Anatomy of the Back and Cervical Spine

Anatomy of the Back and Cervical Spine The Vertebral Column Atypical Vertebrae Atypical Cervical Vertebrae Atlas (C1) • Articulates with the occiput of the head and axis C2. • The anterior arch contains a facet for articulation with the dens of the axis. - This is secured by the transverse ligament of the atlas which attaches to the lateral masses. • The posterior arch has a groove for the vertebral artery and C1 spinal nerve Axis (C2) • Contains superior articular facets. - Articulate with the inferior articular facets of the atlas to form the two lateral atlanto-axial joints Vertebrae Prominens (C7) • Articulates with a rudimentary cervical rib Atypical Feature • No vertebral body • No spinous process • Lateral masses which are connected by an anterior and posterior arch. - Each lateral mass contains superior articular facet. ✓ This is for articulation with the occipital condyles. - Each also contain an inferior articular facet. ✓ This is for articulation with C2 • • Easily identifiable due to its dens (odontoid process) - These extend superiorly from the anterior portion of the vertebra. The dens articulate with the anterior arch of the atlas. - This creates the medial alanto-axial joint. ✓ This allows for rotation of the head independently of the torso Typical cervical vertebrae • C3-C6 Thoracic vertebrae • T1-T12 Lumbar Vertebrae • L1-L5 Sacrum Features on a vertebra. • • • Body Vertebral arch - Pedicles ✓ Forms the vertebral notches. ✓ Vertebral notches of adjacent form the intervertebral foramina, through which the spinal nerves travel - Laminae Articular surfaces - Intervertebral disc - Zygapophyseal or facet joints - With ribs (thoracic vertebra) costal facets Comparison and contrasting vertebrae. Thoracic Vertebra Upper Thoracic Middle Thoracic Lower Thoracic Lumbar Vertebra Upper Lumbar Lower Lumbar Protects the spinal cord in their vertebral arches Provide a bony enclosure for the cauda equina nerves that descend from the spinal cord Deduce from the articular facets the movements of different regions of the spine Movements of the spine - Identify the movements produced at the following joints and regions Atlantooccipital joint Atlantoaxial joint Cervical spine Thoracic spine Lumbar spine • • • • • • • • Lateral masses of atlas that articulate with occipital condyles Flexion/extension and limited lateral bending and rotation Rotation of the head Flexion/extension: facilitated by position of zygapophyseal joints Lateral flexion: facilitated by large intervertebral disk Most stable region of the spine due to the ribs Rotation permitted around zygaphyseal joints Flexion/extension and lateral rotation both facilitated by curved and interlocking zygapophyseal joints Identify the bony attachments of the following major ligaments. - NOTE: THESE LIGAMENTS MAINTAIN JOINT STABILITY WHILE ALLOWING FOR MOVEMENT Of? Vertebral bodies Ligament Intervertebral discs Vertebral bodies Anterior and posterior longitudinal ligaments IMPORTANT NOTE: THE POSTERIOR LONGITUDINAL LIAGMENT IS NARROW AT THE BODY AND WIDER AT THE DISC Vertebral arches Ligament flava IMPORTANT NOTE: THICK, FIBREOELASTIC YELLOW CONNECTIVE TISSUE Interspinous and supraspinous ligaments Vertebral arches Atlas and axis Atlantooccipital ligaments Atlas and axis Atlantoaxial ligaments Bony attachments • Superiorly to the occipital bone • Anteriorly to the foramen magnum • Anteriorly to the tubercle of vertebra C1 (atlas) • Extends caudally to the anterior (pelvic) surface of the upper sacrum ANTERIOR • Vertebral bodies • Intervertebral discs along its length from the body of C2 (axis) POSTRIOR • Attached to the vertebral bodies. • Mainly the intervertebral discs along its length from the body of C2 (axis) to the sacrum • From the superior attachment, the posterior longitudinal ligament extends into the intracranial aspect of the base of the skull as the tectorial membrane. • • Connects laminae of adjacent vertebral arches o each side Runs almost vertically from the anterior surface of the lamina above to the posterior surface of the lamina below INTERSPINOUS LIGAMENT • Connect adjacent vertebral spinous processes • Attaches from the base of the apex of ach spinous process. SUPRASPINOUS LIGAMENT • Connects the tips of the spinous process from vertebra C7 to the sacrum • Between the superior articular surfaces of the atlas and condyles of the occipital bones • Superiorly on the posterior aspect of the lateral mass of the atlas near its transverse ligament • Hold the vertebrae together. ANTERIOR • Only ligament that prevents hyperextension of the spine POSTERIOR • Resists hyperflexion of the vertebral column and helps prevent posterior herniation of the nucleus pulposus of an IV disc • • Resist separation of the lamina during flexion Aids in the extension of the vertebral column back to its erect anatomical posture INTERSPINOUS LIGAMENT • Limits flexion of the spine SUPRASPINOUS LIGAMENT • Prevents separation of spinous processes during flexion and resists hyperflexion • Flexion/extension • Rotation Boundaries of the intervertebral foramina • The particular spinal nerve which emerges from each intervertebral foramen • Where the vertebral vessel travel IMPORTANT NOTE: THE INTERVERTEBRAL DISC ANTERIROLY AND THE ZYGAPOPHYSEAL POSTERIROLY Muscles of the back Thoracolumbar fascia • • • • Description - Large roughly diamond shaped area pf connective tissue that is made up by the thoracic and lumbar pats of the deep fascia enclosing the intrinsic back muscles. Course - Extends from the vertebrae to the sacrum. Functions - Separates the paraspinal muscles from the muscles of the posterior abdominal wall. - Divides muscles into compartments. - Serves as an attachment site for various muscles of the back. - Involved in the movement and lad transfer between the trunk and the limbs. - Houses several deep muscles of the back such as the quadratus lumborum. Transersospinalis, spinal erectors and multifidus. - Contains several nociceptive nerve endings that may be responsible for some forms of the pack pain. Attachments - Nuchal ligaments, spinous process, supraspinous ligament, median crest of sacrum Superficial Muscles of the back IMPORTANT NOTE: THESE ATTACH FROM THE UPPER LIMB TO THE VERTEBRAL COLUMN Muscles Trapezius Origin Sup. Nuchal line, external occipital protuberance, spinous processes C7-12 Insertion Spine of the scapula Innervation Spinal accessory nerve (CN XI) + C3-4 Latissimus dorsi Spinous processes T712, thoracolumbar fascia + post. Iliac crest Transverse process C14 Ligamentum nuchae, spinous processes C7T1 Spinous processes of T2-5 Intertubercular groove Dorsal scapular nerve + C3-4 Medial border of scapula (superior) Medial border of the scapula Dorsal scapular nerve + C3-4 Dorsal scapular nerve Elevate scapula Medial border of scapula (lower) Dorsal scapular nerve Retract + elevate scapula Levator scapulae Rhomboid minor Rhomboid major Function Descending: elevate scapula Middle: retract scapula Ascending: depress scapula Adduction, med. Rotation + extension Retract + elevate scapula Muscles of the intermediate back IMPORTANT NOTE: MUSCLES WHICH ATTACH TO THE RIBS FOR RESPIRATION Serratus posterior superior Serratus posterior inferior Origin Nuchal ligament, spinous processes of vertebrae C7-T3 Spinous processes of vertebrae T11-L2 Insertion Superior borders of ribs 2-5 Innervation 2nd-5th Intercostal nerves Function Elevates the ribs Inferior borders of ribs 9-12 Anterior rami of spinal nerves T9-T12 (a.k.a. 9th-11th Intercostal nerves + subcostal nerve) Depresses ribs/ Draws ribs inferoposteriorly Deep back muscles - IMPORTANT NOTE: THESE ARE KNOWN AS THE INTRSIC MUSCLS OF THE BACK Erector spinae group (long muscles) Iliocostalis Longissimus Origin • Iliocostalis cervicis: Angle of ribs 3-6 • Iliocostalis thoracis: Angle of ribs 7-12 • Iliocostalis lumborum: Lateral crest of sacrum, medial end of iliac crest, thoracolumbar fascia • • • Spinalis • • • Longissimus capitis: Transverse processes of vertebrae C4-T5 Longissimus cervicis: Transverse processes of vertebrae T1-T5 Longissimus thoracis: - Lumbar part - Lumbar intermuscular aponeurosis, medial part of sacropelvic surface of ilium, Posterior sacroiliac ligament - Thoracic part - Spinous and transverse processes of vertebrae L1-L5, median sacral crest, posterior surface of sacrum and posterior iliac crest Capitis: spinous processes of C7 – T1 vertebrae Cervicis: spinous processes of C7 – T1 vertebrae; nuchal ligament Thoracis: spinous process of T11 – L2 Insertion • Iliocostalis cervicis: Transverse processes of vertebrae C4-C6 • Iliocostalis thoracis: Angles of ribs 1-6, transverse process of vertebra C7 • Angle of ribs 5-12, transverse processes of vertebrae L1-L4 (+ Adjacent thoracolumbar fascia • Longissimus capitis: Mastoid process of temporal bone • Longissimus cervicis: Transverse processes of vertebrae C2-C6 • Longissimus thoracis: - Lumbar part - Accessory and transverse processes of vertebrae L1-L5 - Thoracic part - Transverse process of vertebrae T1T12, Angles of ribs 7-12 • • • Capitis: occipital bone (midline) Cervicis: spinous process of C2 – C4 vertebrae Thoracis: spinous process of T2 – T8 vertebrae Innervation Lateral branches of posterior rami of spinal nerves Function Bilateral contraction: Extension of spine Unilateral contraction: Lateral flexion of spine (ipsilateral) Lateral branches of posterior rami of spinal nerves Entire muscle: Bilateral contraction - Extension of spine Unilateral contraction - Lateral flexion of spine (ipsilateral) Longissimus capitis only: Bilateral contraction - Extension of head and neck Unilateral contraction - Lateral flexion and rotation of head (ipsilateral) Lateral branch of posterior rami of spinal nerves • • Bilateral contraction: extension of head, cervical and thoracic spines Unilateral contraction: ipsilateral lateral flexion of cervical and thoracic spine Transversospinalis groups (oblique muscles) Muscles Semispinalis Multifidus Origin Articular processes of vertebrae C4-C7, transverse processes of vertebrae T1-T6 • • • Multifidus cervicis: Superior articular processes of vertebrae C4-C7 Multifidus thoracis: Transverse process of thoracic vertebra Multifidus lumborum: Mammillary processes of lumbar vertebrae, posterior aspect of sacrum, posterior superior iliac spine (PSIS) of ilium and posterior sacroiliac ligamen • Innervation Descending branches of greater occipital nerve (C2) and spinal nerve C3 Lateral aspect and tips of the spinous processes of vertebrae 2-5 levels above origin Medial branches of posterior rami of spinal nerves • Rotatores • Insertion Between superior and inferior nuchal lines of occipital bone Rotatores breves: Transverse processes of vertebrae T2-T12 Rotatores longi: Transverse processes of thoracic vertebrae • Rotatores breves: Laminae/Spinous process of vertebra (1 level above origin) Rotatores longi: Laminae/Spinous process of vertebra (2 levels above origin) Medial branches of posterior rami of spinal nerves Function Bilateral contraction extension of head, cervical and thoracic spine Unilateral contraction lateral flexion of head, cervical and thoracic spine (ipsilateral), rotation of head, cervical and thoracic spine (contralateral) • Bilateral contraction: Extension of spine • Unilateral contraction: Lateral flexion of spine (ipsilateral), rotation of spine (contralateral) stabilizers, extensors and rotators of the spine. Ungrouped deep muscles. Muscles Splenius Interspinales Origin Spinous processes of vertebrae C7-T3, nuchal ligament • • • Intertransversarri • • Levator costarum Interspinales cervicis: Superior aspect of spinous processes of vertebrae C3-T1 Interspinales thoracis: Superior aspect of spinous process of vertebrae T2, T11 & T12 (variable) Interspinales lumborum: Superior aspects of spinous processes of vertebrae L2-L5 Lateral lumbar intertransversarii: Transverse and accessory processes of vertebrae L1-L4 Medial lumbar intertransversarii: Accessory processes of vertebrae L1-L4 Transverse processes of the C7 – T11 Insertion Lateral superior nuchal line of occipital bone, mastoid process of temporal bone • Interspinales cervicis: Inferior aspect of spinous processes of vertebrae C2-C7 • Interspinales thoracis: Inferior aspect of spinous processes of vertebrae T1, T10 & T11 • Interspinales lumborum: Inferior aspects of spinous processes of vertebrae L1-L4 • Lateral lumbar intertransversarii: Transverse process of succeeding vertebra • Medial lumbar intertransversarii: Mammillary processes of succeeding vertebra Superior border/external surface of rib one level below origin Innervation Lateral branches of posterior rami of spinal nerves C2-C3 Posterior rami of spinal nerves Function • Bilateral contraction: Extends head/neck • Unilateral contraction: Lateral flexion and rotation of head (ipsilateral) Extension of cervical and lumbar spine Anterior rami of spinal nerves Assists lateral flexion of the spine; Stabilizes spine Posterior rami of spinal nerves T1 – T12 • • Elevation of the ribs Rotation of thoracic spine \ Fascia Describe the fascial layout of the neck, noting the fascia indicated below and the muscular compartments created. Key Information • • • Structures making up the neck are surrounded by a layer of subcutaneous tissues called the cervical fascia and are compartmentalised by a second group of fasciae referred to as the deep cervical fascia. Superficial cervical fascia - Subcutaneous connective tissue located between the dermis and investing layer of deep cervical fascia. Deep cervical fascia - Investing layer - Pretracheal layer - Carotid sheath Important Parts Part Cervical fascia (deep fascia of the neck) Description • guide against the spread of pus and debris (abscesses) resulting from diseased or abnormal tissues, however, a potential pathway for spread of infection exists. • most walls of several regions of the body, structures making up the neck are surrounded by a layer of subcutaneous tissue called the superficial cervical fascia and are compartmentalized by a second group of fasciae referred to as deep cervical fascia. Investing fascia (deep fascia of roof of posterior triangle) Prevertebral fascia (deep fascia of the floor of posterior triangle) Pretracheal fascia Carotid sheath most superficial, enclosing trapezius, sternocleidomastoid, submandibular and parotid glands occupies the anterior part of the neck, consisting of muscular and visceral parts Suprapleural membrane encloses vertebral column, longus colli and longus capitis muscles contains the common carotid arteries, internal carotid arteries, internal jugular vein, the vagus nerve (CN X), some deep cervical lymph nodes, carotid sinus nerve, and sympathetic nerve fibres dense fascial layer that is attached to the inner border of the first rib and costal cartilage anteriorly, C7 transverse process posteriorly and to the mediastinal pleura medially Superficial Muscles within the fascia Muscle Platysma (In superficial fascia) Origin Skin/fascia of infraand supraclavicular regions Sternocleidomastoid Sternal head: (in investing fascia) superior part of anterior surface of manubrium sterni Clavicular head: superior surface of medial third of the clavicle Insertion Lower border of mandible, skin of buccal/cheek region, lower lip, modiolus, orbicularis oris muscle Lateral surface of mastoid process of the temporal bone, Lateral half of superior nuchal line of the occipital bone Innervation Cervical branch of facial nerve (CN VII) Accessory nerve (CN XI), branches of cervical plexus (C2C3) Function Depresses mandible and angle of mouth, tenses skin of lower face and anterior neck • • Unilateral contraction: cervical spine: neck ipsilateral flexion, neck contralateral rotation Bilateral contraction: atlantooccipital joint/ superior cervical spine: head/neck extension; Inferior cervical vertebrae: neck flexion; sternoclavicular joint: elevation of clavicle and manubrium of sternum Suprahyoid Muscles Muscle Digastric Origin • Anterior belly: digastric fossa of mandible • Posterior belly: mastoid notch of temporal bone Stylohyoid Styloid process of temporal bone Thyrohyoid Oblique line of thyroid cartilage Omohyoid • • Inferior belly: superior border of scapula near the suprascapular notch Superior belly: intermediate tendon Insertion Body of hyoid bone (via intermediate tendon and its fibrous sling) Body of hyoid bone Inferior border of body and greater horn of hyoid bone • Inferior belly: intermediate tendon • Superior belly: body of hyoid bone Innervation • Anterior belly: mylohyoid nerve (of inferior alveolar nerve) (CN V3) • Posterior belly: digastric branch of facial nerve (CN VII) Stylohyoid branch of facial nerve (CN VII Anterior ramus of spinal nerve C1 via hypoglossal nerve (CN XII) Anterior rami of spinal nerves C1-C3 (via ansa cervicalis) Function depress the mandible for jaw opening, chewing, and speech. Elevates and draws hyoid bone posteriorly • Depresses hyoid bone • Elevates larynx • • Depresses and retracts hyoid and larynx Tenses carotid sheath Muscles deep to prevertebral fascia Anterior (pre)vertebral muscles Muscles Longus Coil Origin • Superior part: Anterior tubercles of transverse processes of vertebrae C3-C5 • Intermediate part: Anterior surface of bodies of vertebrae C5T3 • Inferior part: Anterior surface of bodies of vertebrae T1-T3 Longus Capitis Anterior tubercles of transverse processes of C3-C6 Rectus capitisanterior and lateral Anterior surface of lateral mass and transverse process of atlas Insertion • Superior part: Anterior tubercle of vertebra C1 • Intermediate part: Anterior surface of bodies of vertebrae C2C4 • Inferior part: Anterior tubercles of transverse processes of vertebrae C5C6 Basilar part of occipital bone Innervation Anterior rami of spinal nerves C2C6 Inferior surface of basilar part of occipital bone Anterior rami of spinal nerves C1, C2 Anterior rami of spinal nerves C1C3 Function • Bilateral contraction: Neck flexion • Unilateral contraction: Neck contralateral rotation, neck lateral flexion (ipsilateral) • Bilateral contraction head flexion. • Unilateral contraction head rotation (ipsilateral) Atlantooccipital joint: Head flexion Lateral Vertebral Muscles – Scalene Muscle Name Scalenus anterior Origin Insertion Innervation anterior tubercle of transverse processes of vertebrae C3-C6 anterior scalene tubercle of rib 1, superior border of rib 1 (anterior to subclavian groove) anterior rami of spinal nerves C4-C6 Scalenus medius posterior tubercles of transverse processes of vertebrae C2-C7 anterior rami of spinal nerves C3-C8 Scalenus posterior posterior tubercles of transverse processes of vertebrae C5-C7 superior border of rib 1 (posterior to subclavian groove) external surface of rib 2 Function • • anterior rami of spinal nerves C6-C8 bilateral contraction neck flexion unilateral contraction neck lateral flexion (ipsilateral), neck rotation (contralateral), elevates rib 1 neck lateral flexion, Elevates rib 2 Posterior vertebral muscles Muscles Splenius (Capitis and cervicis) Semispinalis (Capitis and cervicis) erector spinae sub-occipital Origin Insertion Innervation Function Suboccipital Muscles Muscle Rectus capitis posterior minor Origin Posterior tubercle of atlas Rectus capitis posterior major Spinous process of axis Obliquus capitis superior Obliquus capitis inferior Transverse process of atlas Spinous process of axis Insertion Medial part of inferior nuchal line of occipital bone Lateral part of inferior nuchal line of occipital bone Innervation Posterior ramus of spinal nerve C1 (suboccipital nerve) Occipital bone (between superior and inferior nuchal lines) Suboccipital nerve (posterior ramus of spinal nerve C1) Transverse process of atlas Posterior ramus of spinal nerve C1 (suboccipital nerve) Suboccipital nerve (posterior ramus of spinal nerve C1) Function Bilateral contraction Atlantooccipital joint: Head extension • • • • • • Bilateral contraction at the atlantooccipital joint: Head extension Unilateral contraction at the atlantoaxial joint: Head rotation (ipsilateral) Bilateral contraction Atlantooccipital joint: Head extension Unilateral contraction Atlantoaxial joint: Head lateral flexion (ipsilateral) Bilateral contraction Atlantooccipital joint: Head extension Unilateral contraction Atlantoaxial joint: Head rotation (ipsilateral)