week 6 anatomy

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Questions and Answers

What is the primary function of the posterior thigh muscles?

Knee extension and hip abduction

Knee extension and hip flexion

Knee flexion and hip extension (correct)

Knee flexion and hip adduction

Which of the following muscles is innervated by the tibial nerve?

Semitendinosus (correct)

Semimembranosus (correct)

Rectus femoris

Biceps femoris long head (correct)

What is the distal attachment point for the semitendinosus muscle?

Ischial tuberosity

Medial surface of the tibia (correct)

Oblique popliteal ligament

Lateral condyle of the tibia

Which action is performed by the semimembranosus muscle?

Knee flexion and hip extension Signup and view all the answers

Which muscle shares the same proximal attachment as the semimembranosus?

Semitendinosus Signup and view all the answers

What is the main action of both the semitendinosus and semimembranosus muscles when the knee is flexed?

They extend the trunk Signup and view all the answers

The proximal attachment for the semimembranosus is located at which anatomical landmark?

Ischial tuberosity Signup and view all the answers

Which of the following describes the innervation pattern of muscles in the posterior thigh?

All except one are innervated by the tibial nerve Signup and view all the answers

What wraps around the femur and anastomoses at the knee?

Descending branch Signup and view all the answers

Which artery branches off the femoral artery in the femoral triangle?

Profunda Femoris Artery Signup and view all the answers

The Saphenous nerve is a motor branch of the femoral nerve.

False Signup and view all the answers

Which muscles insert at the superior medial tibia to form the Pes Anserinus?

Sartorius, Gracilis, and Semitendinosus Signup and view all the answers

The _____ Nerve descends through the pelvis, pierces the obturator membrane, and divides into anterior and posterior branches.

Obturator Signup and view all the answers

What provides sensory innervation to the medial leg?

Saphenous nerve Signup and view all the answers

What does the term 'pes anserinus' refer to?

A common insertion of specific muscles Signup and view all the answers

Match the following bony landmarks of the thigh with their descriptions:

Greater Trochanter = A prominent bony landmark on the femur Lateral Epicondyle = Located at the outer side of the knee Adductor Tubercle = Bony projection located on the femur Intertrochanteric Crest = Area between the greater and lesser trochanters Signup and view all the answers

What are the three compartments of the thigh?

Anterior, medial, and posterior compartments Signup and view all the answers

What is the primary function of the muscles in the anterior compartment of the thigh?

Extend the knee Signup and view all the answers

The iliotibial tract is a separate structure from the fascia lata.

False Signup and view all the answers

What nerve innervates the majority of the anterior thigh muscles?

Femoral nerve Signup and view all the answers

The femoral canal contains loose connective tissue and transmits ______.

lymphatics Signup and view all the answers

Which of the following muscles is the longest muscle in the body?

Sartorius Signup and view all the answers

What artery serves the anterior compartment of the thigh?

Femoral artery Signup and view all the answers

Which nerve primarily innervates the muscles of the medial thigh?

Obturator nerve Signup and view all the answers

What clinical significance does the gracilis muscle have?

It provides medial stability to the extended knee. Signup and view all the answers

Study Notes

Posterior Thigh

Primary function: knee flexion, hip extension
All muscles of the posterior thigh are innervated by the tibial nerve, except the short head of the biceps femoris, which is innervated by the common fibular nerve.
The Semitendinosus, Semimembranosus, and Biceps femoris are the three muscles of the posterior thigh
The Semitendinosus and Semimembranosus muscles extend the thigh, flex the leg, and rotate it medially when the knee is flexed.
When the thigh and leg are flexed, these muscles can extend the trunk.
The Semitendinosus muscle originates on the ischial tuberosity, and inserts on the medial surface of the superior part of the tibia.
The Semimembranosus originates on the ischial tuberosity and inserts on the posterior part of the medial condyle of the tibia, and its reflected attachment forms the oblique popliteal ligament.

Thigh Anatomy

The thigh is divided into three compartments: anterior, medial, and posterior.
Each compartment has specific innervation and blood supply.
The deep fascia of the thigh is called the fascia lata.
The fascia lata thickens along the lateral thigh to form the iliotibial tract (IT tract).
The gluteus maximus and tensor fascia lata insert into the IT tract, providing lateral stability to the pelvis.
The fascia lata blends with the crural fascia of the leg inferiorly.

Anterior Thigh

The muscles of the anterior compartment are primarily extensors of the knee and flexors of the hip.
All muscles of the anterior thigh are innervated by branches of the femoral nerve.
The blood supply is from the femoral artery.

Anterior Thigh Muscles

The iliopsoas arises from two muscles: iliacus and psoas major.
The iliacus is innervated by the femoral nerve, and the psoas is innervated by the ventral rami of L1-L3.
The psoas minor does not cross the hip joint.
The psoas major is the primary hip flexor past 90° of flexion.
The tensor fascia lata is functionally grouped with the gluteal muscles.
The sartorius is the longest muscle in the body.
The sartorius tendon inserts at the pes anserinus with the semitendinosus and gracilis.

Quadriceps Muscles

The quadriceps insert via a common tendon that splits to insert into the superior aspect of the patella, then rejoins to insert into the tibial tuberosity.
The patella helps align the forces of the four muscles and improves the lever arm.
The articularis genu arises from the inferior fibers of the vastus intermedius muscle and inserts into the superior part of the suprapatellar bursa.
The articularis genu raises the bursa superiorly during knee extension, preventing the synovium from getting caught.

Femoral Triangle

The femoral triangle is a space in the anterior thigh bounded laterally by the medial edge of sartorius, medially by the lateral edge of adductor longus, and superiorly by the inguinal ligament.
The apex of the triangle is formed where sartorius crosses adductor longus.
The floor of the femoral triangle is formed by the iliopsoas and pectineus.
The roof of the femoral triangle is made up of fascia lata perforated by vessels and nerves, called the cribriform fascia.

Femoral Triangle Contents

The femoral nerve and its branches are located within the femoral triangle.
The femoral sheath encases the femoral artery and its branches, the femoral vein and its tributaries, and the femoral canal.
The femoral canal contains loose connective tissue and transmits lymphatics from the lower extremity to the trunk.

Femoral Hernia

A femoral hernia occurs when abdominal contents herniate through the femoral ring, the superior opening of the femoral canal at the inguinal ligament.

Adductor Canal

The adductor canal is a tunnel formed by adductor longus/magnus (medially), vastus medialis (laterally), and sartorius (anteriorly).
The adductor canal contains the femoral artery and vein, and terminal portions of the femoral nerve (nerve to vastus medialis and saphenous nerve).

Medial Thigh

Most medial thigh muscles are innervated by the obturator nerve (except for part of adductor magnus and pectineus).
Most medial thigh muscles originate on the pubic body or rami and insert on the posterior femur.

Medial Thigh Muscles

The gracilis is the thinnest and weakest of the adductor muscles, and the only one to cross the knee.
The gracilis works with the other "pes anserinus" muscles to provide medial stability to the extended knee.

Blood Supply of Anterior and Medial Thigh

The femoral artery is the continuation of the external iliac artery as it passes under the inguinal ligament.
The femoral artery serves the anterior compartment and travels in the adductor/subsartorial canal.
The femoral artery becomes the popliteal artery after passing through the adductor hiatus.
The medial and lateral femoral circumflex arteries branch off the profunda femoris in the femoral triangle.
The profunda femoris artery branches off the femoral artery in the femoral triangle and supplies the adductors.

Innervation of Anterior and Medial Thigh

The femoral nerve emerges from the lumbar plexus.
The obturator nerve emerges from the lumbar plexus and descends through the pelvis.

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Description

Test your knowledge on the anatomy and functions of the posterior thigh muscles, including the Semitendinosus, Semimembranosus, and Biceps femoris. This quiz covers their innervation, origins, insertions, and actions in knee flexion and hip extension. Perfect for students of anatomy or physiology!