Post on 03-Jan-2016
Anatomy of the Pelvisin Computed Tomography
Michael C. Ficorelli, RT
Lesson Description
To explain the various exams pertaining to the pelvis using computed tomography, incorporating cross sectional anatomy from images
Lesson Description
• To be able to identify anatomy within the pelvis. Understand the clinical indications for exams. To understand the methods of patient scanning, positioning, and protocols. To understand indications for contrast.
CT of the Pelvis
Pelvis
• Provides structural support for the body and contains both the male and female reproductive organs
• Bony Pelvis – contains the sacrum, coccyx and two innominate bones
Bony Pelvis
Bony Pelvis
• Sacrum – Triangular shaped bone formed by 5 fused vertebrae– S-1 contains prominent ridge on anterior surface referred
to as sacral promontory – separates abdomen from pelvis– Transverse process of the 5 are fused to form the lateral
mass (ala)– Sacral foramina – located within the lateral mass for
transmission of the sacral nerves
• Coccyx – 3 to 5 fused small bony segments
Bony Pelvis
Bony Plevis• Innominate bone – Made of 3 bones
– Ilium – largest and superior portion• Body and ala• Superior rim – Iliac crest
– Slopes downwards to ASIS (Anterior Superior Iliac Spine) and PSIS
• Body is uppermost portion of acetabulum
– Ischium – inferior portion• Body and 2 rami• Superior ischial ramus extends posteriorly and inferiorly to ischial tuberosity (you sit
on it)• Body is lowermost portion of acetabulum• Greater and Lesser sciatic notches extend from ischial spine and allows transmission of
nerves and vessels• Obrturator Foramen – opening enclosing the union of pubic and ischial rami
– Pubis – lower anterior portion of acetabulum• Body and 2 rami (superior and inferior)• Bodies of both sides meet at midline – Symphysis Pubis
Bony Pelvis
Pelvic Muscles
• Rectus Abdominus – anterior surface of abdomen and pelvis
• Psoas Muscle – Lateral to the lumbar vertebrae and medial to the ilium
• Gleuteus Muscles– Maximus - outermost– Medius– Minimus – innermost (lateral to pelvic bone)
Pelvic Muscles
Perineum
• Posterior to pubic arches; anterior to coccyx• 2 divisions– Anal Triangle – contains inferior 1/3 of anal canal
and sphincter muscles– Urogenital diaphragm – openings of the urethra
and vagina in females; urethra and root structures of penis in males
Pelvic Organs
• Bladder – lies on the pelvis floor immediately posterior to symphysis pubis and is responsible for the storage of urine– Pyramid shaped– Storage capacity 750 cc Max– Urethra – muscular tube which drains urine from the bladder
• Rectum – Terminal colon extending from L-3– Anus – Exit– Anal Sphincter – ring of muscle fibers under voluntary control
• Prostate Gland – largest accessory gland in the male reproductive system– Inferior to the bladder and surrounds the urethra
Bladder and Prostate
Pelvic Vasculature
• Abdominal Aorta descends into the pelvic cavity and bisects at the level of L-4 into the Right and Left Iliac arteries– Right and Left Iliac bifurcate again at the level of the SI
Joints into Internal and External Iliac arteries
• Internal and External Iliac Veins run similar courses as the arteries and meet at the level of the SI joints to form the Right and Left Iliac Veins– Meet at L-4 to form the IVC
Pelvic Vasculature
Pelvis Standard1 2
3
4
1 – Ascending Colon
2 – Ileum
3 – Descending Colon
4 – Iliac Artery
Pelvis Standard
1
1 - Cecum
Pelvis Standard
12
3
1 – Uterus
2 – Ovary
3 - Rectum
Pelvis Standard
112
3
4
1 – Bladder
2 – Uterus
3 – Ovarian Cyst
4 - Rectum
Pelvis Standard
1
1 - Bladder
Pelvis Standard
1
1 - Anus
Pelvis Bone1
2
1 – L – 5
2 – Iliac Crest
Pelvis Bone1
2
1 – Sacral Promontory
2 – SI Joint
Pelvis Bone
1
2
1 – Ilium
2 - Sacrum
Pelvis Bone
1
1 – Ilium (top of acetabulum)
Pelvis Bone
1
2
3
1 – Pubic Bone
2 – Acetabulum
3 - Iscium
Pelvis Bone
12
3
1 – Pubic Rami
2 – Femoral Head
3 – Iscium
Pelvis Bone
12
3
1 – Symphysis Pubis
2 – Femoral Neck
3 – Iscial Tuberosity
Pelvis Bone
1
1 – Pubic and Iscial Ramus