Posterior Thigh Muscles Flashcards
What are the muscles in the posterior compartment of the thigh known as?
The hamstrings
What do the hamstrings consist of?
Biceps femoris Semitendinosus
Semimembranosus
What do the hamstrings do as a group?
Extend at the hip and flex at the knee
What are the hamstrings innervated by?
The sciatic nerve (L4-S3) as it descends through the thigh
What to the hamstrings form?
Prominent tendons medially and laterally at the back of the knee
What does the biceps femoris have?
Two heads, a long and a short
Where does the biceps femoris lie?
More laterally
Where can the common tendon of the two heads be felt?
Laterally at the posterior knee
What happens to the biceps tendon at the lateral side of the head of the femur?
It is split by the fibular collateral ligament of the knee
What is the innervation of the long head of the biceps femoris?
Tibial division of the sciatic nerve (L5, S1, S2)
What is the innervation of the short head of the biceps femoris?
Common fibular division of the sciatic nerve (L5, S1, S2)
What is the arterial supply of the biceps femoris?
Perforating arteries of the deep femoral artery
What is the main action of the biceps femoris?
Flexes leg and laterally rotates it when the knee is flexed
Extends thigh
What can be said of the semitendinosus?
It is a largely tendinous muscle
Where does the semitendinosus muscle lie?
Medially to the biceps femoris
What does the semitendinosus cover?
The majority of the semimembranosus
What do the semitendinosus and semimembranosus share?
Innervation
Action
Arterial supply
Proximal attachment
What shape is the semimembranosus?
Flattened, broad
Where is the semimembranosus muscle located?
Underneath the semitendinosus
What does the reflected attachment of the semimembranosus form
The oblique popliteal ligament to lateral femoral condyle
What is the innervation of the semitendinosus and semimembranosus?
Tibial division of the sciatic nerve part of tibia (L5, S1, S2)
What is the arterial supply of the semitendinosus and semimembranosus?
Perforating arteries of deep femoral arteries
What is the main action of thesemitendinosus and semimembranosus?
Extend thigh
Flex leg and rotate it medially when knee is flexed
When knee and leg are flexed, can extend trunk
What does a hamstring strain refer to?
Excessive stretch or tearing of the muscle fibres
What is damage to the hamstring muscle fibres likely to do?
Rupture surrounding blood vessels, causing a haemotoma
What contains a haemotoma formed by hamstring strain?
The overlying fascia lata
When does an avulsion fracture occur?
When a fragment of bone breaks away from the main body of bone
What happens in an avulsion fracture of the ischial tuberosity?
The hamstring tendons ‘tear off’ a piece of the ischial tuberosity
