Week 4 Movement Science Study Guide PDF

Study Guide: Cervical Spine Osteology Objectives Identify the basic osteologic features of the cervical spine. Overview of the Cervical Spine Cervical Spine: Composed of seven vertebrae (C1-C7). Unique features distinguish the cervical spine from thoracic and lumbar regions. Basic O...

Study Guide: Cervical Spine Osteology Objectives Identify the basic osteologic features of the cervical spine. Overview of the Cervical Spine Cervical Spine: Composed of seven vertebrae (C1-C7). Unique features distinguish the cervical spine from thoracic and lumbar regions. Basic Osteologic Features Similar to thoracic and lumbar spines with standard components: ○ Spinous Process ○ Lamina ○ Pedicle Unique Features of the Cervical Spine 1. Transverse Foramen: ○ Open foramen located in each cervical vertebra. ○ Function: Passage for the vertebral artery, which supplies blood to the brain as it ascends through the foramen magnum. 2. Articular Facets: ○ Large facets facilitate movement. ○ Orientation: Superior articular facets: oriented superiorly and posteriorly. Inferior articular facets: oriented inferiorly and anteriorly. ○ Orientation affects the direction and type of motion allowed in the cervical spine. 3. Uncinate Processes: ○ Vertical projections found on vertebrae C3 to C6 (and partially on C7). ○ Function: Provide vertical and frontal plane stability, enhancing the structural integrity of the cervical spine and intervertebral discs. Key Cervical Vertebrae C1 (Atlas)  Name Origin: Atlas supports the head (occiput). Unique Features: ○ No spinous process (instead, has a posterior tubercle). ○ Large transverse processes for muscle attachment. ○ Superior Articular Facets: Large and concave, accommodating the convex occipital condyles of the cranium. Atlanto-Occipital (AO) Joint: ○ Formed between C1 and the occiput. ○ Function: Allows for approximately 50% of cervical spine flexion and extension. C2 (Axis) Unique Features: ○ Features a prominent vertical projection known as the dens (odontoid process). Atlantoaxial (AA) Joint: ○ Formed between C1 and C2. ○ Function: Acts as a fulcrum for rotation, facilitating about 50% of cervical rotation. ○ Characterized by relatively flat facets and the vertical dens Study Guide: Thoracic and Lumbar Spine Osteology Objectives 1. Identify basic osteologic features of the thoracic spine and lumbar spine. 2. Understand the structure and function of the interbody joints. Overview of the Spinal Column Thoracic Spine: Contains 12 vertebrae (T1-T12). Lumbar Spine: Contains 5 vertebrae (L1-L5). Thoracic Spine Features Spinous Processes Orientation: Most spinous processes in the thoracic region (especially T6-T8) are oriented inferiorly. Facet Joints Orientation: ○ Superior articular facets: oriented posteriorly. ○ Inferior articular facets: oriented anteriorly. Joint Type: These joints are referred to as apophyseal joints or zygapophyseal joints. Lumbar Spine Features Vertebral Body Size: Larger than those in the thoracic or cervical spines to support greater weight-bearing. Spinous Process Orientation: Projects directly posteriorly without an inferior projection. Mammillary Process Function: Attachment site for multifidus muscles, enhancing stability and movement. Articular Facets Orientation: ○ Superior articular facets: vertical with slight concavity. ○ Inferior articular facets: vertical with slight convexity. Articulation: Superior facet of L1 articulates with inferior facet of L2. Interbody Joints Structure Composed of: ○ Two vertebral bodies (e.g., L1 and L2). ○ Vertebral endplate. ○ Intervertebral disc. Intervertebral Disc Components: ○ Nucleus Pulposus: Central, gel-like structure providing shock absorption.  ○ Annulus Fibrosis: Composed of 15-25 concentric layers of collagen fibers, providing stiffness and support. Function Shock Absorption: Nucleus pulposus absorbs compressive loads, allowing the spine to withstand pressure during activities. Hydration: The disc must remain hydrated; dehydration can lead to reduced shock absorption and potential arthritis. Common Issues with Intervertebral Discs Dehydration: Can occur due to aging, injury, or disease, leading to: ○ Loss of shock absorption. ○ Bone-on-bone contact. ○ Development of osteophytes (bone spurs) that can impinge on nerves. Symptoms of Nerve Impingement Radicular symptoms: Tingling, numbness, warmth, or weakness along the nerve distribution affected. Vertebral Endplate Functions Provides continuity between the intervertebral disc and vertebral body. Composed of: ○ Fibrocartilage (inner side) for strong binding to the annulus fibrosis. ○ Calcified cartilage (outer side) for binding to the vertebral body. Nutrient Supply Supplies nutrients (oxygen, glucose) to the nucleus pulposus and annulus fibrosis, as these structures lack blood vessels. Pressure Distribution in Intervertebral Discs Load Distribution: About 80% of body load is transmitted through the lumbar vertebrae into the interbody joints. Pressure Effects: ○ Normal standing generates high pressure in the discs.  ○ Activities like bending, lifting, or poor sitting posture can significantly increase disc pressure. Diurnal Variation Discs may change height throughout the day due to hydration levels; typically, individuals are taller in the morning than at night. The extent of this variation may differ between younger (e.g., 25-year-olds) and older adults (e.g., 65-year-olds). Study Guide: Spine Osteokinematics and Arthrokinematics Lecture Overview Topic: Spine Osteokinematics and Arthrokinematics Objectives: ○ Describe basic osteokinematic motions throughout the spine. ○ Understand and interpret basic arthrokinematic motions. ○ Identify key features of specific joints (e.g., atlanto-occipital joint, atlanto-axial joint) and regions (C spine, T spine, L spine). Key Terminology Osteokinematics Definition: Movement of bones in space. Key Terms: ○ Flexion and Extension: Occur in the sagittal plane around a medial-lateral axis (forward and backward bending). ○ Lateral Flexion (Side Bending): Occurs in the frontal plane with an anterior-posterior axis (right or left). ○ Axial Rotation: Occurs in the horizontal plane around a vertical axis (rotation). Arthrokinematics Definition: Movement occurring at the joint surfaces. Key Terms: ○ Approximation/Compression: Articular facets come together (e.g., during axial rotation).  ○ Separation/Gapping: Articular facets move apart. ○ Sliding/Gliding: Translation across joint surfaces (e.g., during flexion/extension). Osteokinematic Movements Describing Movements: ○ Movements are described from a cranial to caudal (superior to inferior) perspective. ○ Example: For C4 on C5 during right axial rotation, the C4 vertebral body moves to the right while the spinous process moves to the left. Regional Kinematics Cervical Spine (C1-C7) Facet Orientation: 45 degrees from horizontal plane. Key Movements: ○ Flexion: Anterior roll and posterior slide at AO joint; anterior/superior slide at C2-C7. ○ Extension: Posterior roll and anterior slide at AO joint; posterior/inferior slide at C2-C7. ○ Axial Rotation: Primarily at AA joint (50% of cervical rotation); involves contralateral slide. ○ Lateral Flexion: Roll in the direction of the flexion with opposite slide; coupling occurs with slight axial rotation. Atlanto-Occipital (AO) and Atlanto-Axial (AA) Joints AO Joint: Allows flexion, extension, and lateral flexion (convex on concave). AA Joint: Allows significant axial rotation (flat surfaces facilitate rotation). Thoracic Spine (T1-T12) Facet Orientation: 15 degrees off the frontal plane. Key Movements: ○ Flexion/Extension: Superior/anterior slide during flexion; posterior/inferior slide during extension. ○ Axial Rotation: Contralateral slide (e.g., right rotation involves left slide). ○ Lateral Flexion: Opposite movement on each side; inferior slide on the flexed side. Lumbar Spine (L1-L5)  Facet Orientation: 25 degrees off the sagittal plane. Key Movements: ○ Flexion: Superior/anterior slide. ○ Extension: Inferior/posterior slide. ○ Limited axial rotation due to facet orientation. Spinal Coupling Definition: Associated movements in different planes (e.g., lateral flexion coupled with axial rotation). Clinical Relevance: Understanding coupling helps in assessing spinal mechanics during movements. Study Guide: Sacroiliac Joint (SI Joint) Objectives 1. Identify the basic osteologic features of the sacroiliac joint. 2. Understand the two primary functions of the SI joint: stress relief and stability. Overview of the Sacroiliac Joint The SI joint is the primary interface between the axial skeleton (spine) and the appendicular skeleton (lower extremities). It is located between the ilium (part of the pelvis) and the sacrum. Key Features The SI joint is not directly palpable; however, it can be approximated. Palpation Method: ○ Place hands on the ilium with thumbs posteriorly to feel the posterior superior iliac spine (PSIS). ○ The SI joint is located just anterior to the PSIS. Clinical Significance  The SI joint is a common source of chronic low back pain, accounting for approximately 25% of cases. It is particularly impacted by activities that involve unilateral torsion, such as running or jumping. Structural Components The pelvic ring consists of: ○ Sacrum ○ SI joints ○ Ilium ○ Pubis ○ Ischium (sitting bones) ○ Pubic symphysis The sacrum acts as the keystone of this ring, providing support and stability. Motion of the Sacroiliac Joint Key Terms Nutation: ○ Defined as the anterior tilt of the sacral promontory relative to the innominate bone. ○ Can involve either sacral-on-iliac or iliac-on-sacral motion. Counternutation: ○ The opposite movement, where the sacral promontory moves posteriorly and the ilium moves anteriorly. Visualization Picture the sacrum and ilium moving in a nodding motion (nutation) and a backward nod (counternutation). Functions of the Sacroiliac Joint 1. Stress Relief  During Gait/Running: ○ The SI joint accommodates the torsion created by the descending force of gravity and the ascending ground reaction force. ○ This torsion is crucial for preventing stress on the spinal column. During Pregnancy: ○ Increased joint laxity occurs, allowing for greater movement (nutation) to widen the pelvic outlet, facilitating childbirth. 2. Stability The SI joint provides stability during various activities: ○ Standing: Stability is enhanced by the close-packed position during nutation. ○ Joint Reaction Forces: Forces acting through the acetabulum create a moment arm that promotes stability. Importance of Nutation Close-Packed Position: ○ Nutation represents the close-packed position of the SI joint, which maximizes stability. ○ The anterior tilt of the sacral promontory under the influence of gravitational forces helps maintain this stability. Study Guide: Trunk Muscles and Associated Movements Objectives 1. Differentiate between bilateral and unilateral trunk muscle contractions. 2. Identify the deep muscles of the back. 3. Explain the actions of the muscles of the anterior-lateral trunk. 4. Describe the role of deep abdominal muscles in trunk stabilization. Overview of Trunk Muscle Actions Bilateral vs. Unilateral Muscle Contraction Bilateral Contraction: ○ Involves activation of both sides of the trunk. ○ Results in pure flexion or extension. ○ Example: Both sides of the back muscles contracting results in extension. Unilateral Contraction: ○ Involves activation of one side. ○ Results in a combination of extension, lateral flexion, and axial rotation. Deep Muscles of the Back Erector Spinae Group Muscle Components: ○ Spinalis ○ Longissimus ○ Iliocostalis Function: Extension of the spine; involved in lateral flexion. Moment Arm: Consider which muscle has the greatest moment arm for lateral flexion. Transversospinal Group Muscle Components: ○ Semispinalis ○ Multifidus ○ Rotators Function: Provide stability and control; involved in fine motor control due to crossing fewer intervertebral junctions. Clinical Relevance: Multifidi are significant in low back pain due to altered timing and intramuscular fat. Short Segmental Group Muscle Components: ○ Interspinalis ○ Intertransversarius Function: Fine motor control, spanning one intervertebral segment. Anterior-Lateral Trunk Muscles Muscle Layers 1. Rectus Abdominis ○ Superficial muscle; characterized by tendinous intersections (e.g., "six-pack"). ○ Function: Flexion of the trunk. 2. External Oblique ○ Originates on ribs and runs inferiorly and medially. ○ Function: Contributes to flexion and lateral flexion; activates in a "pocket" orientation. 3. Internal Oblique ○ Originates on the iliac crest and runs superiorly and medially. ○ Has the largest physiological cross-sectional area, producing significant isometric force. 4. Transverse Abdominis ○ Known as the "corset muscle." ○ Role: Compresses the abdomen and stabilizes the lower back. Role in Stabilization Study Findings: Deep abdominal muscles (internal oblique, transverse abdominis) activate before prime movers (like anterior deltoid) to stabilize the spine. Muscle Actions and Movements Flexion and Lateral Flexion Involved Muscles in Flexion: ○ Rectus abdominis ○ External oblique ○ Internal oblique Lateral Flexion: ○ Identifying muscles involved in left and right lateral flexion. ○ Understanding which muscles have the largest moment arm for these movements. Unilateral Activation and Movements Frontal Plane Motion:  ○ Side bending occurs on the same side (e.g., right external oblique = right lateral flexion). Horizontal Plane Motion: ○ Rotation occurs on the opposite side for the external oblique and on the same side for the internal oblique. Key Takeaways Understanding the differences between bilateral and unilateral contractions is crucial for analyzing trunk movements. Familiarity with the deep back muscles and their functional significance helps in clinical contexts, especially in low back pain. The anterior-lateral trunk muscles play essential roles in stabilization, flexion, and rotational movements. Study Guide: Head and Neck Muscles and Movements Objectives 1. Identify the muscles of the anterior and posterior cranial cervical region. 2. Understand the associated actions of these muscles. 3. Discuss clinical applications related to muscle function. Anterior and Lateral Cranial Cervical Region Muscles 1. Sternocleidomastoid (SCM) Origin: Mastoid process (posterior), sternum, and clavicles. Actions: ○ Unilateral Activation: Lateral flexion on the ipsilateral side (e.g., right SCM → right lateral flexion). Axial rotation to the contralateral side (e.g., right SCM → left rotation).  ○ Bilateral Activation: Extension of the upper cervical spine (C1 and C2). Flexion of the mid to lower cervical spine (C3 and below). Result: Protraction of the head and neck. 2. Scalene Muscles Groups: Anterior, Middle, and Posterior Scalene. Origin: Transverse processes of cervical vertebrae. Insertion: First and second ribs. Actions: ○ Primarily elevate the ribs (aids in ventilation). ○ Can assist with cervical flexion if arms are fixed. Clinical Application COPD: Hyperactive scalenes can indicate respiratory issues, as patients may recruit neck muscles to assist in breathing. Thoracic Outlet Syndrome: Hypertrophy of scalene muscles can compress the brachial plexus, leading to pain in the upper extremities. 3. Longus Colli and Longus Capitis Longus Colli: ○ Origin/Insertion: Extends from C1 to T3. ○ Actions: Stabilizes the spine and assists with cervical flexion. Longus Capitis: ○ Origin: Occipital bone. ○ Insertion: Transverse processes of mid to lower cervical spine. ○ Clinical Note: Can help correct forward head posture through specific exercises (e.g., longus coli nod). Posterior Cranial Cervical Region Muscles 4. Splenius Muscles Muscle Groups: Splenius Cervicis and Splenius Capitis. Origin: ○ Capitis: Occipital bone. ○ Cervicis: Transverse processes of upper cervical vertebrae.  Actions: ○ Unilateral Activation: Lateral flexion and ipsilateral rotation. ○ Bilateral Activation: Extension of the upper craniocervical region. 5. Suboccipital Muscles Location: Small muscles spanning the atlanto-occipital (AO) and atlanto-axial (AA) joints. Function: Provide fine motor control and stability in head movements. Importance of Craniocervical Stability Good posture is crucial; ideally, the ear should align with the shoulder. Forward Head Posture: ○ Caused by muscular imbalances, often due to chronic strain on the anterior muscles (SCM and scalene). ○ Results in excessive stress on posterior muscles (e.g., semispinalis capitis). Clinical Implications Poor posture can lead to: ○ Suboccipital headaches. ○ Scalp pain. ○ TMJ syndrome. Analogy Guy Wires: SCM and semispinalis capitis function like guy wires stabilizing a tower, helping maintain proper alignment and stability of the craniocervical region.