| Obliquus capitis inferior muscle | |
|---|---|
 Deep muscles of the back. (Obliq. infer. labeled at upper left.) | |
| Details | |
| Origin | Spinous process of theaxis |
| Insertion | Lateral mass of atlas |
| Nerve | Suboccipital nerve |
| Actions | Rotation of head and neck |
| Identifiers | |
| Latin | musculus obliquus capitis inferior |
| TA98 | A04.2.02.007 |
| TA2 | 2252 |
| FMA | 32528 |
| Anatomical terms of muscle | |
Theobliquus capitis inferior muscle (/əˈblaɪkwəsˈkæpɪtɪs/) is a muscle in the upper back of the neck. It is one of thesuboccipital muscles. Its inferior attachment is at thespinous process of theaxis; its superior attachment is at thetransverse process of theatlas. It is innervated by thesuboccipital nerve (theposterior ramus offirst cervical spinal nerve). The muscle rotates the head to its side.
Despite what its name suggest, it is the only capitis (Latin: "head") muscle that does not actually attach to the skull.
The obliquus capitis inferior is one of thesuboccipital muscles (and the only one of these to have no attachment to the skull).[1] It is larger than theobliquus capitis superior muscle. It forms the inferolateral boundary of thesuboccipital triangle.[2]
The muscle extends laterally and somewhat superiorly from its inferior attachment to its superior attachment.[2]
its inferior attachment is at the lateral[2] external aspect of the bifidspinous process[3] of theaxis (cervical vertebra C2)[2][3] (inferior to the attachment of therectus capitis posterior major muscle[3]) and thelamina of the axis.[2]
Its superior attachment is at (the inferoposterior aspect of[2]) thetransverse process of theatlas (cervical vertebra C1).[2][3]
The muscle receives motor innervation from thesuboccipital nerve (theposterior ramus ofcervical spinal nerve C1).[3][2]
It lies deep to thesemispinalis capitis andtrapezius muscles.[citation needed]
The muscle acts to rotate the atlas[3] (and thus[3] the head) ipsilaterally.[3][2] It acts together with therectus capitis posterior major muscle.[2]
The muscle is responsible for rotation of the head and firstcervical vertebra (atlanto-axial joint).[3]
The obliquus capitis inferior muscle, like the other suboccipital muscles, has an important role inproprioception. This muscle has a very high density of Golgi organs and muscle spindles which accounts for this.[4] It is believed that proprioception may be the primary role of the inferior oblique (and indeed the other suboccipital muscles), allowing accurate positioning of the head on the neck.[citation needed]
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This article incorporates text in thepublic domain frompage 402 of the 20th edition ofGray's Anatomy(1918)
