Posterior Thigh Flashcards
What are the 3 posterior thigh muscles? What are they generally referred to as?
-Semitendinosus -Semimembranosus -Biceps Femoris (long head) -These are generally known as hamstrings (except biceps brevis)
Why is the biceps femoris not a hamstring muscle?
It crosses only the knee joint (others act on two joints) and is innervated by the fibular nerve (fibular division as opposed tibial division)
Innervation of the semitendinosus & semimembranosus muscles is supplied by which nerve?
Tibial division of sciatic nerve (L5, S1, S2)
Long head of biceps of femoris is supplied by which nerve fibre?
Tibial division of sciatic nerve (L5, S1, S2)
Short head of biceps femoris is supplied by which nerve fibre?
Common fibular division of sciatic nerve
Action of the semitendosus, semimembranosus and biceps femoris (long head) muscle? (2)
-Extension of thigh -Flexor of leg
Action of biceps femoris (short head)?
-Flexor of leg
Where does the sciatic nerve most commonly separate?
Inferior third of the thigh
Does the sciatic nerve contribute to innervation of the gluteal region?
No - it innervates the posterior thigh muscles, all leg and foot muscles and skin of most of leg and foot.
Gluteal region arteries emerge from which larger vessel?
Internal iliac
Posterior Cutaneous Nerve supplies which region of the thigh?
Skin of buttocks and over lateral perineum.
Pudendal nerve emerges from which levels? It enters the gluteal region through which foramen? To which area does it supply innervation?
Emerges from S2, S3, S4 (S2-S3-S4 keeps your guts off the floor), enters via the greater sciatic foramen, supplies most innervation to perineum (no structures in gluteal region)
List the structures as indicated
A = Biceps femoris (short & long heads)
B = Semitendinosus
C = Semimembranosus
