hip joint

Question 1

Describe and name the articular surfaces of the hip joint

Answer 1

Name ⇒ Hip Joint

Type of Joint ⇒ Ball and socket type of synovial joint that is a multi-axial joint.

synovial → To provide wide range of ogement
multiaxial → To provide more than 6 movements

Articulation surfaces ⇒ Hemispheric head of femur with the acetabulum

Question 2

Describe the ligament support of the hip joint

Answer 2

1. Ilio femoral ligament (extracapsular)
   - inverted Y-shaped (triangular) and is the strongest ligament in the body
   - Apex attaches to the lower half of AIIS and the base attaches to the intertrochanteric line.
   - Prevents the trunk from falling backwards in the standing posture
   - Clinically can be used to lever the head of the femur back into the acetabulum after a hip dislocation.
2. Pubo femoral ligament (extracapsular)
   - Extends from pubic bone to the obturator membrane
   - Results in an increase likelyhood of posterior dislocation of hip joint.
3. Ischio femoral ligament (extracapsular)
   - Very weak band which arises from the ischium below the acetabulum
4. Fibrous capsule
   - Originates on the hip bone from the acetabular labrum, the transverse acetabular ligament, and the acetabulum
   - Inserts onto the intertrochanteric line in front, and 1cm medial to the intertrochanteric crest behind, on the femur. (ant.sup → thick. post.inf → thin)
   - The outer fibers are longitudinal (very strong and thick, found anteriorly)
   - The inner circular ones are called zona orbicularis (Not as strong, thin, found posteriorly)
   - Functions to provide mobility and stability, keep synovial fluid in place, and providing extracapsular ligaments.
5. Ligament of head of femur
   - Round ligament
   - The apex is attached to the fovea capitis and the base is attached to the transverse ligament and the margins of the acetabular notch.
   - Importantly it transmits arteries to the head of the femur (from acetabular branches of the obturator and medial circumflex femoral arteries)
6. The acetabular labrum
   - Fibrocartilaginous rim that attaches to the mragins of the acetabulum
   - Increases the depth of the acetabular cavity, and narrows its mouth my sloping inwards to facilitate holding the head of the femur in position
   - Acts as a shock absorber
7. The transverse acetabular ligament
   - Is a strong band of fibers that bridges acess the inferior aspect of the acetabular notch to complete the rim of the acetabulum (notch → Foramen)
   - Acetabular branches from the obturator and medial circumflex femoral arteries, and obturator nerve enter the ligament through the acetabular notch.

Question 3

Describe the blood supply and the nerve supply of the hip joint

Answer 3

From the attachment of the fibrous capsule to the femur, a number of fibre bundles turn back on the neck of the femur ⇒ Retinacula

Arterial anastomosis is formed around the neck of the femur between the following pairs of vessels:
1. Ascending branches of the medil and lateral circumflex femoral arteries
2. Actuabular branches of the obturator and medial circumflex femoral arteries
3. Branches of the superior and inferior gluteal arteries
- Avascular necrosis if the retinacula (normally holds fragments together) is torn when the neck is fractured. Can also occur during disclocation

Nerve Supply:
1. Nerve to Quadratus femoris
2. Femoral nerve through the nerve to the rectus femoris
3. Anterior division of the obturator nerve

Question 4

Movements of the hip joint and the muscles that produce it

Answer 4

1. Flexion → Illiopsoas
2. Extension → Gluteus maximums and hamstrings
3. Medial Rotation → TFL, Gluteus minimus, medius, adductors, illiopsoas
4. Lateral Rotation → Sartorius, gluteus maximus, obturator internus + gemelli, obturator externus, piriformis
5. Abduction → Restricted by pubofemoral ligament. Gluetus medius, minimus, TFL, piriformis, obturator internus
6. Adduction → restricted by the iliofemoral ligament and upper part of fibrous capsule. Adductors, gracilis, pectineus, quadratus femoris

Question 5

Mention three main conditions where Trendelenburg’s sign is positive

Answer 5

 Paralysis of gluteus medius and minimus
 Congenital or pathological dislocation of hip
 Ununited fracture of neck of femur