Pelvic Wall

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Questions and Answers

What bones comprise the pelvic girdle?

Left and right hip bones, sacrum, and coccyx (correct)

Left and right radius and ulnar

Sternum and vertebrae

Left and right femur and pelvis

Which ligaments are crucial for preventing rotation of the sacrum at the sacroiliac joints?

Gluteal and iliotibial ligaments

Sacrospinous and sacrotuberous ligaments (correct)

Transverse and arcuate ligaments

Coracoacromial and coracohumeral ligaments

Which muscle is a major component of the pelvic diaphragm?

Transversus abdominis

External oblique

Puborectalis (correct)

Serratus anterior

What is the significance of the pelvic inlet in childbirth?

It is the entry point to the pelvic cavity. Signup and view all the answers

What dimension measures the distance between the two ischial spines?

Interspinous distance Signup and view all the answers

How can fecal incontinence arise from injury to a specific muscle?

Injury to the puborectalis muscle Signup and view all the answers

Which structure is essential in the development of the sacral plexus?

Ventral rami of sacral nerves Signup and view all the answers

What defines the boundaries of the 'true' pelvis?

Enclosed by the pelvic brim Signup and view all the answers

What is characteristic of the gynecoid pelvic form?

Straight side walls with a wide subpubic angle Signup and view all the answers

Which of the following nerves is NOT part of the sacral plexus?

Femoral nerve Signup and view all the answers

Which description best fits the anthropoid pelvic form?

Long anterior-posterior diameters and narrow subpubic angle Signup and view all the answers

Which of the following correctly identifies the components of the lumbosacral trunk?

Fusion of lumbar nerves L4 and L5 Signup and view all the answers

Which function is NOT provided by the lumbosacral plexus?

Motor innervation to the thoracic region Signup and view all the answers

Which of the following diameters is NOT associated with the pelvic inlet?

Lateral Signup and view all the answers

What are the three fused bones that make up the hip bone?

Ilium, ischium, and pubis Signup and view all the answers

Which structure does NOT pass through the pelvic inlet?

Femoral artery Signup and view all the answers

What is the anatomical term for the hip bone?

Os coxae Signup and view all the answers

Which part of the ilium contributes to the formation of the acetabulum?

Body Signup and view all the answers

Which feature is associated with the ala of the ilium?

Iliac fossa Signup and view all the answers

What is the informal name given to the hip bone due to its shape?

Innominate bone Signup and view all the answers

The ilium is divided into which two main parts?

Body and ala Signup and view all the answers

Which surface of the ilium articulates with the sacrum?

Auricular surface Signup and view all the answers

The term 'synostosis' refers to which aspect of the hip bone?

The fusion of bones Signup and view all the answers

What comprises the bony pelvis?

The right and left hip bones, sacrum, and coccyx Signup and view all the answers

Which structure forms the pelvic inlet?

Superior rim of the pelvic cavity Signup and view all the answers

What is the main function of the pelvic girdle?

To transmit body weight from the lower extremities Signup and view all the answers

Which of the following is NOT found in the greater pelvis?

Urinary bladder Signup and view all the answers

How does the female pelvis differ from the male pelvis?

It is larger and wider to accommodate childbirth Signup and view all the answers

Which structures are involved in the formation of the pelvic inlet?

Sacral promontory and pubic symphysis Signup and view all the answers

Where is the lesser pelvis located in relation to the greater pelvis?

Below the greater pelvis Signup and view all the answers

Which organ is primarily contained within the lesser pelvis?

Urinary bladder Signup and view all the answers

What do the sacrococcygeal and sacroiliac joints connect?

Sacrum to the coccyx and iliac bones Signup and view all the answers

What is the role of the linea terminalis in the pelvis?

It separates the greater and lesser pelvis Signup and view all the answers

What lies along the posterior gluteal line?

Border between gluteus maximus and medius Signup and view all the answers

Which iliac crest lip is associated with the abdominal wall muscle attachment?

Outer lip Signup and view all the answers

What is the function of the dimples of Venus?

Result from a ligament stretching between bones Signup and view all the answers

What feature does the pubic tubercle primarily provide?

Attachment of the superior pubic ligament Signup and view all the answers

In which section does the superior pubic ramus contribute to the acetabulum?

Ventral section Signup and view all the answers

Which structure acts as the medial surface articulating at the pubic symphysis?

Symphysial surface Signup and view all the answers

Which line marks the inferior border for gluteus minimus origin?

Inferior gluteal line Signup and view all the answers

What do the three lips of the iliac crest allow for?

Muscle attachments Signup and view all the answers

What is the shape of the rami when viewed anteriorly?

Letter 'K' Signup and view all the answers

What is the role of the arcuate line in the ilium?

Part of the linea terminalis Signup and view all the answers

What is the main function of the pelvic girdle?

To transmit body weight from the axial skeleton to the lower extremities Signup and view all the answers

Which of the following accurately defines the boundaries of the pelvic inlet?

Anterior - pubic symphysis, Posterior - sacral promontory Signup and view all the answers

What differentiates the greater pelvis from the lesser pelvis?

The greater pelvis primarily supports the lower abdominal viscera Signup and view all the answers

Which bones compose the bony pelvis?

Right hip bone, left hip bone, sacrum, coccyx Signup and view all the answers

What is the function of the linea terminalis in the pelvis?

To form the pelvic inlet Signup and view all the answers

Which organ is primarily contained within the lesser pelvis?

Urinary bladder Signup and view all the answers

What is the significance of the pelvic cavity?

It contains and protects abdominal and pelvic organs Signup and view all the answers

Which statement is true about the differences in female and male pelvises?

The female pelvis is larger and wider to accommodate the birth canal Signup and view all the answers

What is the primary function of the inferior gluteal nerve?

Innervation of the gluteus maximus Signup and view all the answers

A positive Trendelenburg sign indicates which type of nerve dysfunction?

Superior gluteal nerve dysfunction Signup and view all the answers

Which anatomical structure does the posterior cutaneous nerve of the thigh NOT innervate?

Anterior thigh Signup and view all the answers

Which of the following describes the function of the inferior clunial nerve?

Sensory innervation to the distal gluteal region Signup and view all the answers

What impairment is associated with paresis of the inferior gluteal nerve?

Difficulty in walking upstairs Signup and view all the answers

Which component of the ilium serves as the origin of the iliacus muscle?

Iliac fossa Signup and view all the answers

What structure serves as the attachment point for the posterior interosseous sacro-iliac ligament?

Iliac tuberosity Signup and view all the answers

What term describes the fusion of the ilium, ischium, and pubis in the hip bone?

Synostosis Signup and view all the answers

Which of the following is NOT a diameter associated with the pelvic inlet?

Median diameter Signup and view all the answers

Which part of the hip bone is considered the most superior?

Ilium Signup and view all the answers

What informal name is given to the hip bone due to its unique shape?

Innominate Signup and view all the answers

Which of the following features is part of the ala of the ilium?

Iliac fossa Signup and view all the answers

What is the cup-shaped hollow on the outer aspect of the hip bone called?

Acetabulum Signup and view all the answers

Which structure passes through the pelvic inlet?

Sympathetic trunk Signup and view all the answers

In the context of the hip bone, which of the following has the role of providing articulation with the sacrum?

Auricular surface Signup and view all the answers

What anatomical feature distinguishes the gynecoid pelvic form from others?

Straight side walls Signup and view all the answers

What is the primary function of the superior gluteal nerve?

Innervates the gluteus medius and minimus Signup and view all the answers

Which pelvic form is most commonly associated with male individuals?

Android Signup and view all the answers

Which of the following nerves is a part of the sacral plexus?

Inferior gluteal nerve Signup and view all the answers

What characteristic is associated with the anthropoid pelvic form?

Long anterior-posterior diameters Signup and view all the answers

Which nerve passes through the infrapiriform foramen?

Sciatic nerve Signup and view all the answers

What anatomical feature does the piriformis muscle divide?

Greater and lesser sciatic foramen Signup and view all the answers

Which of the following is NOT a function of the lumbosacral plexus?

Contributing to the autonomic nervous system Signup and view all the answers

Which component forms the lumbosacral trunk?

Fusion of lumbar nerves L4 and L5 Signup and view all the answers

What anatomical feature separates the origins of the gluteus maximus and medius?

Posterior gluteal line Signup and view all the answers

Which structure serves as the attachment site for the inguinal ligament?

Pubic tubercle Signup and view all the answers

Which iliac crest lip is primarily associated with the muscles of the abdominal wall?

Outer lip Signup and view all the answers

What is the shape of the rami of the pubis when viewed anteriorly?

Letter 'K' Signup and view all the answers

Which line marks the caudal border for the origin of the gluteus minimus?

Inferior gluteal line Signup and view all the answers

What is primarily formed by the superior pubic ramus?

Ventral 1/3 of the acetabulum Signup and view all the answers

Which ligament contributes to the formation of the dimples of Venus?

Ligament connecting the posterior superior iliac spine to the skin Signup and view all the answers

Which structure is considered the medial surface of the pubis that articulates at the pubic symphysis?

Symphysial surface Signup and view all the answers

Which part of the iliac crest is a bony projection formed by the origin of the gluteus medius?

Tuberculum of iliac crest Signup and view all the answers

What anatomical term is used for the lateral lumbar indentations known as the dimples of Venus?

Fossae lumbales laterales Signup and view all the answers

Study Notes

Pelvic Girdle

The pelvic girdle consists of the left and right hip bones, sacrum, and coccyx.
The pelvic bones connect via the pubic symphysis anteriorly, sacrococcygeal and sacroiliac joints posteriorly.

Functions of the Pelvic Girdle

Transmits body weight from the axial skeleton to the lower extremities.
Provides attachment to a large number of muscles.
Contains and protects the abdominopelvic and pelvic viscera.

Pelvic Inlet

Separates the abdominal and pelvic cavities.
Located at the superior rim of the pelvic cavity.
Borders include: sacral promontory, sacral wings, arcuate line of ilium, pectineal line of pubis, and pubic symphysis.
Structures passing through: ureter, spermatic cord, round ligament of the uterus, suspensory ligament of the ovary, median sacral vessels, gonadal vessels, iliolumbar vessels, lumbosacral trunk, sympathetic trunk, obturator nerve.

Hip Bone - Os Coxae

Consists of three fused bones: ilium, ischium, and pubis.
The bones fuse at the acetabulum.
It articulates with the opposite hip bone anteriorly and the sacrum posteriorly.

Ilium - Os Ilium

Most superior component of the hip bone.
Divided into body and ala (wing).
The body contributes to the acetabulum formation.
The ala has four borders and three surfaces:
- Iliac fossa (origin of iliacus muscle).
- Sacropelvic surface: contains the auricular surface (articulates with the sacrum) and iliac tuberosity (attachment of posterior interosseous sacroiliac ligament).
- Gluteal surface (origin of gluteal muscles): includes the posterior, anterior, and inferior gluteal lines, which demarcate origin areas of different gluteal muscles.
- Iliac crest: has three lips for attachment of abdominal wall muscles (outer, intermediate, inner). It also includes the tuberculum of iliac crest (origin of gluteus medius), anterior superior and inferior iliac spine, and posterior superior and inferior iliac spine.

Pubis - Os Pubis

Located anteromedially.
Has a body, superior pubic ramus, and inferior pubic ramus.
The body connects to the pubic symphysis.
The superior pubic ramus forms the ventral portion of the acetabulum.

Pelvic Form

Gynecoid (most common female form): transverse oval inlet, wide sacrum, wide sacrosciatic notch, straight side walls, wide subpubic angle.
Android (most common male form): triangular inlet, converging side walls, narrow sacrosciatic notch, narrow subpubic angle.
Anthropoid (common in males): long anterior-posterior diameters, short transverse diameters, wide sacrosciatic notch, narrow subpubic angle.
Platypelloid (flat variation of gynecoid): short anterior-posterior diameters, long transverse diameters, narrow sacrosciatic notch, wide subpubic angle.

Innervation of the Lower Limb

The lower limb is innervated by branches of the lumbosacral plexus.
The lumbosacral plexus is formed by the lumbar and sacral plexuses.
- Lumbar plexus: formed by T12 and L1-L4 nerves.
- Sacral plexus: formed by L4-L5 and S1-S4 nerves.
The lumbosacral trunk is formed by the fusion of L4 and L5 and contributes to the sacral plexus.

Sacral Plexus

Arises from S1-S4 nerve roots and receives contributions from L4 and L5 via the lumbosacral trunk.
Located on the pelvic surface of the sacrum.
Provides somatomotor and somatosensory innervation to the lower limb.

Branches of the Sacral Plexus

Superior gluteal nerve (L4-S1): innervates gluteus medius, gluteus minimus, and tensor fasciae latae, passes through the suprapiriform foramen.
Inferior gluteal nerve (L5-S2): innervates gluteus maximus.
Posterior cutaneous nerve of thigh (S1-S3): innervates skin of the posterior thigh.
Pudendal nerve (S2-S4): innervates external genitalia, perineum, pelvic floor muscles, and anal sphincter.
Sciatic nerve (L4-S3): major nerve of the lower limb.
The piriformis muscle divides the greater sciatic foramen into the suprapiriform foramen and the infrapiriform foramen.

Pelvic Girdle

The pelvic girdle is made up of the two hip bones, the sacrum, and the coccyx.
The hip bones are made up of three fused bones: the ilium, the ischium, and the pubis.
The sacrum and coccyx are actually variably fused vertebrae.
The pelvic girdle transmits body weight from the axial skeleton to the lower extremities.
It provides attachment to numerous muscles and contains and protects the abdominopelvic and pelvic viscera.

Pelvic Inlet

The pelvic inlet is the plane that separates the abdominal and pelvic cavities.
It’s located at the superior rim of the pelvic cavity (upper pelvic aperture).
The pelvic inlet is made up of the sacral promontory, sacral wings, arcuate line, pectineal line, and pubic symphysis.
Structures passing through the pelvic inlet include the ureter, spermatic cord, round ligament of the uterus, suspensory ligament of the ovary, median sacral vessels, gonadal vessels, iliolumbar vessels, lumbosacral trunk, sympathetic trunk, and obturator nerve.

Greater Pelvis

The greater pelvis, also known as the false pelvis, is located superiorly.
It provides support for the lower abdominal viscera, such as the ileum and sigmoid colon.
It has little obstetric relevance.

Lesser Pelvis

The lesser pelvis, also known as the true pelvis, is located inferiorly.
The pelvic cavity, which is the space within the pelvic girdle, resides within the lesser pelvis.
The pelvic cavity contains abdominal and pelvic organs and is protected by the pelvic girdle.

Ilium

The ilium is the most superior component of the hip bone.
It consists of two main parts, the body and the ala (wing).
The body contributes to the formation of the acetabulum.
The ala is expanded and has four borders and three surfaces.
The iliac fossa is the ventromedial concave fossa, which is the origin of the iliacus muscle.
The sacropelvic surface is the medial surface behind and below the iliac fossa.
The auricular surface articulates with the sacrum.
The iliac tuberosity is the attachment of the posterior interosseous sacro-iliac ligament.
The gluteal surface is the dorsolateral surface and is the origin of the gluteal muscles.
The anterior, posterior, and inferior gluteal lines mark borders between the origins of the gluteus maximus, medius, and minimus muscles.
The iliac crest has three lips: the outer lip, the intermediate zone, and the inner lip, which are attachment points for the abdominal wall muscles.
The tubercle of the iliac crest is a bony projection formed by the origin of the gluteus medius muscle.

Ischium

The ischium is the inferior component of the hip bone and forms the posterior part of the acetabulum.
The ischial spine, ischial tuberosity, and ischial ramus are important anatomical structures of the ischium.

Pubis

The pubis is the anterior component of the hip bone and contributes to the formation of the acetabulum.
The pubic body connects to the pubic symphysis.
The pubic tubercle is an attachment point for the inguinal ligament and superior pubic ligament.
The pubic crest is the insertion of the rectus abdominis muscle and the origin of the pyramidalis muscle.
The symphysial surface articulates at the pubic symphysis.
The superior pubic ramus forms the ventral 1/3 of the acetabulum.
The obturator crest is located between the pubic tubercle and acetabular notch.
The pecten pubis forms part of the linea terminalis.

Pelvic Form

There are four main pelvic forms: gynecoid, android, anthropoid, and platyelpelloid.
The gynecoid form, most common in females, is characterized by a transverse oval inlet, wide sacrum, wide sacrosciatic notch, straight side walls, and wide subpubic angle.
The android form, most common in males, is characterized by a triangular inlet, converging side walls, narrow sacrosciatic notch, and narrow subpubic angle.
The anthropoid form, common in male individuals, is characterized by long anterior-posterior diameters, short transverse diameters, wide sacrosciatic notch, and narrow subpubic angle.
The platyelpelloid form, a flat variation of the gynecoid type, is characterized by short anterior-posterior diameters, long transverse diameters, narrow sacrosciatic notch, and wide subpubic angle.

Lumbosacral Plexus

The lumbosacral plexus is a network of nerves composed of two distinct plexuses: the lumbar plexus and the sacral plexus.
The lumbar plexus is formed by the subcostal nerve (T12) and the first four lumbar nerves (L1–L4).
The sacral plexus is formed by the last two lumbar nerves (L4–L5) and the first four sacral nerves (S1–S4).
The lumbosacral trunk is formed by the fusion of lumbar nerves L4 and L5 and contributes to the sacral plexus.

Sacral Plexus (L4–S4)

The sacral plexus arises from the spinal nerves of S1 to S4 and receives contributing branches from L4 and L5 via the lumbosacral trunk.
It is located on the pelvic surface of the sacral bone.
Along with the lumbar plexus, it provides somatomotor and somatosensory innervation to the lower limb.

Nerves of the Sacral Plexus

The sacral plexus includes the superior gluteal nerve, inferior gluteal nerve, posterior cutaneous nerve of the thigh, pudendal nerve, and sciatic nerve.
The piriformis muscle divides the greater sciatic foramen into the suprapiriform foramen and the infrapiriform foramen.

Superior Gluteal Nerve (L4–S1)

The superior gluteal nerve runs through the suprapiriform foramen with the superior gluteal artery and veins.
It innervates the gluteus medius, gluteus minimus, and tensor fasciae latae muscles.

Inferior Gluteal Nerve (L5–S2)

The inferior gluteal nerve runs through the infrapiriform foramen with the inferior gluteal artery and veins.
It innervates the gluteus maximus muscle.

Posterior Cutaneous Nerve of Thigh (S1–S3)

The posterior cutaneous nerve of the thigh runs through the infrapiriform foramen.
It provides somatosensory innervation to the dorsal thigh.
It distally travels with the cranial extension of the small saphenous vein.
It contains inferior clunial nerves, which provide somatosensory innervation to the distal part of the gluteal region.
It contains perineal branches, which provide somatosensory innervation to the perineal skin.

Pudendal Nerve (S2–S4)

The pudendal nerve will be discussed in the lecture on the perineum.

Sciatic Nerve (L5–S2)

The sciatic nerve, with contributions from L4 and S3, will be discussed in the lecture on the thigh.

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Description

Test your knowledge of the pelvic girdle, including its structure, functions, and components. This quiz covers key aspects about the hip bones and pelvic inlet, along with their anatomical significance. Perfect for students of anatomy and related fields.