Hip Joint

Question 1

the fusion of what 3 bones forms the hip bone?

Answer 1

• Ilium
• Ischium
• Pubis

Question 2

what separates the 3 bones fused to make the hip bone?

Answer 2

• Tri-radiate cartilage which begins fusion at 15-17 years and completes at 20-25 years.

Question 3

what forms the socket of the joint?

Answer 3

the acetabulum.

Question 4

the labrum strengthens the joint. how?

Answer 4

• fibrocartilaginous rim at margin of acetabulum increases articular contact area by 10% so more than 50% of head fits in.

Question 5

the joint capsule also increases strength of the joint. how?

Answer 5

• the capsular fibres are spiral in course, this pulls femoral head into acetabulum.
• posterior part in extra-capsular while anterior attaches to intertrochanteric line.

Question 6

the capsule is strengthened by 3 strong ligaments. what are they?

*extra : name 2 other accessory ligaments.

Answer 6

• iliofemoral.
• ishiofemoral.
• pubofemoral.

*ligament of head of femur ( ligamentum teres)

Question 7

what does the Iliofemoral ligament do to improve strength?

Answer 7

• body’s strongest ligament.
• protects hip joint superiorly and anteriorly.

*prevent hyperextension.

Question 8

what does the Pubofemoral ligament do to improve strength?

Answer 8

• protects interiorly and inferiorly.

* prevents hyperextension and over-abduction.

Question 9

what does the Ischiofemoral ligament do to improve strength?

Answer 9

• weakest of the 3.
• positioned posteriorly attached to greater trochanter.

*prevents excessive internal (medial) rotation.

Question 10

what are the muscles involved in hip flexing? and what is the nerve supply?

Answer 10

• main flexor : Iliopsoas (iliacus and psoas major)
• supported by : rectus femoris, sartorius, pectineus.
• femoral nerve.

Question 11

what are the muscles that adduct the hip joint? what never supplies the adduction?

Answer 11

• main : magnus, brevis and longus.
• assisted by : pectineus, gracilis, obtrurator externus.
• obturator nerve

Question 12

what are the muscles that extend the hip joint?

Answer 12

• gluteus maximus, long head of biceps femoris, semimebranous, semitendinosus.

Question 13

what are the muscles involved in hip abduction?

Answer 13

• main : gluteus medius and gluteus minimus.

- assisted by : tensor fascia lata and sartorius.