Inominate Flashcards

Questions and Answers

What is the sacroiliac joint?

Medial, posterior, and superior; transmits weight from axial spine; can affect angle and rotation of acetabular fossa.

Describe the Pubic Symphysis.

Medial, anterior, and inferior; point of stabilization for both hips; can affect angle and rotation of acetabular fossa.

List the three inominant bones.

Ilium, Ischium, Pubis.

The anatomical landmarks include the _____ and PSIS.

iliac crest Signup and view all the answers

What are palpatory landmarks?

ASIS, pubic tubercles, iliac crest, greater trochanters, medial malleoli, ASIS to midline, PSIS, sacral sulci, ischial tuberosity. Signup and view all the answers

What defines a true ligament?

Bone to bone. Signup and view all the answers

What is an accessory ligament?

Bone to another ligament, tendon, or fascia. Signup and view all the answers

What is the purpose of ligaments?

Limit abnormal or excessive movement, permit normal motion, slightly elastic, part of a reflex response to excessive movement. Signup and view all the answers

List the ligaments of the pelvis.

Iliolumbar (accessory), sacrospinous (accessory), sacrotuberous (accessory), sacroiliac (true: anterior, interosseous, posterior). Signup and view all the answers

What does the iliolumbar ligament restrict?

Restricts anterior motion of L5 and some rotation of L5. Signup and view all the answers

How does the sacrospinous ligament function?

It restrains anterior movement of the sacrum and divides the space into greater and lesser sciatic foramen. Signup and view all the answers

What is the role of the sacrotuberous ligament?

Restrains anterior movement of sacrum with sacrospinous ligament. Signup and view all the answers

Describe the sacroiliac ligament.

Covers most of the sacroiliac joint: anterior, interosseous, and posterior. Signup and view all the answers

What are the muscles of the inominates?

Flexors, extensors, adductors, abductors, external rotators. Signup and view all the answers

What is the function of hip flexors?

Pulls pelvis anterior (anterior rotation of inominates). Signup and view all the answers

Which muscles are considered hip extensors?

Semimembranosus, semitendinosis, biceps femoris, gluteus maximus. Signup and view all the answers

What is the role of hip adductors?

Stabilize and pull pelvis medially. Signup and view all the answers

What is the function of hip abductors?

Stabilize and pulls pelvis laterally. Signup and view all the answers

What do hip external rotators do?

Externally rotates pelvis. Signup and view all the answers

Describe the piriformis muscle.

Only external rotator that connects directly to sacrum; acts as abductor when hip is flexed and external rotator when extended. Signup and view all the answers

What types of motion do inominates perform?

Anterior/Posterior rotation, superior/inferior translation (shear), caliper/scapation. Signup and view all the answers

What characterizes an anterior pelvic tilt?

Lordotic back with pelvis tilting forward into hyper-lordosis. Signup and view all the answers

What defines a posterior pelvic tilt?

The pelvis tilts backward, flattening the lumbar spine. Signup and view all the answers

Study Notes

Sacroiliac Joint

Located medial, posterior, and superior; critical for weight transmission from the axial spine.
Influences the angle and rotation of the acetabular fossa.

Pubic Symphysis

Positioned medial, anterior, and inferior; stabilizes both hips.
A secondary cartilaginous joint, featuring hyaline cartilage and fibrocartilage, allowing slight movement.

Inominate Bones

Composed of three bones: ilium (largest and superior), ischium (inferior and posterior), and pubis (inferior and anterior).

Anatomic Landmarks

Notable landmarks include iliac crest, ASIS (anterior superior iliac spine), AIIS (anterior inferior iliac spine), pubic tubercle, PSIS (posterior superior iliac spine), and PIIS (posterior inferior iliac spine).

Palpatory Landmarks

Key palpatory points include ASIS, pubic tubercles, iliac crest, greater trochanters, medial malleoli, midline from ASIS, PSIS, sacral sulci, and ischial tuberosity.

Ligaments

True Ligaments connect bone to bone.
Accessory Ligaments connect bone to ligaments, tendons, or fascia.
Purpose: limit abnormal movement, allow normal motion, provide elasticity, and participate in reflex responses to excessive movements.

Ligaments of the Pelvis

Key ligaments include iliolumbar (accessory), sacrospinous (accessory), sacrotuberous (accessory), and sacroiliac (true ligaments: anterior, interosseous, posterior).

Iliolumbar Ligament

Connects ilium to the 5th lumbar vertebra.
First ligament associated with low back pain; restricts anterior motion and some rotation of L5.

Sacrospinous Ligament

Extends from the sacrum to the ischial spine, dividing spaces into greater and lesser sciatic foramen.
Part of the coccygeus muscle; resists anterior movement of the sacrum alongside the sacrotuberous ligament.

Sacrotuberous Ligament

Runs from the sacrum to the ischial tuberosity, helping to check anterior movement of the sacrum.
Has four attachments for muscles: gluteus maximus, long head of biceps femoris, piriformis, and pelvic fascia.

Sacroiliac Ligaments

Cover most areas of the sacroiliac joint, categorized into anterior, interosseous, and posterior portions.

Muscles of the Inominates

Functionally categorized into flexors, extensors, adductors, abductors, and external rotators.

Hip Flexors

Anteriorly rotate the pelvis; hip flexor contractures indicated through:
- Iliacus (from ala to lesser trochanter)
- Psoas (from 5th lumbar vertebra to lesser trochanter)
- Iliopsoas muscle complex
- Rectus femoris and sartorius.

Hip Extensors

Posteriorly rotate the pelvis; hip extensor contractures indicated through:
- Semimembranosus, semitendinosis (ischial tuberosity to medial tibia)
- Biceps femoris and gluteus maximus.

Hip Adductors

Stabilize and medially pull the pelvis:
- Include adductor magnus, adductor brevis, adductor longus, pectineus, and gracilis; all attach from the pubic ramus to the femur.

Hip Abductors

Stabilize and laterally pull the pelvis:
- Comprises gluteus medius, gluteus minimus, and tensor fascia lata.

Hip External Rotators

Externally rotate the pelvis:
- Includes piriformis, obturator internus, obturator externus, gemellus superior, gemellus inferior, and quadratus femoris.

Piriformis Muscle

Unique among external rotators for connecting directly to the sacrum.
Functions as an abductor when the hip is flexed and as an external rotator when extended.
Often linked to sciatic nerve issues due to its anatomical position.

Inominate Motion Types

Anterior/Posterior rotation.
Superior/Inferior translation (shear).
Caliper/Scapation (inflare/outflare movements).

Pelvic Tilts

Anterior Pelvic Tilt leads to lordotic back; pelvic forward tilt increases lumbar hyper-lordosis.
Posterior Pelvic Tilt impacts positioning and motion, though details are not provided.

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Description

Test your knowledge on the anatomy and function of the sacroiliac joint and pubic symphysis. These flashcards provide an insightful overview of their locations and roles in stabilizing the hips. Enhance your understanding of these essential joints in the human body.