Topics

Topic

design image
Zygomaticus minor muscle

The zygomaticus minor muscle is a slender, band-like muscle of facial expression located in the cheek region. It plays a significant role in elevating the upper lip, contributing to expressions such as smiling or showing sadness. This muscle lies just medial to the zygomaticus major and is part of the muscular infrastructure that forms the dynamic contour of the face. Its anatomical positioning, blood supply, innervation, and distinct imaging features make it relevant for clinical, surgical, and radiological considerations.

Origin

  • Arises from the lateral aspect of the zygomatic bone, specifically just posterior to the zygomaticomaxillary suture.

Insertion

  • Inserts into the skin and muscle of the upper lip, often blending with fibers of the orbicularis oris muscle.

Function

  • Elevates the upper lip, exposing the upper teeth.

  • Assists in creating facial expressions such as smiling, sneering, or expressing sadness.

Nerve Supply

  • Supplied by the zygomatic and buccal branches of the facial nerve (cranial nerve VII).

Artery Supply

  • Receives arterial blood mainly from branches of the facial artery.

  • May also receive small contributions from the transverse facial artery.

Vein Supply

  • Venous drainage primarily via the facial vein.

MRI Appearance

  • T1-weighted images: Appears as a muscle of intermediate signal intensity.

  • T2-weighted images: Normal muscle demonstrates relatively low signal intensity, but increased signal may indicate edema or pathology.

  • STIR (Short Tau Inversion Recovery): Muscle appears as intermediate signal intensity; edema or pathology will show as increased (bright) signal.

CT Appearance

  • On CT scans, the zygomaticus minor is seen as a thin, soft-tissue structure running obliquely from the zygomatic bone to the upper lip.

  • It is distinguishable from the adjacent zygomaticus major and levator labii superioris, especially on thin-slice, high-resolution images.

MRI images

Zygomaticus minor muscle mri axial image -img-00000-00000

MRI images

Zygomaticus minor muscle MRI axial image

CT images

Zygomaticus minor muscle CT axial image-img-00000-00000