Movement Science Week 4 - Kinesiology Principles - Head, Neck, & Trunk (Transcripts)

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Questions and Answers

What is a unique feature of the atlas (C1) vertebra?

It has a prominent spinous process.

It contains multiple vertebral bodies.

It possesses large transverse processes. (correct)

It is entirely flat without articular facets.

What function does the dens (odontoid process) of the axis (C2) serve?

It connects the cervical and thoracic vertebrae.

It allows for flexion of the cervical spine.

It restricts lateral movement of the head.

It acts as a fulcrum for rotation. (correct)

Which statement about the thoracic spine's spinous processes is correct?

They are oriented anteriorly.

They are absent in the thoracic region.

They are oriented in a horizontal plane.

They project inferiorly. (correct)

What is the significance of the intervertebral disc in the lumbar spine?

It provides flexibility between adjacent vertebrae. Signup and view all the answers

How is the superior articular facet of L1 oriented in relation to the inferior articular facet of L2?

Vertically with a slight concavity. Signup and view all the answers

What occurs during right axial rotation of the cervical spine?

The left apophyseal joints experience compression. Signup and view all the answers

What is spinal coupling in the context of vertebral movement?

Movement in one plane causes compensatory movement in another plane. Signup and view all the answers

Which motion occurs in the atlanto-occipital joint?

Flexion and extension. Signup and view all the answers

What is the primary artery that passes through the transverse foramen of the cervical spine?

Vertebral artery Signup and view all the answers

During axial rotation to the right, which joint motion occurs?

The contralateral side joints compress. Signup and view all the answers

Which feature of the cervical spine is primarily responsible for directing motion?

Articular facets Signup and view all the answers

What angle is associated with the orientation of facets in the cervical spine?

45 degrees vertically. Signup and view all the answers

The uncinate processes in the cervical spine are important for providing stability in which plane?

Frontal plane Signup and view all the answers

Which of the following describes the orientation of the superior articular facets in the cervical spine?

Superiorly and posteriorly Signup and view all the answers

What role do the uncinate processes play in the cervical spine?

Provide vertical stability Signup and view all the answers

What role does the vertebral endplate play in the health of the nucleus pulposus?

It distributes nutrients and oxygen to the nucleus pulposus. Signup and view all the answers

How does compressive load impact the intervertebral disk?

It pushes the vertebral endplates inward toward the nucleus pulposus. Signup and view all the answers

What effect does poor sitting posture have on the spine?

It results in elevated pressure on the disk. Signup and view all the answers

How does the method of lifting influence the pressure on the intervertebral disk?

Correct lifting technique minimizes pressure increase on the disk. Signup and view all the answers

In which plane does lateral flexion of the spine occur?

Frontal plane. Signup and view all the answers

What is the primary function of the nucleus pulposus in the intervertebral disc?

To absorb shock through a hydrated gel structure Signup and view all the answers

How many concentric layers of collagen fibers make up the annulus fibrosis?

15 to 25 layers Signup and view all the answers

What happens to the intervertebral disc when the nucleus pulposus becomes dehydrated?

It loses its ability to absorb shock Signup and view all the answers

What role does the vertebral endplate play in the intervertebral disc?

It connects the intervertebral disc to the vertebral body Signup and view all the answers

Why is the orientation of collagen fibers in the annulus fibrosis significant?

It enhances resistance to multidirectional forces Signup and view all the answers

What occurs on the contralateral side during right lateral flexion in the thoracic region?

Left-sided superior and anterior slide Signup and view all the answers

Which describes the slide that occurs during thoracic extension?

Posterior and inferior slide Signup and view all the answers

In the lumbar region, what type of slide occurs during flexion?

Superior and anterior slide Signup and view all the answers

What motion is primarily limited in the thoracic spine?

Flexion and extension Signup and view all the answers

How are the facets in the thoracic region oriented?

15 degrees off the frontal plane Signup and view all the answers

What is the primary function of the sacroiliac joint?

Connect the axial and appendicular skeletons Signup and view all the answers

What happens when a person looks over their right shoulder in terms of thoracic rotation?

Leftward slide occurs Signup and view all the answers

What is primarily responsible for approximately 50% of axial rotation in the cervical spine?

Atlanto-axial joint Signup and view all the answers

During neck flexion, what happens at the atlanto-occipital joint?

Anterior roll and posterior slide Signup and view all the answers

What movement is observed at the atlanto-axial joint during flexion of the neck?

Anterior tilt only Signup and view all the answers

When the head is protracted, which motion occurs in the mid to lower cervical segments?

Flexion Signup and view all the answers

During craniocervical axial rotation, which statement is true regarding the lateral movements of the C2 through C7 segments?

Right sides slide inferiorly and left sides slide superiorly Signup and view all the answers

How does lateral flexion primarily occur in the cervical spine?

Mostly from C2 through C7 Signup and view all the answers

What type of slide occurs on the contralateral side during axial rotation at the AA joint?

Anterior slide Signup and view all the answers

What is the role of the dens in the atlanto-axial joint?

Facilitates rotation Signup and view all the answers

Study Notes

Cervical Spine Osteology

The cervical spine consists of seven unique vertebrae, each with distinct osteologic features.
Key structural components include spinous processes, lamina, and pedicles, similar to thoracic and lumbar regions.
The transverse foramen allows passage of the vertebral artery, crucial for brain blood supply.
Articular facets in the cervical region affect motion; superior facets are oriented posteriorly and superiorly, while inferior facets are oriented anteriorly and inferiorly.
The uncinate processes (C3-C6) enhance vertical stability and aid in preserving intervertebral disc integrity.
C1, or the atlas, supports the skull and lacks a spinous process but features large transverse processes for muscle attachment.
The superior articular facet of the atlas is concave to accommodate the convex occipital condyles of the skull, forming the atlanto-occipital (AO) joint, responsible for 50% of cervical flexion and extension.
The atlantoaxial (AA) joint, featuring a vertically projecting dens from the axis, is pivotal for rotational movement—accounting for 50% of cervical rotation.

Thoracic and Lumbar Spine Osteology

The thoracic spine comprises 12 segments with spinous processes oriented inferiorly, particularly prominent from T6 to T8.
Lumbar spine consists of five segments, characterized by larger vertebral bodies to support greater weight distribution.
Lumbar spinous processes project posteriorly, with distinct mammillary processes serving as muscle attachment sites for multifidi muscles.
The apophyseal (or zygapophyseal) joints of the thoracic spine are formed by the articulation of superior and inferior articular facets.
Interbody joints between lumbar vertebrae involve vertebral bodies, endplates, and intervertebral discs; critical for load-bearing and stabilization.
Intervertebral discs consist of a nucleus pulposus for shock absorption and annulus fibrosis for structural integrity.
Dehydration of the nucleus pulposus can lead to decreased shock absorption, increasing the risk of arthritis and nerve impingement due to bone spurs.

Intervertebral Disc Function and Pressure Distribution

The nucleus pulposus is a gel-like structure vital for absorbing load and maintaining hydration; comprises water and collagen.
Annulus fibrosis consists of 15-25 concentric layers of collagen, providing stiffness and support against compressive forces.
Vertebral endplates help connect discs to vertebrae, supply nutrients, and prevent sliding during spinal movement.
Lumbar vertebrae carry 80% of the body's load; high pressure is exerted during activities such as sitting or bending.
Poor posture increases disc pressure compared to good posture, while ergonomic lifting techniques can significantly reduce disc strain.
Diurnal variations affect disc height, with individuals generally being taller in the morning due to hydration of the discs overnight.

Spine Osteokinematics and Arthrokinematics

Understanding osteokinematic movements involves knowing the motions, planes, and axes of rotation for the spine.
Flexion and extension occur in the sagittal plane around a medial-lateral axis, often referred to as forward or backward bending.
Lateral flexion occurs in the frontal plane, allowing movement to the right or left, around an anterior-posterior axis.
Axial rotation occurs in the horizontal plane around a vertical axis, commonly referred to as rotation.### Osteokinematics and Arthrokinematics
Osteokinematic terminology is described using a cranial to caudal approach, indicating movement from superior to inferior.
Axial rotation example: C4 acting on C5 with right axial rotation results in the C4 vertebral body moving to the right and the spinous process moving to the left.
Key arthrokinematic motions at apophyseal joints include approximation, separation, sliding, and gliding.
Joint approximation occurs during axial rotation, compressing contralateral apophyseal joints.
Separation or gapping occurs on the same side during axial rotation, creating space in the corresponding apophyseal joints.
Sliding or gliding occurs with flexion and extension of the cervical spine, evident as translation between apophyseal joints.

Spinal Segment Orientation

Orientation of facet joints varies across spine regions affecting arthrokinematics:
- Cervical spine: Facets oriented at approximately 45 degrees.
- Thoracic spine: Facets 15 degrees off the frontal plane.
- Lumbar spine: Facets oriented about 25 degrees off the sagittal plane.

Spinal Coupling

Spinal coupling refers to combined movements in different planes during vertebral motion.
Example: Lateral flexion of C3-C7 involves automatic axial rotation; clinically imperceptible.

Atlanto-Occipital and Atlanto-Axial Joints

Atlanto-occipital joint: Convex occipital condyle articulates with the concave superior facet of the atlas, allowing flexion, extension, and lateral flexion, with limited rotation.
Atlanto-axial joint: Major site of axial rotation in the cervical spine, allowing about 50% of horizontal plane motion.

Craniocervical Movements

Craniocervical flexion: Occipital condyle rolls anteriorly and slides posteriorly at the atlanto-occipital joint due to the concave-convex rule.
At the atlanto-axial joint during flexion, only an anterior tilt occurs.
C2-C7: During flexion, the inferior facets slide anteriorly and superiorly on the superior facets of the adjacent segment.

Combined Movements: Protraction and Retraction

Protraction involves flexion at mid to lower cervical joints with extension at upper segments (C1-C2).
Retraction results in the opposite movement pattern.

Craniocervical Lateral Flexion & Axial Rotation

Right lateral flexion at the AO joint causes a roll to the right and slide to the left.
At C2-C7, right lateral flexion results in inferior and posterior sliding on the right and superior and anterior sliding on the left.

Thoracic Spine Movements

Thoracic flexion and extension involve a superior and anterior slide during extension, while extension induces a posterior and inferior slide.
Axial rotation in the thoracic spine results in a leftward slide when turning to the right.

Lumbar Spine Movements

Lumbar flexion involves a superior and slight anterior slide, while extension results in an inferior and slight posterior slide.

Importance of the Sacroiliac Joint

The sacroiliac (SI) joint connects the axial skeleton to the appendicular skeleton.
Estimated source of chronic low back pain in about 25% of people due to various stressors like unilateral torsion.
SI joint is part of the pelvic ring, a structure composed of the sacrum, ilium, pubis, ischium, and pubic symphysis, with the sacrum as the keystone of this ring.
Motion at the SI joint includes nutation (akin to flexion) and counternutation (akin to extension).### Nutation and Counternutation
Nutation refers to the anterior tilt of the sacral promontory relative to the innominate bone of the pelvis.
Counternutation is the opposite movement where the sacral promontory moves posteriorly, and the ilium moves anteriorly.
Important for understanding sacroiliac (SI) joint dynamics.

Functional Importance of the SI Joint

Provides two main functionalities: stress relief and stability.
Stress relief during activities like running occurs due to the interplay of descending gravitational forces and ascending ground reaction forces.
Joint laxity during pregnancy allows for nutation, increasing pelvic outlet size for childbirth.
Stability at the SI joint is enhanced in the close-packed position of nutation, crucial for standing and resisting gravitational forces.

Trunk Muscles and Movements

Bilateral contraction of trunk muscles leads to pure flexion or extension; unilateral contraction results in lateral flexion and axial rotation.
Deep muscles of the back include:
- Erector spinae group: spinalis, longissumus, iliocostalis.
- Transversospinal group: semispinalis, multifidi, rotators.
- Short segmental group: interspinalis and intertransversarius.
Multifidi play a role in spinal stability; altered timing due to intramuscular fat is associated with low back pain.

Abdominal Muscles

Rectus abdominis: superficial layer, involved in trunk flexion.
External obliques: fibers run inferior and medial, facilitating flexion and rotation.
Internal obliques: largest physiological cross-sectional area; significant in isometric force production.
Transverse abdominis: stabilizes the lower back and compresses the abdomen.

Muscle Activation and Coordination

Deep abdominal muscles (internal obliques and transverse abdominis) activate before prime movers like the anterior deltoid during motion to stabilize the core.
The oblique muscles contribute to flexion, lateral flexion, and rotation depending on the plane of activation.

Head and Neck Muscles

Identify major muscle groups in the craniocervical region:
- Sternocleidomastoid (SCM): unilateral activation causes lateral flexion and contralateral rotation; bilateral activation results in cervical flexion and upper cervical extension.
- Scalene muscles (anterior, middle, posterior) elevate the ribs and assist with ventilation.
- Longus coli and longus capitis stabilize the cervical spine and assist with flexion.

Clinical Implications

Thoracic outlet syndrome can occur due to hypertrophy of scalene muscles compressing the brachial plexus.
Activation techniques for longus coli can help address forward head posture and neck pain by improving cervical flexion stability.

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Description

This quiz explores the unique features and functions of specific vertebrae in the cervical and lumbar spine. Questions cover the atlas, axis, thoracic spine, and intervertebral discs, providing an in-depth analysis of spinal anatomy. Test your knowledge and understanding of vertebral structures and their significance in the human body.