The Hip Joint Flashcards
What does the hip joint consist of and what are its properties?
• Joint consists of:
– Ball (femoral head)
– Socket (acetabulum of hip bone)
• Large range of movement
• Strong joint
– Takes a lot to disrupt
– Very stable joint
Label the proximal part of the femur
See slide for image
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Femoral head Femoral neck Greater trochanter Lesser trochanter Intertrochanteric line (anterior) Intertrochanteric crest (posterior)
Name the 3 bones which fuse to form the hipbone. What are they separated by and when do they fuse?
• Formed by fusion of 3 bones
– Ilium
– Ischium
– Pubis
• Separated by Tri-radiate cartilage
– Begins to fuse at 15-17 years
– Fusion complete by 20-25 years
What is the acetabulum?
• Socket of joint
• Where hip bones converge
• Margin of acetabulum is incomplete inferiorly
– Acetabular notch
What strengthens the joint?
- Labrum
- Joint capsule
- Ligaments
- Muscles
What are the acetabular labrum and transverse acetabular ligament?
• Fibrocartilaginous rim attached to margin of acetabulum
• Increases the articular contact area by 10% – More than 50% of head of femur fits in
• Transverse acetabular ligament strengthens inferior portion of acetabulum
– Where acetabular notch is
What is the joint capsule?
• Capsular fibres take a spiral course • Anterior – Attaches at intertrochanteric line – In extension capsule helps pull femoral head into acetabulum • Posteriorly – Lateral part of neck is extra-capsular
Back of the neck of the femurs is extracapsullar
Fibres run in spiral - extending hip twists the fibres to pull joint together
What are the 3 strong ligaments which strengthen the capsule?
- Capsule is strengthened by 3 strong ligaments
* Iliofemoral • Pubofemoral • Ischiofemoral
What are the accessory ligaments?
- Accessory ligaments
- Ligament of head of femur
- Transverse acetabular ligament
What are the properties of the iliofemoral ligament?
- Y shaped ligament
- Bodies strongest ligament
- Protects hip joint superiorly & anteriorly
- Prevents hyperextension
What are the properties of the pubofemoral ligament?
- Protects anteriorly and inferiorly
* Prevents over abduction
What are the properties of the ischiofemoral ligament?
– Weakest of the three
– Positioned posteriorly (attaches to greater trochanter)
– Limits extension
What are the muscles that move the hip joint?
- iliopsoas
- rectus femorus
- sartorius
Must cross the joint to move it
Iliopsoas is the most powerful flexor - 2 muscles with a common insertion - psoas major and iliacus
Reclusive femoral is the only quad muscle to cross the hip joint
What are the hip adductors?
Hip Adductors • Adductor – Magnus – Brevis – Longus • Pectineus • Gracilius • Obturator externus
See slide for image
Name the hip extensors
- Gluteus maximus
- Long head of Biceps femoris
- Semimebranosus
- Semitendinosus
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Name the hip abductors
- Gluteus medius
- Gluteus minimus
- Tensor fasciae latae
Medius and minimus supplied by Superior gluteal nerve
Medius and minimus make sure pelvis doesnt droop down on one side so you can walk
Name the lateral rotators of the hip joint
- Piriformis
- Superior gemellus
- Obturator internus
- Inferior gemellus
- Quadratus femoris
Describe the nerve supply to the hip joint
• Hiltons law – “the nerves supplying the muscles extending directly across and acting at a given joint also innervate the joint” • Femoral nerve (anterior) • Obturator nerve (inferior) • Superior Gluteal nerve (superior) • Nerve to Quadratus femoris (posterior)
Describe the blood supply to the hip joint
• Major source (deep femoral artery)
– Medial circumflex femoral artery
– Lateral circumflex femoral artery
• Minor source (adult)
– Obturator artery (via ligament of head of femur)
• Blood supply from ligament of the head of femur is often not adequate if only supply
• If you get a femoral neck # you can tear Retinacula arteries
• Result can be AVN of femoral head
Blood supply come from branches of the profunda femoris - deep femoral artery
2 branches - Lateral has smaller branches
Synovial membrane doubles back on itself forming folds
Arteries come very close to the bone - if you break that bone the vessels can be damages (retinacular aretereis)
What happens if the superior gluteal nerve is damaged?
Superior gluteal nerve damage • Supplies hip abductors • Damage to SGN leads to: – weakened abduction – Changes to stance phase of gait cycle • Trendelenberg sign – Pelvis droops on the unaffected side Hip adductors keep pelvis level - if not - trendelenburg sign (drooping on one side) - CONTRALATERL side to injury, e.g. “right sided positive trendelenburg sign” means damage on left side, droop on right side
Where are the 2 innominate bones connected?
Anteriorly at pubic symphysis
Posteriorly at the sacrum
Describe the muscles of the gluteal region
• Located posteriorly to the pelvic girdle at the proximal end of the femur.
• The muscles in this region move the lower limb at the hip joint.
• Muscles divided into 2 groups:
- Superficial
- Deep
Collectively abduct, extend, and laterally rotate the femur at the hip joint.
What are the 3 superficial gluteal muscles?
ACTION: Gluteus Maximus • Main extensor of the thigh • Assists with lateral rotation. - Used when force is required, such as running or climbing.
Gluteus Medius and Minimus
• Abducts and medially rotates thigh
• Stabilises pelvis during walking, preventing pelvis drop on the opposite limb
INNERVATION AND BLOOD SUPPLY:
Gluteus Maximus = Inferior Gluteal Nerve and Artery
Gluteus Medius and Gluteus Minimus = Superior Gluteal Nerve and Artery
What are the 5 deep muscles
See slide for diagram
INNERVATION:
Piriformis = Nerve to Piriformis
Gemellus Superior = Nerve to Obturator internus
Obturator Internus = Nerve to Obturator Internus.
Gemellus Inferior = Nerve to Quadratus Femoris
Quadratus Femoris = Nerve to Quadratus Femoris.
Why is the pirformis an important anatomical landmark?
- Divides up the gluteal region into an superior and inferior part.
- The sciatic nerve usually enters the gluteal region directly inferior to the piriformis, and is visible as a flat band, approximately 2cm wide
What are the “safe areas” for injection of the gluteal region?
- Dorsogluteal safe to use from 3 years old
- Ventrogluteal site preferred in children over 7 and adults but requires compliance
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What are the muscles of the posterior thigh?
See side for diagram
• Biceps femoris – Long head – Short head • Semitendinosus • Semimembranosus
• All originate from ischial tuberosity
– Except short head of biceps (linea aspera)
• All innervated by tibial part of sciatic nerve
– Except short head of biceps (common fibular division of sciatic nerve)
