S3) The Hip

Question 1

What is the hip joint?

Answer 1

The hip joint is a ball and socket synovial joint which connects the lower limb to the pelvic girdle

Question 2

Describe the articulating surfaces of the hip joint

Answer 2

• Head of femur articulates with the acetabulum of the pelvis
• Acetabular labrum is a fibrocartilaginous collar which deepens the concavity

Question 3

Describe the arterial supply of the hip joint

Answer 3

Arterial supply via the medial and lateral circumflex femoral arteries which are branches of the profunda femoris artery

Question 4

What is the clinical significance of the medial circumflex artery?

Answer 4

• Medial circumflex femoral artery is responsible for the majority of the arterial supply (lateral artery has to penetrate through the thick iliofemoral ligament)
• Damage to the medial circumflex femoral artery can result in avascular necrosis of the femoral head

Question 5

Describe the innervation of the hip joint

Answer 5

The hip joint is innervated by the femoral nerve, obturator nerve, superior gluteal nerve, and nerve to quadratus femoris

Question 6

The only intracapsular ligament of the hip is the ligament of the head of the femur.

Describe its structure, function and anatomical location

Answer 6

• Structure: relatively small ligament
• Function: increases stability, encloses a branch of the obturator artery (artery to head of femur)
• Location: runs from the acetabular fossa to the fovea of the femur

Question 7

Identify the 3 extracapsular ligaments of the hip joint

Answer 7

• Iliofemoral ligament
• Pubofemoral ligament
• Ischiofemoral ligament

Question 8

Describe the structure, function and location of the iliofemoral ligament

Answer 8

• Structure: ‘Y’ shaped appearance
• Function: prevents hyperextension of the hip joint
• Location: spans between the anterior inferior iliac spine and the intertrochanteric line of the femur

Question 9

Describe the structure, function and location of the pubofemoral ligament

Answer 9

• Structure: triangular shape
• Function: prevents excessive abduction and extension
• Location: spans between the superior pubic rami and the intertrochanteric line of the femur

Question 10

Describe the structure, function and anatomical location of the ischiofemoral ligament

Answer 10

• Structure: spiral orientation
• Function: prevents excessive extension
• Location: spans between the body of the ischium and the greater trochanter of the femur

Question 11

Identify and describe the factors that stabilise the hip joint

Answer 11

• Acetabulum – encompasses nearly all of the femoral head (decreases chance of dislocation)
• Acetabular labrum – increases depth provides a larger articular surface
• Intracapsular & extracapsular ligaments
• Joint capsule

Question 12

Explain how the muscles and ligaments work in a reciprocal fashion at the hip joint

Answer 12

• Anteriorly, where the ligaments are strongest, the medial flexors are fewer and weaker

- Posteriorly, where the ligaments are weakest, the medial rotators are greater in number and stronger

Question 13

Identify the possible movements at the hip joint as well as the muscles involved

Answer 13

- Flexion: iliopsoas, rectus femoris, sartorius

- Extension: gluteus maximus, semimembranosus, semitendinosus, biceps femoris

- Abduction: gluteus medius, gluteus minimus and deep gluteals

- Adduction: adductors longus, brevis & magnus, pectineus, gracillis

- Lateral rotation: biceps femoris, gluteus maximus, deep gluteals

- Medial rotation: gluteus medius & minimus, semitendinosus, semimembranosus

Question 14

Identify and describe the three articulations of the hip bone

Answer 14

• Sacroiliac joint – articulation with sacrum
• Pubic symphysis – articulation with the corresponding hip bone
• Hip joint – articulation with the head of femur

Question 15

Which three parts compose the hip bone?

Answer 15

Question 16

How do the bones composing the hip joint vary before and after puberty?

Answer 16

• Prior to puberty, the triradiate cartilage separates these constituents
• After age 15-17 the three parts begin to fuse (forms acetabulum)

Question 17

The superior part of the hip bone is formed by the ilium, the widest and largest of the three parts.

Describe its structure

Answer 17

• Body: forms the superior part of the acetabulum
• Wing: expansion above the acetabulum
• Iliac fossa: concave inner surface
• Gluteal surface: convex external surface
• Iliac crest: thickened superior margin (extends from ASIS to PSIS)

Question 18

Which muscles attach to the ilium?

Answer 18

• Gluteal muscles attach to the gluteal surface of the Ilium (at anterior, posterior and inferior gluteal lines)
• Iliacus muscle attaches medially at the iliac fossa

Question 19

Why is the anterior superior iliac spine clinically relevant?

Answer 19

The ASIS serves as the attachment site of the inguinal ligament, which runs from the ASIS to the pubic tubercle

Question 20

The most anterior portion of the hip bone is formed by the pubis

Describe its structure

Answer 20

• Body – located medially & articulates with opposite pubic body at the pubic symphysis
• Superior ramus – extends laterally from the body, forming part of the acetabulum (encloses the obturator foramen)
• Inferior ramus – projects towards and joins the ischium (encloses the obturator foramen)

Question 21

The posterioinferior part of the hip bone is formed by the ischium.

Describe its structure

Answer 21

• Inferior ischial ramus – combines with inferior pubic ramus to form the ischiopubic ramus (encloses part of obturator foramen)
• Ischial tuberosities – found on posterorinferior aspect of the ischium (carries body weight when sitting)
• Greater sciatic notch – found on the posterior aspect of the ischium

Question 22

Which ligaments attach to the ischium and what do they do?

Answer 22

• Sacrospinous ligament which runs from the ischial spine to the sacrum, forming the greater sciatic foramen
• Sacrotuberous ligament which runs from the sacrum to the ischial tuberosity, forming the lesser sciatic foramen

Question 23

What is fascia?

Answer 23

Fascia is defined as a sheet or band of fibrous tissue lying deep to the skin that lines, invests and separates structures within the body

Question 24

The fascia lata is a deep fascial investment of the whole thigh musculature.

Describe its structure and location

Answer 24

• Structure: strong, extensible and elasticated
• Location: begins around the iliac crest and inguinal ligament, ends at the bony prominences of the tibia (becomes crural fascia)

Question 25

Identify and describe the 3 types of fascia

Answer 25

- **Superficial fascia:** blends with the reticular layer beneath the dermis - **Deep fascia:** envelopes muscles, bones and neurovascular structures - **Visceral fascia:** provides membranous investments that suspend organs within their cavities

Question 26

The width of the fascia lata varies considerably at different regions of the thigh. Where is it thinnest and where is it thickest?

Answer 26

- **Thickest**: superolateral aspect of the thigh - **Thinnest**: adductor muscles of the medial thigh

Question 27

Describe the divisions of the fascia lata in the leg

Answer 27

- The deepest aspect of fascia lata gives rise to **three** **intermuscular septa** that attach centrally to the femur - This divides the thigh musculature into **three compartments:** anterior, medial lateral

Question 28

Which of the intermuscular septa is strongest?

Answer 28

The **lateral intermuscular septum** is the strongest of the three due to reinforcement from the iliotibial tract

Question 29

What is the saphenous opening and what does it do?

Answer 29

- The **saphenous opening** is an ovoid hiatus which is found in the fascia lata inferior to the inguinal ligament - It is an entry point for **efferent lymphatic vessels** and the **great saphenous vein,** draining into superficial inguinal lymph nodes and the femoral vein respectively

Question 30

Describe the structure and location of the Iliotibial Tract (ITT)

Answer 30

- **Structure**: a longitudinal thickening of fascia lata, strengthened posteriorly by fibres from the gluteus maximus - **Location**: lies laterally in the thigh, extending from the iliac tubercle to the lateral tibial condyle

Question 31

Describe the three functions of the Iliotibial Tract (ITT)

Answer 31

- Acts as an **extensor, abductor** and **lateral rotator** of the hip - ITT extends centrally to form the **lateral intermuscular septum** - Forms a **muscular sheath** for the tensor fascia lata

Question 32

What is the tensor fascia lata?

Answer 32

The **tensor fascia lata** is a superficial gluteal muscle involved in hip flexion, abduction, internal rotation

Question 33

State the origin and attachment of the tensor fascia lata?

Answer 33

- **Origin**: iliac crest (descends down superolateral thigh) - **Attachment**: anterior aspect of ITT

Question 34

When stimulated, the tensor fasciae lata tightens the iliotibial band and braces the knee. Why is this clinically important?

Answer 34

- When the fascia lata is **pulled taut**, it forces muscle groups closer together within their intermuscular septa towards the femur - This **centralises muscle weight** and **limits outward expansion**, which **reduces the overall force** required for movement at the hip joint

Question 35

What effect does tensing the fascia lata have on veins?

Answer 35

- Makes muscle contraction more efficient in **compressing** **deep veins** - Ensures adequate **venous return** to the heart from the lower limbs

Question 36

What are the superior attachments of the fascia lata?

Answer 36

**- Posterior**: sacrum, coccyx - **Lateral**: iliac crest - **Anterior**: inguinal ligament, superior pubic rami - **Medial**: inferior ischiopubic rami, ischial tuberosity, sacrotuberous ligament

Question 37

Describe the inferior attachments of the fascia lata

Answer 37

The fascia lata atttaches at **bony prominences around the knee joint** (femoral & tibial condyles, patella, head of fibula, tibial tuberosity) then becomes the deep fascia of the leg (crural fascia)

Question 38

Describe the lateral attachments of the fascia lata

Answer 38

The lateral thickening of fascia lata forms the **iliotibial tract** which descends the lateral thigh and attaches to the **lateral tibial condyle**

Question 39

Describe the central attachments of the fascia lata

Answer 39

The deep aspect of fascia lata produces three **intermuscular septa** which attach centrally to the femur

Question 40

The fascia lata is also continuous with regions of deep and superficial fascia at its superior aspect. Explain this.

Answer 40

- The **deep iliac fascia** from the thoracic region covers the iliopsoas and blends with the fascia lata superiorly - **Superficial fascia** from the inferior abdominal wall and perineal region both blend with the fascia lata just below the inguinal ligament

Question 41

Identify the superficial gluteal muscles

Answer 41

- Gluteus maximus - Gluteus medius - Gluteus minimus - Tensor fascia lata

Question 42

Describe the structure, function and innervation of the gluteus maximus muscle

Answer 42

- **Structure:** largest & most superficial of the gluteal muscles - **Function:** hip extension, lateral rotation - **Innervation:** inferior gluteal nerve

Question 43

State the origin and attachment of the gluteus maximus muscle

Answer 43

- **Origin**: gluteal surface of the ilium, sacrum and coccyx - **Attachment**: iliotibial tract and the gluteal tuberosity of femur

Question 44

Describe the structure, function and innervation of the gluteus medius muscle

Answer 44

- **Structure:** fan-shaped, lies between to gluteus maximus and minimus **- Function**: abduction, medial rotation **- Innervation**: superior gluteal nerve

Question 45

State the origin and attachment of the gluteus minimus muscle

Answer 45

- **Origin**: gluteal surface of the ilium - **Attachment**: lateral surface of the greater trochanter

Question 46

Describe the structure, function and innervation of the gluteus minimus muscle

Answer 46

- **Structure:** deepest and smallest of the superficial gluteal muscles - **Function**: abduction, medial rotation - **Innervation**: superior gluteal nerve

Question 47

State the origin and attachment of the gluteus minimus muscle

Answer 47

- **Origin**: ilium - **Attachment**: anterior side of the greater trochanter

Question 48

Describe the structure, function and innervation of the tensor fascia lata muscle

Answer 48

- **Structure:** small superficial muscle, lies towards anterior edge of the iliac crest **- Function:** abduction, medial rotation (tightens fascia lata) **- Innervation:** superior gluteal nerve

Question 49

State the origin and attachment of the tensor fascia lata muscle

Answer 49

- **Origin**: anterior iliac crest & ASIS - **Attachment**: ITT (lateral condyle of tibia indirectly)

Question 50

Identify the deep gluteal muscles

Answer 50

- Piriformis - Obturator internus - Superior & inferior gemelli - Quadrator femoris

Question 51

Describe the structure, function and innervation of the piriformis muscle

Answer 51

- **Structure:** most superior of the deep muscles - **Function**: lateral rotation, abduction - **Innervation**: nerve to piriformis

Question 52

State the origin and attachment of the piriformis muscle

Answer 52

- **Origin**: anterior surface of the sacrum (travels through greater sciatic foramen) - **Attachment**: greater trochanter of the femur

Question 53

Describe the structure, function and innervation of the obturator internus muscle

Answer 53

- **Structure:** forms the lateral walls of the pelvic cavity - **Function**: lateral rotation, abduction - **Innervation**: nerve to obturator internus

Question 54

State the origin and attachment of the obturator internus muscle

Answer 54

- **Origin**: pubis and ischium at the obturator foramen (travels through lesser sciatic foramen) - **Attachment**: greater trochanter of the femur

Question 55

Describe the structure, function and innervation of the gemelli muscles

Answer 55

- **Structure:** superior and inferior gemelli are two narrow triangular muscles, separated by the obturator internus tendon - **Function**: lateral rotation, abduction - **Innervation**: superior – nerve to obturator internus, inferior – nerve to quadratus femoris

Question 56

State the origin and attachment of the gemelli muscles

Answer 56

- **Origin**: superior – ischial spine, inferior – ischial tuberosity - **Attachment**: greater trochanter of the femur

Question 57

Describe the structure, function and innervation of the quadrator femoris muscle

Answer 57

- **Structure:** flat, square-shaped muscle, most inferior of the deep gluteal muscles **- Function**: lateral rotation **- Innervation**: nerve to quadratus femoris

Question 58

Describe the arterial supply of the gluteal region

Answer 58

**Arterial supply** via superior and inferior gluteal arteries (arise from internal iliac artery) which enter the gluteal region via the greater sciatic foramen

Question 59

Describe the venous drainage of the gluteal region

Answer 59

**Venous drainage** via inferior and superior gluteal veins (empty into the internal iliac vein)

Question 60

State the origin and attachment of the quadrator femoris muscle

Answer 60

- **Origin**: lateral side of the ischial tuberosity - **Attachment**: quadrate tuberosity on the intertrochanteric crest

Question 61

What is osteoarthritis?

Answer 61

- **Osteoarthritis** is a non-inflammatory chronic disease of the synovial joints in the musculoskeletal system (no systemic involvement) - No joint ankylosis is observed in the course of the disease

Question 62

Compare and contrast the aetiology of primary and secondary osteoarthritis

Answer 62

- **Primary OA:** aetiology is unknown - **Secondary OA:** trauma, infection (septic arthritis), inflammation (RA), metabolic (gout), endocrine (DM)

Question 63

Describe how articular cartilage changes in osteoarthritis

Answer 63

- Increased tissue swelling - Cartilage fibrillation - Cartilage erosion down to subchondral bone

Question 64

What are the risk factors for arthritis?

Answer 64

- Obesity - Past injury in a joint - Occupational factors - Genetics - Age

Question 65

What are the signs and symptoms of arthritis?

Answer 65

- Joint pain - Crepitis (grinding) - Joint deformity - Osteophytes - Joint stiffness

Question 66

Outline the investigation of osteoarthritis in terms of bloods, imaging and radiological findings.

Answer 66

**- Bloods** – FBC, U&Es , LFTs, CRP **- Imaging** – look for subchondrial sclerosis, osteophytes, narrowing of joint space, subchondrial cysts

Question 67

What is a pelvic bone fracture?

Answer 67

- **Pelvic bone fractures** are fractures which result from direct trauma to the pelvic bones or indirectly through forces transmitted from the lower limb - Fractures often occur at the weaker points of the bones (pubic rami, acetabulum, region of sacroiliac joint)

Question 68

A common complication of pelvic fractures is soft tissue injury. Which structures are at high risk?

Answer 68

- Bladder - Urethra