After the Palmar introsseous, now its turn to see what is there on the dorsal aspect of hand. The quiz from this section is going to be amazing one. So try not to just read and forget but try to spend some time and understand the anatomy and how complex it is but yet it is amazing.
The four smaller muscles are placed between the metacarpal bones and numbered from lateral to the medial side.
Dorsal muscle abducts- DAB
ATTACHMENTS:
1. First- Originates from Shafts of 1st and 2nd metacarpals and attaches to the lateral side of the index finger.
2. Second- Originates from Shafts of 2nd and 3rd metacarpals and attaches to the lateral side of the middle finger.
3. Third- Originates from Shafts of 3rd and 4th metacarpals and attaches to the medial side of the middle finger.
4. Fourth- Originates from Shafts of 4th and 5th metacarpals and attaches to the medial side of 4th digit.
ACTIONS:
Abduction of the digits away from the line of the middle finger.
NERVE SUPPLY: Ulnar nerve (C8, T1)
MUSCLE TESTING:
The dorsal interossei are tested by asking the subject to spread out the fingers against resistance.
CLINICAL: Injury is most commonly caused by a hyperextension force sufficient to rupture the volar plate and cause dorsal dislocation.
Reference:
Surface Anatomy: The Anatomical Basis of Clinical Examination
Muscles: Testing and Function, with Posture and Pain
BD Chaurasias Human Anatomy
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