Pelvis

Description

The pelvis consists of the sacrum, the coccyx,the ischium, the ilium, and the pubis. The structure of the pelvis supports the contents of the abdomen while also helping to transfer the weight from the spine to the lower limbs. During gait, the joints within the pelvis work together to decrease the amount of force transferred from the ground and lower extremities to the spine and upper extremities.

Anatomy

Osteology

• sacrum
• coccyx
• two innominate bones, which consist of the:
  • ischium
  • ilium
  • pubis

Joint Articulations

There are three articulations within the pelvis:

• inferiorly between the sacrum and the coccyx
• posteriorly between the sacrum and each ilium (sacroiliac (SI) joint)
• anteriorly between the pubic bodies (pubic symphysis).

Other articulations:

• the pelvis and femur articulate via the acetabulum

Ligaments

Ligaments of the Pelvis

• Iliolumbar ligament
• Lateral lumbosacral ligament
• Sacrotuberous ligament
• Sacrospinous ligament

Sacroiliac Ligaments

• Ventral/Anterior sacroiliac ligament
• Dorsal/Posterior sacroiliac ligament
• Interosseous sacroiliac ligament

Sacrococcygeal Ligaments

• Ventral/Anterio sacrococcygeal ligament
• Dorsal sacrococcygeal ligament
• Lateral sacrococcygeal ligament

Pubic Symphysis Ligaments

• Superior pubic ligament
• Inferior pubic ligament
• Anterior pubic ligament
• Posterior pubic ligament

Muscles

There are 36 muscles that attach to the sacrum or innominates. The purpose of these muscles is primarily to provide stability to the joint not to produce movement.

Muscles that attach to the sacrum or innominates are:

Adductor brevis	Adductor longus	Adductor magnus	Biceps femoris - long head	Coccygeus
Erector spinae	External oblique	Gluteus maxiumus	Gluteus medius	Gluteus minimus
Gracilis	Iliacus	Inferior gemellus	Internal oblique	Latissimus dorsi
Levator ani	Multifidus	Obturator internus	Obturator externus	Pectineus
Levator ani	Piriformis	Psoas minor	Pyramidalis	Quadratus femoris
Quadratus lumborum	Rectus abdominis	Rectus femoris	Sartorius	Semimembranosus
Semitendonosus	Sphincter urethrae	Superficial transverse perineal ischiocavernous	Superior gemellus	Tensor fascia lata
Transversus abdominus

Clinical Examination

Assessment

• Prior to the assessment of the sacroiliac joint both the lumbar spine and hip should be assessed and any underlying pathologist should be ruled out.

Special Tests

SI Joint stress tests

• Anterior Gapping test
• Sacroiliac Distraction test
• Sacrotuberous Ligament Stress test
• Sacral Compression test
• Rotational Stress test

Leg Length tests

• Prone test
• Standing leg length test
• Functional leg length test

Other Special Tests

• Seated Flexion test (Piedallu's Sign)
• Long Sit test
• Sign of the Buttock
• Posterior Pelvic Pain Provocation test
• Gaenslen's test
• Yeoman's test
• FABER (Figure-Four) test
• Fortin Finger Test
• Straight Leg Raise - 70-90deg
• Gillet's test (Ipsilateral posterior rotation test)

Outcome Measures

• Pelvic Girdle Questionnaire (PGQ)

Pathology/Injury

• Pubic Symphysis Dysfunction
• Spondyloarthropathies
• Pregnancy Related Pelvic Pain
• Pelvic Fractures
• Sacroiliitis