Anatomy of Hip Joint in a Nutshell

Anatomy of Hip Joint

• Joint type: spherical joint
• Joint surfaces: Part of the femoral head with articular cartilage & acetabulum (only lunate surface)
  • Special features of the acetabular fossa:  acetabular labrum, fat pad, transverse acetabular ligament
• Joint capsule: attached to the edges of the acetabulum & neck of femur.
• Ligaments:
  1. Iliofemoral ligament (strongest ligament in the body; terminates extension in the joint)
  2. Pubofemoral ligament (reduces abduction and external rotation)
  3. Ischiofemoral ligament (restricts adduction and internal rotation)
  4. Zona orbicularis (ligament ring)
  5. Ligament of head of femur

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• Movements: flexion and extension, abduction and adduction, rotation
• Vessels: Branches of superior & inferior gluteal, Obturator artery, Circumflex femoris arteries, Interna Pudendal artery, External Iliac artery, Femoralis artery, Profunda femoris artery & Perforating branches
• Innervation: femoral nerve, obturator nerve, sciatic nerve, superior gluteus nerve

• Acetabulum
  • Has fairly large articular surface (smooth) in a horseshoe shape
  • Has gap in inferior limit where a nonarticular region is filled by transverse acetabular ligament
  • Deep in acetabulum, have another region that is not articular with small fat pad and synovial membrane fold that extends to similar area on head of femur.

1. 1. • Contains a small artery = artery of the head of the femur (not enough to supply head of femur on its own) is a branch of obturator artery.
      • Most blood for femur head / neck is from medial / lateral femoral circumflex.

• • Around rim of acetabulum, have labrum of fibrocartilage that helps to deepen the socket.
  • Fibrous capsule surrounds entire joint.

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• The hip is a relatively stable joint
  • as increase stability, sacrifice mobility (shoulder is mobile/unstable)
  • Extension of the hip joint is limited whereas knee has greater mobility
  • Most of the limit of extension is due to fibrous capsule
  • • Has thickened portions called ligaments:
      1. All attach intertrochanteric line
      2. Iliofemoral ligament
         • Ofrom ilium and extends anteriorly across hip joint
         • Called the strongest ligament in the body
         • As approach femur, it splits into 2 parts, thus called Y ligament (of Bigelow)
         • Function: as extend hip joint, it becomes tight- holds the head of femur into acetabulum
      3. Pubofemoral ligament
         • From the pubis
         • Abduction of the hip joint is restricted by this ligament
      4. Ischiofemoral ligament
         • Origin from ischium, radiates toward intertrochanteric line
         • Weakest of 3 ligaments, is drawn tighter in flexion of hip, but doesn’t restrict
      5. Will have gaps between ligaments
         • Form numerous bursae that allow muscles crossing the hip to slide freely
         • Many bursae have stalk of synovial membrane to bind it.

• The majority of the head of femur is within the acetabulum
  • Fovea of the femur:

1. 1. • Portion of non-articulating surface on head of femur
      • Ligament of head of femur (with small artery) attaches here

• • • Ligament has no restrictive action on the hip

• The common term “breaking the hip” refers to a fracture to the neck of the femur

• Most important muscles for keeping this connection = Lateral rotators

• • Pull the head of the femur into the socket
  • More often it is the strength of the muscle that is most important for normal joint function

Also read:

1. The Hip Joint @ TeachMeAnatomy
2. Practice Anatomy tests for free!
3. Best Anatomy books for Medical students
4. Best Anatomy websites & journals
5. Anatomy syllabus in (CBME) in India
6. Anatomy syllabus in Russia & Other CIS
7. Anatomy syllabus in China

Also Watch:

• Hip joint – Bones, ligaments, blood supply, and innervation @ Kenhub