Gluteal Region Back Of Thigh And Popliteal Fossa Question And Answers

The gluteal region, back of the thigh, and popliteal fossa

Question 1. Enumerate major muscles of the gluteal region.
Answer:

Gluteal region:

They are 4 in number:

• Gluteus maximus
• Gluteus medius
• Gluteus minimus
• Tensor fasciae latae

gluteal region Note:

• The tensor fasciae latae has migrated to the lateral aspect of the thigh.
• All the muscles of the gluteal region are supplied by the superior gluteal nerve except the gluteus maximus, which is supplied by the inferior gluteal nerve.

Question 2. Give the origin, insertion, nerve supply, and actions of gluteus maximus, gluteus medius, and gluteus minimus muscles.
Answer:

Gluteus minimus muscles:

These are given in the following box:

Question 3. Give the anatomical basis of Trendelenburg’s sign.
Answer:

Trendelenburg’s sign:

When one foot is off the ground, the pelvis is prevented from sagging on the side by the downward pull of the opposite gluteus medius (mainly) and gluteus minimus muscles. But if the gluteus medius and minimus muscles are paralyzed on one side and the opposite healthy foot is elevated (i.e., off the ground), the pelvis will sag on that (i.e., healthy) side. This is called Trendelenburg’s sign.

Question 4. Write a short note on the piriformis muscle.
Answer:

Piriformis muscle:

• The piriformis is a pear-shaped key muscle of the gluteal region.
• It lies partly within the pelvis and partly in the gluteal region.

Piriformis muscle Origin:

From the pelvic surface of the middle three pieces of sacrum, leaves the pelvis through the greater sciatic notch to reach the gluteal region.

Piriformis muscle Insertion:

Tip of the greater trochanter.

Piriformis muscle Nerve supply:

Superior gluteal nerve (L5, S1).

Piriformis muscle Action:

Abduction of the hip joint to help stabilize the pelvis while walking.

Piriformis muscle Applied anatomy:

Provides key to understanding the relationship of structures in the gluteal region, viz.

• Superior gluteal nerve and vessels emerge above it.
• Inferior gluteal nerve and vessels emerge below it.
• The sciatic nerve emerges below it.

Piriformis muscle Applied anatomy:

Piriformis muscle Piriformis syndrome:

It occurs due to irritation of the sciatic nerve by the piriformis muscle due to its overuse.

Piriformis muscle Clinically it presents as:

1. Pain, tingling, numbness,
2. Pain radiating from the back of the thigh to the foot and
3. The intensity of pain increases during climbing stairs, walking, and running.

Question 5. Enumerate the hamstring muscles and give their characteristic features.
Answer:

Characteristic features:

They are 4 in number:

• Semitendinosus
• Semimembranosus
• The long head of the biceps femoris
• The ischial part of the adductor magnus

Characteristic features:

• All arise from ischial tuberosity.
• All are inserted into one of the two leg bones (i.e., tibia or fibula).
• All are supplied by the tibial part of the sciatic nerve.
• All extend the hip joint and flex the knee joint.

Question 6. Give the origin, insertion, nerve supply, and actions of the biceps femoris muscle.
Answer:

Femoris muscle:

It is the muscle of the back of the thigh, which it crosses obliquely from the medial to the lateral side.

Femoris muscle Origin

• Long head from inferomedial impression on the upper part of the ischial tuberosity along with semitendinosus.
• Short head from
  • the lower part of the lateral lip of the linea aspera and
  • upper 2/3rd of the lateral supracondylar line of the femur.

Femoris muscle Nerve supply

• Long head by tibial part of the sciatic nerve.
• Short head by common peroneal part of the sciatic nerve.

Femoris muscle Actions

• It is the chief flexor of the knee joint.
• It is a weak extensor of the hip joint while standing and walking.
• It is the lateral rotator of the leg in the semiflexed knee.
• It is the lateral rotator of the leg when the hip is extended.

Question 7. Describe the sciatic nerve in brief.
Answer:

The sciatic nerve in brief:

It is the thickest and widest nerve of the body. It consists of two components:

• Tibial
• Common peroneal

The sciatic nerve in brief Origin and root value

• A tibial part from ventral divisions of the anterior primary rami of L4, L5, S1, S2, and S3.
• A common peroneal part from dorsal divisions of anterior primary rami of L4 and L5 and S1 and S2.

The sciatic nerve in brief Course:

• In the pelvis: The sciatic nerve lies in front of the piriformis under the cover of its fascia.
• In the gluteal region: The nerve enters the gluteal region through the greater sciatic foramen below the piriformis. It runs downward with a slight lateral convexity passing between the ischial tuberosity and the greater trochanter.
• In the thigh: The nerve emerges from the lower border of the gluteus maximus to enter the back of the thigh where it runs vertically downward up to the superior angle of the popliteal fossa where it terminates by dividing into the tibial and common peroneal nerves.

The sciatic nerve in brief Relations:

The sciatic nerve in brief In the gluteal region:

• Superficial: Gluteus maximus.
• Deep
  • Body of the ischium.
  • Tendon of the obturator internus with the gemelli.
  • Quadratus femoris and obturator externus.
  • Ascending branch of the medial circumflex femoral artery.
  • Capsule of the hip joint.
  • Upper transverse fibers of adductor magnus.

The sciatic nerve in brief In the thigh:

• Superficial: Long head of the biceps femoris.
• Deep: Adductor magnus.
• Medial
  • The posterior cutaneous nerve of the thigh.
  • Semimembranosus and semitendinosus.
• Lateral: Biceps femoris.

The sciatic nerve in brief Branches

The sciatic nerve in brief Articular:

To hip joint

The sciatic nerve in brief Muscular:

• The tibial part supplies hamstring muscles, viz:
  • Semitendinosus
  • Semimembranosus
  • The long head of the biceps femoris
  • Ischial head of adductor magnus
• The common peritoneal part supplies a short head of biceps femoris.

The sciatic nerve in brief Applied anatomy:

• Sleeping foot: It is the feeling of tingling and numbness in the lower limb. It often occurs due to compression of the sciatic nerve against the femur for a long duration, such as sitting on a bicycle rod.
• Sciatica: It is a shooting pain along the cutaneous distribution of the sciatic nerve usually due to compression and irritation of one or more of its nerve roots. The pain begins in the gluteal region and radiates successively to the back of the thigh, lateral side of the leg, and dorsum of the foot.
• Sciatic nerve injury: Any injury to the nerve, for Example: due to penetrating wounds or hip dislocation, results in loss of all movements below the knee, sensory loss on the back of the thigh, the whole of the leg, and foot except area supplied by the saphenous nerve.

Question 8. Describe the popliteal fossa under the following headings

1. introduction,
2. boundaries,
3. contents and
4. applied anatomy.

Answer:

Headings:

It is a diamond-shaped fossa on the posterior aspect of the knee, and its lower part is homologous to the cubital fossa in front of the elbow.

Headings Boundaries:

Headings Superolaterally:

Biceps femoris.

Headings Superomedially:

Semimembranosus and semitendinosus.

Headings Inferolaterally:

The lateral head of the gastrocnemius is supplemented by the plantaris.

Headings Inferomedially:

The medial head of the gastrocnemius.

Headings Roof:

It is formed by popliteal fascia.

Headings Floor:

From above downward, it is formed by a popliteal surface of the femur, capsule of the knee joint, oblique popliteal ligament, and fascia covering the popliteus muscle.

Headings Note:

• Structures piercing the roof
  • Sural nerve
  • Posterior femoral cutaneous nerve
  • Short saphenous vein
• Structures piercing the floor
  • Middle genicular vessels
  • Middle genicular nerve
  • Genicular branch of the posterior division of the obturator nerve

Headings Contents

• Tibial nerve
• Common peroneal nerve
• Popliteal vein
• Popliteal artery
• Popliteal lymph nodes
• Popliteal pad of fat

Headings Note:

The relationship (relative positions) between nerve and vessels differs in the upper, middle, and lower parts of the popliteal fossa.

• In the upper part from medial to lateral:
  • Popliteal artery
  • Popliteal vein
  • Tibial nerve
• In the middle part from posterior to anterior:
  • Tibial nerve
  • Popliteal vein
  • Popliteal artery
• In the lower part from medial to lateral:
  • Tibial nerve
  • Popliteal vein
  • Popliteal artery

Headings Applied anatomy

• Popliteal aneurysm: The popliteal artery is the commonest site for aneurysm. Clinically, it presents as a pulsatile swelling in the popliteal fossa.
• Baker’s cyst: It is cystic swelling in the popliteal fossa which occurs either due to inflammation of the synovial bursa underneath the semimembranosus or by the protrusion of the synovial cavity of the knee joint through its capsule.
• Popliteal pulse: It can be felt by flexing the knee so that the tight popliteal fascia is relaxed.

Question 9.  Write a short note on the popliteal artery.
Answer:

Popliteal artery:

It is the continuation of the femoral artery in the popliteal fossa.

Popliteal artery Origin and course:

It begins at the 5th osseoaponeurotic opening of the adductor magnus (adductor hiatus) and runs downward and laterally in the popliteal fossa to reach the lower border of the popliteus muscle, where it terminates by dividing into anterior and posterior tibial arteries.

Popliteal artery Branches:

• Genicular branches (5 in number).
  • Middle genicular artery
  • Inferior medial and lateral genicular arteries
  • Superior medial and lateral genicular arteries
• Muscular branches
  • Upper muscular branches to adductor magnus and hamstring muscles
  • Lower muscular to gastrocnemius, soleus, and planters
• Terminal branches
  • Anterior tibial
  • Posterior tibial

Popliteal artery Applied anatomy:

• Popliteal aneurysm: It is the balloon-like dilatation and weakness in the wall of
  popliteal artery.
• Popliteal pulse: It is felt in the popliteal fossa by flexing the knee to relax the popliteal fascia.