POSTERIOR THIGH MUSCLES (HAMSTRINGS) Flashcards
- semitendinosus
- semimembranosus
- biceps femoris
these muscles are known collectively as the**
hamstring muscles
hamstring muscles have a common origin (except the short head of the biceps femoris) from the….**
ischial tuberosity
hamstring muscles are all supplied by what nerve
sciatic nerve (L4-S3)
the muscle is situated on the medial-posterior aspect of the femur
it is medial to the biceps femoris and is superficial to the semimembranosus
its tendon of insertion is very long and thus gives the muscle its name
Semitendinosus
Semitendinosus origin:
ischial tuberosity
Semitendinosus insertion:
medial condyle/ tibia
Semitendinosus action:
flexion at the leg at the knee
Semitendinosus nerve supply:
sciatic nerve (L4-S3)
this is the name given to describe the tendons of insertion of the semitendinosus, gracilis and sartorius
the name translates to “Goose’s Foot”**
Pes Anserinus
this muscle is named because of the flattened nature of the its proximal attachment
proximally it lies deep to the semitendinosus
Semimembranosus
Semimembranosus origin:
ischial tuberosity
Semimembranosus insertion:
medial condyle/ tibia
Semimembranosus action:
flexion at the leg at the knee
Semimembranosus nerve supply:
sciatic nerve (L4-S3)
this is the most laterally situated of the hamstring muscles
Biceps Femoris
Biceps Femoris origin:
ischial tuberosity (L.H.)
Linea Aspera (S.H.)
Biceps Femoris insertion:
head/fibula
lateral condyle/tibia
Biceps Femoris action:
flexion at the leg at the knee
Biceps Femoris nerve supply:
sciatic nerve (L4-S3)
the length of the muscles will vary considerable from one individual to another
in some individuals they are not long enough to allow someone to touch their toes when they flex their
vertebral column and keep their legs from flexing at the knee joint
in other individuals, this muscle is long and flexible enough that these individuals can easily touch
their toes with little or no flexion at the knee joint
Length of the Hamstrings
is a common sports injury
it is twice as common as strains of the quadriceps
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seen in athletes who run very hard and have quick starts
Pulled Hamstring
may result from forcible flexion of the hip when the knee is extended**
Avulsion of the Ischial Tuberosity
Actions of the hamstrings
All muscles:**
Flexion of the leg at the knee joint
Actions of the hamstrings
All except the short head of the biceps femoris**
- stabilize the hip joint
- extension of the femur
Actions of the hamstrings
The semitendinosus and semimembranosus also**
medialy rotates the leg
Actions of the Hamstrings
The biceps femoris also**
laterally rotates the leg
the body may compensate by changing the position of the pelvic bone
this can place stress on other muscles in the area and may compress spinal nerves
Weak or Tight Hamstrings
