Ch. 21: Gluteal and Posterior Femoral Regions

Question 1

Gluteus Maximus

Answer 1

O: b/w posterior crest of ilium and posterior gluteal line and sacrotuberous ligament

I: gluteal tuberosity of femur and iliotibial tract

A: Extension, lateral rotation of thigh. Action on ITT with tensor fascial latae stabilizes knee

N: INferior gluteal n.

important going up stairs or getting up from sitting

Question 2

Gluteus Medius

Answer 2

“deltoid of lower limb”

O: ilium b/w postioer and anterior gluteal lines

I: greater trochanter of femur

A: abduction of thigh

• Posterior fibers: act with glut. maximus to laterally rotate thigh
• Anterior fibers: act with gluteus minimus medially rotate thigh
• levels sacral base when opposite limb is unsupported

N: Superior gluteal n.

Question 3

Gluteus Minimus

Answer 3

underneath glutius medius

O: ilium b/w anterior and inferior gluteal lines

I: greater trochanter of femur - anterior surface

A: abduction and medial rotation of thigh: actis with gluteus medius in leveling sacral base

N: superior gluteal n.

Question 4

Tensor Fascia Lata

Answer 4

important for bracing and butressing the knee

O: anterior outer portion of iliac crest next to ASIS

I: iTT to lateral tibial condyle

A: Abducts, flexes, medially rotates thigh; by tensing ITT maintains knee in extended position

N: Superior gluteal n.

Question 5

Piriformis

Answer 5

almost at 12’oclock position like supraspinatus

O: anterior surface of sacrum, lateral to anterior sacral foramina

I: greater trochanter of femur

A: Abduction of thigh, lateral rotation of thigh

Question 6

Hip Drop condition

Answer 6

Gluteus Medius/Superior Gluteal N. (L 4, 5, S1)

Question 7

Gemellus Superior

Answer 7

lateral rotation of thigh

N: nerve to obturator internus

Question 8

Obturator internus

Answer 8

A: lateral rotation and abduction of thigh

N: nerve to obturator internus

Question 9

Gemellus inferior

Answer 9

A: Lateral rotation of thigh

N: nerve to quadratus femoris

Question 10

Quadratus Femoris

Answer 10

A: lateral rotation of thigh

N: nerve to quadratus femoris

Question 11

Biceps Femoris

Answer 11

O: long head- ischial tuberosity; short head- inea aspera of femur

I: lateral condyle of tibia, head of fibula

A: both flex the leg, long head extends the thigh

N: long head = tibial component of sciatic n. ; short head = common fibular n.

Question 12

Semimembranous

Answer 12

O: Ischial tuberosity

I: posterior surface, medial condyle of tibia

A: extends thigh, flexes leg and medialy rotates leg when kee is flexed (especially good for navigating directional change)

N: Tibial component of sciatic n.

Question 13

Semitendinosus

Answer 13

O: Ischial tuberosity

I: medial anterior surface of tibia below condyle

A: extends thigh, flexes and medially rotates leg when knee is flexed

N: tibial component of sciatic

Question 14

Pes Anserinus

Answer 14

medial, anterior aspect of tibia inferior to medial tibial condyle

• sartorius, gracilis and semitendinosus attach here

Question 15

Superior gluteal a.

Answer 15

• branch of internal iliac a.
• passes through greater sciatic foramen superior to piriformis muscle

Divisions:

1. Superficial: to gluteus maximus
2. Deep: divides into superior and inferior branches, both go to gluteus medius and minimus

Question 16

Inferior Gluteal a.

Answer 16

• branch of internal iliac a.
• passes to gluteal area from pelvic cavity via greater sciatic foramen inferior to piriformis muscle

Branches:

1. muscular (to gluteus maximus)
2. anastomotic branch (to cruciate anastomosis)
3. branch to sciatic n.
4. Coccygeal (pierve sacrotuberus ligament to gain gluteus maximus)
5. cutaneous (accompany posterior femoral cutaneous n.)

Question 17

Sacaral Plexus

Answer 17

• composed of ventral rami of spinal nerves L4,5 - S1,2,3
• provides motor and cutaneous innervation to lower limb muscles of pelvis and perineum and skin of perineum

Question 18

Superior gluteal n.

Answer 18

L4,5-S1

originates from sacral plexusand exits the pelvis via the greater sciatic foramen above the piriformis muscle in company with the superior gluteal artery and v.

• courses b/w glutues medius and minimus
• innervates gluteus medius, minimus, and tensor fascia lata muscles

Question 19

Inferior Gluteal n.

Answer 19

L5-S1,2

• Originates from sacral plexus and exits pelvis via greater sciatic foramen ANTERIOR to piriformis in company with sciatic, pudendal, and posterior femoral cutaneous nn, inferior gluteal and internal pudendal vessles
• passes directly into gluteus maximus which it innervates

Question 20

Sciatic n.

Answer 20

L4,5-S1,2,3

* goes to all flexors on posterior side

• largest peripheral nerve of body and principle nerve of sacral plexus
• contains two components:

1. tibial: composed of anterior divisions of ventral rami
2. common fibular: composed of posterior divisions of ventral ramia

• exits pelvis via greater sciatic foramen, passes anteriorally or through the piriformis muscle, superficial to deep lateral rotators and deep to gluteus max. to enter thigh
• in thigh it lies on posterior surface of adductor muscle, deep to hamstrings
• splits into tibial and common fibular
• tibial innervates semimenbranosus, tendinosus, and long head of biceps femoris, part of adductor magnus
• common fibular innervates short head of biceps femoris muscel