Axilla & Arm – Part 2, Muscles of the Back PDF

Axilla & Arm – Part 2 Muscles of the Back BiBi Singh,DPM September 23, 2024  Describe the vertebral column – regions, curvatures, joints and ligaments. Describe the parts of a typical vertebra and discuss specific characterist...

Axilla & Arm – Part 2 Muscles of the Back BiBi Singh,DPM September 23, 2024  Describe the vertebral column – regions, curvatures, joints and ligaments. Describe the parts of a typical vertebra and discuss specific characteristics by region. Describe the arrangement of the structures comprising the back from superficial to deep. Objectives Identify specific areas of the back (boundaries and contents) and discuss the clinical significance of these areas – Triangle of Auscultation and the lumbar triangle (Triangle of Petit). Discuss disc herniations. Superficial Muscles of the Back Connects the upper limb to the vertebral column Includes: Latissmus Dorsi Muscle Trapezius Muscle Layer below: Levator scapulae Rhomboid minor Rhomboid major Superficial Extrinsic muscles of the back Muscle Origin Insertion Innervation Action Latissmus Dorsi Spinous processes of lower 6 thoracic vertebrae Intertubercular Groove Thoracodorsal nerve Adductor & Extensor of the arm *Forms the axillary fold with Indirectly: the spinous processes of the lumbar Teres major and sacral vertebrae – Thoracolumbar Fascia Iliac crest Trapezius Spinous process of Cv7 Lateral 1/3 of the clavicle Accessory nerve Elevates shoulder Spinous process and supraspinous ligament of Acromion and crest of spine of Cervical plexus Pull scapula backwards the thoracic vertebra scapula plus tubercle Ligamentum Nuchae Superior nuchal line Levator scapulae Posterior tubercles of transverse processes of CV Medial Border of the scapula Cn3,Cn4 Elevates the scapula 1-4 Rhomboid minor Uppermost slip of spinous process CV 7 Scapula Dorsal scapular nerve Retracts and fixes the scapula Ligamentum nuchae – TV1 Rhomboid major Spines of Tv 2-5 Scapula Dorsal scapular nerve Retracts and fixes the scapula Serratus posterior superior Cv7 Ribs 2- 5 Ventral rami of C8 – T3 Elevates ribs *Lies deep to the rhomboids Aids in respiration Serratus posterior inferior Lower lumbar and thoracic spine Attached to 4 lower ribs T9 – T11 Depresses the ribs during *Lies deep to Latissimus dorsi forced exhalation, and may also help with deep inspiration, trunk rotation, and extension Triangle of Auscultation Trapezius Latissimus dorsi Medial border of scapula  Proximal Nerve Muscle Distal Attachment Main Action(s) Attachment Supply Superficial Splenius capitis: Fibers run Intrinsic Nuchal ligament and superolaterally to mastoid process of temporal bone and Posterior Acting unilaterally: laterally flexes the neck and Muscle Splenius spinous processes of C7–T6 lateral third of superior nuchal line of occipital bone. rami of spinal nerves rotates the head to side of active muscles Splenius Acting vertebrae cervicis: tubercles bilaterally: extend the of transverse head and neck processes of C1– C3 or C4 vertebrae Deep Muscles of the Back Erector spinae Muscles/Sacrospinalis Muscles All supplied by the Dorsal rami of spinal nerves Named based on location 3 parallel groups or columns Lateral Intermediate and Medial Erector Spinae Muscles/ Lateral Intermediate Medial Innervation Iliocostalis Longissmus Spinalis Dorsal rami Sacrospinalis Lumborum Thoracis Thoracis of spinal Muscles Thoracis Cervicis Cervicis Capitis Cervicis Capitis nerves Deeper Muscles of the Back Transverso-spinal muscles 1. Mutifidus 2. Interspinalis 3. Intertransversarii 4. Rotatores (longus & brevis) 5. Semispinalis Suboccipital triangle Boundaries Rectus capitis posterior major Obliquus capitis superior Obliquus capitis inferior Contents Vertebral artery Suboccipital nerve Vertebral column 33 Vertebrae 7 Cervical 12 Thoracis 5 Lumbar 5 Sacral 4 Coccyx Primary vs. Secondary Curvature Primary Curvature Secondary curvature  Primary Curvature (Same as embryo) Thoracic Sacral Secondary Curvature ( After birth) Cervical Lumbar Typical vertebra Body Arch Lamina Pedicle Vertebral foramen Intervertebral notch Arch Inferior articular process Lamina Cervical and Thoracic region Between spinous process and transverse process Lamina Lumbar region Between spinous process and mamillary process Intervertebral notch Becomes a foramen when 2 vertebra are together Exit for spinal nerves Offers protection for spinal root ganglion Cervical Vertebra Bony axis of the neck Foramen transversarium on the transverse process of all 7 cervical vertebra. Vertebral vein passes through all 7 Vertebral artery passes through CV6 - 1 Short bifid proceses Cervical vertebra 1,2 & 7 are atypical Atlas Supports the skull Does not have a body Does not have a spinous process Has a Foramen transversarium Has 2 articulating facets for the condyles of the skull Has a facet to articulate with the Dens (Odontoid process)of the Axis Atlanto – Axial Joint & Atlanto- Occipital Joint The lateral atlanto-axial joints are gliding-type synovial joints, whereas the median atlanto-axial joint is a pivot joint. The atlanto occipitaljoint are synovial joints of the condyloid type and have thin, loose joint capsules. Axis 2 flat articulating surfaces Dens/Odontoid process Vertebra Prominens Transitional vertebra from cervical region to thoracic region May or may not have a bifid spine Long spinous process Important landmark Thoracic vertebra 12 Articulate with ribs Articulate with facets and demi-facets Long spinous process No foramen transversarium No bifid spine No mammillary process Thoracic Vertebra 6 Articulates with Superior articular process of TV 7 Inferior articular process of TV 5 Tubercle of head of rib 6 Head of rib 6 Costovertebral joint - Synovial plane joint Lumbar Vetebra 5 No costal facets No Foramen Transversarium Thick Pedicle and Lamina Mammillary processes Size increases from Lv1 – Lv5 Triangle of Petit Boundaries Posteriorly by latissimus dorsi Anteriorly ny the exyernal oblique Inferiorly by the iliac crest The floor of the triangle is the internal oblique muscle. Hernia may occur at this location Sacral Vertebra Fused 4 Foramina for spinal nerves Sv1 – Sacral promontory Coccyx Tailbone small triangular bone that is usually formed by fusion of the four rudimentary coccygeal vertebrae Coccygeal vertebra 1 (vertebra Co1) may remain separate from the fused group. The coccyx is the remnant of the skeleton of the embryonic tail-like caudal eminence, which is present in human embryos from the end of the 4th week until the beginning of the 8th week Intervertebral discs Fibrocartilage 2 parts: Nucleus pulposus – center contains water and is a remnant of the notochord Annulus fibrosis – periphery If the annulus fibrosis degenerates, the nucleus pulposus may herniate into the vertebral canal and compress the spinal cord or roots of the cauda equina Clinical Pearls – Intervertebral Disc In older adults the intervertebral disc Decrease in size Person may appear shorter Slip disc/herniation of nucleus pulposus ¼ length of the vertebral column Limited movement and fexibilty Abnormal Curvatures of the Vertebral Column Curvature Definition Kyphosis Humpback – Exaggerated in the Thoracic region Lumbar Kyphosis Reverse normal curvature of the lower back Spondylolysis Disruption of pars interarticularis Lordosis Abnormal curvature of the spine in the lumbar region Scoliosis Side to side curvature of the back Functional scoliosis Caused by limb length discrepancy or other functional disorder Spondylolysis Pars interarticularis defect occurs following stress or repetitive microtrauma. Bilateral pars fracture may lead to spondylolisthesis with the vertebra slipped on the vertebra below dragging its nerve root against the normally placed disc (so-termed pseudobulge) which results in patient's symptomatology. Functional Scoliosis Vertebral Rotation in Functional Scoliosis Caused by Limb-Length Inequality: Correlation between Rotation, Limb Length Inequality, and Obliquity of the Sacral Shelf - by Martina Marsiolo,Silvia Careri,Diletta Bandinelli,Renato Maria Toniolo Journal of Clinical Medicine