The Pelvis and Hip Flashcards
What are the 4 regions of the lower limb?
- Gluteal region
- Thigh
- Leg
- Foot
What 3 important neurovascular spaces are found in the lower limb?
- Femoral triangle (groin)
- Popliteal fossa (behind knee)
- Tarsal tunnel (posterior to medial ankle)
What is the most commonly replaced joint in the body?
Hip
What bones make up the pelvis?
3 bones:
- Sacrum
- Right and left innominate bones (right and left ‘hip bones’)
How does the pelvis remain abnchored to the axial skeleton?
Via extremely strong and stable joints between the sacrum and each innominate bone: the sacroiliac joints
What does the head of the femur articulate with?
The acetabulum of the pelvis at the hip joint
Articulation between inomminate (hip) bone and sacrum
At the sacroiliac joint
Where do the 2 inomminate bones articulate with each other anteriorly?
At the pubic symphysis
What is this highlighted region?
Pelvic brim
Diagram of the iliac crest
What is the highlighted region?
Greater sciatic notch
What is the highlighted projection of bone?
Ischial spine
What are the highlighted regions?
superior and infreior pubic rami
Diagram of pelvis
What is the highlighted region?
Body of the pubis
Diagram of the pubic tubercle
Name the highlighted region
Obturator foramen (superior pubic ramus above it and inferior pubic ramus below it)
Label
Sacrum (orange)
Posterior aspect of iliac crest (light blue)
Greater sciatic notch (black)
Ischial spine (pink)
Ischial tuberosity (blue)
Bony landmarks of pelvis from lateral angle
What 3 bones come together during development and fuse to form the inomminate bone?
- Ilium (lies speriorly)
- Ishium (posterior)
- Pubic bone (anterior)
What is the point at which the ilium, ischium and pubic bone fuse?
Acetabulum
What are hip fractures?
Fractures of the neck of the femur
What is found below the head of the femur?
The neck of the femur
What does the proximal aspect of the femur articulate with?
The acetabulum of the pelvis to form the hip joint
What is the greater trochanter?
- The most lateral palpable projection of bone that originates from the anterior aspect, just lateral to the neck
- Site of attachment to many muscles in the gluteal region
i.e. similar to greater tubercle of humerus
What is the lesser trochanter?
Smaller than the greater trochanter. It projects from the posteromedial side of the femur, just inferior to the neck-shaft junction
Posterior diagram of femur
What is the intertrochanteric line?
A ridge of bone that runs in an inferomedial direction on the anterior surface of the femur, spanning between the two trochanters.
Name the highlighted landmarks
- Blue –> iliac crest
- Black –> neck of femur
- Pink –> iscial spine
- Yellow –> ischial tuberosity
- Purple –> inferior pubic ramus
- Pink –> greater trochanter
- Blue –> lesser trochanter
- Orange line –> intertrochanteric crest
What is the intertrochanteric crest?
Like the intertrochanteric line, this is a ridge of bone that connects the two trochanters but is located on the posterior surface of the femur
Difference between the intertrochanteric line and intertrochanteric crest?
Line –> anterior aspect
Crest –> posterior aspect
What is the trochanteric fossa?
What is the gluteal tuberosity?
Point of attachment of gluteus maximus
What type of joint is the hip joint?
Ball and socket –> very stable
Why is the hip joint so stable?
- Good fit
- Acetabular labrum
- Strong joint capsule
- Surrounding ligaments
- Muscles also add stability
What are the 2 bony ridges connecting the 2 trochanters?
- The intertrochanteris line anteriorly
- The trochanteric crest posteriorly
What is the acetabulr labrum?
Attaches from the acetabulum (pelvis) to the intertrochanteric line (proximal femur)
What is the purpose of the acetabular labrum?
Deepens the acetabulum
What are the 2 ligaments in the pelvis?
- Sacrospinous ligament
- Sacrotuberous ligament
Both are extremely strong
Where is the sacrospinous ligament?
Runs from sacrum to the ischial spine
What does the sacrospinous ligament form?
The greater sciatic foramen
Where is the sacrotuberous ligament?
Runs from the sacrum to the ischial tuberosity
What does the sacrotuberous ligament form?
The lesser sciatic foramen
What important nerve passes through the greater sciatic foramen?
The sciatic nerve (amongst other things)
Describe route of sciatic nerve
Passes from inside the pelvis out into the limb via the greater sciatc foramen
What are the 3 hip ligaments?
- Pubofemoral
- Iliofemoral
- Ischiofemoral
Attachments of the pubofemoral ligament (green)? What is its function?
- Between superior pubic rami and intertrochanteric line of the femur
- Reinforces capsule anteriorly and inferiorly
- Has a triangular shape
- Prevents excessive abduction and extension
Attachments of the iliofemoral (orange)? Function?
- From anterior inferior iliac spine, then bifurcates before inserting into the intertrochanteric line of the femur
- ‘Y shaped’ appearance
- Prevents hyperextension of the hip joint
- Supports superiorly and anteriorly
- Strongest ligament of the hip
Attachment of the ischiofemoral ligament (pink)? Function?
- Between body of ischium and greater trochanter of femur
- Reinforces capsule posteriorly
- Prevents hyperextension
- Holds femoral head in the acetabulum
- Weakest ligament
What are the movments at the hip joint?
- Flexion
- Extension
- Abduction
- Adduction
- Medial rotation
- Lateral rotation
- Circumduction –> combination movement achieved for very supple/fit/flexible people
Where do hip extensor muscles generally lie? Flexors?
Extensors generally lie posterior to hip joint
Flexors generally lie anteriorly
Where do abductors of the hip generally lie? Adductors?
Abductors –> lateral
Adductors –> medial
Where do medial and lateral rotators of the hip generally lie?
Medial rotators –> anterior/lateral
Lateral rotators –> posterior/lateral
What are most of the hip flexors innervated by?
Femoral nerve (L2-L4)
What muscle is the prime flexor of the hip?
Iliopsoas (lies within abdomen/pelvis)
What other muscles contribute to hip flexion?
- Iliopsoas
- Rectus femoris
- Sartorius
- Pectineus
What is iliopsoas made up of?
Made up of 2 muscles; psoas major and iliacus. These originate in different areas, but come together to form a tendon.
Where does iliopsoas insert?
On the lesser trochanter
Where does psoas major originate? Where does iliacus originate? Where do they both insert?
The psoas major originates from the lumbar vertebrae, and the iliacus originates from the iliac fossa of the pelvis. They insert together onto the lesser trochanter of the femur.
What structure does iliopsoas travel under?
Under the inguinal ligament
What are the attachments of the inguinal ligament?
ASIS to the pubic tubercle
What nerve travels between iliacus and psoas major and under the inguinal ligament?
Femoral nerve (purple)
Label diagram
- Inguinal ligament (black)
- Iliacus (yellow)
- Psoas major (blue)
- Femoral nerve
All travel under the inguinal ligament into the proximal part of the thigh.
What is the action of iliopsoas?
Flexes the thigh at the hip joint
Where do the other hip flexors lie?
In the anterior thigh
What is iliopsoas innervated by?
Psoas major is innervated by anterior rami of L1-L3
Iliacus is innervated by the femoral nerve
What are the attachments of pectineus?
It originates from the pectineal line on the anterior surface of the pelvis, and attaches to the pectineal line on the posterior side of the femur, just inferior to the lesser trochanter.
(shown in purple)
Action of pectineus?
Adduction and flexion at the hip joint
Innervation of pectineus?
Femoral nerve
What are the attachments of rectus femoris?
AIIS –> tibial tuberosity
(orange)
What are the actions of rectus femoris?
Flexes the thigh at the hip joint, and extends at the knee joint
What is the innervation of rectus femoris?
Femoral nerve
What are the attachents of sartorius?
Runs across the thigh in an interomedial direction and crosses knee.
- Originates from ASIS and attaches to the superior, medial turface of the tibia
- (shown in blue)
What are the actions of sartorius?
At the hip joint; it is a flexor, abductor and lateral rotator.
At the knee joint: it is a flexor.
Innervation of sartorius?
Femoral nerve
What are the attachments of tensor fascia latae?
Laterally positioned muscle.
- Originates from ASIS and inserting into the iliotibial tract
- Shown here laterally in green
What are the actions of tensor fascia latae?
Assists the gluteus medius and minimus in abduction and medial rotation of the lower limb. It also plays a supportive role in the gait cycle.
Innervation of tensor fascia latae?
Superior gluteal nerve
Label the highlighted muscles
- Purple: pectineus
- Orange: rectus femoris
- Blue: sartorius
- Green: tensor fascia latae
Where do extensors of the hip lie?
Behind the hip joint
What are the 2 main hip extensors?
- Gluteus maximum
- ‘Hamstrings’
Describe the gluteus maximus
The gluteus maximus is the largest of the gluteal muscles. It is also the most superficial, producing the shape of the buttocks.
What are the attachments of gluteus maximus?
Origin: Originates from the gluteal (posterior) surface of the ilium, sacrum and coccyx.
It slopes across the buttock at a 45 degree angle.
Inserts:
- Sends most fibres to insert onto the iliotibial tract
- Sends some fibres to insert onto the gluteal tuberosity of the femur
What is gluteus maximum innervated by?
Inferior gluteal nerve (L5, S1, S2)
What are the actions of gluteus maximum?
- Main extensor of the thigh
- Assists with lateral rotation (only when required e.g. running/climbing)
What is circled in black?
Ischial tuberosity
Where do the hamstring muscles originate?
Ischial tuberosity
Where do abductors of the hip lie?
Lie posterolateral to the joint (gluteal region)
Which muscles mainly abduct the hip?
Gluteus medius and gluteus minimus
What are gluteus medius and gluteus minimum innervated by?
Superior gluteal nerve (L4, L5, S1)
Attachments of gluteus medius?
- Originates from gluteal surface of ilium (shown in green)
- Insert onto lateral surface of greater trochanter
Actions of gluteus medius?
Abducts and medially rotates the lower limb. During locomotion, it secures the pelvis, preventing pelvic drop of the opposite limb
Attachments of gluteus minimus?
Deepest and smallest of the superficial gluteal muscles.
- Originates from ilium
- Converges to form a tendon, inserting to the anterior side of the greater trochanter (shown in pink)
Actions of gluteus minimus?
Abducts and medially rotates the lower limb. During locomotion, it secures the pelvis, preventing pelvic drop of the opposite limb.
Where do the adductors of the hip lie in relation to the joint?
Lie medial to the joint (thigh)
What are most of the adductors of the hip innervated by?
Mostly by obturator nerve (L2-L4)
What muscles make up the adductor group of the hip?
- Adductor brevis
- Adductor longus
- Adductor magnus (2 parts)
All insert on posterior aspect of the femur (different insertion points)
What other muscles make up the medial compartment of the thigh?
- Obturator externus
- Gracilis
- Pectineus
Where do the lateral rotators of the hip lie?
Lie deep in the gluteal region
Where do the lateral rotators of the hip insert?
Insert on the posterior aspect of the femur
What muscles in the shoulder region can the lateral rotators of the hip be compared to?
Shoulder cuff muscles
What muscles make up the lateral rotators (deep gluteal muscles)?
- Piriformis
- Obturator internus
- The Gemelli - superior and inferior
- Quadratus femoris
N.B. gluteus maximum also rotates