Suboccipital triangle
The suboccipital triangles are a paired triangular-shaped space formed by the configuration of three paired muscles in the posterior neck between the occipital bone, C1 and C2.
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Gross Anatomy
The suboccipital triangle has an inferomedial pointing apex (pointing towards the nuchal ligament) formed by the rectus capitis posterior major (superomedial border) and the obliuus capitis inferior (inferomedial border) muscles. The base of the triangle is superolaterally formed by the obliquus capitis superior muscle.
The suboccipital triangle 'floor' is deep to the muscular triangle (i.e. anterior), formed by the posterior atlantooccipital membrane and posterior arch of the atlas 1. The 'roof' is located superficially (i.e. posterior) and is formed by the semispinalis capitis muscle and a dense layer of adipose tissue 1.
Boundaries
- superomedial border: rectus capitis posterior major
- superolateral border: obliquus capitis superior
- inferomedial border: obliquus capitis inferior
Contents
- dorsal ramus of the first cervical nerve (suboccipital nerve)
- third part of the vertebral artery
- suboccipital venous plexus
Relations
- superior
- occipital bone
- foramen magnum
- medial: nuchal ligament
- anterior ('floor')
- posterior elements of C1 and C2
- posterior atlanto-occipital membrane
- superficial ('roof')
- adipose tissue
- semispinalis capitis muscle
- inferior
- second cervical dorsal ramus
- second part of the vertebral artery
Blood Supply
- arterial: branches of the vertebral artery and occipital artery, deep descending branches supply the sub-occipital muscles 1
- venous: via the sub-occipital venous plexus
Innervation
The muscles of the sub-occipital triangle are innervated by the suboccipital nerve (dorsal ramus of C1) 1.
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Anatomy: Head and neck
- skeleton of the head and neck
-
cranial vault
- scalp (mnemonic)
- fontanelle
-
sutures
- calvarial
- facial
- frontozygomatic suture
- frontomaxillary suture
- frontolacrimal suture
- frontonasal suture
- temporozygomatic suture
- zygomaticomaxillary suture
- parietotemporal suture (parietomastoid suture)
- occipitotemporal suture (occipitomastoid suture)
- sphenofrontal suture
- sphenozygomatic suture
- spheno-occipital suture (not a true suture)
- lacrimomaxillary suture
- nasomaxillary suture
- internasal suture
- basal/internal
- skull landmarks
- frontal bone
- temporal bone
- parietal bone
- occipital bone
- skull base (foramina)
-
facial bones
- midline single bones
- paired bilateral bones
- cervical spine
- hyoid bone
- laryngeal cartilages
-
cranial vault
- muscles of the head and neck
- muscles of the tongue (mnemonic)
- muscles of mastication
-
muscles of facial expression
- occipitalis muscle
- circumorbital and palpebral muscles
- nasal muscles
- buccolabial muscles
- elevators, retractors and evertors of the upper lip
- levator labii superioris alaeque nasalis muscle
- levator labii superioris muscle
- zygomaticus major muscle
- zygomaticus minor muscle
- malaris muscle
- levator anguli oris muscle
- risorius muscle
- depressors, retractors and evertors of the lower lip
- depressor labii inferioris muscle
- depressor anguli oris muscle
- mentalis muscle
- compound sphincter
- orbicularis oris muscle
- incisivus superior muscle
- incisivus inferior muscle
- muscle of mastication:
- elevators, retractors and evertors of the upper lip
- muscles of the middle ear
- orbital muscles
- muscles of the soft palate
- pharyngeal muscles
- suprahyoid muscles
- infrahyoid muscles
- intrinsic muscles of the larynx
- muscles of the neck
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- deep cervical fascia
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deep spaces of the neck
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- danger space
- deep cervical fascia
- infratemporal fossa
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- parotid space
- pharyngeal (superficial) mucosal space
- perivertebral space
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- pterygopalatine fossa
- retropharyngeal space
- suprasternal space (of Burns)
- visceral space
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- orbit
- ear
- paranasal sinuses
- nose
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- pharynx
- larynx
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-
arterial supply
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common carotid artery
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- variants
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common carotid artery
- venous drainage
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arterial supply
- innervation of the head and neck
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cranial nerves
- olfactory nerve (CN I)
- optic nerve (CN II)
- oculomotor nerve (CN III)
- trochlear nerve (CN IV)
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trigeminal nerve (CN V) (mnemonic)
- trigeminal ganglion
- ophthalmic division
- maxillary division
- mandibular division
- abducens nerve (CN VI)
- facial nerve (CN VII)
-
vestibulocochlear nerve (CN VIII)
- vestibular ganglion (Scarpa's ganglion)
- glossopharyngeal nerve (CN IX)
-
vagus nerve (CN X)
- superior laryngeal nerve
- recurrent laryngeal nerve (inferior laryngeal nerve)
- (spinal) accessory nerve (CN XI)
- hypoglossal nerve (CN XII)
- parasympathetic ganglia of the head and neck
- greater occipital nerve
- third occipital nerve
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cervical plexus
- muscular branches
- longus capitis
- longus colli
- scalenes
- geniohyoid
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ansa cervicalis
- omohyoid (superior and inferior bellies separately)
- sternothyroid
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- contribution to the accessory nerve (CN XI)
- cutaneous branches
- muscular branches
- brachial plexus
- pharyngeal plexus
-
cranial nerves
- lymphatic drainage of the head and neck
- embryological development of the head and neck