musculoskeletal system

• Vertebral column consists of 33 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccyx
• Spinal nerves are paired and carry sensations anteriorly and posteriorly, forming plexuses from the network of anterior rami
• Features of typical cervical vertebrae include foramen transversarium, triangular vertebral foramen, and bifid spinous process
• Atypical cervical vertebrae like C1 (Atlas) and C2 (Axis) have unique characteristics such as C1 not having a vertebral body but an arch, and C2 having a bony prominence known as dens
• Unique to the cervical spine are joints like the Atlanto-occipital joint and Atlanto-axial joints
• Ligaments present throughout the vertebral column include the nuchal ligament, transverse ligament of the atlas, alar ligament, and apical ligament
• Ligaments unique to the thoracic spine include the radiate ligament, costotransverse ligament, lateral costotransverse ligament, and superior costotransverse ligament
• Features of typical lumbar vertebrae include superior and inferior articular facets orientation, mammillary processes, and accessory processes
• Important ligament in the sacrum and coccyx region is the anterior sacroiliac ligament, which plays a role in childbirth
• Back muscles are categorized into deep, intermediate, and superficial layers, each associated with different movements
• Deep layer back muscles include spinotransversalis, erector spinae, transversospinalis, and minor deep intrinsic muscles
• Movements of the vertebral column include flexion, extension, lateral flexion, and rotation
• Degenerative spine disease can cause chronic back pain due to disk herniation or age-related degenerative changes, generating significant inflammatory response and mechanical neural compression
• Radicular symptoms in the upper and lower limbs can be experienced due to degenerative spine disease
• Management of mechanical back pain involves controlling pain and inflammation with painkillers or anti-inflammatories, restoring joint range of movement and soft tissue extensibility through physiotherapy, and improving and maintaining muscle strength
• Disc herniation symptoms can include lumbar pain, occasional numbness in lower limbs, sudden onset of sharp pain, and stiffness affecting trunk flexion
• MRI can show disc herniation at specific vertebrae levels, inflammation of the sacroiliac joint, and may require a combination of medications to avoid gastric problems
• The vertebral column contains 33 vertebrae divided into 5 regions: 7 Cervical, 12 Thoracic, 5 Lumbar, 5 fused Sacrum, and 4 fused Coccyx
• Primary curvatures like Thoracic and Sacrococcygeal are formed at birth, while secondary curvatures like Cervical and Lumbar develop after birth
• Cervical vertebrae have unique features like the foramen transversarium in their transverse processes and a bifid spinous process
• Thoracic vertebrae have demi-facets on the sides of each vertebral body that articulate with the heads of the ribs, and costal facets on the transverse processes that articulate with the tubercles of the ribs
• Lumbar vertebrae have kidney-shaped vertebral bodies, short and broad spinous processes, and mamillary and accessory processes on the articular and transverse processes
• Intervertebral discs permit flexibility of the spine, act as shock absorbers, and support the curvature of the spine
• The spinal cord ends at L1, but spinal nerve fibres below that region form the cauda equina
• Ligaments of the vertebral column include the anterior and posterior longitudinal ligaments, ligamentum flavum, interspinous ligament, supraspinous ligament, and intertransverse ligament
• The spinal nerve roots pass through the intervertebral foramina, containing arteries, vessels, nerves, and transforaminal ligaments
• Dermatomes, strips of skin innervated by a single spinal nerve, are used to understand sensory symptoms related to spinal nerve damage
• The sciatic nerve, from L4-S3, innervates the skin and muscles of the lower limb and foot, and irritation or compression can lead to symptoms like pain, numbness, and weakness
• Bones of the pectoral girdle

  • Manubrium sterni
  • Clavicle (collarbone)
  • Scapula (shoulderblade)
  • Humerus
• Clavicle


  • No medullary cavity, trabecular bone surrounded by compact shell
  • Great variation in shape and ossification timeline
• Acromio-clavicular joint

  • Synovial joint with incomplete articular disc
  • Stabilised by ligaments like trapezoid and conoid
  • Injury leads to separated shoulder
• Regions of the shoulder

  • Anterior: pectoral region
  • Lateral: deltoid region
  • Posterior: scapular region
• Gleno-humeral joint

  • Synovial joint with ball-and-socket structure
  • Extremely mobile, prone to dislocation
  • Glenoid labrum for stability
• Sternoclavicular joint

  • Synovial joint with articular disc
  • Stabilised by short ligaments
  • Allows for greater movement between axial skeleton and pectoral girdle/upper limb
• Clavicle

  • Sternal facet found on the medial end for the SC joint
  • Acromial facet found on the lateral end for the AC joint
  • Trapezoid line for trapezoid ligament attachment
  • Conoid tubercle for conoid ligament attachment
  • Subclavian groove for subclavian muscles attachment
• Scapulo-thoracic joint


  • Not an anatomically correct joint
  • Known by movements like elevation, depression, retraction, protraction, upward and downward rotations
• Scapula


  • Long bone with head, neck, and body
  • Anterior surface is flat, posterior surface has a pronounced spine
  • Glenoid cavity for humerus articulation
  • Various fossae and processes like acromion and coracoid
• Joints of the pectoral girdle

  1. Sternoclavicular joint

  2. Acromio-clavicular joint

  3. Scapulo-thoracic joint

  4. Gleno-humeral joint
• Ligaments of the shoulder joint

  • Acromioclavicular ligament
  • Coraco-clavicular ligament
  • Coraco-acromial ligament
  • Coraco-humeral ligament
  • Gleno-humeral ligament (superior, middle, and inferior)
• Posterior axio-appendicular muscles

  Deep muscles elevate, retract, and rotate the scapula. Levator scapulae and rhomboid minor elevate the scapula. Rhomboid minor and major help to retract the scapula. Levator scapulae rotates the scapula counterclockwise whereas the rhomboid major rotates the scapula clockwise. Serratus anterior protracts the scapula. Trapezius originates from the external occipital protuberance, the superior nuchal line, and the spinous processes of C7-T12. Latissimus dorsi originates from the spinous process of T7-T12, thoracolumbar fascia, and the iliac crest