REVIEW OF ANATOMY OF SPINE UNDERLYING INTERVERTEBRAL DISC

REVIEW OF ANATOMY OF SPINE UNDERLYING INTERVERTEBRAL DISC REPAIR

CERVICAL SPINE IS NOSE CERVICAL SPINE LOCATED IN CENTER ISOF LOCATED IN NECK CENTER OF NECK SURROUNDED BY MANY STRUCTURES THAT STRUCTURES ARE MANY ESSENTIAL, SMALL THAT ARE ESSENTIAL, AND READILY SMALL AND FRAGILE DAMAGED BODY OF CERVICALVERTEBRA INTERVERTEBRAL DISC THESE SLIDES REVIEW THE ANATOMY OF VERTEBRAE, STRUCTURE OF THE NECK AND SPINAL CORD TO APPRECIATE THE TECHNIQUE OF CERVICAL DISC REPAIR

ANATOMY OF TYPICAL VERTEBRA 1. BODY – anterior, solid transmits weight 2. VERTEBRAL ARCH – posterior, surrounds vertebral canal, spinal cord; consists of a) PEDICLES – project from body b) LAMINAE – unite to form arch posteriorly anterior NOSE BODY { VERTEBRAL ARCH PEDICLE LAMINA TRANSVERSE PROCESSLATERAL SPINOUS PROCESS POSTERIOR 3. TRANSVERSE AND SPINOUS PROCESSES - projections from arch for muscle, ligament attach

LATERAL VIEW OF VERTEBRA JOINTS BETWEEN VERTEBRAE PERMIT MOVEMENTS HOWEVER, CAN POTENTIALLY DAMAGE SPINAL NERVES 1. Location of Intervertebral Discs between bodies NOSE Sup. Vertebral Notch Inf. Vertebral Notch 2. Spinal nerves leave vertebral canal via INTERVERTEBRAL FORAMINA - between vertebrae; bordered by – Superior and Inferior Vertebral Notches

VERTEBRA IN DIFFERENT REGIONS ARE SPECIALIZED Cervical (neck) - 7 vertebrae (C 1 -C 7) Thoracic (chest) - 12 vertebrae (T 1 -T 12) Lumbar (lower back) - 5 vertebrae (L 1 -L 5) Sacral (pelvis) - 5 fused vertebrae (S 1 -S 5) Coccygeal (tail) - 3 -5 vertebrae (Co 1 -Co 3) Vertebral column functions like structural support column Most weight is supported at base of column (lumbar and sacral vertebrae are large) Cervical vertebrae are relatively small

NOSE CERVICAL VERTEBRA - small and highly mobile BODY ant. – body is small Foramen Transversarium - in transverse process (C 1 -C 7) for Vertebral artery & veins TRANSVERSE PROCESS post. SPINOUS PROCESS – bifid (divided) for Ligamentum nuchae lat. view ARTICULAR FACETS - angled superiorly & medially - PERMIT CONSIDERABLE MOVEMENT

VERTEBRAE ARE STABILIZE BY BEING LINKED BY LIGAMENTS, INTERVERTEBRAL DISCS 1. ANTERIOR LONGITUDINAL LIGAMENT Strong band joins bodies on anterior side Adjacent vertebrae held tightly together (protect spinal cord) Anterior view

VIEW FROM INSIDE VERTEBRAL COLUMN On post. Side of bodies LOOK ANTERIOR LOOK POSTERIOR 2. POSTERIOR LONGITUDINAL LIGAMENTweaker, narrower band on posterior side of bodies 3. LIGAMENTA FLAVA yellow elastic bands connecting laminae

STRUCTURE/ FUNCTION OF INTERVERTEBRAL DISC Intervertebral discs function as shock absorbers; there are strong but undergo degeneration with age (begins at about age 20) a) Nucleus pulposusinner gelatinous core b) Anulus fibrosus collagen fibers & fibrocartilage

MRI OF 'SLIPPED DISK' FROM SNELL'S TEXTBOOK ANTERIOR POSTERIOR HERNIATION OF NUCLEUS PULPOSUS

DAMAGE TO INTERVERTEBRAL DISCS Posterolateral post POSTERIOR LONGITUDINAL LIGAMENT lateral ANTERIOR LONGITUDINAL LIGAMENT Typically in Postero-Lateral Direction, lateral to Posterior Longitudinal Ligament (Anterior Longitudinal Ligament is broad and strong) Disc herniation can lead to nerve compression at intervertebral foramen

DAMAGE TO CERVICAL INTERVERTEBRAL DISCS CAN PRODUCE SYMPTOMS IN UPPER EXTREMITY LOWER CERVICAL SPINAL NERVES FORM BRACHIAL PLEXUS Ventral rami of spinal nerves: C 5 C 6 C 7 C 8 T 1 DAMAGE TO SPINAL NERVES CAN PRODUCE SENSORY AND MOTOR LOSS

SENSORY LOSS - DERMATOME MAP THUMB = C 6 LITTLE FINGER = C 8 Dermatomes of upper extremity: C 6 - thumb C 7 - middle finger C 8 - little finger Questions: What is the level of a herniated disc that would produce numbness of thumb? Little finger?

NUMBERING OF CERVICAL SPINAL NERVES LEVELS OF SPINAL NERVES Cervical (C 1 -C 8) CONVENTION FOR NAMING LEVELS Thoracic (T 1 -T 12) Lumbar (L 1 -L 5) Sacral (S 1 -S 5) Coccygeal (Co 1) Spinal nerves C 1 -C 7 above vertebra C 8 and all others below vertebra Spinal nerves - arise from/project to spinal cord; there are 31 spinal nerves (8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal). Note: Cervical spinal nerves 1 -7 (C 1 -C 7) exit above corresponding vertebrae; Spinal nerve C 8 exits below vertebra C 7; All other spinal nerves exit below corresponding vertebrae. SPINAL NERVE C 6 ARISES ABOVE VERTEBRA C 6

TESTING OF SPINAL NERVE DAMAGE STRETCH REFLEXES CLINICAL TESTING OF STRETCH REFLEX: TENDON TAP 1 - Tendon tap elicits twitch because it excites almost all muscle spindles simultaneously 2 - Use stretch reflexes to test nerve function at different spinal levels Ia sensory neuron TENDON TAP Alpha motor neuron

REFLEXES USED FOR CLINICAL TESTS Nerve compressions can produce reduced spinal reflexes; also muscle weakness

NECK CONTAINS A NUMBER OF VITAL STRUCTURES SPINAL CORD TRACHEA COMMON CAROTID ARTERY INTERNAL JUGULAR VEIN ESOPHAGUS INTERVERTEBRAL DISC

ANATOMY OF NECK: NECK IS COMPARTMENTALIZED 1. Posterior Compartment Vertebrae and muscles which support and move head & neck Plane of section ANT. LAT. 2. Anterior Compartment. Viscera and rostral continuation GI & Respiratory Systems 3. Lateral Compartment. Blood vessels & nerve POST. HORIZONTAL SECTION THROUGH NECK: NOTE VERTEBRAE ARE IN CENTER OF NECK

Plane of section N O S E LOCATION OF STRUCTURES IN NECK: COMPARTMENTALIZED BY FASCIA Carotid Sheath Pretracheal layer Prevertebr al Layer- surrounds vert. column & muscles back of neck, prevertebral, lateral vertebral and suboccipital m. Pretracheal Layer- surrounds trachea, esophag. & thyroid continues to mediastinum Carotid Sheath- surrounds common & int carotid, int jugular and X (not: Symp. Chain) LOCATION OF INTERVERTEBRAL DISC Prevertebral layer

DISCS ARE POSTERIOR TO PREVERTEBRAL MUSCLES ACT - FLEX NECK/HEAD INN - CERVICAL VENTRAL RAMI 2. Longus capitis O - Trans processes C 3 -C 6 I - Occipital bone 1. Longus colli muscle O- Trans processes Lower cervical vertebrae I - Bodies upper cervical vertebrae Colli = neck in Latin View of anterior side of Cervical Vertebrae with structures of Anterior and Lateral Compartments removed

HOW IS DAMAGE TO CERVICAL INTERVERTEBRAL DISC REPAIRED? SEE DR. LECLERCQ'S LECTURE INTERVERTEBRAL DISC