The abductor digiti minimi (abductor minimi digiti, abductor digiti quinti) is a muscle which lies along the lateral (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 a separate organ at the terminal part of the leg made ...

, and is in relation by its medial margin with the

lateral plantar artery The lateral plantar artery (external plantar artery), much larger than the medial, passes obliquely lateralward and forward to the base of the fifth metatarsal bone. It then turns medialward to the interval between the bases of the first and secon ...

vein Veins are blood vessels in 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 the pulmonary and umbilical veins, both of which carry oxygenated b ...

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) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock. S ...

, 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 (; plural: ''aponeuroses'') is a type or a variant of the deep fascia, in the form of a sheet of pearly-white fibrous tissue that attaches sheet-like muscles needing a wide area of attachment. Their primary function is to join musc ...

, and from the intermuscular septum between it and the flexor digitorum brevis. 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 of the

fifth toe Toes are the digits (fingers) of the foot of a tetrapod. Animal species such as cats that walk on their toes are described as being '' digitigrade''. Humans, and other animals that walk on the soles of their feet, are described as being '' pl ...

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.

Function

Its function is flexion and abduction of the fifth (little) toe at the

metatarsophalangeal joint The metatarsophalangeal joints (MTP joints), also informally known as toe knuckles, are the joints between the metatarsal bones of the foot and the proximal bones (proximal phalanges) of the toes. They are condyloid joints, meaning that an ellipt ...

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 or polydactylism (), also known as hyperdactyly, is an anomaly in humans and animals resulting in supernumerary fingers and/or toes. Polydactyly is the opposite of oligodactyly (fewer fingers or toes). Signs and symptoms In humans ...

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 or corpse is a dead human body that is used by medical students, physicians and other scientists to study anatomy, identify disease sites, determine causes of death, and provide tissue to repair a defect in a living human being. Stud ...

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 o ...

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 coronal plane (also known as the frontal plane) is an anatomical plane that divides the body into Anatomical terms of location#Dorsal and ventral, dorsal and ventral sections. It is perpendicular to the sagittal plane, sagittal and transverse ...

through right

talocrural The ankle, or 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 ...

and talocalcaneal joints.

References

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