The suboccipital region Flashcards
What is the suboccipital region?
The suboccipital region is the space between the occiput and spine of axis vertebra[C2]
What is the suboccipital triangle?
The suboccipital triangle is the muscular space situated deep in the suboccipital region
List the structures that form the boundaries of the suboccipital region/triangle
Superomedially
• Rectus capitis posterior major
• Rectus capitis posterior minor
Superolaterally
* Superior oblique
Inferiorly
* Inferior oblique
What does the roof of the suboccipital region/triangle consist of medially and laterally?
Medially • Dense fibrous tissue covered by semispinalis capitis Laterally • Longissimus capitis • Splenius capitis
What does the floor of the suboccipital region/triangle consist of?
- Posterior arch of atlas
* Posterior atlanto-occipital membrane
What are the contents of the suboccipital region/triangle?
- Third part of vertebral artery
- Dorsal ramus of nerve C1 (suboccipital nerve)
- Suboccipital plexus of veins
List the suboccipital muscles.
- Rectus capitis posterior major
- Rectus capitis posterior minor
- Obliquus capitis inferior
- Obliquus capitis superior
Where does the rectus capitis posterior major originate?
Spine of axis
List the actions of the rectus capitis posterior major.
- Mainly postural
- Turns face to same side (single muscle)
- Extends head (both muscles)
Where is the insertion of rectus capitis posterior major?
At the lateral part of area below
inferior nuchal line
Which nerve supplies the rectus capitis posterior major?
The suboccipital nerve
Where does the rectus capitis posterior minor originate?
Posterior tubercle of atlas
List the actions of the rectus capitis posterior minor.
- Mainly postural
* Extends head
Where is the insertion of the rectus capitis posterior minor?
At the medial part of the area below inferior
nuchal line
Which nerve supplies the rectus capitis posterior minor?
Suboccipital nerve
Where does the obliquus capitis superior originate?
At the transverse process of the atlas
List the actions of the obliquus capitis superior.
- Extends head (both muscles)
* Laterally flexes (bends) head
Where is the insertion of the obliquus capitis superior?
At the lateral area between nuchal lines
Which nerve supplies the obliquus capitis superior?
Suboccipital nerve
Where does the obliquus capitis inferior originate?
Spine of axis
List the actions of the obliquus capitis inferior.
- Mainly postural
* Turns face to same side
Which nerve supplies the obliquus capitis inferior?
Suboccipital nerve
List the nerves and vessels of the suboccipital region/triangle
- Dorsal[posterior] ramus of the 1st cervical nerve
- Greater occipital nerve
- Third occipital nerve
- Vertebral artery
- Occipital artery
- Deep cervical artery
- Suboccipital plexus of veins
Where does the dorsal ramus of the 1st cervical nerve emerge?
The dorsal ramus of the 1st cervical nerve emerges between the posterior arch of atlas & vertebral artery
Which structures does the dorsal ramus of the 1st cervical nerve supply ?
The dorsal ramus of the 1st cervical nerve supplies the 4 suboccipital muscles and semispinalis capitis
What does the nerve of the inferior oblique muscle do?
The oculomotor nerve gives off a communicating branch to the greater occipital nerve
Describe the greater occipital nerve
- The greater occipital nerve is the large medial branch of the dorsal ramus of occipital[C2] nerve
- The greater occipital is the thickest cutaneous nerve in the body
What does the greater occipital nerve wind around?
The greater occipital nerve winds around the lower border of the inferior oblique & then runs upwards & medially
What does the greater occipital nerve cross?
The greater occipital nerve crosses the suboccipital triangle
What does the greater occipital nerve pierce?
The greater occipital nerve pierces the semispinalis capitis & trapezius muscles to ramify on back of head to vertex
Which structures does the greater occipital nerve supply?
The greater occipital nerve supplies the semispinalis capitis & scalp
Describe the third occipital nerve
The third occipital nerve is the medial branch of the dorsal ramus of the c3 nerve
Where does the third occipital nerve ascend?
The third occipital nerve ascends medial to the greater occipital nerve
Which structure[s] does the third occipital nerve supply?
The third occipital nerve supplies the skin of the back and the neck up to the external occipital protuberance
Describe the vertebral artery
The vertebral artery is the first and the largest branch of the 1st part of the subclavian artery and it consists of 4 parts
Which part of the vertebral artery appears in the suboccipital region?
Only the third part appears in
suboccipital region
Where does the 3rd part of the vertebral artery appear and where does it leave the suboccipital triangle?
This part appears at the foramen transversarium of atlas, grooves atlas & leaves the triangle by passing deep to the posterior atlanto-occipital membrane
How is the vertebral artery separated from the posterior arch of the atlas?
The vertebral artery is separated from the posterior arch of the atlas by the C1 nerve and its dorsal and ventral rami
Where does the occipital artery arise?
The occipital artery arises from the external carotid artery
The occipital artery runs deep to the…
posterior belly of the digastric
What does the occipital artery cross?
The occipital artery crosses the carotid sheath & XI and XII cranial nerves
What does the occipital artery pierce and where does it lie?
The occipital artery pierces the trapezius and lies along the greater occipital nerve
List the branches of the occipital artery .
Mastoid
Meningeal
Muscular
Name the branch of the costocervical trunk of the subclavian artery
The deep cervical artery
Where does the deep cervical artery pass?
The deep cervical artery passes into the back of neck and the first rib
Where does the deep cervical artery ascend?
The deep cervical artery ascends deep to the semispinalis capitis & anastomoses with descending branch
of occipital artery
Where does the suboccipital plexus of veins lie?
The suboccipital plexus of veins lies in and around the suboccipital triangle
List the structures that the suboccipital plexus of veins
Muscular veins
Occipital veins
Internal vertebral venous plexus
Condylar emissary vein
What does the suboccipital plexus of veins drain into?
The plexus itself drains into the deep
cervical & vertebral plexus of veins
