Anatomy dissection notes 3

Question 1

What part of the lower limb does the sciatic nerve supply and then what does its branches supply ?

Answer 1

• Sciatic nerve - supplies posterior compartment of the thigh
• Braches (tibial and fibular) - supplies all the compartments of the leg, and the intrinsic muscles of the foot

Question 2

What does the sciatic nerve branch into and where does this occur ?

Answer 2

• Branches into the common fibular and tibial nerves
• Occurs anywhere between gluteal region and popliteal fossa - most commonly inferior 1/3rd of the thigh

Question 3

What are the muscles of the posterior compartment of the thigh ?

Answer 3

Collectively known as the hamstrings:

• Semimembranosus
• Semitendinosus (medially)
• The long and short heads of biceps femoris (laterally).

Question 4

What is the function of the hamstring muscles (posterior compartment of the thigh)?

Answer 4

The span the hip and knee joint and act to extend and flex these joints respectively.

Question 5

3 of the 4 hamstring muscles attach to the ischial tuberosity proximally - which one does not ?

Answer 5

The short head of the biceps femoris

Question 6

Which of the hamstring muscles is not considered a true hamstring muscle and why ?

Answer 6

The short head of the biceps femoris

Because:

1. It attaches proximally to the linea aspera of the femur, not to the ischial tuberosity.
2. It does not cross the hip joint and therefore does not contribute to the movement of the hip joint.
3. It supplied by the common fibular branch of the sciatic nerve rather than the tibial branch.

Question 7

Describe the nerve supply of the posterior compartment of the thigh

Answer 7

All the hamstrings are supplied by the tibial branch of the sciatic nerve except the short head of the biceps femoris

Question 8

What does the long and short head of the biceps femoris attach too ?

Answer 8

Attaches to the lateral aspect of the head of the fibula

Question 9

What does the semimembranous and semitendinous muscles attach to distally ?

Answer 9

The proximal tibia (remember makes sense where they took the semitendinous for your ACL graft

Question 10

Describe the appearance of the semitendinous and semimembranous muscles

Answer 10

• Semitendinous - has a longer tendon than the other muscles
• Semimebranous - has a shiny membranous appearance.

Question 11

Describe the main structures of the hip joint

Answer 11

• The hip joint consists of an articulation between the head of femur and acetabulum of the pelvis.
• The acetabulum is a cup-like depression located on the inferolateral aspect of the pelvis. Its cavity is deepened by the presence of a fibrocartilaginous collar – the acetabular labrum.
• The ligament of the head of the femur attaches femur to depth of acetabulum and is ruptured during dislocation.