The abductor digiti minimi (abductor minimi digiti, abductor digiti quinti) is a muscle which lies along the

lateral Lateral is a geometric term of location which may also refer to: Biology and healthcare * Lateral (anatomy), a term of location meaning "towards the side" * Lateral cricoarytenoid muscle, an intrinsic muscle of the larynx * Lateral release ( ...

(outer) border of the

foot The foot (: feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is an organ at the terminal part of the leg made up o ...

, and is in relation by its medial margin with the lateral plantar artery,

vein Veins () are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and feta ...

and nerves. Its homolog in the arm is the abductor digiti minimi muscle in the hand.

Origin and insertion

It arises, by a broad origin, from the lateral process of the tuberosity of the

calcaneus In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel; : calcanei or calcanea) or heel bone is a bone of the Tarsus (skeleton), tarsus of the foot which constitutes the heel. In some other ...

, from the under surface of the calcaneus between the two processes of the tuberosity, from the forepart of the medial process, from the plantar

aponeurosis An aponeurosis (; : aponeuroses) is a flattened tendon by which muscle attaches to bone or fascia. Aponeuroses exhibit an ordered arrangement of collagen fibres, thus attaining high tensile strength in a particular direction while being vulnerable ...

, and from the intermuscular septum between it and the

flexor digitorum brevis The flexor digitorum brevis or flexor digitorum communis brevishttps://www.anatomyatlases.org/AnatomicVariants/MuscularSystem/Text/F/14Flexor.shtml is a muscle which lies in the middle of the sole of the foot, immediately above the central part ...

. Its tendon, after gliding over a smooth facet on the under surface of the base of the

fifth metatarsal bone The fifth metatarsal bone is a long bone in the foot, and is palpable along the distal outer edges of the feet. It is the second smallest of the five metatarsal bones. The fifth metatarsal is analogous to the fifth metacarpal bone in the hand. As ...

, is inserted, with the flexor digiti quinti brevis, into the fibular side of the base of the first

phalanx The phalanx (: phalanxes or phalanges) was a rectangular mass military formation, usually composed entirely of heavy infantry armed with spears, pikes, sarissas, or similar polearms tightly packed together. The term is particularly used t ...

of the fifth toe.

Innervation

The abductor digiti minimi is innervated by the

lateral plantar nerve The lateral plantar nerve (external plantar nerve) is a branch of the tibial nerve, in turn a branch of the sciatic nerve and supplies the skin of the fifth toe and lateral half of the fourth, as well as most of the deep muscles, its distribution ...

, a branch of the

tibial nerve The tibial nerve is a branch of the sciatic nerve. The tibial nerve passes through the popliteal fossa to pass below the arch of soleus. Structure Popliteal fossa The tibial nerve is the larger terminal branch of the sciatic nerve with root val ...

Function

Its function is

flexion Motion, the process of movement, is described using specific anatomical terminology, anatomical terms. Motion includes movement of Organ (anatomy), organs, joints, Limb (anatomy), limbs, and specific sections of the body. The terminology used de ...

and abduction of the fifth (little) toe at the

metatarsophalangeal joint The metatarsophalangeal joints (MTP joints) are the joints between the metatarsal bones of the foot and the proximal bones (proximal phalanges) of the toes. They are analogous to the knuckles of the hand, and are consequently known as toe knuckles ...

Clinical relevance

Due to its role in posture during all physical activity while in an upright position, the abductor digiti minimi is often the target of injury. In case of

polydactyly Polydactyly is a birth defect that results in extra fingers or toes. The hands are more commonly involved than the feet. Extra fingers may be painful, affect self-esteem, or result in clumsiness. It is associated with at least 39 genetic mut ...

it may insert to the sixth toe instead, if there is one.

Etymology

The Latin name abductor digiti minimi translates to ''abductor of the small digit'' while the alternative name abductor digiti quinti means ''abductor of fifth digit''.

Additional images

Image: Muscles in the human foot (seen from below).jpg, Human

cadaver A cadaver, often known as a corpse, is a Death, dead human body. Cadavers are used by medical students, physicians and other scientists to study anatomy, identify disease sites, determine causes of death, and provide tissue (biology), tissue to ...

dissection Dissection (from Latin ' "to cut to pieces"; also called anatomization) is the dismembering of the body of a deceased animal or plant to study its anatomical structure. Autopsy is used in pathology and forensic medicine to determine the cause of ...

of the muscles in the foot seen from below. Image:Gray269.png, Bones of the right foot seen from below. Image:Gray357.png,

Coronal section The dorsal plane (also known as the coronal plane or frontal plane, especially in human anatomy) is an anatomical plane that divides the body into dorsal and ventral sections. It is perpendicular to the sagittal and transverse planes. Human an ...

through right

talocrural The ankle, the talocrural region or the jumping bone (informal) is the area where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint. The ...

and

talocalcaneal joint In human anatomy, the subtalar joint, also known as the talocalcaneal joint, is a joint of the foot. It occurs at the meeting point of the talus and the calcaneus. The joint is classed structurally as a synovial joint, and functionally as a pl ...

References

. {{Authority control Foot muscles Muscles of the lower limb