Opponens digiti minimi muscle
By : Omar M. Subhi Altaie• NAME
The name indicates that the main action of this muscle is opposition (which is moving the finger to touch other fingers), and the word " digiti " means finger and " minimi " means the smallest, which is the little finger that the action is applied on.
• GENERAL
The opponens digiti minimi is one of the three muscles of the hypothenar muscle group that presents medially on the palmer side of the hand. It is a quadrangular-shaped muscle that lies deep into the other two muscles of the group.
The opponens digiti minimi attaches to the metacarpal bone of the little finger, and the opponens digiti minimi and the other two muscles of the group apply for their work on the little finger exclusively at the carpometacarpal joint (or CMC joint ) of the little finger.
The opponens digiti minimi attaches to the metacarpal bone of the little finger, and the opponens digiti minimi and the other two muscles of the group apply for their work on the little finger exclusively at the carpometacarpal joint (or CMC joint ) of the little finger.
• SUPPLY
- The nerve supply of flexor digiti minimi brevis is by the deep branch of the ulnar nerve (C8, T1) which originates from the brachial plexus.
- The blood supply of the deep palmar branch of the ulnar artery and the deep palmar arch which is the terminal branch of the radial artery and a branch from the Ulnar artery.
- The blood supply of the deep palmar branch of the ulnar artery and the deep palmar arch which is the terminal branch of the radial artery and a branch from the Ulnar artery.
• ORIGIN AND INSERTION
◇ Origin
Originate from the Flexor Retinaculum and the hook of the hamate (which is the most medial one of the second row of the carpal bones)
◇ Insertion
The fibres of the muscle are coarse to insert in the anterior and medial aspect of the fifth Metacarpal bone, (which is the little finger), crossing the CarpoMetaCarpal joint of the same finger.
Originate from the Flexor Retinaculum
Note
(band above the carpal bones)◇ Insertion
The fibres of the muscle are coarse to insert in the anterior and medial aspect of the fifth Metacarpal bone, (which is the little finger), crossing the CarpoMetaCarpal joint of the same finger.
• Movement and action
As mentioned, this muscle only passes over the CarpoMetaCarpal joint, thus any movement that it is capable of is occurring at this particular joint.
The first basic action of this muscle is opposition when the top palmar surface of the finger meets the same palmar surface of the thumb.
The other actions like flexion are done by the muscle due to the fibres passing anterior on the shaft of the metacarpal bone, when it contracts it pulls the bone anteriorly, perpendicular to the palmar surface.
The muscle fibres originate from the slightly medial side of the flexor retinaculum which makes the muscle inserts at the anterior and a little bit of the lateral surface of the metacarpal bone, so when it contracts it pulls the finger to the lateral side and that is what called lateral rotation
It also crosses the metacarpal bone laterally so if the opponens digiti minimi contracts laterally, it adducts the little finger by adducting the metacarpal of the little finger at the Carpometacarpal joint.
The first basic action of this muscle is opposition when the top palmar surface of the finger meets the same palmar surface of the thumb.
The other actions like flexion are done by the muscle due to the fibres passing anterior on the shaft of the metacarpal bone, when it contracts it pulls the bone anteriorly, perpendicular to the palmar surface.
The muscle fibres originate from the slightly medial side of the flexor retinaculum which makes the muscle inserts at the anterior and a little bit of the lateral surface of the metacarpal bone, so when it contracts it pulls the finger to the lateral side and that is what called lateral rotation
It also crosses the metacarpal bone laterally so if the opponens digiti minimi contracts laterally, it adducts the little finger by adducting the metacarpal of the little finger at the Carpometacarpal joint.
• Reverse action
As we know the normal action of any muscle is when the proximal attachment of the origin of that muscle is fixed and the distal attachment which is the insertion is the movable portion, but when the opposite of that happens we call it Reverse action.
The reverse action of opposition involves the reverse actions of all three components of opposition.
The opposite of any of those actions that this muscle is capable of doing is required the fixation of the metacarpal bones due to some particular reason and moving the carpal bones of origin toward them and that makes the muscle contract not in the usual way.
The reverse action occurs when the hamate bone moves toward the metacarpal of the little finger at the Carpometacarpal joint. This occurs when the metacarpal is fixed, Movement of the hamate would likely involve a slight movement of the entire wrist (all other carpal bones) and maybe some near parts of the forearm.
The reverse action of opposition involves the reverse actions of all three components of opposition.
The opposite of any of those actions that this muscle is capable of doing is required the fixation of the metacarpal bones due to some particular reason and moving the carpal bones of origin toward them and that makes the muscle contract not in the usual way.
The reverse action occurs when the hamate bone moves toward the metacarpal of the little finger at the Carpometacarpal joint. This occurs when the metacarpal is fixed, Movement of the hamate would likely involve a slight movement of the entire wrist (all other carpal bones) and maybe some near parts of the forearm.
• ANTAGONIST FUNCTIONS
• Restrains reposition of the little finger at the CMC joint and Stabilizes the joint.
• slows extension and abduction of the muscles that apply those actions of the finger at the CMC joint of it.
• slows medial rotation (opposite of lateral rotation) of the metacarpal of the CMC joint of the little finger .
• slows extension and abduction of the muscles that apply those actions of the finger at the CMC joint of it.
• slows medial rotation (opposite of lateral rotation) of the metacarpal of the CMC joint of the little finger .
• Examination
Ask the patient to oppose his little finger against the pressure you put on that finger, by that you can check if the muscle from been injured.
• Clinical notes
We use the opponens digiti minimi all the time when we hold some round or cylindrical objects like when we go cycling. The muscle is supplied by the ulnar nerve and passes around the hook of hamate and pisiform bone ( Guyon's canal ), the nerve could be injured in that place by compression put on it and thus stops the muscle to function. There might be numbness and pain fingers that the ulnar nerve supply.
That compression in the wrist within or distal to Guyon's canal could be seen after cycling, people often have a hyperextended position of the wrist resting on the handlebars of the bike, contributing to the neuropathy by compressing and stretching the nerve as it passes that area of the hand and make the hand feel numbness, weakness or even pain.
That compression in the wrist within or distal to Guyon's canal could be seen after cycling, people often have a hyperextended position of the wrist resting on the handlebars of the bike, contributing to the neuropathy by compressing and stretching the nerve as it passes that area of the hand and make the hand feel numbness, weakness or even pain.
• Relations
Opponens digiti minimi is located deep to flexor digiti minimi brevis and abductor digiti minimi muscles. Along its course, opponens digiti mini partly blends with the surrounding muscles, often fusing with the neighbouring hypothenar muscles.
Opponens digiti minimi is closely related to two neurovascular structures. The deep palmar branch of the ulnar artery courses deep, or directly through opponens digiti minimi, before anastomosing with the radial artery. The deep branch of the ulnar nerve also perforates opponens digiti minimi on its way towards the flexor tendons .
Opponens digiti minimi is closely related to two neurovascular structures. The deep palmar branch of the ulnar artery courses deep, or directly through opponens digiti minimi, before anastomosing with the radial artery. The deep branch of the ulnar nerve also perforates opponens digiti minimi on its way towards the flexor tendons .
● REFERENCES
• JOSEPH E. MUSCOLINO THE MUSCULAR SYSTEM MANUAL The Skeletal Muscles of the Human Body FOURTH EDITION 406, 416-419
• Keith L. Moore, Arthur F. Dalley, Anne M. R Clinically Oriented Anatomy (7th Edition) page 778
• Snell's clinical anatomy by Region's (10th edition) pages 324-326
• Opponens Digiti Minimi physiopedia website https://www.physio-pedia.com/Opponens_Digiti_Minimi
• Opponens digiti minimi muscle of hand Author: Adrian Rad BSc (Hons) • Reviewer: Jana Vasković MD Last reviewed: July 06, 2022 kenhub website https://www.kenhub.com/en/library/anatomy/opponens-digiti-minimi-muscle#:~:text=Opponens%20digiti%20minimi%20is%20a,and%20the%20adjacent%20palmar%20surface.
• Keith L. Moore, Arthur F. Dalley, Anne M. R Clinically Oriented Anatomy (7th Edition) page 778
• Snell's clinical anatomy by Region's (10th edition) pages 324-326
• Opponens Digiti Minimi physiopedia website https://www.physio-pedia.com/Opponens_Digiti_Minimi
• Opponens digiti minimi muscle of hand Author: Adrian Rad BSc (Hons) • Reviewer: Jana Vasković MD Last reviewed: July 06, 2022 kenhub website https://www.kenhub.com/en/library/anatomy/opponens-digiti-minimi-muscle#:~:text=Opponens%20digiti%20minimi%20is%20a,and%20the%20adjacent%20palmar%20surface.
● MAGES REFERENCES
• Fig1 Anterior view of the right opponens digiti minimi FIGURE 9-12. JOSEPH E. MUSCOLINO THE MUSCULAR SYSTEM MANUAL The Skeletal Muscles of the Human Body FOURTH EDITION page 417
• Fig2 Frank H. Netter, Atlas of Human Anatomy (7th edition) plate 452
• Fig3 Hand muscles Hypothenar muscles learn anatomy website: https://e-learn.anatomy.uzh.ch/anatomie/Bewegungsapparat/bewapp_HTML_eng/hand/handMlehr32.htm
• Fig2 Frank H. Netter, Atlas of Human Anatomy (7th edition) plate 452
• Fig3 Hand muscles Hypothenar muscles learn anatomy website: https://e-learn.anatomy.uzh.ch/anatomie/Bewegungsapparat/bewapp_HTML_eng/hand/handMlehr32.htm
