In human anatomy, the rhomboid minor is a small

skeletal muscle Skeletal muscle (commonly referred to as muscle) is one of the three types of vertebrate muscle tissue, the others being cardiac muscle and smooth muscle. They are part of the somatic nervous system, voluntary muscular system and typically are a ...

of the back that connects the

scapula The scapula (: scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on either side ...

to the

vertebrae Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

of the

spinal column The spinal column, also known as the vertebral column, spine or backbone, is the core part of the axial skeleton in vertebrates. The vertebral column is the defining and eponymous characteristic of the vertebrate. The spinal column is a segmen ...

. It arises from the

nuchal ligament The nuchal ligament is a ligament at the back of the neck that is continuous with the supraspinous ligament. Structure The nuchal ligament extends from the external occipital protuberance on the skull and median nuchal line to the spinous p ...

, the 7th cervical and 1st

thoracic vertebrae In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebra (anatomy), vertebrae of intermediate size between the ce ...

and intervening

supraspinous ligament The supraspinous ligament (also known as the supraspinal ligament) is a ligament extending across the tips of the spinous processes of the vertebra of the vertebral column. Anatomy The supraspinous ligament connects the tips of the spinous proces ...

s; it inserts onto the medial border of the scapula, and is innervated by the

dorsal scapular nerve The dorsal scapular nerve is a branch of the brachial plexus, usually derived from the ventral ramus of cervical nerve C5. It provides motor innervation to the rhomboid major muscle, rhomboid minor muscle, and levator scapulae muscle. Dorsal ...

. It acts together with the rhomboid major to keep the scapula pressed against the thoracic wall.

Anatomy

Origin

The rhomboid minor arises from the inferior border of the

, from the

spinous process Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

es of the vertebrae C7–T1, and from the intervening

Insertion

It inserts onto a small area of the medial border of the scapula at the level of the

scapular spine The spine of the scapula or scapular spine is a prominent plate of bone, which crosses obliquely the medial four-fifths of the scapula at its upper part, and separates the Supraspinatous fossa, supra- from the infraspinatous fossa. Structure It b ...

Innervation

It is innervated by the

(a branch of the

brachial plexus The brachial plexus is a network of nerves (nerve plexus) formed by the anterior rami of the lower four Spinal nerve#Cervical nerves, cervical nerves and first Spinal nerve#Thoracic nerves, thoracic nerve (cervical spinal nerve 5, C5, Cervical spi ...

), with most of its fibers derived from the C5 nerve root and only minor contribution from C4 or C6., p. 4

Blood supply

The rhomboid minor receives

arterial An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...

blood supply from the

dorsal scapular artery The transverse cervical artery (transverse artery of neck or transversa colli artery) is an artery in the neck and a branch of the thyrocervical trunk, running at a higher level than the suprascapular artery. Structure It passes transversely ...

Relations

It is located inferior to levator scapulae, and superior to rhomboid major. It lies deep to

trapezius The trapezius is a large paired trapezoid-shaped surface muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae of the human spine, spine and laterally to the spine of the scapula. It moves the scapula and ...

, and superficial to the long spinal muscles.

Variation

It is usually separated from the rhomboid major by a slight interval, but the adjacent margins of the two muscles are occasionally united.''

Gray's Anatomy ''Gray's Anatomy'' is a reference book of human anatomy written by Henry Gray, illustrated by Henry Vandyke Carter and first published in London in 1858. It has had multiple revised editions, and the current edition, the 42nd (October 2020 ...

'' (1918), see infobox

Actions/movements

Together with the rhomboid major, the rhomboid minor retracts the scapula when the trapezius is contracted. Acting as a synergist to the trapezius, the rhomboid major and minor elevate the medial border of the scapula medially and upward, working in tandem with the

levator scapulae muscle The levator scapulae is a slender skeletal muscle Skeletal muscle (commonly referred to as muscle) is one of the three types of vertebrate muscle tissue, the others being cardiac muscle and smooth muscle. They are part of the somatic nervous s ...

to rotate the scapulae downward. While other shoulder muscles are active, the rhomboid major and minor stabilize the scapula.

Additional images

References

External links

* {{Authority control Muscles of the upper limb