Common questions

What is the origin of the medial rectus?

What is the origin of the medial rectus?

The medial rectus muscle is the largest of the extraocular muscles, with its size probably resulting from the frequency of its use in convergence. Its origin is from both the upper and the lower parts of the common ring tendon and from the sheath of the optic nerve.

Where is the lateral rectus located?

The lateral rectus muscle originates in the bottom of the orbital cavity in the surrounding area of the optic canal, specifically in the lateral part of the common tendinous ring; the annulus of Zinn.

Where do rectus muscles originate?

The four recti muscles all arise from a connective tissue ring called the common tendinous ring (annulus of Zin). This is located at the apex of orbit, surrounding the optic canal. Respectively, the recti muscles insert onto the superior, inferior, medial and lateral sides of the eyeball.

Where is the lateral rectus muscle and how does it move the eye?

The lateral rectus muscle is a muscle on the lateral side of the eye in the orbit. It is one of six extraocular muscles that control the movements of the eye. The lateral rectus muscle is responsible for lateral movement of the eyeball, specifically abduction.

What Innervates the lateral rectus?

The abducens nerve (cranial nerve VI) exits the brainstem from the pons-medullary junction and innervates the lateral rectus muscle.

What is medial and lateral rectus muscles?

The medial rectus is an adductor, and functions along with the lateral rectus which abducts the eye. These two muscles allow the eyes to move from side to side. With the head facing straight and the eyes facing straight ahead, the eyes are said to be in primary gaze.

What is the origin of the abdominal muscles?

Origin and insertion

Origin Pubic symphysis, Pubic crest
Insertion Xiphoid process, Costal cartilages of ribs 5-7
Innervation Intercostal nerves (T6-T11), Subcostal nerve (T12)
Blood supply Inferior and superior epigastric vessels
Function Trunk flexion, Compresses abdominal viscera, Expiration

Where in the brain are the motor neurons MNS of the medial and lateral rectus located?

The MIF motoneurons of the lateral rectus muscle (LR) are scattered around the medial aspect of the abducens nucleus, those of the superior oblique muscle (SO) form a dorsal cap over the trochlear nucleus.

What Innervates the superior rectus?

The superior rectus is innervated by the superior division of the oculomotor nerve, which enters the muscle on its inferior face. Branches pass either through the muscle or around it to innervate the levator.

What rectus means?

straight muscles
Definition of rectus : any of several straight muscles (as of the abdomen)

What is the lateral rectus?

Lateral rectus, along with the other rectus muscles, arises from the annulus of Zinn, the common tendinous ring at the apex of the orbit that surrounds the optic canal 1. Lateral rectus runs anteriorly on the lateral surface of the eye and inserts into the lateral surface of the sclera just posterior to the junction of cornea and sclera 2.

What artery supplies the lateral rectus muscle?

The lateral rectus muscle is supplied by the ophthalmic artery that stems from the internal carotid artery. The ophthalmic artery supplies it either directly, or through its lacrimal branch. The lateral rectus muscle abducts the eye and directs the gaze laterally in the horizontal plane.

Is the lateral rectus part of the ophthalmic artery?

Branches of the ophthalmic artery, itself a branch of the internal carotid artery. Lateral rectus is unique among the extraocular muscles in being supplied by the abducens nerve.

What is the anatomy of the rectus abdominius muscle?

The rectus abdominius muscle is one of four muscles of the anterior abdominal wall. It acts as a flexor of the spine and an accessory muscle of respiration. In those with low body fat, is clearly visible beneath the skin. In this article we will discuss the gross and functional anatomy of the rectus abdominis muscle.