Back and Spine

Primary Curve: Kyphosis Thoracic and Sacral 

Concave: Anterior

Convex: Posterior

Secondary Curve: Lordotic Cervical and Lumbar 

Concave: Posterior

Convex: Anterior

Typical Vertebrae

• Vertebrae whose structure depicts the typical anatomy of a vertebra

• Includes C3, C4,C5, and C6

Atypical Vertebrae

• Vertebrae with modified structures due to their function and position

• Includes C1, C2, and C7

ATLAS + Occiput 

• YES joint 

• AO joint 

• 50% of flexion and extension

• Condyloid joint 

ATLAS + AXIS 

• NO joint 

• AA joint 

• 50% of rotation 

• pivot joint / trochoid joint 

Intersegmental Ligament (3 types)

• Anterior Longitudinal Ligament

• Posterior Longitudinal Ligament

• Supraspinous Ligament

ALL (Anterior Longitudinal Ligament) 

• connects anterior vertebral bodies 

• taut / stretched during extension 

PLL (Posterior Longitudinal Ligament) 

• connects the posterior vertebral bodies 

• taut / stretched during flexion 

• Tectorial Membrane: superior continuation of PLL 

• incomplete below L2

Supraspinous Ligament 

• connect tip of spinous processes 

• Taut and stretched during flexion 

Intrasegmental Ligament

• Ligamentum Flavum / Yellow ligament

• Ligamentum Nuchae

• Interspinous Ligament

• Intertransverse Ligament

Ligamentum Flavum / Yellow ligament

connects adjacent lamina 

Ligamentum Nuchae

connects tip of spinous process from C7 to occiput

Interspinous Ligament

connects adjacent spinous process

Intertransverse Ligament

connects adjacent transverse process 

Transverse Ligament 

• holds the dens / odontoid process against the Atlas 

• prevents posterior subluxation of dens when fractured 

Alar Ligament 

prevents / limits skull & ATLAS rotation on AXIS 

AAA Ligament (Accessory Atlanto Axial)

Assist the Alar Ligament 

Apical Ligament 

from anterior foramen magnum down to apex of dens 

Manubriosternal Joint 

• where manubrium and the body articulate 

• AKA: sternal angle of the angle of louis 

Xiphisternal Joint 

• inferior aspect of the sternal body and the xiphoid process 

• ossifies by 40 - 50 years of age 

Muscles of the Back

• Trapezius Muscle

• Latissimus Dorsi Muscle

• Levator Scapulae Muscle

• Rhomboid Minor Muscle

• Rhomboid Major Muscle

Trapezius Muscle 

O: Occiput + Ligamentum Nuchae + C7-T1-T2 spines 

I: Lateral ⅓ of clavicle & acromion of spine 

N: CN 11 

A: Elevates & depresses shoulder, retracts scapula & / head

Latissimus Dorsi Muscle 

O: T6-T12 vertebral spine & iliac crest 

I: bicipital groove 

N: Thoracodorsal Nerve 

A: Adducts, extends and IR shoulder 

Levator Scapulae Muscle 

O: Transverse process of C1-C4 

I: Superior angle & medial border of scapula 

N: Dorsal Scapular Nerve 

A: Adducts and elevates the scapula 

Rhomboid Minor Muscle 

O: Vertebral spines of C7-T1 

I: Medial border of scapula 

N: Dorsal Scapular Nerve 

A: Adducts and elevates the scapula 

Rhomboid Major Muscle 

O: Vertebral spines of T2-T5 

I: Medial border of inferior angle of scapula 

N: Dorsal Scapular Nerve 

A: Adducts and elevates the scapula 

Intermediate Muscles of the Back

• Levatores Costarum Muscle

• Serratus Posterior Superior Muscle

• Serratus Posterior Inferior Muscle

Levatores Costarum Muscle

O: Transverse processes of C7, T1-T11 

I: Ribs 

N: Dorsal rami of thoracic spinal nerves 

A: Raises ribs during inspiration

Serratus Posterior Superior Muscle

O: Vertebral spine of cervical & upper thoracic vertebrae 

I: Ribs 

N: Intercostal nerves 

A: Raises ribs during inspiration 

Serratus Posterior Inferior Muscle

O: Vertebral spine of the upper lumbar and lower thoracic vertebrae

I: Ribs 

N: Intercostal nerves 

A: Lowers ribs during expiration 

Erector Spinae Muscle

• Iliocostalis

• Longissimus

• Spinalis

Iliocostalis

O: Ilium and ribs

I: Ribs and transverse processes

A: Extends trunk and vertebral column

N: Dorsal rami of spinal nerves

Longissimus

O: Transverse process of vertebrae

I: Transverse process

A: Extends trunk and vertebral column

N: Dorsal rami of spinal nerves

Spinalis

O: Spinous process

I: Spinous processes

A: Extends trunk and vertebral column

N: Dorsal rami of spinal nerves

Transversospinalis Muscle

• Semispinalis

• Multifidus

• Rotatores

Semispinalis

O: Transverse processes of vertebrae

I: Extends across 5/6 vertebrae

A: Extends trunk in bilateral action and rotate vertebral column in unilateral action

N: Dorsal rami of spinal nerves

Multifidus

O: Transverse processes of vertebrae

I: Extends across ¾ vertebrae

A: Extends trunk in bilateral action and rotate vertebral column in unilateral action

N: Dorsal rami of spinal nerves

Rotatores

O: Transverse processes of vertebrae

I: Extends across ½ vertebrae

A: Extends trunk in bilateral action and rotate vertebral column in unilateral action

N: Dorsal rami of spinal nerves

Vertebral Body

Cervical (C3-C6): Small

Thoracic (T5-T8): Medium size | Heart Shape

Lumbar (L1-L4): Large size | Kidney Shape

Spinous Process

Cervical (C3-C6): Short & bifid

Thoracic (T5-T8): Long and inclined downward

Lumbar (L1-L4): Short, broad, flat & quadrilateral shape

Vertebral Foramen

Cervical (C3-C6): Largest and triangular shape

Thoracic (T5-T8): Smallest and circular

Lumbar (L1-L4): Triangular shape