3. Ext & Int Muscles of the Back_NB.pdf

MUSCLES OF THE BACK Prof Nanette Briers Head: Division of Clinical Anatomy [email protected] Room 4015, Level 4, Tygerberg Campus Copyright Material which is made available by way of an electronic database may be subject to certain licensing conditions. These conditions no...

MUSCLES OF THE BACK Prof Nanette Briers Head: Division of Clinical Anatomy [email protected] Room 4015, Level 4, Tygerberg Campus Copyright Material which is made available by way of an electronic database may be subject to certain licensing conditions. These conditions normally entail that you may only use the material for your own private study and research at the University and not for any other purpose. It is expected of you to adhere to these conditions at all times. Printed material is also only made available for class discussion, private study and research purposes. Further reproduction of such material is prohibited. Slides may not be shared on open or closed websites.  Learning Outcomes The vertebral column and back: 1. Name the functions of the vertebral column. 2. Describe the typical characteristics of the vertebral column. 3. Describe the characteristics of a typical vertebra as well as the regional (cervical; thoracic; lumbar; sacral; coccygeal) characteristics of vertebrae. 4. Name, identify and classify all the joints of the vertebral column. 5. Discuss the anatomy of the atlanto-occipital and atlanto-axial joints (aka craniovertebral joints), intervertebral and sacroiliac joints. 6. Name and identify all the ligaments involved in the vertebral column. 7. Name, identify and classify the extrinsic and intrinsic back muscles and indicate in which movements of the vertebral column these muscles are involved in. Content Extrinsic back muscles:  Deep layer: (AKA Intrinsic mm)  Superficial Superficial layer  Splenius capitis Trapezius  Splenius cervicis Latissimus dorsii  Intermediate (Erector spinae): Levator scapulae  Iliocostalis Rhomboid major  Longissimus Rhomboid minor  Spinalis  Deep: Intermediate layer  Transversospinales Serratus posterior superior  Semispinales Serratus posterior inferior  Multifidus  Rotatores Suboccipital triangle  Minor deep back muscles:  Interspinales  Intertransversarii  Levatores costarum EXTRINSIC BACK MUSCLES Superficial extrinsic back muscles: Posterior axio-appendicular muscles Connect axial skeleton with superior appendicular skeleton Trapezius Latissimus dorsi Levator scapulae Rhomboid major Rhomboid minor  Innervation:  Anterior rami of cervical nerves  Exception: Trapezius Motor fibers - Spinal accessory nerve (CN XI) Posterior view EXTRINSIC BACK MUSCLES TRAPEZIUS LATISSIMUS DORSI EXTRINSIC BACK MUSCLES LEVATOR SCAPULAE RHOMBOID MINOR EXTRINSIC BACK MUSCLES LEVATOR SCAPULAE RHOMBOID MAJOR  EXTRINSIC BACK MUSCLES Intermediate extrinsic back muscles Serratus posterior superior Serratus posterior inferior Description: Designated superficial respiratory muscles Superior = elevate ribs Inferior = depress ribs More likely proprioceptive Innervation: Intercostal nerves (Specify!) Serratus posterior superior: T1-4 Serratus posterior inferior: T8 - 12 EXTRINSIC BACK MUSCLES SERRATUS POSTERIOR SUPERIOR SERRATUS POSTERIOR INFERIOR INTRINSIC BACK MUSCLES Muscles: Extend between pelvis and cranium Enclosed deep fascia Thoracolumbar fascia Grouped: Superficial Intermediate Deep Innervation: Posterior rami of spinal nerves  SUPERFICIAL LAYER SPLENIUS CAPITIS SPLENIUS CERVICIS Muscle Origin Insertion Action Nerve Other Supply Nuchal ligament Cervicis: Tubercles of Unilateral: Thick and flat transverse process C1-3/4 Laterally flex neck Lateral + posterior Spinous processes Posterior rami and rotate head aspect of neck C7-T6 spinal nerves Splenius Bilateral: Capitis: Lateral ⅓ superior Splenion = L. bandage Extension neck/ nuchal line & mastoid Cover vertical muscles head process like bandage  INTERMEDIATE LAYER Muscle Origin Insertion Action Nerve Supply Other Arises by tendon Iliocostalis: Lumborum, Unilateral: Fill “groove” on from posterior Thoracis, Cervicis Laterally flex vertebral column part of iliac crest, vertebral Posterior rami sides between posterior surface Longissimus: Thoracis, column spinal nerves spinous Erector Cervicis, Capitis spinae of sacrum, processes and sacroiliac Bilateral: the angels of ribs Spinalis: Thoracis, Extend ligaments, sacral Cervicis, Capitis Each column and inferior vertebral divided regionally lumbar spinous column and according to processes and head superior supraspinous attachment ligament  ERECTOR SPINAE (lateral to medial) ILIOCOSTALIS LONGISSIMUS SPINALIS  DEEP LAYER Rotatores Short, obliquely orientated muscles Transversospinales Semispinales Semispinalis capitis Semispinalis cervicis Semispinalis thoracis Multifidus Rotatores Minor deep back muscles: Interspinales Intertransversarii Levatores costarum  DEEP LAYER Short, obliquely orientated muscles Transversospinales Semispinales Semispinalis capitis Semispinalis cervicis Semispinalis thoracis Multifidus Rotatores Minor deep back muscles: Interspinales Intertransversarii Levatores costarum  DEEP LAYER SEMISPINALIS MULTIFIDUS  ROTATORES Origin: Transverse processes Fibers: Fibers have superomedial direction Insertion: Junction of lamina and transverse process of vertebrae Spinous process of vertebra Immediately superior: Brevis 2 segments superior: Longus Functions: Stabilizes vertebrae Assist extension and rotation of vertebral column brevis May function as organs of proprioception longus INTERSPINALES Origin: Superior surface of spinous process (C+L) Insertion: Inferior surface of spinous process of superior vertebrae Function: Aid in extension and rotation of column INTERTRANSVERSARII Origin: Transverse processes (C+L) Insertion: Transverse processes adjacent vertebrae Innervation: Anterior and posterior rami of spinal nerves Function: Unilaterally: Aid lateral flexion of column Bilaterally: Stabilizes column