Thigh and gluteal region (own notes, raw anatomy)

Question 1

List and describe the muscles of the medial thigh

Answer 1

• Obturator externus: from obturator membrane to posterior greater trochanter (loops under neck of femur). Adduction and lateral rotation. Obturator n.
• Adductor magnus: has an adductor and hamstring compartment.
  -adductor originates from inferior rami of pubis and rami of ischium and attaches to linea aspera. Does adduction and flexion, lateral rotation of thigh. Obturator nerve.
  -hamstring: originates from ischial tuberosity, attaches to adductor tubercle and medial supracondylar line;, medial rotation and extension of thigh. Tibial component of sciatic n (L4-S3)
• Adductor brevis: body of pubis and inferior rami to linea aspera (proximal to adductor longus. Adduction (flexion and medial rotation) of thigh. Obturator n.
• Adductor longus: pubis and broad distal attachment along linea aspera. Adduction (flexion and medial rotation of thigh). Obturator nerve. Medial border of femoral triangle.
• Gracilis: inferior rami of pubis and body of pubis to medial aspect of tibial shaft. Adduction (flex and medially rotate) of thigh at hip, flexion of leg at knee. Obturator n.

Note: gracilis crosses both joints
Note 2: adductors are adductors of hip

all obturator nerve exc. hamstring portion of adductor magnus

Question 2

List the muscles of the anterior thigh

4: Queen Ilia Sat Pretty

Answer 2

• Iliopsoas
  -iliacus: originates at iliac crest, inserts onto lesser trochanter, works to flex thigh
  -psoas: originates from lumbar vertebrae (T12-L5), inserts onto lesser trochanter, flexes hip; ventral rami L1-3 – also involved in flexion, and lateral flexion of lumbar spine; femoral nerve

Together they produce flexion of the thigh at the hip joint

• Quadratus femoris
  -vastus medialis: extends knee. Runs from intertrochanteric line and medial lip of linea aspera to QT. Innervated by: femoral n. Also stabilises patella
• vastus intermedius: extends knee and stabilises patella. Runs from the anterior/lateral shaft of femur to quadriceps tendon. Innervated by: femoral n
  -vastus lateralis: extends knee, runs from lateral lip to QT. Innervated by: femoral n. Also stabilises patella
  -rectus femoris: extends knee and flexes hip. From ASIS and ilium of pelvis, attaches via QT. Innervated by: femoral n
• Sartorius: originates from ASIS attaches to superomedial aspect of tibia. Hip: flexor, abductor, lateral rotator. Knee: flexion. Femoral n. Lateral border of femoral triangle.
• Pectineus: flat and quadrangular. From pectineal line of pubis to pectineal line on posterior femur, just below lesser trochanter. Floor of femoral triangle. NO ACTION AT KNEE. Adduction and flexion AT HIP.

Question 3

List and describe the muscles of posterior thigh

Answer 3

• Hamstrings
• -semimembranosus: deep to semitendinosus. From ischial tuberosity to medial tibial condyle. Flexes leg at knee. Extends thigh at hip. Medially rotates thigh at hip, and leg at knee. Tibial portion of sciatic nerve

-semitendinosus: ischial tuberosity to medial surface of tibia. Flexes leg at knee, extends thigh at hip. Medially rotates thigh at hip and leg at knee. Tibial portion of sciatic nerve.

-biceps femoris: long from ischial tuberosity, short from linea aspera on femur, inserts onto fibular head. Flexion at knee, less extension of thigh at hip, and lateral rotation at both hip and knee. Long is tibial of sciatic, short is fibular portion

Question 4

List and describe the superficial abductors and extenders of the gluteal region

Answer 4

Gluteus Maximus

Attachments: Originates from the gluteal (posterior) surface of the ilium, sacrum and coccyx. Insert onto the iliotibial tract and gluteal tuberosity of the femur.
Actions: It is the main extensor of the thigh, and assists with lateral rotation. However, it is only used when force is required, such as running or climbing.
Innervation: Inferior gluteal nerve.

Gluteus Medius
Attachments: Originates from the gluteal surface of the ilium and inserts into the lateral surface of the greater trochanter.
Actions: Abduction and medial rotation of the lower limb. It stabilises the pelvis during locomotion, preventing ‘dropping’ of the pelvis on the contralateral side.
Innervation: Superior gluteal nerve.

Gluteus Minimus
Attachments: Originates from the ilium and converges to form a tendon, inserting to the anterior side of the greater trochanter.
Actions: Abduction and medial rotation of the lower limb. It stabilises the pelvis during locomotion, preventing ‘dropping’ of the pelvis on the contralateral side.
Innervation: Superior gluteal nerve.

Tensor Fascia Lata

Attachments: Originates from the anterior iliac crest, attaching to the anterior superior iliac spine (ASIS). It inserts into the iliotibial tract, which itself attaches to the lateral condyle of the tibia.
Actions: Assists the gluteus medius and minimus in abduction and medial rotation of the lower limb. It also plays a supportive role in the gait cycle.
Innervation: Superior gluteal nerve.

Question 5

Describe the deep muscles of the gluteal region

Answer 5

Piriformis:
- origin: anterior surface of sacrum and sacrotuberous ligament
- insertion: branches of ventral rami S1/S2
- action: laterally rotates extended thigh, abducts flexed thigh, steady femoral head in acetabulum (with other small rotator muscles)
- note: use to find sciatic nerve, emerges below lower edge
- note also: obturator internus and superior/inferior gemelli attach to GT also, produce lateral rotation.
- Ob int n, quad fem for superior and inferior

Obturator internus:
- Attachments: Originates from the pubis and ischium at the obturator foramen. It travels through the lesser sciatic foramen, and attaches to the greater trochanter of the femur
- Actions: Lateral rotation and abduction.
- Innervation: Nerve to obturator internus.

Superior and inferior gemelli
- Attachments: The superior gemellus muscle originates from the ischial spine, the inferior from the ischial tuberosity. They both attach to the greater trochanter of the femur
- Actions: Lateral rotation and abduction
- Innervation: The superior gemellus muscle is innervated by the nerve to obturator internus, the inferior gemellus is innervated by the nerve to quadratus femoris.

Quadratus femoris
- Attachments: Originates from the lateral aspect of the ischial tuberosity and attaches to the quadrate tuberosity on the intertrochanteric crest
- Actions: Lateral rotation.
- Innervation: Nerve to quadratus femoris.

Obturator externus
- could also be considered part of medial thigh
- Attachments: Originates from the membrane of the obturator foramen and adjacent bone. It passes under the neck of femur and attaches onto the posterior aspect of the greater trochanter
- Actions: Adduction and lateral rotation of the thigh
- Innervation: Obturator nerve (L2-L4).