Muscles of the thigh Flashcards
What bones is the pelvic girdle composed of?
Sacrum (posteriorly)
Hip bone - ischium, ilium, pubis
Femur
What are the bones that fuse to make up the hip bone and what are the points where the hip bones articulate?
Ilium, ischium, pubis
- articulates with the sacrum at the sacro-iliac joints
- articulates with each other at the pubic symphysis
What is the orientation of the axis of the acetabulum? (which direction is it facing)
Lateral, downwards, and slightly posterior
What are the important landmarks of the top of the ilium?
- moving round to back from front ASIS (anterior superior iliac spine) Iliac tubercle (just posterior to ASIS) Iliac crest PSIS (posterior superior iliac spine)
What are the other important landmarks of the ilium?
Ala (wing of ilium, just the big wing of bone, not the name of the surfaces)
Iliac fossa (internal surface of ala
Posterior inferior iliac spine
Anterior inferior iliac spine
Greater sciatic notch (lesser SN is part of the ischium)
Arcuate line (just inferior to iliac fossa
What kind of joints are the sacro-iliac joints?
Synovial joints combined with fibrous joints
What kind of joint is the pubic symphysis?
Secondary cartilaginous joint
- ossifies with age, may expand in parturition (childbirth)
What are the important landmarks of the ischium?
Ischial tuberosity Lesser sciatic notch Body of ischium Ischial spine Ramus of ischium
What are important proximal attachment points for muscles on the external surface of the ilium?
Gluteus medius, minimus and part of gluteus maximus
What are important proximal attachment points for muscles on the external surface of the ilium?
Gluteus minimus - between anterior and inferior gluteal lines
Gluteus medius - between anterior and posterior gluteal lines
Gluteus maximus - posterior to the posterior gluteal line
Iliacus - from internal surface of the ilium
Sartorius - from ASIS
Rectus femoris - from AIIS (inferior spine)
What are important muscle attachments to the ischiopubic ramus and body of the pubis?
Adductor longus Adductor brevis Adductor part of adductor magnus Gracilis Pectineus
What are important muscle attachments to the ischial tuberosity?
Semimembranosus
Semitendinosus
Long head of biceps femoris
Part of adductor magnus
What are the two parts of the acetabulum?
Acetabular fossa (non-articular) Lunate surface (articular)
What is the function of the acetabular fossa?
Doesn’t articulate with anything but provides attachment point for the ligament of the head of the femur
Acetabular notch is continuous with the fossa and blood vessels/nerves pass through here
What does the lunate surface surround and what is its function?
Surrounds the anterior, superior and posterior margins of the acetabular fossa (not inferior - transverse acetabular ligament)
- articulates with head of the femur
What are the landmarks of the proximal end of the femur?
Head Neck Greater and lesser trochanters Intertrochanteric crest (posteriorly) Intertrochanteric line (anteriorly)
What are the features of the shaft of the femur?
Smooth anterior surface Gluteal tuberosity (posterior surface, superior to linea aspera) Linea aspera (medial and lateral lip)
What is the orientation of the head of the femur and why is this?
Directed superiorly, medially and slightly anteriorly (needs to fit into the acetabulum)
What is the anteversion of the femoral neck, what are the normal values for adults and children and what does a higher/abnormal anteversion angle cause?
Difference in angle between the axis of the femoral neck and the transcondylar axis of the knee
- adults = around 12 degrees
- birth = around 30-40, decreases with age up to 20 yrs old
A higher anteversion angle results in intoed feet (feet turned towards the midline)
What are the two layers of fascia over the thigh and what does one of the layers become?
Superficial - subcutaneous tissue
Deep - fascia lata, extends like a stocking beneath the skin from the pelvis down the leg
- this forms the iliotibial tract which is a lateral thickened stretch of fascia from the ischial tuberosity down to the lateral tibial condyle
What kind of joint is the hip joint?
Synovial ball-and-socket joint between head of femur and acetabulum
What is the rim of tissue around the acetabulum called and what ligament is found within the acetabulum?
Acetabular labrum
Transverse acetabular ligament on inferior border of acetabular fossa
Where does the capsule of the hip joint extend and does it extend further anteriorly or posteriorly?
Capsule of the hip joint extends down the neck of the femur and extends further anteriorly than posteriorly
Why is the capsule of the hip joint important and what medical terms have been derived from its importance?
Important blood supply to the head of the femur inside the capsule
- hip fractures are described as extracapsular or intracapsular to reflect whether the fracture disrupted this blood supply or not
What are the 4 important ligaments at the hip joint?
Ilio-femoral ligament (y-shaped, attaches at AIIS and femur)
Pubo-femoral ligament
Ischio-femoral ligament
Ligament of the head of the femur
What are the main arteries that supply the hip joint/head of the femur and what can happen in a hip fracture?
Medial and lateral circumflex arteries
- easily damaged in intracapsular fractures of the proximal femur which can lead to avascular necrosis of the femoral head
What structures pass through the greater sciatic foramen above the piriformis muscle?
Superior gluteal nerve, artery, vein
What structures pass through the greater sciatic foramen below the piriformis muscle?
Sciatic nerve
Inferior gluteal nerve, artery, vein
Pudendal nerve
Internal pudendal artery, vein
Nerve to obturator internus + superior gemellus
Nerve to quadratus femoris + inferior gemellus
(Posterior femoral cutaneous nerve)
What structures pass through the lesser sciatic foramen?
Obturator internus muscle tendon
Pudendal nerve and internal pudendal vessels pass into perineum from gluteal region (go through greater THEN lesser sciatic foramina)