Gluteal Region and Hip - SDL Flashcards
What is the pelvic girdle?
A bony ring formed by the left and right innominate bones and the sacrum
What are the 4 articulations with the pelvis?
- 2x sacroiliac joints
- Sacrococcygeal symphysis
- Pubic symphysis
What does each innominate bone articulate with posteriorly?
The sacrum at the sacroiliac joint
What does each innominate bone articulate with anteriorly?
Each other at the pubic symphysis
How does the innominate bone develop?
Develops in the embryo as three separate bones – the ilium, ischium and pubic bone.
What is the area at which the ilium, ischium and pubis fuse?
Acetabulum - a ‘socket’ which articulates with the head of the femur to form the hip joint
What are the functions of the pelvis?
- Transfer of weight from the upper axial skeleton to the lower appendicular components of the skeleton, especially during movement.
- Provides attachment for a number of muscles and ligaments used in locomotion.
- Contains and protects the abdominopelvic and pelvic viscera.
What is the pubic symphysis?
A secondary cartilaginous joint between the 2 pubic bones
What is the pubic symphysis made of?
The articular surfaces are covered by a layer of hyaline cartilage and are connected by a fibrocartilaginous disc.
In the latter stages of pregnancy, the pelvis of the mother-to-be undergoes changes – what are these and why are they necessary?
Elasticity of the symphysis pubic joint and pelvis ligaments is increased à allowing expansion of pelvic outlet.
Why can major pelvic fractures be fatal?
The pelvis supports many internal organs and this can damage these organs
The pelvic girdle is strengthened by very strong ligaments. What are these?
Sacrospinous and sacrotuberous ligaments
What are the sacrotuberous and sacrospinous ligaments attachments between?
Between the sacrum and the innominate bones
In addition to providing stability, what do these ligaments transform the greater and lesser sciatic notches of the ischium into?
The greater and lesser sciatic foramina
What do the foramina allow?
They allow important structures, including vessels and nerves, to pass between the inside of the pelvis and the gluteal region
What does the femur articulate with proximally?
The acetabulum to form the hip joint
What does the femur articulare with distally?
The tibia to form the knee joint
Femur labelled diagram
What type of joint is the hip joint?
Ball and socket (synovial) formed by the articulation between the acetabulum of the pelvis (innominate bone) and the head of the femur.
Why is the hip joint a stable joint? What factors contribute to stability?
Stable:
- Good fit
- Acetabular labrum
- Strong joint capsule
- Surrounding ligaments and muscles
Mobility:
- Ball and socket joint
Diagram of internal structure of hip joint
Diagram of iliofemoral, pubofemoral and ischiofemoral ligament
What are the main arteries delivering blood to the hip?
- The medial and lateral circumflex arteries - these anastamose around the hip joint
- (There is also a good contribution from the obturator artery)
What are the medial and lateral circumflex arteries branches of?
The profunda femoris (deep artery of the thigh)
What may fractures of the femoral neck lead to?
Fractures of the femoral neck which disrupt the blood supply to the head of the femur may lead to avascular necrosis of the femoral head
What movements are possible at the hip joint?
- Flexion
- Extension
- Adduction
- Abduction
- Medial rotation
- Lateral rotation
- (Circumduction)
What are the 2 groups of muscles in the gluteal region?
Superficial and deep
How do the superficial gluteal muscles generally move the hip?
Generally extend, abduct or rotate the hip
How do the deep gluteal muscles generally move the hip?
Generally act as rotators of the hip
What do the superficial muscles in the gluteal region consist of?
- 3 glutei
- Gluteus maximum
- Gluteus medius
- Gluteus minimus
- Tensor fascia lata (TFL)
Order of glutei muscles from superficial to deep?
- Gluteus maximus
- Gluteus medius
- Gluteus minimus
Why is gluteus maximum often used as a site for placing intramuscular injections?
Gluteus maximus is the largest and most superficial muscle of the buttock
What are the actions of gluteus maximus?
It is the main extensor of the thigh, and assists with lateral rotation. However, it is only used when force is required, such as running or climbing.
Origin and insertion of gluteus maximus?
Origin: sacrum, sacrotuberous ligament
Insertion: iliotibial tract and the gluteal tuberosity of the femur
Innervation of gluteus maximus?
Inferior gluteal nerve.
What is the iliotibial tract?
a lateral thickening of the fascia lata.
What is the fascia lata? What is the function of the iliotibial tract?
Fascia lata is the deep fascia of the thigh.
The iliotibial tract acts to stabilise the hip and knee, and originates from the gluteus maximus and tensor fascia lata.
Labelled diagram of gluteus medius and minimus
Origin and insertion of gluteus medius?
Origin: the gluteal surface of the ilium
Inserts: into the lateral surface of the greater trochanter
Origin and insertion of gluteus minimus?
Origin: from the ilium and converges to form a tendon
Inserts: the anterior side of the greater trochanter.
Which nerve innervates both gluteus medius and minimus? Which spinal nerves contribute to this nerve?
Superior gluteal nerve. L4-S1.
Actions of gluteus medius and minimus?
Abducts and medially rotates the leg
When one leg is being abducted away, how does the pelvis stay level? What is this important for?
The pelvis stays ‘level’ because the hip abductors on the right - the ‘stance’ limb – contract and pull on the right side of the pelvis, making sure that the pelvis doesn’t tilt down to the left.
This action is extremely important for normal gait – when we’re walking, most of the time we only have one foot or the other on the ground.
What causes a ‘waddling’ gait. What is this called?
The Trendelenburg sign – seen if the abductors on one side are paralysed.
What is tensor fascia lata?
Is considered a muscle of the superficial gluteal region
Origin and insertion of tensor fascia lata?
Origin: ASIS
Inserts: into the iliotibial tract
Action of tensor fascia lata?
When it contracts it tenses the fascia lata and the iliotibial tract (as the iliotibial tract inserts onto the lateral tibia): this is extremely important for stabilising the extended knee. It also contributes to flexion of the hip joint
Innervation of tensor fascia lata?
Superior gluteal nerve
What are the actions of the deep gluteal muscles?
These are lateral rotators of the hip (similat to the rotator cuff muscles in the shoulder)
What are the deep gluteal muscles?
- Piriformis
- Obturator internus
- Quadratus femoris
- Superior gemellus
- Inferior gemellus
Diagram of deep gluteal muscles
Where do the deep gluteal muscles generally arise/insert?
They arise from the posterior parts of the pelvis, and insert, generally, on the more posterior regions of the proximal femur
Which muscle acts as an important landmark for the identification of vessels and nerves of the gluteal region?
Piriformis
Origin and insertion of piriformis?
Originates from within the pelvis and passes out into the gluteal region through the greater sciatic foramen
Origin: anterior surface of the sacrum. It then travels infero-laterally, through the greater sciatic foramen
Inserts: into the greater trochanter of the femur.
Action of piriformis?
Lateral rotation and abduction.
Innervation of piriformis?
The muscle is innervated by the ventral rami of S1 and S2 (and L5 to a lesser extent), which join to form the nerve to the piriformis.
How does the sciatic nerve exist the pelvis (in relation to piriformis)?
Emerges from the pelvis through the greater sciatic foramen –> inferior to the lower border of piriformis
Origin and insertion of the gemelli?
Origin: The superior gemellus muscle originates from the ischial spine, the inferior from the ischial tuberosity.
Insert: They both attach to the greater trochanter of the femur.
Action of the gemelli?
Lateral rotation and abduction.
Origin and insertion of obturator internus?
Origin: Originates from the pubis and ischium at the obturator foramen. It travels through the lesser sciatic foramen.
Inserts: attaches to the greater trochanter of the femur.
Action of obturator internus?
Lateral rotation and abduction
Origin and insertion of quadratus femoris?
Origin: It originates from the lateral side of the ischial tuberosity
Insert: attaches to the quadrate tuberosity on the intertrochanteric crest.
Action of quadratus femoris?
Lateral rotation
How do the vessels and nerves that supply the gluteal region enter and exit the pelvis? What is an important landmark for this?
Via the sciatic foramina.
Piriformis is an important landmark for some of these structures, which enter the gluteal region either superior, or inferior, to the muscle
Diagram of the major arteries and nerves of the gluteal region
What structures emerge superior to piriformis?
Superior gluteal nerve and superior gluteal vessels.
What structures emerge inferior to piriformis?
Inferior gluteal nerve and vessels and the sciatic nerve
What is the vascular supply of the gluteus maximus, medius and minimus muscles? Which larger vessels do these arteries branch from?
- Gluteus maximus: supplied by the superior and inferior gluteal artery
- Gluteus medius: inferior gluteal artery
- Gluteus minimus: inferior gluteal artery
The superior gluteal artery is the largest branch of the internal iliac artery and arises from its posterior division.
The inferior gluteal artery originates from the anterior division of the internal iliac artery.
Which larger veins do the gluteal veins drain into?
They drain into the internal iliac vein
Which nerves accompany the gluteal vessels and what spinal nerves contribute to them?
Superior gluteal nerve:
- Is accompanied by the superior gluteal artery and vein for much of its course
- Roots: L4, L5, S1
Inferior gluteal nerve:
- Is accompanied by the inferior gluteal artery and vein for much of its course
- Roots: L5, S1, S2
Sciatic nerve:
- Roots: L4, L5, S1, S2, S3
Looking at the diagram, can you explain why, when giving an intramuscular injection into the buttock, you must always place it in the upper, lateral quadrant of the buttock?
The upper outer quadrant of this area must be used to avoid any damage to the sciatic nerve
What muscle is the principal flexor of the hip joint?
Iliopsoas
origin of psoas major?
The psoas major originates from the lumbar vertebrae
Innervation of psoas major?
anterior rami of L1-3
Origin of iliacus?
Iliacus originates from the iliac fossa of the pelvis
Innervation of iliacus?
femoral nerve
Where does iliacus and psoas major insert?
These muscles insert onto the lesser trochanter of the femur
Under what structure do these muscles (iliacus and psoas major) pass on their way from the pelvis into the anterior thigh?
Inguinal ligament
Iliopsoas forms the lateral part of the ‘floor’ of which important neurovascular region in the anterior thigh?
Femoral triangle
What muscles are involved in flexion at the hip?
Iliopsoas, sartorius, rectus femoris, adductor magnus (adductor component)
What muscles are involved in adduction at the hip?
Adductor magnus, adductor longus, adductor brevis, pectineus
What muscles are involved in lateral rotation at the hip?
Piriformis, obturator internus, the gemelli, quadratus femoris, sartorius
What muscles are involved in abduction at the hip?
Piriformis, obturator interus, the gemelli, sartorius, gluteus medius, gluteus minimus
What muscles are involved in extension at the hip?
Gluteus maximus, adductor magnus (hamstring portion)
What muscles are involved in medial rotation at the hip?
Gluteus medius, gluteus minimus, (tensor fascia lata)
Is this a right or a lieft hip?
Right
Identify muscle 2, 3 and 4
2 - Gluteus medius
3 - Gluteus maximus
4 - Piriformis
Tensor fascia lata attaches to what landmark?
2 - ASIS
Landmark number 5 is the …
Ischial tuberosity
Where does muscle 2 insert?
On the greater trochanter
Name muscles 1, 2, 3, 4 and 7
1 - Piriformis
2 - Superior gemellus
3 - Tendon of obturator internus
4 - Inferior gemellus
7 - Quadratus femoris
The nerve indicated by the number 6 is typically formed by which spinal nerves?
L4-S3
Muscle 3 inserts distally into the … ?
What blood vessel supplies muscle 3?
Gluteal tuberosity and iliotibial tract
Inferior gluteal artery
What is the common hamstring origin?
Ischial tuberosity
The muscle indicated by the number 1 originates from the…
Anterior surface of the sacrum
What is structure 5? How does it leave the pelvis?
Sciatic nerve - leaves the pelvis via the greater sciatic foramen
Name 1-8
1 - Piriformis
2 - Superior gemellus
3 - Tendon of obturator internus
4 - Inferior gemellus
5 - Sacrotuberous ligament
6 - Sciatic nerve
7 - Quadratus femoris
8 - ischial tuberosity
Iliopsoas inserts onto which landmark?
6
Identify muscle 2.
What is 3? What inserts into it? What is its function?
2 - tensor fascia lata
3 - iliotibial tract: gluteus maximus and tensor fascia lata insert into it, it stabilises the knee joint
What are the lateral rotators of the hip joint?
- Obturator internus
- Piriformis
- Superior and inferior gemelli
- Quadratus femoris
- Gluteus maximus
What is 5? What are its attachments?
Sacrotuberous ligament - attaches from the sacrum to the ischial tuberosity
The muscle indicated by number 3 emerges into the gluteal region via the?
Lesser sciatic foramen
Vessel number 1 is a branch of the?
Internal iliac artery
How does muscle 2 act upon the hip?
Medial rotator and abductor
Which muscles inserts into region 9?
Gluteus maximus
Which nerve innervates muscle 2?
Superior gluteal nerve
What passes through the greater sciatic foramen?
- Piriformis
- Sciatic nerve
- Superior gluteal nerve, artery and vein
- Pudendal nerve
- Inferior gluteal nerve, artery and vein
Which gluteal muscles insert in the region indicated by the number 2?
- Inferior gemellus
- Superior gemellus
- Obturator internus
What is the obturator artery a branch of?
The internal iliac artery
Which vessel typically gives rise to the medial and lateral circumflex arteries of the hip joint?
Profunda femoris
