Illustrated Encyclopedia of Human Anatomic Variation: Opus I: Muscular System: Alphabetical Listing of Muscles: F

Flexor Digiti Minimi Brevis (Manus)

Ronald A. Bergman, PhD
Adel K. Afifi, MD, MS
Ryosuke Miyauchi, MD
Peer Review Status: Internally Peer Reviewed

Macalister reported the variations of opponens digiti minimi as follows:

1. The muscle may be split into an upper and lower part;
2. It may be absent;
3. It may be inseparably united with abductor digiti minimi.

Tensor capsularis articulationis metacarpophalangei digiti minimi is a small muscle that arises from the ligaments joining the pisiform and hamate bones. It inserts into the palmar surface of the metacarpophalangeal joint of the fifth digit. Calori (1867) found a small muscle passing from the hamate to the pisiform bone. The tendon of palmaris longus may give rise to an additional muscle, accessorius ad flexorem digiti minimi, which usually inserts on the body and head of the fifth metacarpal between abductor digiti minimi and flexor digiti minimi brevis. see also Palmaris longus.

Palmaris brevis may join flexor digiti minimi brevis Although not an intrinsic hand muscle, the rare ulnaris externus brevis arises about 6.5 cm proximal to the distal end of the ulna. It inserts onto the fifth metacarpal not unlike opponens digiti minimi, which inserts onto the fifth metacarpal, to which it may be functionally related.

Syn.: m. Flexor brevis digiti quinti.

Accessory Flexor (Opponens) Digiti Minimi Brevis
and Palmaris Longus with a reversed belly.
Dissecting room specimen.
University of Iowa.

Accessory Flexor Digiti Minimi Brevis from Tendon of Palmaris Longus.
source unknown.

Pisiuncinatus
This small muscle was found extending between the hamate to the pisiform bones
from Calori (1867)

References

Calori, L. (1867) Di alcuni varieta muscolari dell'avambraccio e dell' eminenza ipothenar. Mem. Accad. R. Sci Istituto di Bologna. S. 2. 7:359-381.

Carr, N.D., O'Callaghan, J.D. and R. Vaughn. (1977) An unusual flexor of the fifth finger. Acta Anat. 98:376-379.

Flower, W.H. and J. Murie. (1867) Account of the dissection of a Bush woman. J. Anat. Physiol. 1:202-208.

Gloobe, H. and P. Pecket. (1973) An anomalous muscle in the canal of Guyon (A possible ulnar compression). Anat. Anz. 133:477-479.

Macalister, A. (1875) Additional observations on muscular anomalies in human anatomy (third series), with a catalogue of the principal muscular variations hitherto published. Trans. Roy. Irish Acad. Sci 25:1-134

Morrison, J.T. (1916) A palmaris longus muscle with a reversed belly, forming an accessory flexor muscle of the little finger. J. Anat. Physiol. 50:324-326.

Saadeh, F.A. and R.A. Bergman. (1986) Doubled palmaris longus muscle with an associated accessorius ad flexorem digiti minimi muscle. Anat. Anz. 161:393-395.

Saadeh, F.A. and R.A. Bergman. (1988) An unusual flexor (opponens) digiti minimi accessorius. Anat. Anz. 165:327-329.

Thomas, Jr., C.G. (1958) Clinical manifestations of an accessory palmaris muscle. J. Bone Joint Surg. (A) 40:929-930.

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