Suboccipital region

• Cutaneous nerves

  The greater and lesser occipital nerves supply sensory innervation to the skin of the suboccipital region.

  
• cutaneous innervation.

  
• Superficial and intermediate muscles

  The most superficial muscle is trapezius and part of levator scapulae and the proximal attachment of sternocleidomastoid can also be seen.

  The muscle layer beneath them is the intermediate layer that contains splenius capitis and cervicis.

  
• Splenius capitis and cervicis

  •Splenius capitis = ligamentum nuchae + C7-T3 spinous processes to occipital bone (superior nuchal) and mastoid

  •Splenius cervicis = T3-T6 spinous processes to C1-C2 transverse processes

  •Posterior rami C1-C6

  •Bilateral = extend neck and head

  •Unilateral = flexes and rotates to same side

  
• •Semispinalis capitis = C4-T7 transverse processes to occipital bone (between nuchal lines)

  •Extends cervical spine (both), bend to same side  and rotates to opposite side (one)

  •Longissimus capitis = T1-T3 plus C4-C7 transverse processes to mastoid process

  •Extends head (both), flexes and rotates head to same side

  •Posterior rami

  The splenius muscles, semispinalis capitis and longissimus capitis work together to extend the head and neck.

  
• Suboccipital muscles

  Collectively they extend the head (tilt it backwards) and are all innervated by the suboccipital nerve (one each side) which originates from the posterior ramus of C1.

  
• Suboccipital muscles

  •Rectus capitis posterior major = C2 spinous process to inferior nuchal line

  •Rectus capitis posterior minor = C1 posterior tubercle to inferior nuchal line

  •Extend head (both), rotate to same side (one)

  •Suboccipital nerve (posterior rami of C1)

  
• Suboccipital muscles

  •Obliquus capitis superior = C1 transverse process to occipital bone (above inf. nuchal line)

  •Extends head (both), tilts head to same side, rotates it to opposite side (one)

  •Obliquus capitis inferior = C2 spinous process to C1 transverse process

  •Extends head (both) and rotates to same side (one)

  •Suboccipital nerve (posterior rami C1)

  
• Nerves

  The suboccipital muscles are supplied by the suboccipital nerve, this nerve is described as only having motor fibres and there is no C1 dermatome for the head and neck. The greater occipital nerve supplies the skin and the dorsal ramus of C3 supplies the skin and muscles of the neck.

  
• Arteries

  The suboccipital region is supplied by the occipital artery, which sends a descending branch to anastomose with the deep cervical artery (from the subclavian). The vertebral arteries lie within the ’suboccipital triangle’ bounded by both obliquus capitis muscles and rectus capitis posterior major.

  
• Vertebral arteries

  •Branch of subclavian in root of neck

  •Ascend neck in foramen transversarium of cervical vertebra

  •Cross the superior surface of C1 to enter foramen magnum

  •R and L vertebral arteries unite to form the basilar artery (joins Circle of Willis to supply the brain)

  
• Deep cervical vein

  •Occipital veins run with the suboccipital nerve

  •Occipital veins join the deep cervical vein

  •Deep cervical vein communicates with the vertebral veins and brachiocephalic vein

  The occipital veins drain the suboccipital region into the deep cervical vein.

  
• Posterior vertebral venous plexus

  •Vertebral venous system = many small veins communicate with each other

  •Communications with occipital veins, emissary veins of the skull, longitudinal vertebral venous sinus (LVVS), veins around the vertebral artery etc

  •Join the brachiocephalic vein (via the deep cervical vein)

  
• Articulations

  The head nodding ‘yes’ movement occurs between the atlas (C1) and the occipital condyles of the skull. The head shaking ‘no’ movement is rotation between the arch of the atlas and the dens (odontoid) process of the axis (C2).

  
• Ligaments

  The cruciate ligament (also called cruciform) is the transverse ligament of the atlas combined with superior and inferior longitudinal ligament bands that collectively form a cross shape between the axis and the occipital bone. The alar ligament passes from the dens of the axis to the medial sides of the occipital condyles. The anterior and posterior longitudinal ligaments also add support, with the anterior attaching to the occipital bone and the posterior becoming the tectorial membrane (that also attaches to the occipital bone).

  
• the movements possible between the atlas (C1) and the base of the skull (condyles of the occipital bone).

  
• Ipsilateral means the same side and contralateral means the opposite side

  
• Cervical vertebrae

  C1, C2 and C7 are modified in appearance but C3 to C6 are ‘typical’ in shape with a bifid spinous process and a foramen transversarium in each transverse process.

  C1 does not possess a body as it articulates with the skull via the occipital condyles and with the axis via a facet on its anterior arch. C2 has a large spinous process and a bony projection called the dens or odontoid process that articulates with the atlas. The large nonbifid spinous process of C7 leads it to be called the ‘vertebra prominens’.

  
• Movements

  Small movements at each level will collectively form a larger movement of the neck as a whole.