Week 8 - The Gluteal Region (inc. Trendelenburg test) Flashcards
What are the actions of gluteus maximus?
Main extensor at the hip
Assists in lateral rotation
However:
Only acts when some degree of force is required in these motions, e.g. cycling
What nerve innervates the gluteus maximus?
The inferior gluteal nerve
Take care! Maximus does not mean superior!
What are the actions of gluteus medius and gluteus minimus?
Abduction
Medial rotation
Prevent pelvis dropping when the foot is lifted off the floor
What other muscle has the same actions as gluteus medius and gluteus minimus?
Tensor of fascia lata
What nerve innervates gluteus medius, gluteus minimus and tensor of fascia lata?
The superior gluteal nerve
Which muscles make up the deep compartment of the gluteal region?
Piriformis
Gemelli x2
Obturator internus
Quadratus femoris
What are the actions of piriformis? Which other muscles have these (and only these) actions?
Abduction and lateral rotation
Obturator internus
The Gemellis
What is the action of quadratus femoris?
Lateral rotation of the hip
Which nerve innervates the piriformis?
Nerve to piriformis
Which nerve innervates the Gemellis?
Superior gemelli - nerve to obturator internus
Inferior gemelli - nerve to quadratus femoris
Which nerve innervates obturator internus?
Nerve to obturator internus
What nerve innervates quadratus femoris?
Nerve to quadratus femoris
Where is the gluteal region found?
Posterior to the pelvic girdle, at the proximal end of the femur
What are the general actions of the superficial compartment of the gluteal region?
Abduct and extend the leg at the hip
What is the general action of the deep compartment of the gluteal region?
Lateral rotation
All but quadratus femoris also abduct
Which muscles make up the superficial compartment of the gluteal region?
Gluteus maximus
Gluteus medius
Gluteus minimus
Explain the pathophysiology behind a positive left Trendelenburg test.
When right leg lifted off floor, left gluteus medius and gluteus minimus should support pelvis on the right side. However, if the superior gluteal nerve is lesioned, these muscles are paralysed. Causes iliac crest to drop on right hand side, but as muscles are on left, it is positive on left.
Which muscles are paralysed if a Trendelenburg test is positive?
Gluteus medius and gluteus minimus
Why would gluteus medius and gluteus minumus be paralysed, as in a positive Trendelenburg test?
Lesion to the superior gluteal nerve
What does the Trendelenburg test look for?
Lesions of the superior gluteal nerve, resulting in glut med and min paralysis and hence pelvic drop
