Gross Lecture 5

Question 1

What ligaments reinforce the hip joint? Where is the hip joint more vulnerable?

Answer 1

iliofemoral, ischiofemoral, and pubofemoral ligaments

more vulnerable posteriorly

Question 2

How does the iliofemoral ligament contribute to locking of the hip joint?

Answer 2

it prevents hyperextension of the joint - prevents movement of the femur past a vertical line, locking it in place

Question 3

Where is the center of gravity relative to the hip joint? How does this relate to the role of the iliofemoral ligament? In what position is the hip joint most stable?

Answer 3

center of gravity = behind hip joint
bc of this, pelvis tends to move backwards on the femoral heads, forcing the hip into extension. the iliofemoral ligament prevents hyperextension of the hip. the joint is most stable in an extended position

Question 4

Describe the primary action of the muscles of the gluteal region and their innervation

Answer 4

1. gluteus maximus: extends hip, inferior gluteal n.
2. gluteus medius and minimus: abduct the hip; superior gluteal n.
3. lateral hip rotators (piriformis, superior and inferior gemelli, obturator internus and quadratus femoris): outwardly/laterally rotate the hip; sacral plexus

Question 5

What happens when there is a lesion of the nerve supplying the gluteus medius and gluteus minimus mescles? What test is used to assess this? Lesion to what other structure can cause the same symptoms?

Answer 5

lesion to superior gluteal n. = impairs abduction of the hip = muscles are unable to provide necessary stability, so pelvis on the uninjured side will sag
Trendelenburg test assesses this
lesion to L5 root can also cause positive sign

Question 6

You are examining a patient who exhibits a positive Trendelenburg sign. Describe the clinical findings that led you to this diagnosis. What spinal nerve might be damaged? If the damage was due to a herniated disc, between which two vertebrae would this spinal nerve be located?

Answer 6

sagging pelvis and impaired hip abduction - L5 spinal nerve could be damaged - herniated disc would be between L5 and S1

Question 7

List the muscles responsible for hip flexion and hip extension and their corresponding innervation?

Answer 7

hip flexion: iliopsoas muscle (L1-L2) and rectus femoris (femoral n)
hip extension: gluteus maximus (interior gluteal n.) and hamstring muscles (sciatic n.)

Question 8

Upon examination of a series of MRIs, you determine that your patient has sustained damage to the L1 and L2 spinal nerves. What action of the hip will be impaired?

Answer 8

hip flexion

Question 9

What are the adductor muscles important for maintaining a normal walking gait? What nerve supplies this muscle group? What happens if there is damage to this nerve?

Answer 9

During normal locomotion, adduction of the hip allows the foot to be placed directly under the pelvis.if the obturator nerve is damaged, normal adduction impaired and the foot is in alignment with the shoulder = “waddling gait”

Question 10

Describe the difference between a varus and valgus deformity of the hip

Answer 10

varus: affected limb deviates toward teh midline due to decreased angle of inclination. limb appears shorter than unaffected one = “bowleg”
valgus: affected limb deviates laterally due to increased angle of inclination. limb appears longer than unaffected one = “knock knees”

Question 11

Describe the clinical consequences of a “broken hip”. Branches of what artery are most likely to be compromised?

Answer 11

“femoral neck fracture”; disruption of blood supply to the head and neck of the femur result in avascular necrosis of the femoral head. medial and lateral circumflex arteries, branches of the deep femoral artery are usually compromised