Pelvis Functions and Structure

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Questions and Answers

What is the primary function of the pelvis?

To support the weight of the trunk and transport it onto the limbs (correct)

To protect the organs in the thoracic cavity

To facilitate movement of the limbs

To aid in respiration

What is the name of the structure formed by the fusion of two hemipelvis and the sacrum?

Sacrum

Pelvic girdle (correct)

Innominate bone

Pelvic cavity

What is the name of the muscle found on the iliac fossa?

Tensor fasciae latae

Iliacus (correct)

Psoas major

Gluteus maximus

What is the term for the angle used to identify gender anthropologically?

Subpubic angle Signup and view all the answers

At what age do the ilium, ischium, and pubis bones typically merge?

In the teenage years-early 20s Signup and view all the answers

What is the term for the four main categories of pelvic shape?

None of the above Signup and view all the answers

Why do phenotypical females have thinner pelvic bones?

Because of the pull strength of the muscles Signup and view all the answers

What is the name of the ligament that joins the sacral bone to the rest of the pelvic girdle?

Sacro-tuberous ligament Signup and view all the answers

Which of the following is NOT a type of pelvic fracture?

Femoral fracture Signup and view all the answers

Which joint is responsible for transferring weight from the spine to the pelvic ring?

Sacroiliac joint Signup and view all the answers

What is the function of the iliolumbar ligament?

Connecting the lumbar vertebrae to the ilium Signup and view all the answers

Which of the following ligaments is NOT involved in the pubic symphysis?

Sacrospinous ligament Signup and view all the answers

What is the primary factor responsible for the increased flexibility of pelvic ligaments during pregnancy?

Action of relaxin Signup and view all the answers

How are sacroiliac joint fractures classified?

By the degree of instability (I, II, or III) Signup and view all the answers

Which of the following is a common cause of pelvic trauma?

Falls Signup and view all the answers

Which of these statements regarding zone 2 sacral fractures is accurate?

It involves a fracture of the neural foramina but not the spinal canal. Signup and view all the answers

Study Notes

Functions of the Pelvis

Protects organs within the pelvic cavity.
Supports trunk weight and transmits it to the limbs.
Connects the trunk to the limbs.

Anatomy of the Pelvis

Composed of two hemipelvis (innominate) bones with the sacrum at the center, forming the pelvic girdle.
Greater and lesser pelvis are divided by the pelvic inlet (pelvic brim).
Pelvic outlet is marked by ischial tuberosity and coccyx.

Muscle and Joint Information

Iliacus muscle located on the iliac fossa.
Anterior superior iliac spine (ASIS) and pubic symphysis aligned vertically in neutral position, contributing to lumbar lordosis.
Posterior superior iliac spine (PSIS) found at L2, discernible via sacral dimples ("Venus dimples").
Posterior inferior iliac spine (PIIS) not visible due to overlying muscles and ligaments.

Gender Identification and Bone Structure

Subpubic angle used for anthropological gender identification.
Ilium, ischium, and pubis initially separate but fuse at triradiate cartilage in early adulthood.
X-rays show whether bones are fused, but not cartilage visibility.
Pelvic shape categorized in four main types, influenced by ethnicity and gender.

Pelvic Considerations for Women

Pelvic shape can affect childbirth; e.g., anthropoid pelvis may hinder vaginal delivery.
Women typically have thinner pelvic bones due to muscle pull, while men develop denser bones from greater tendon tension.
Osteoporosis risk in women due to thinner pelvic structure.

Ligaments and Joints of the Pelvis

Inguinal ligament may be visible beneath the skin; obturator membrane covers the obturator foramen.
Sacro-tuberous and sacro-spinous ligaments connect the sacrum to the pelvic girdle, forming the sciatic foramina.
Sacroiliac joints and pubic symphysis are key pelvic joints, forming a stable bone ring transferring spinal weight.

Joint Anatomy and Flexibility

Sacroiliac joints consist of both synovial and syndesmosis parts.
The sacroiliac ligament covers the interosseous ligament filling the syndesmosis area.
Pubic symphysis held together by superior and inferior pubic ligaments, which change with age and gender.

Additional Pelvic Joints and Ligaments

Lumbosacral joints and sacrococcygeal joints, with iliolumbar ligament supporting quadratus lumborum attachment.
Pelvic ligaments crucial for pelvic girdle integrity and become more flexible during pregnancy under relaxin influence.

Pelvic Trauma

Commonly caused by vehicle accidents or falls.
Types of fractures: ring disruptions, sacral fractures, acetabular fractures, and avulsion injuries; can be life-threatening if accompanied by hemorrhage.
Ring disruptions graded I to III; classifications include lateral compressions, antero-posterior compression, and vertical shear.
Sacral fractures classified into three zones based on nerve involvement:
- Zone 1 affects the spinal nerve, lateral to foramina.
- Zone 2 impacts the foramina but not the spinal canal.
- Zone 3 involves fractures medial to the foramina, affecting the spinal structures.

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Description

This quiz covers the functions and structure of the pelvis, including its role in protecting organs, supporting the trunk, and attaching to limbs. It also explores the composition of the pelvis and its various parts.