Good morning SUBOCCIPITAL TRIANGLE Dr Qudusia sultana n

Good morning

SUBOCCIPITAL TRIANGLE Dr. Qudusia sultana

n Suboccipital region…. . n Above – Inferior nuchal line n Below – massive bifid spine and laminae of axis vertebra n Laterally – mastoid processes, transverse process of atlas and axis vertebra

n IMPORTANCE……. . n This region is clinically important because the neurosurgeons approach the posterior cranial fossa through this region.

How to approach suboccipital triangle…?

Rectus capitis posterior major n n ORIGIN spine of axis vertebra INSERTION lateral half of inferior nuchal line ACTION Extends and rotates atlanto-occipital joint NERVE Suboccipital nerve (posterior primary ramus C 1)

Rectus capitis posterior minor n n ORIGIN Posterior process of atlas (C 1) INSERTION Medial half of inferior nuchal line ACTION Extends and rotates atlanto-occipital joint NERVE Suboccipital nerve (posterior primary ramus

Obliquus capitis superior n n ORIGIN Transverse process of atlas vertebra INSERTION Between superior and inferior nuchal line ACTION moves the neck to same side or lat flexes the atlantooccipital joint NERVE Suboccipital nerve (posterior primary ramus C 1)

n n Obliquus capitis inferior ORIGIN Spinous process of axis vertebra INSERTION Transverse process of atlas vertebra ACTION moves the neck to same side or lat flexesand rotates the atlanto-axial joint NERVE Suboccipital nerve (posterior primary ramus C 1)

Definition n Suboccipital triangle is a triangular muscular space situated deep in the suboccipital region of the neck

n Boundaries : n Superiomedial Superolateral Inferior n Roof – dense fiberous tissue, semispinalis n capitis, splenius capitis Floor – posrterior arch of atlas, posterior atlanto-occipital membrane. n n

Roof

Floor • Posterior atlantooccipital membrane. • Posterior arch of atlas

Contents… n n Suboccipital venous plexus Greater occipital nerve Dorsal ramus of 1 st cervical nerve 3 rd part of vertebral artery

Contents

Suboccipital venous plexus. . . It collects the blood from the following veins n n muscular veins from the neighbouring muscles occipital veins internal vertebral venous plexus Plexus of veins around the vertebral artery

Clinical importance… Carbuncles of the neck Connection between interverbral venous plexus and suboccipital venous plexus serves as a path for intra-cranial infection

Greater occipital nerve n Thickest cutaneous nerve of the body n It winds around the inferior border of inferior oblique muscle and runs upwards and medially n It supplies the back of scalp up to vertex

Third part of vertebral artery n It is on the groove on the upper surface of the cervical posterior arch of atlas. n tortuous n It is separated from the arch of atlas by 1 st cervical nerve. n n Clinical importance…. Tortuous – damp down the arterial pulsation in the cranial cavity

Vertbral artery n n The vertebral artery is one of the first branches of the subclavian artery. it passes through the neck. From its origin, it enters the foramen in the transverse process of the 6 th cervical vertebra passes upward through all foramina transversaria until it reaches the top of the posterior arch of the atlas.

n n n At this point it lies in a groove there and then enters the cranial cavity through the foramen magnum. Joins with opp vertebral artery to form basilar artery. One of its primary supplies is the visual cortex in the occipital lobe of the cerebrum.

Dorsal ramus of 1 st cervical nerve Also called suboccipital nerve Situated on the groove of posterior arch of atlas It supplies 5 muscles Rectus capitis posterior major Rectus capitis posterior minor Obliquus capitis superior Obliquus capitis inferior Semispinalis capitis

Applied aspect n Cisternal puncture Ø It is a procedure to approach cisterna magna in the posterior cranial fossa through the foramen magnum for therapeutic & diagnostic purpose Ø To obtain CSF Ø Via the suboccipital triangle Ø By piercing the posterior atlantooccipital membrane

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