Gluteal Region

Question 1

OINF Obturator Internus

Answer 1

Origin- inner surface of obturator membrane and rim of pubis and ischium bordering membrane

Insertion: middle part of medial aspect of greater trochanter of femur

Action: laterally rotates and stabilizes thigh

Nerve: nerve to obturator internus (L5, S1, 2)

Question 2

OINF Gemellus superior

Answer 2

Origin: spine of ischium

Insertion: middle part of medial aspect of greater trochanter of femur

Action: laterally rotates and stabilizes thigh

Nerve: nerve to obturator internus (L5, S1,2)

Question 3

OINF Gemellus Inferior

Answer 3

Origin: upper border of ischial tuberosity

Insertion: middle part of medial aspect of greater trochanter of femur

Action: laterally rotates and stabilizes thigh

Nerve: nerve to quadratus femoris (L4,5, S1)

Question 4

What are the short lateral rotators?

Answer 4

gemellus superior, gemellus inferior, obturator internus

Question 5

OINF Piriformis

Answer 5

Origin: 2,34 costotransverse bars of anterior sacrum (inside of pelvis), few fibers from superior border of greater sciatic notch

Insertion: anterior part of medial aspect of greater trochanter of femur

Action: laterally rotates and stabilizes thigh

Nerve: anterior primary rami of S1, 2 (“nerve to piriformis”)

Question 6

OINF Gluteus minimus

Answer 6

Origin: outer surface of ilium between middle and inferior gluteal lines

Insertion: anterior surface of greater trochanter of femur

Action: abducts and medially rotates thigh. Tilts pelvis on walking

Nerve: superior gluteal nerve (L4,5, S1)

Question 7

OINF Gluteus medius

Answer 7

Origin: outer surface of ilium between posterior and middle gluteal lines

Insertion: posterolateral surface of greater trochanter of femur

Action: abducts and medially rotates thigh. tilts pelvis on walking

Nerve: superior gluteal nerve (L4,5, S1)

Question 8

OINF Quadratus femoris

Answer 8

Origin: lateral border of ischial tuberosity

Insertion: quadrate tubercle of femur and a verticle line below this to the level of lesser trocanter

action: laterally rotates and stabilizes hip

Nerve: nerve to quadratus femoris (L4,5, S1)

Question 9

OINF Gluteus maximus

Answer 9

Origin: ilium, sacrum, sacrotuberous ligament

Insertion: gluteal tuberosity, iliotibial tract

Action: extends and laterally rotates hip, aids in knee extension via iliotibial tract

Nerve: inferior gluteal L5, S1, S2

Question 10

OINF Tensor Fascia Lata

Answer 10

Origin: outer surface of anterior iliac crest between tubercle of iliac crest and anterior superior iliac spine

Insertion: iliotibial tract (anterior surface of lateral condyle of tibia)

Action: maintains knee extended (assists gluteus maximus) and abducts thigh

nerve: superior gluteal nerve (L4,5, S1)

Question 11

What are the roots of the sciatic nerve?

Answer 11

L4 L5 S1 S2 S3

Question 12

Describe the following nerves (roots and relative location) 
superior gluteal n
inferior gluteal n
posterior femoral cutaneous n
pudendal n

Answer 12

superior gluteal n (L4,5, S1) above piriformis

inferior gluteal n (L5, S1, S2) below piriformis

posterior femoral cutaneous n (S1,2,3)

pudendal n (S2,3,4) gives 3 branches (dorsal which is sensation to clitoris/penis, inferior rectal, and perineal which does all muscles and some sensory)

Question 13

OINF Biceps femoris

Answer 13

Origin:
long head- upper inner quadrant of posterior surface of ischial tuberosity
short head- middle third of linea aspera, lateral supracondylar ridge of femur

insertion: styloid process of head of fibula. lateral collateral ligament and lateral tibial condyle
action: flexes and laterally rotates knee. long head extends hip (long head crosses knee AND hip joint too)

nerve:
long head- tibial portion of sciatic nerve
short head- common peroneal/fibular portion of sciatic
(both are L5,S1)

Question 14

OINF Semimembranosus

Answer 14

Origin: upper outer quadrant of posterior surface of ischial tuberosity

Insertion: medial condyle of tibia below articular margin, fascia over popliteus and oblique popliteal ligament

action: flexes and medially rotates knee, extends hip
nerve: tibial portion of sciatic nerve (L5, S1)

Question 15

OINF Semitendinosus

Answer 15

Origin: upper inner quadrant of posterior surface of ischial tuberosity

Insertion: upper medial shaft of tibia below gracilis

action: flexes and medially rotates knee. extends hip
nerve: tibial portion of sciatic nerve (L5, S1)

Question 16

What four arteries make up the cruciate anastomosis?

Answer 16

in the upper thigh

inferior gluteal artery, lateral and medial circumflex femoral arteries, first perforating artery of profunda femoris artery

(FILM)

Question 17

Why is the cruciate anastomosis clinically relevant?

Answer 17

if there is a blockage between the femoral artery and external iliac artery, blood can reach the popliteal artery by means of the anastomosis

Question 18

What is the route of blood with cruciate anastomosis?

Answer 18

through internal iliac, to inferior gluteal artery, to lateral circumflex femoral artery, to an ascending perforating branch of the deep femoral artery, then to its descending branch into the superior lateral genicular artery and thus into the popliteal artery

Question 19

What is the Tredelenberg sign?

What causes it?

Answer 19

buttock opposite gluteus medius weakness droops
pelvis tilts toward unaffected side

injury to superior gluteal nerve

…pt can abduct pelvis on left femur if lifting right foot (normal)
…pt unable to abduct pelvis on left femur so right buttock droops when lift right foot (Trendelenberg sign +)

Question 20

Describe the posterior femoral cutaneous nerve

Answer 20

posterior femoral cutaneous (S1-3) (cluneal n to buttocks, perineal branch to perineum)

Question 21

Describe the blood supply to the gluteal region.

Answer 21

(branches of internal iliac)
superior gluteal- superficial division ( to glut. max.) deep division to glut med. and minim.

inferior gluteal: muscular
cutaneous, coccygeal, sciatic

Question 22

Describe the sciatic nerve.

Answer 22

From greater sciatic foramen, descends midway between the ischial tuberosity and the greater trochanter, subcutaneous at lower border of gluteus maximus, then travels deep to hamstrings

tibial nerve-preaxial
supplies hamstrings and posterior part of adductor mangus (ventral divisions of L4-S3)

common peroneal/fibular =postaxial, supplies short head of biceps femoris

Question 23

What is the blood supply of the posterior thigh?

Answer 23

perforating branches of profunda femoris

Question 24

What is the popliteal fossa?

What does it contain (from superficial to deep)?

Answer 24

diamond shaped space posterior to knee joint
contains fat, vessels nerves

from superficial to deep: sciatic nerve or its two main branches, popliteal vein (receives saphenous vein here), popliteal artery and its branches (superior medial and lateral genicular, inferior medial and lateral genicular, middle genicular)

Question 25

What are the boundaries of the popliteal fossa?

Answer 25

upper medial: semimembranosus and semitendinosus
upper lateral: biceps femoris m.
lower- two heads of gastrocnemius m.
floor- femur, articular capsule of knee joint, and fascia over popliteus m.