WEEK 3: Functional & Clinical Anatomy of the Hip

Question 1

State all the bony structures that make up the hip joint.

Answer 1

Pelvic bones (acetabulum)
*Ilium
*Ischium
*Pubis

Femur
*Head of the femur

Question 2

What type of joint is the hip joint? State the joint components.

Answer 2

Synovial joint: Ball and socket joint.

Question 3

The acetabulum is formed by the fusion of three pelvic bones. Together, these bones create a concave structure that receives the femoral head, forming the hip joint.

Outline them.

Answer 3

The ilium, ischium, and pubis.

Question 3

Being a ball-and-socket joint, the hip joint permits movements in three degrees of freedom.

State the different movements of the hip joint.

Answer 3

Flexion, extension, abduction, adduction, external rotation, internal rotation and circumduction.

Question 4

The articular surface of the acetabulum, where it meets the femoral head, is shaped like a horseshoe.

What is the significance of this design?

Answer 4

This design allows for a better fit and movement within the joint.

Question 5

Describe the orientation of the acetabulum orientation.

Answer 5

The opening of the acetabulum is directed inferiorly and anteriorly.

This orientation contributes to the overall stability of the hip joint.

Question 6

State the parts of the acetabulum and their functions.

Answer 6

Acetabular fossa
The central, non-articular portion of the acetabulum is referred to as the acetabular fossa.

It is deeper and does not contribute directly to the joint’s movement but plays a role in the overall structure and function.

Acetabular notch (opening)
The acetabular notch is a gap or opening in the acetabulum, contributing to its horseshoe shape.

Acetabular Labrum:
The acetabular labrum is a ring of fibrocartilage attached to the rim of the acetabulum.

It forms a complete circle and deepens the acetabulum, enhancing the congruency between the acetabulum and the femoral head.

The labrum acts as a stabilizer, gripping the femoral head and helping to hold it in place within the joint.

Question 7

The superior (upper) part of the acetabulum is thicker. What is the significance of that?

Answer 7

The superior (upper) part of the acetabulum is thicker, providing additional support to accommodate the weight-bearing forces transmitted through the hip joint.

Question 8

State the 2 main characteristics exclusive to the femur.

Answer 8

Largest bone in the body.
Only bone in the thigh.

Question 9

Comment on the shaft of the femur and functional reasons form that.

Answer 9

Thicker compact bone in the shaft to support weight-bearing.

Question 10

Which end of the femur is wider?

Answer 10

*Wider at the proximal end.

Question 11

The proximal end of the femur contains trabeculae (spongy bone) and thin compact bone.

Describe the alignment of the trabeculae and the significance of that.

Answer 11

Trabeculae are aligned along lines of stress to absorb and disperse forces.

Question 12

Describe the neck of the femur.

What is the angle between the shaft and the neck of the femur size?

Answer 12

Neck of the Femur:

*The femur has a short neck joining the head.

*The angle between the shaft and the neck is approximately 125-130 degrees.

This angle of inclination may vary between individuals and populations.

Question 13

What are females at a high risk developing femoral neck fractures compared to men?

Answer 13

Men generally have a greater angle between the shaft and neck compared to women.

The angle of inclination is thought to be a factor in femoral neck fractures, with a lesser angle potentially contributing to such fractures in women compared to men.

Question 14

What is angle of inclination?

How is it important?

Answer 14

The angle of inclination refers to the angle between the femoral shaft and neck.

It influences the biomechanics of the hip joint and weight distribution during activities like walking and standing.

Variations in this angle can affect the risk of certain hip conditions, including femoral neck fractures.

Question 15

The femoral head is offset from the shaft by the neck. This neck joins the head to the rest of the femur.

Describe the position of the femoral head and the acetabulum.

Answer 15

The femoral head sits snugly in the acetabulum, forming the ball-and-socket joint of the hip.

The femoral head is almost congruent with the acetabulum, contributing to the stability and smooth movement of the hip joint.

Question 16

The articular capsule encloses the femoral head and neck. This capsule is a fibrous structure that surrounds the joint, providing stability.
Fovea:

What is fovea (on the femoral head)?

Where does the fovea rests opposite to on the acetabulum?

What is its function?

Answer 16

The femoral head has a fovea, which is the only non-articulating surface.

The fovea on the femoral head rests opposite the acetabular fossa in the acetabulum.

This small depression serves as an attachment point for the ligament of the head of the femur.

Question 17

Name the ligament that attaches to the fovea and is surrounded by the synovial membrane.

Answer 17

The ligament of the head of the femur.

Question 18

The ligament of the head of the femur, while associated with the vascular supply, is not a primary stabilizer of the hip joint.

State the stabilizers of the hip joint.

Answer 18

The primary stabilizers include the joint capsule, ligaments, and surrounding musculature.

Question 19

The ligament of the head of the femur conveys a small artery to the femoral head.
This artery is a branch of the _________ artery.

Answer 19

Obturator artery.

Question 20

State the function of the transverse ligament of the acetabulum.

Answer 20

The transverse ligament of the acetabulum is a strong flat ligament that bridges the acetabular notch creating the acetabular foramen through which neurovascular structures enter the hip joint.

It completes the inferior deficiency of the acetabular rim and is continuous peripherally with the acetabular labrum.

Question 21

The femoral artery is a major branch of what artery?

What does it pass into the thigh through?

Answer 21

The femoral artery is a major branch of the external iliac artery, and it passes into the thigh through the femoral triangle.

Question 22

Name the major branch of the femoral artery that provides a significant supply to the muscles of the thigh.

Answer 22

The profunda femoris artery

Question 23

State the 2 branches of the Profunda femoris that supply the thigh.

Answer 23

Medial circumflex femoral artery
Lateral circumflex femoral artery

Question 24

The blood supply to the neck and head of the femur is particularly vulnerable during femoral neck fractures.

Which branch of the Profunda femoris plays a crucial role in supplying blood to the neck and head of the femur?

Answer 24

The medial circumflex femoral artery, in particular, is at risk due to its proximity to the femoral neck.

Question 25

Name the artery formed by the medial and lateral circumflex femoral arteries which also contribute to the blood supply of the neck and head of the femur.

Answer 25

Retinacular arteries

Question 26

Why are the vessels supplying the femoral head and neck vulnerable to injury especially during femoral neck fractures?

Answer 26

They are firmly anchored to the bone by the synovial membrane.
This anchoring makes them vulnerable to injury, especially during femoral neck fractures.

Question 27

State the factors that contribute to hip stability.

Answer 27

1. Anatomy of labrum – review
2. Fibrous part of capsule reinforced by 3 ligaments

Question 28

State the capsular and intracapsular ligaments of the hip joint.

Answer 28

Capsular: iliofemoral, pubofemoral, ischiofemoral

Intracapsular: transverse ligament of the acetabulum, ligament of the head of the femur

Question 29

The fibrous part of the hip joint capsule is reinforced by three ligaments.

These ligaments extend from the pelvic bones to the distal capsule and blend with the joint capsule.

Name the strong ligament that contributes significantly to hip stability.

Describe its attachments.

Answer 29

The iliofemoral ligament,

It extends from the anterior inferior iliac spine (AIIS) and the body of the ilium to the intertrochanteric line of the femur.

Question 30

What is the other name for iliofemoral ligament?

Why?

Answer 30

It is also known as the Y ligament.

The Y ligament is named for its bifurcation or splitting into two arms that attach to different parts of the pelvis and the femur, forming a Y or V shape.

Question 31

State the function of the that allows it to contribute to stability during weight-bearing activities like standing and walking.

Answer 31

The iliofemoral ligament tightens with hip extension (moving the thigh backward), contributing to stability during weight-bearing activities like standing and walking.

Question 32

Why is the iliofemoral ligament capable of providing substantial support, even in individuals with paralysis (paraplegics)?

Answer 32

This ligament is the strongest in the human body.

The strength of the iliofemoral ligament makes it capable of providing substantial support, even in individuals with paralysis (paraplegics).

Question 33

Describe the attachments for the ischiofemoral ligament.

State its 2 functions.

Answer 33

From body of ischium, fibers spiral around neck & attach to greater troch (anteriorly, inferiorly, and laterally).

*Tightens with extension
*Screws head into acetabulum

Question 34

Describe the attachments for the pubofemoral ligament.

State its function.

Why is it less important than other 2 ligaments?

Answer 34

From body & sup ramus of pubis to intertrochanteric line & fem neck

Crosses anterior aspect of hip joint

Tightens with abduction.
Less important than other 2 ligaments

The hip joint is particularly vulnerable in flexion (bending the hip joint), and the pubofemoral ligament may have a limited role in providing stability in this position.

Question 35

Dislocations of the hip joint are more common with accidents and post-total hip arthroplasty (THA).

What is THA?

Although the pubofemoral ligament is not considered a major stabilizer, the contribution of muscles is appreciated in the posterior approach total hip arthroplasty (THA).

What is posterior approach in THA?

Answer 35

THA involves the surgical replacement of the hip joint with a prosthetic implant.

The posterior approach to THA involves accessing the hip joint from the back, allowing the surgeon to replace the damaged joint with a prosthetic implant.

Question 36

Describe the role of pubofemoral ligament in posterior approach in THA.

Answer 36

Ligament Release: During the posterior approach, surgeons often need to release or detach the pubofemoral ligament to provide better exposure and access to the hip joint. This release allows the surgeon to dislocate the femoral head, providing the necessary space for the removal of the damaged or arthritic hip joint components and the placement of the prosthetic components.

Soft Tissue Management: Addressing the pubofemoral ligament is part of the soft tissue management required for the posterior approach. Proper handling of ligaments and muscles is essential to achieve optimal exposure while minimizing damage to surrounding structures.

Reattachment or Repair: After completing the joint replacement procedure, surgeons may reattach or repair the ligaments and soft tissues that were released or detached. This is done to restore stability and function to the hip joint postoperatively.

Question 37

Name the muscle, which is a powerful hip flexor, responsible for lifting the thigh toward the abdomen.

Answer 37

Iliopsoas Muscle:

Question 38

The iliopsoas muscle is often referred to as a combination of two muscles: the iliacus and the psoas major.

These muscles work together and are commonly considered as a single functional unit due to their similar actions and close anatomical relationship.

State their origin, insertion, action and innervation

Answer 38

liacus Muscle:

Origin: Iliac fossa (inside the pelvis).

Insertion: Lesser trochanter of the femur (joins with the psoas major).

Action: Primary hip flexor.

Innervation: Femoral nerve (L2-L4).

Psoas Major Muscle:

Origin: Lumbar vertebrae (specifically the transverse processes of L1-L5) and the lateral aspects of the intervertebral discs.

Insertion: Lesser trochanter of the femur (joins with the iliacus).

Action: Hip flexor.

Innervation: Anterior rami of lumbar nerves (L1-L3) and sometimes contributions from the femoral nerve.

Question 39

The quadriceps is a group of four muscles located at the anterior of the thigh.

Outline them as well as their origin and insertion points.

Answer 39

Rectus Femoris (crosses the hip joint, originating from the anterior inferior iliac spine (AIIS) and ilium, inserting into the patella via the quadriceps tendon)

Vastus Lateralis (on the lateral side of the thigh)

Vastus Medialis (on the medial side of the thigh)

Vastus Intermedius (lies between the vastus lateralis and vastus medialis, deep to the rectus femoris)

Question 40

State the function of the quadriceps.

Answer 40

The primary action is knee extension, straightening the leg.
The rectus femoris also assists in hip flexion.

Question 41

What is the innervation of the quadriceps?

Answer 41

The femoral nerve, primarily from the roots L2-L4, innervates the quadriceps muscles.

Question 42

It is the largest and most superficial of the gluteal muscles, primarily responsible for hip extension.
It also functions as an external rotator of the hip, aiding in turning the thigh outward.

Name the muscle.

Answer 42

Gluteus Maximus