Rhomboid minor muscle
Encyclopedia
In human anatomy, the rhomboid minor is a small skeletal muscle
on the back that connects the scapula
with the vertebrae of the spinal column.
Located inferior to levator scapulae
and superior to rhomboid major
, it acts together with the latter to keep the scapula pressed against the thoracic wall.
It lies deep to trapezius
but superficial to the long spinal muscles.
, from the spinous process
es of the seventh cervical
and first thoracic vertebrae
, and from the intervening supraspinous ligament
s.
It is inserted into a small area of the medial border
of the scapula at the level of the scapular spine
.
to rotate the scapulae downward. While other shoulder muscles are active, the rhomboids stabilize the scapula.
, with most of its fibers derived from the C5 nerve root and only minor contribution from C4 or C6.
The rhomboid minor gets its arterial blood supply from the dorsal scapular artery
.
Skeletal muscle
Skeletal muscle is a form of striated muscle tissue existing under control of the somatic nervous system- i.e. it is voluntarily controlled. It is one of three major muscle types, the others being cardiac and smooth muscle...
on the back that connects the scapula
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....
with the vertebrae of the spinal column.
Located inferior to levator scapulae
Levator scapulae muscle
In human anatomy, the levator scapulae is a skeletal muscle situated at the back and side of the neck. As the name suggests, its main function is to lift the scapula.-Origin and insertion:...
and superior to rhomboid major
Rhomboid major muscle
The rhomboid major is a skeletal muscle on the back that connects the scapula with the vertebrae of the spinal column. In human anatomy, it acts together with the rhomboid minor to keep the scapula pressed against thoracic wall and to retract the scapula toward the vertebral column.-Structure:The...
, it acts together with the latter to keep the scapula pressed against the thoracic wall.
It lies deep to trapezius
Trapezius muscle
In human anatomy, the trapezius is a large superficial muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae and laterally to the spine of the scapula...
but superficial to the long spinal muscles.
Origin and insertion
The rhomboid minor arises from the inferior border of the nuchal ligamentNuchal ligament
The paxwax or nuchal ligament is a fibrous membrane, which, in the neck, represents the supraspinal ligaments of the lower vertebræ...
, from the spinous process
Spinous process
The spinous process of a vertebra is directed backward and downward from the junction of the laminae , and serves for the attachment of muscles and ligaments. In animals without an erect stance, the process points upward and may slant forward or backward...
es of the seventh cervical
Cervical vertebrae
In vertebrates, cervical vertebrae are those vertebrae immediately inferior to the skull.Thoracic vertebrae in all mammalian species are defined as those vertebrae that also carry a pair of ribs, and lie caudal to the cervical vertebrae. Further caudally follow the lumbar vertebrae, which also...
and first thoracic vertebrae
Thoracic vertebrae
In human anatomy, twelve thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. They are intermediate in size between those of the cervical and lumbar regions; they increase in size as one proceeds down the spine, the upper...
, and from the intervening supraspinous ligament
Supraspinous ligament
The supraspinal ligament is a strong fibrous cord, which connects together the apices of the spinous processes from the seventh cervical vertebra to the sacrum; at the points of attachment to the tips of the spinous processes fibrocartilage is developed in the ligament.It is thicker and broader in...
s.
It is inserted into a small area of the medial border
Medial border of scapula
The medial border of the scapula is the longest of the three borders, and extends from the medial to the inferior angle....
of the scapula at the level of the scapular spine
Spine of scapula
The spine of the scapula is a prominent plate of bone, which crosses obliquely the medial four-fifths of the scapula at its upper part, and separates the supra- from the infraspinatous fossa....
.
Action
Together with the rhomboid major, the rhomboid minor retracts the scapula when trapezius is contracted. Acting as an antagonist to the trapezius, both rhomboids elevate the medial border of the scapula medially and upward, working in tandem with the levator scapulae muscleLevator scapulae muscle
In human anatomy, the levator scapulae is a skeletal muscle situated at the back and side of the neck. As the name suggests, its main function is to lift the scapula.-Origin and insertion:...
to rotate the scapulae downward. While other shoulder muscles are active, the rhomboids stabilize the scapula.
Innervation and blood supply
The nerve supply comes from the dorsal scapular nerveDorsal scapular nerve
The dorsal scapular nerve arises from the brachial plexus, usually from the plexus root of C5.It provides motor innervation to the rhomboid muscles, which pull the scapula towards the spine and levator scapulae muscle, which elevates the scapula....
, with most of its fibers derived from the C5 nerve root and only minor contribution from C4 or C6.
The rhomboid minor gets its arterial blood supply from the dorsal scapular artery
Dorsal scapular artery
The dorsal scapular artery is a blood vessel which supplies thelevator scapulae, rhomboids, and trapezius.-Origin:...
.