Human Anatomy Week 2: Trunk Arthrology

Questions and Answers

What is the primary function of the Anterior Longitudinal Ligament?

Limits flexion of the spine

Runs from the sacrum to the occiput

Limits extension of the spine (correct)

Attaches exclusively to the intervertebral discs

Which structure acts as a shock absorber and accounts for 20-25% of the height of the spine?

Anterior Longitudinal Ligament

Nucleus pulposus

Intervertebral discs (correct)

Annulus fibrosis

What distinguishes the Posterior Longitudinal Ligament from the Anterior Longitudinal Ligament?

It has primary attachment to intervertebral discs (correct)

It is much thicker and stronger

It is more posteriorly located

It limits extension of the spine

Which ligament connects from spinous process to spinous process?

Interspinous Ligament Signup and view all the answers

Where is the thickest portion of the Ligamentum flavum found?

Lumbar region Signup and view all the answers

Which ligament is primarily responsible for limiting flexion of the spine?

Posterior Longitudinal Ligament Signup and view all the answers

What happens to intervertebral discs as one ages?

They lose water, decreasing height Signup and view all the answers

What type of joint is classified as a facet joint?

Plane joint Signup and view all the answers

What is the role of the annulus fibrosis in intervertebral discs?

Stabilizes the disc structure Signup and view all the answers

Which joint allows for the widest range of rotation in the vertebral column?

Atlantoaxial joint Signup and view all the answers

Which muscle group is critical in back pain?

Multifidus Signup and view all the answers

What is the primary action of the levatores costarum muscles?

Stabilize ribs Signup and view all the answers

Which group of muscles spans 2-4 vertebral levels?

Semispinalis Signup and view all the answers

What are the components of the rotatores muscles?

Longus and brevis Signup and view all the answers

Which layer of the thoracolumbar fascia is the most superficial?

Superficial layer Signup and view all the answers

Which nerves are responsible for the motor and sensory innervation of the intrinsic back muscles?

Posterior primary rami Signup and view all the answers

What do the interspinales muscles primarily do?

Lie between spinous processes Signup and view all the answers

What connects to the thoracolumbar fascia to aid in stabilization?

Abdominal muscles Signup and view all the answers

What is the primary role of deep minor intrinsic muscles?

Maintain space between vertebral segments Signup and view all the answers

What is the significance of the term 'attachment' in muscle terminology?

It is a less specific term for origin and insertion. Signup and view all the answers

What type of joint is formed by the first rib with the sternum?

Synchondrosis Signup and view all the answers

Which movement is primarily achieved in the cervical region of the spine?

Both flexion and rotation Signup and view all the answers

Which joint type allows movement during inhalation for ribs 1-6?

Synovial planar Signup and view all the answers

What is the primary role of the intercostal muscles during forced exhalation?

Depress the ribs Signup and view all the answers

What condition describes the herniation of the nucleus pulposus through the annulus of an intervertebral disc?

Disc protrusion Signup and view all the answers

Which of the following best describes a laminectomy?

Procedure to relieve pressure on spinal nerve roots Signup and view all the answers

What is the segmental artery in the context of spine neurovascular supply?

Branch of the aorta at each vertebral level Signup and view all the answers

Which of the following spinal movements has the greatest range of motion?

Cervical spine Signup and view all the answers

What is the primary characteristic of the xiphisternal joint?

Synchondrosis with no movement Signup and view all the answers

Which muscle group primarily stabilizes the trunk and is innervated by the posterior primary rami?

Deep intrinsic back muscles Signup and view all the answers

Study Notes

Trunk Arthrology

Spinal Ligaments: Comprise various ligaments including Anterior Longitudinal Ligament (ALL), Posterior Longitudinal Ligament (PLL), Supraspinous Ligament, Interspinous Ligament, Ligamentum Flavum, and Ligamentum Nuchae.
Anterior Longitudinal Ligament (ALL): Extends from the basilar area of the occiput to the sacrum; wider distally; limits spinal extension.
Posterior Longitudinal Ligament (PLL): Runs from C2 to the sacrum, narrower than ALL; restricts spinal flexion and prevents posterior disc herniation.
Supraspinous Ligament: Connects the spinous processes from C7 to the sacrum; aids in limiting flexion.
Interspinous Ligament: Connects adjacent spinous processes; maintains space and slightly limits extension.
Ligamentum Nuchae: An extension of the supraspinous ligament in the cervical region; supports the neck’s lordotic curve.
Ligamentum Flavum: Contains high elastic fiber content; lines the spinal canal, aiding in controlling rapid spinal flexion.

Intervertebral Discs

Anulus Fibrosis: Outer fibrous layer of the disc; consists of concentric layers of fibrocartilage, thicker anteriorly.
Nucleus Pulposus: Inner gelatinous core, about 88% water; facilitates spinal mobility and shock absorption.
Aging Effects: Discs lose water, reducing height and mobility; contributes to spinal degeneration.

Vertebral Column Joints

Craniovertebral Joints: Atlanto-occipital (occiput-C1) and Atlantoaxial (C1-C2) joints allow for head movement.
Intervertebral Joints: Formed between vertebral bodies from C2 to S1; key for spinal stability.
Zygapophyseal (Facet) Joints: Provide gliding movement; orientation varies by region (lumbar allows flexion/extension, cervical allows rotation).

Movements of the Trunk

Types of Movements: Include extension/flexion, lateral flexion, rotation of head and neck, with cervical region having the most range.
Rib Movement: Upper ribs elevate during inhalation, while lower ribs expand laterally.

Neurovascular Supply of the Spine

Arterial Supply: Primarily through segmental arteries branching from the aorta; important for vertebral support.
Venous Drainage: Managed via intervertebral veins and plexus.

Clinical Considerations

Osteoporosis: Leads to weakened bone density, primarily affecting spongy bone.
Laminectomy: Surgical procedure aimed at alleviating nerve root pressure by removing lamina.
Disc Protrusion: Occurs when nucleus pulposus herniates through the annulus, often posterolateral due to PLL structure.

Intrinsic Back Muscles

Superficial Intrinsics: Include the splenius cervicis and capitis, involved in rotation and lateral flexion.
Erector Spinae: Intermediate group with three muscles (Iliocostalis, Longissimus, Spinalis); essential for trunk extension and side bending.
Transversospinales: Deep muscle group; muscles (Semispinalis, Multifidus, Rotatores) involved in rotational movements and stabilization.

Thoracolumbar Fascia

Structure: Composed of superficial and deep layers; connects to muscles, providing stability across the lumbar region.

Innervation of Back Muscles

Intrinsic Back Muscles: Primarily innervated by posterior primary rami; unique nerve distribution for sensory and motor functions.
Extrinsic Back Muscles: Innervated by anterior primary rami linked to upper extremity.

Terminology in Anatomy

Attachments vs. Origin/Insertion: Attachment refers to the general area where muscles connect. In anatomical context, origin is more stable whereas insertion is the moving end during contraction.

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Description

Dive into the second week of Human Anatomy focusing on trunk arthrology. This quiz covers various back ligaments, intervertebral discs, and their functions, including the anterior longitudinal ligament and more. Test your knowledge on the structural components that support the spinal column.