anatomy of the Hip Joint and clinical significance

The hip joint is one of the most important and stable joints in the human body, playing a crucial role in supporting the weight of the upper body and enabling a wide range of lower limb movements. It is a ball-and-socket synovial joint, formed between the head of the femur and the acetabulum of the pelvis.

This joint combines strength and mobility, allowing activities such as walking, running, sitting, and jumping, while providing the necessary stability to maintain balance and posture. Understanding the anatomy of the hip joint—including its bones, ligaments, muscles, and surrounding structures—is essential for grasping how it functions in health and how it can be affected by injuries or diseases like arthritis.
In this section, we will explore the detailed anatomy of the hip joint, its biomechanical functions, and clinical significance, laying the foundation for further study of lower limb movement and pathology.

1. Hip Joint BY ASWANI CLEVIN

2. OBJECTIVES Anatomical location, Classification & Articular surfaces Stability factors Anatomical relations Mobility and movements Blood and nerve supply Clinical significance

3. Introduction Joints/articulations is any point where two bones meet Functions of joints: supports the body permits effective movement protects the softer organs Joints can be:- mobile e.g. shoulder, elbow, and knee less movable e.g. vertebral column Immobile e.g. Bones of the cranium freely movable joints of the limbs are most severely compromised by disabling diseases such as arthritis.

4. Classification of Joints functional classification:- focuses on amount of movement allowed. synarthroses ;-immovable joints amphiarthroses ;-slightly movable joints diarthroses ; freely movable joints predominantly in limbs structural classification based on: material that binds the bones together presence or absence of a joint cavity. classified as : Bony joints Fibrous joints Cartilaginous joints Synovial joints

5. SYNOVIAL JOINT Many are freely movable such as elbow, knee, or knuckles Others have more limited mobility e.g. wrist and ankle . Synovial joints are: most structurally complex most likely to develop uncomfortable and crippling dysfunctions. ASWANI CLEVIN

6. Classes of Synovial Joints distinguished by patterns of motion determined by shapes of the articular surfaces of the bones: multiaxial joint move in any of the three planes E.g. Ball-and-socket biaxial joint move in two planes e.g. condylar, saddle, and plane monaxial moves in one plane e.g. hinge and pivot ASWANI CLEVIN

7. Hip joint Synovial, Multiaxial , ball & socket joint Made of head of femur & cup-shaped acetabulum of the hip bone.

8. Acetabulum c- shaped and formed by all 3 hip bones, ( illium , ischium & pubis). Anteverted and inferiorly inclined Parts: Lunate surface: lined with articular cartilage (hyaline) & is articulating suface . Acetabular fossa; filled with fatty tissue Atcetabular notch; deficient inferiorly bridged by transverse acetabular ligament . Acetabular labrum: fibrocartilage rim. Articular surfaces are lined with cartilage

9. Head of femur Suspended by the neck Lined with Articular cartilage except the fovea capitis passage of ligamentum teres capitis .

10. Radiographic features Ileopectineal line ; anterior column of acetabulum Ilioischial line; posterior column of acetabulum tear drop sign formed by acetabulum floor and pelvic Shenton's line: shows continuity of the inferior femoral neck and inferior margin of the superior pubic ramus

11. Important measurement angles Sharps angle; measures acetabulum inclination.>45° is dysplasia Tonnis angle; normal 0-10 ° Femoral neck-shaft angle; normal 125-145° Femoral –acetabulum width; distance btwn head & acetabulum

12. Femoral anteversion / tortion angle; angle of anterior diviation of the neck and head of femur.normal 10-15°

13. Stability factors of the hip joint They prevent dislocation and limit excessive movements. Divided in to: static (bony, capsular and ligaments) Dynamic (muscular and tendinious )

14. a. Static stability factors i . Bony factors Head & acetabulum fusion , acetabulum labrum deepens the acetabulum enhancing the bony factors Acetabulum labrum also; facilitates normal maturation of the acetabulum. Seals synovial fluid within the hip joint Enhances the vacuum effect within the hip joint Has proprioceptive functions; contains receptors creating awareness e.g. standing in darkness

15. Acetabulum coverage: Covers about 75%of the head Measurements of acetabulum coverage: Lateral center edge( wibergs ) angle ; measures lateral coverage normal 25-40° Femoral head extrusion index: less then 25%

16. ii. Joint capsule Encloses the joint and reinforced by ligaments. Attachments of capsule Medially - attached to acetabular labrum. Laterally - attached to intertrochanteric line of femur infront & neck behind. At the intertrochanteric line some fibers, accompanied by blood vessels, are reflected upward along the neck as bands called retinacula. These nutrient arteries supply the head & neck of femur & in fracture of femoral neck they tear causing avascular necrosis of the head.

17. iii. Ligaments 1- Iliofemoral ligament Strongest of all. Attachments Superiorly attached to AIIS above Inferior: 2 limbs of Y - attached to the upper & lower parts of the intertrochanteric line of the femur. Function : prevents hyperextension during standing.

18. 2-Pubofemoral ligament It’s triangular. Attachments Base - attached to superior pubic ramus Apex - attached below to lower part of the intertrochanteric line. Function - limits extension & abduction

19. 3 - Ischiofemoral ligament Spiral shaped Attachments attached to ischial body near the acetabular margin. Fibers pass upward & laterally to the greater trochanter. Function - Limits extension

20. 4 - Transverse acetabular ligament Formed by the acetabular labrum Bridges the acetabular notch in the inferior part to complete the cavity. Converts the notch into a tunnel through which blood vessels & nerves enter joint

21. 5 – Ligamentum teres ( Ligament of the head of femur) Flat and triangular. Attachments Apex – attached to pit of femoral head (fovea capitis ) Base – attached to transverse ligament & the margins of acetabular notch. Lies within the joint ensheathed by synovial membrane .

22. Synovial Membrane Lines the capsule & is attached to the margins of the articular surfaces. Covers part of femoral neck in the joint. Ensheathes the ligament of femoral head & covers the fat pad in the acetabular fossa. pouch of the membrane may protrude through a gap in the anterior wall of the capsule btwn pubofemoral and iliofemoral ligaments forming psoas bursa beneath psoas tendon.

23. B. Dynamic Stability Factors Muscle and tendons surrounding the hip joint Iliopsoas tendon, anterior to joint and has a bursa between Obturator externus :below the neck of femur All other muscles surrounding the hip joint

24. Important Relations of the joint Anteriorly: -floor and contents of femoral triangle; Iliopsoas , pectineus & rectus femoris muscles. ( Iliopsoas & pectineus separate the femoral vessels and nerve from the joint). Posteriorly: - Obturator internus , gemelli , & quadratus femoris separate the joint from the sciatic nerve. Superiorly: - reflected head of rectus femoris , Piriformis and gluteus minimus . Inferiorly: - pectinius and Obturator externus tendon.

25. Nerve Supply Superior gluteal n. Femoral n. Obturator n. Sciatic nerves Nerve to the quadratus femoris .

26. Blood supply Main Branch is PFA PFA gives LCFA & MCFA which gives rise to two anastomosis a. Cruciate anastomosis formed by: Transverse branch of LCFA & MCFA Branch of inferior gluteal artery superiorly Ascending branch from 1 st perforating artery inferiorly

27. B. Trochanteric anastomosis at the level of tronchanteric fossa formed by Ascending branch of LCFA Superior and inferior gluteal arteries

28. Retinacular arteries arise from anastomosis and contribute to most of the supply to the head in adults. Ligamentum teres carpitis has acetabular branch from the obturator artery which is the major blood supply to the head of femur in children. Nutrient artery also may give blood supply to head of femur

29. Movements Has a wide range of movement. Joint strength depends on shape of the bones involved & strength of ligaments. When the knee is flexed, flexion is limited by the thigh on the anterior abdominal wall. When the knee is extended, flexion is limited by the the hamstrings

30. Control of movements Extension is limited by the iliofemoral , pubofemoral & ischiofemoral ligaments. Abduction - limited by pubofemoral ligament. Adduction is limited by contact with opposite limb & ligament of femoral head. Lateral rotation is limited by the iliofemoral and pubofemoral ligaments. Medial rotation is limited by ischiofemoral lig .

31. Movements at the joint Flexion - iliopsoas , rectus femoris , sartorius & adductor muscles. Extension - gluteus maximus & the hamstrings. Abduction - gluteus medius and minimus , assisted by sartorius , tensor fasciae latae & piriformis Adduction - adductor longus & brevis & adductor fibers of adductor magnus assisted by pectineus and gracilis .

32. Movements cont’d Lateral rotation - by piriformis , obturator internus and externus , superior & inferior gemelli quadratus femoris & gluteus maximus . Medial rotation - by anterior fibers of gluteus medius & minimus and tensor fasciae latae . Circumduction - combination of all the movements. Extensors are more powerful than flexors & lateral rotators more powerful than the medial rotators.

33. Clinical significance Referred Pain From the Hip Joint Femoral nerve supplies the hip joint & the skin of front & medial side of the thigh. Thus pain from the hip joint may be referred to the front and medial side of the thigh. The posterior division of the obturator nerve supplies both the hip and knee joints. This is why hip joint disease may give rise to pain in the knee joint.

34. Congenital Dislocation of the Hip Stability of the hip joint depends on ball-and-socket arrangement of articular surfaces & ligaments. In congenital hip dislocation the upper lip of the acetabulum isn’t well developed The head of the femur having no stable socket to lodge rides up out of the acetabulum onto the gluteal surface of the ilium .

35. Traumatic Dislocation of the Hip Its rare because of its stability It’s usually caused by motor vehicle accidents. It occurs when the joint is flexed and adducted. The head of the femur is displaced posteriorly out of the acetabulum It comes to rest on the gluteal surface of the ilium (posterior dislocation). The sciatic nerve close to the posterior surface of the joint may be injured.

36. Hip Joint Stability & Trendelenburg's Sign Stability of the hip joint on standing on one leg with the opposite foot raised depends on; The gluteus medius & minimus must be normal. The femur head must fit well in the acetabulum . The neck of the femur must be intact with a normal angle with the shaft of the femur. If any one of these factors is defective, the pelvis will sink downward on the opposite, unsupported side. The patient is exhibits a positive Trendelenburg's sign.

37. Arthritis of the Hip Joint Patients with inflamed hip joints place the femur in a position giving the least pain. The position allowing increased joint space to contain the increased synovial fluid. The joint is partially flexed, abducted, and externally rotated.

38. Osteoarthritis Commonest disease of the hip joint in adults. Causes pain, stiffness and deformity. The pain is the hip joint or referred to the knee (obturator nerve supplies both joints). Stiffness is due to pain and reflex spasm of the surrounding muscles. The deformity is flexion, adduction & external rotation produced initially by muscle spasm but later by muscle contracture.

39. Surgical approach to the hip Indications Athrotomy – draining of pus from the hip Removal of femoral head (dead one) Total hip replacement Approaches Anterior Antero-lateral Lateral posterior

40. Surgical Approaches- Anterior

41. Surgical Approaches- Anterolateral