangular in shape, the large iliacus muscle originally is called psoas.

[09:00] originates along the flat surface of the ilium on the superior two-thirds of the iliac fossa. The muscle then crosses over the hip joint and inserts into the psoas major tendon before terminating on the lesser trochanter of the femur. It is innervated by the femoral nerve branching from

[09:20] the L2 to L4 nerve roots. The iliacus contributes deflection of the trunk through the hip joint as well as external rotation of the femur. The psoas major is a thick, long fusiform muscle that originates along the thoracic and lumbar vertebral bodies of

[09:40] T12 to L4 and the transverse processes of the fifth lumbar vertebrae. Moving distally, the psoas major fuses with the iliacus before terminating at its insertion on the lesser trochanter of the femur. The psoas major is innervated through the iliac.

[10:00] anterior rami of spinal nerves L1 to L3. The psoas major functions to forward and laterally flex the trunk. More commonly, it is known as a primary flexor of the hip. Given the shared responsibility for hip flexion and their common insertion on the lesser trochanter, the

[10:20] The iliacus and psoas major muscles are often referred to simply as the iliosaur. The psoas minor muscle is variably present in patients and may only be identified in approximately 40% of the population.

[10:40] It is positioned anterior and medial to the psoas major and is both long and thin. When present, this muscle originates along the vertebral bodies of T12 to L1 and inserts distally at the iliopubic eminence and pectineal line of the pubis.

[11:00] Like the psoas major, the psoas minor is innervated through the anterior rami of spinal nerve L1 and functions to assist in forward and lateral flexion of the trunk. The gluteal muscle group can be further divided into those that are superficial and those that are deep.

[11:20] The superficial muscles of the gluteal group are larger in size and made up of the gluteus maximus, gluteus medius, gluteus minimus, and tensor fascia latte. The deep gluteal muscles include the pyriformis, obturator externus, obturator internus,

[11:40] gluteus, gemelus superior, gemelus inferior, and quadratus femoris. The largest and most superficial of the gluteal group is the gluteus maximus. The gluteus maximus muscle blankets the other gluteal muscles except for the most superior portion of the gluteus medius.

[12:00] This quadrangular shaped muscle originates through a broad attachment spanning the bony surfaces of the ilium, sacrum, and coccyx, fibers of the muscle corsoblecly in the infrolateral direction and insert onto the iliotibial tract and gluteal tuberosity of the femur.

[12:20] The gluteus maximus is innervated by the inferior gluteal nerve originating from the L5 to S2 nerve roots. Contraction of the gluteus maximus results in extension and lateral rotation through the hip joint and contributes

[12:40] to both abduction through its upper fibers and adduction through its lower fibers. Beneath the overlying gluteus maximus sits the gluteus medius and further deep to that sits the gluteus minimus. Both are fan-shaped and originate between the anterior and posterior gluteal lines

[13:00] of the ilium and course infrilaterally to their insertion on the greater trochanter of the femur. Intervation of both the gluteus medius and minimus is from the superior gluteal nerve originating from the sacral plexus from the posterior divisions of the L4 to S1 nerve rans.

[13:20] Working in concert, these muscles function to produce abduction of the hip while resisting adduction, and also produce internal rotation of the hip. Superficially, along the lateral aspect of the thigh is the tensor fascia latte. The tensor fascia latte originates from the hip to the hip.

[13:40] along the lateral aspect of the anterior superior iliac spine and courses distally along the lateral femur, inserting distally along the iliotibial tract with a terminal insertion into the lateral condyle of the tibia. Tensor fascia latte is innervated by the

[14:00] superior gluteal nerve. This muscle functions to produce internal rotation, flexion, and weak abduction through the hip joint and aids in stabilization of the pelvis when weight-bearing. Given its far-distal insertion, it also functions to externally rotate and weakly flex the knee.

[14:20] stabilization of both the hip and knee joints is another important function of the tensor fascia latte. Moving now to the deep gluteum muscles, which include the piriformis, obturator externus, obturator internus, jumelus superior, jumelus inferior,

[14:40] and the quadratus femoris. The piriformis is the most superior of the deep gluteal muscles and is named for its pear-like shape. It originates from the anterior sacrum between the second, third, and fourth anterior sacral foramina through the greater sciatic foramen before inserting onto the greater foramen.

[15:00] trochanter. It is innervated by the nerve to the pyriformis. The pyriformis plays a role in both abduction and external rotation of the hip. The gemelli are two accessory fascicles aligned with the tendon of the obturator internus.

[15:20] The long tendon of the obturator internus makes a path between the gemelosuperior and gemelosinferior, where the muscle first originates in a flat, fan-shaped form from the inner surface of the obturator membrane and the margin of the obturator foramen. It then passes between the gemelosuperior and infinitesimally.

[15:40] inferior, before inserting above the trochanteric fossa on the medial surface of the greater trochanter. The gemelos superior muscle originates on the posterior surface of the ischial spine, while the gemelos inferior muscle originates more distally on the ischial tuberosity.

[16:00] Both gemelli course laterally, along with the obturator internus, to their insertion points on the medial aspect of the greater trochanter. Inervation to the superior and inferior gemelli and the obturator internus comes from the nerve to the obturator internus

[16:20] and the nerve to the quadratus femoris. Together, the superior and inferior gemalae, along with the obturator and ternus, form the triceps cocci, which function to externally rotate the hip in the neutral and flex position, but not in hip extension.

[16:40] In addition, they provide deep stabilization of the hip joint. The obturator externus muscle is best viewed anteriorly and originates from the bony margin of the obturator foramen, extending from the 12 o'clock to 10 o'clock position in a clockwise direction, on the pubic and ischial rami.

[17:00] Some fibers also arise from the obturator membrane. The muscle passes laterally and inferior to the acetabulum before inserting as a cylindrical tendon onto the trochanteric fossa, primarily, with some fibers extending to the piriformis fossa.

[17:20] aggravated by the posterior branch of the obturator nerve. During neutral or a flex position of the hip, the obturator externus externally rotates the hip and may also assist in adduction during hip flexion. The quadratus femoris is a rectangular shaped muscle

[17:40] cell that originates along the lateral border of the ischial tuberosity and inserts on the intertrochantaric crest of the femur at the quadrate tubercle and extends just slightly inferior. It is innervated by the nerve to the quadratus femoris and functions primarily to externally rotate the femur.

[18:00] the thigh, while assisting in stabilization of the femoral head within the acetabulum and adduction of the thigh. The adductor muscle group is comprised of the adductor longus, adductor brevis, adductor magnus, adductor minimus, which is variably present and not dependent.

[18:20] depicted here in this model, Gracilis and Pectinius. These muscles constitute the primary adductors of the hip and originate along the superior and inferior pubic rami of the pelvis, with the adductor magnus origin extending further laterally into the ischium.

[18:40] these muscles all insert along the linea aspera of the femur through broad attachments. The adductor magnus is unique in that is a thick, large, triangular-shaped muscle consisting of two distinct sections, the medially positioned hamstring segment and the laterally positioned anterior.

[19:00] adductor segment. The hamstring segment inserts distally at the adductor tubercle, while the adductor segment inserts through a broad aponeurosis onto the gluteal tuberosity, the lineospora, and the medial supracondylar line of the femur.

[19:20] Adductors of the hip are innervated by the anterior branch of the obturator nerve. The adductor magnus is also innervated by the tibial division of the sciatic nerve. The primary function of this muscle group is to bring the lower extremity toward or beyond the midline of the body via adductor.

[19:40] obstruction at the hip joint. The complex and unique anatomy of the hip enables both stability and weight-bearing, along with a considerable amount of flexibility for a wide range of movement.