Anatomy of the Pelvis and Upper Femora

Female vs. Male Pelvis

*♂ Male*: - narrow/deep/vertical; - round shaped inlet; - Pubic Arch angle < 90°; - Heavier & Thicker; *♀ Female*: - broad/shallow; - more flared alae; - large inlet; - oval shaped inlet; - *Pubic Arch angle > 90°*; - Wider Sciatic Notch;

*THE PELVIS*

- Base of the trunk; - Girdle for the attachment of the lower limbs; 1. *HIP BONES* (R & L): • *Ilium*; • *Ischium*; • *Pubis*; 2. SACRUM; 3. COCCYX;

Pelvic *Inlet/Outlet*

1. Inlet: oblique plane from the upper border of the *PS* to the upper *prominence of the sacrum*; 2. Outlet: plane formed by the tip of the *coccyx* and the *ischial tuberosity*;

The six fundamental radiographic landmarks

1. posterior wall of the acetabulum; 2. anterior wall of the acetabulum; 3. roof (dome or tectum); 4. teardrop; 5. ilioischial line; 6. iliopectineal line;

*HIP BONE*

Aka *Os Coxae* or *Innominate Bone*; 1. *Ilium*; 2. *Pubis*; 3. *Ischium*; Note: these 3 bones join together to form the *acetabulum*;

Acetabulum oblique view

Interest: anterior/posterior lips & pelvic brim

Iliac Oblique view/Obturator oblique view.

Judet Method for *Acetabulum*: Iliac oblique view: (2) Anterior wall; (5) Ilioischial line; Obturator oblique view: (1) Posterior wall; (6) Iliopectineal line;

Ischial rami

Superior Ramus: toward the Ilium; Inferior Ramus: toward the Pubis; Note: other consider only the inferior ramus as the only ramus of the ischium, identifying the body of the ischium with the portion forming the acetabulum.

Joints of the pelvis and upper femora

● *HIP JOINT*: - Synovial tissue; - *Diarthrodial* (freely movable) joint: - *Ball-and-Socket* joint type; ● *PS JOINT*: - Cartilaginous tissue; - *Amphiarthrodial* (slightly movable) *cartilageneous* joint; - *Symphysis* joint type; ● *SI JOINT*; - Synovial-fibrous tissue; - *Amphiarthrodial* (slightly movable) *fibrous* joint: - *Irregular Gliding* joint type; The SI joints are both diarthrotic and amphiarthotic: - The inferior 2/3 of each joint is a true synovial articulation; - The superior 1/3 is a fibrocartilaginous amphiarthrosis supported by the short but strong sacroiliac ligaments;

*Hip Joint*

● Femoral head/acetabulum joint: - Synovial tissue; - *Diarthrodial* (freely movable) joint; - *Ball-and-Socket* joint type;

Femur anteversion/inclination

● Inclination: long axis of the femur and long axis of the neck @ *120°-130°*; ● Anteversion: the femoral neck projects anteriorly from the body's coronal plane @ *15°-20°*;

Pelvic *Brim*

- Oblique plane that separates the *Greater Pelvis* (false) and the *lesser pelvis* (true); - Pelvic "Inlet" line (red) to the lesser (true) pelvis;

*Acetabulum*

- The femur articulates with this pocket of the coxal bone that literally means "vinegar cup"; - The ball-and-socket joint;

Acetabulum lips

1. Anterior lip; 2. Posterior lip;

(2) *Ischium*

1. Body; 2. Ramus; 3. Ischial Tuberosity; 4. Ischial Spine; 5. Obturator Foramen; 6. Lesser Sciatic Notch; Note: it forms appox. 2/5 of posterior acetabulum.

(3) *Pubis*

1. Body; 2. Superior Ramus; 3. Inferior Ramus; 4. Pubic Symphysis; Note: it forms approx. 1/5 of anterior acetabulum.

(1) *Ilium*

1. Body; 2. Wing or Ala; 3. Iliac Crest; 4. ASIS; 5. AIIS; 6. PSIS; 7. PIIS; 8. Fossa (anterior ala); 9. Gluteal surface (posterior ala); 10. Arcuate line (anterosuperior pelvic brim R&L); 11. Auricular Surface; 12. Greater Sciatic Notch;

*Proximal Femur*

1. Head; 2. Neck; 3. Greater Trochanter; 4. Lesser Trochanter; 5. Fovea Capitis; 6. Intertrochanteric Crest;

Femoral natural obliqueness

The longitudinal plane of the femur is angled about *10°* from vertical;

*Pelvic columns*

The hip bone is also divided in: 1. *Iliopubic column* (anterior) - yellow; 2. *Ilioischial column* (posterior) - blue; Note: used to identify fractures around the acetabulum;